Merge tag 'pwm/for-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
"This round contains a couple of new drivers for the Marvell Berlin
family of SoCs, various SoCs from Renesas and Broadcom as well as the
backlight PWM present on MediaTek SoCs.

Further existing drivers are extended to support a wider range of
hardware.

The remaining patches are minor fixes and cleanups across the board.

Note that one of the patches included in this pull request is against
arch/unicore32. I've included it here because I couldn't get a
response from Guan Xuetao and I consider the change low-risk.
Equivalent patches have been merged and tested in Samsung and PXA
trees. The goal is to finally get rid of legacy code paths that have
repeatedly been causing headaches"

* tag 'pwm/for-4.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (24 commits)
pwm: sunxi: Fix whitespace issue
pwm: sysfs: Make use of the DEVICE_ATTR_[RW][WO] macro's
pwm: sysfs: Remove unnecessary temporary variable
unicore32: nb0916: Use PWM lookup table
pwm: pwm-rcar: Revise the device tree binding document about compatible
pwm: Return -ENODEV if no PWM lookup match is found
pwm: sun4i: Add support for PWM controller on sun5i SoCs
pwm: Set enable state properly on failed call to enable
pwm: lpss: Add support for runtime PM
pwm: lpss: Add more Intel Broxton IDs
pwm: lpss: Support all four PWMs on Intel Broxton
pwm: lpss: Add support for multiple PWMs
pwm-pca9685: enable ACPI device found on Galileo Gen2
pwm: Add MediaTek display PWM driver support
dt-bindings: pwm: Add MediaTek display PWM bindings
pwm: tipwmss: Enable on TI DRA7x and AM437x
pwm: atmel-hlcdc: add sama5d2 SoC support.
pwm: Add Broadcom BCM7038 PWM controller support
Documentation: dt: add Broadcom BCM7038 PWM controller binding
pwm: Add support for R-Car PWM Timer
...

Documentation/devicetree/bindings/pwm/brcm,bcm7038-pwm.txt

···
+Broadcom BCM7038 PWM controller (BCM7xxx Set Top Box PWM controller)
+
+Required properties:
+
+- compatible: must be "brcm,bcm7038-pwm"
+- reg: physical base address and length for this controller
+- #pwm-cells: should be 2. See pwm.txt in this directory for a description
+  of the cells format
+- clocks: a phandle to the reference clock for this block which is fed through
+  its internal variable clock frequency generator
+
+
+Example:
+
+	pwm: pwm@f0408000 {
+		compatible = "brcm,bcm7038-pwm";
+		reg = <0xf0408000 0x28>;
+		#pwm-cells = <2>;
+		clocks = <&upg_fixed>;
+	};

Documentation/devicetree/bindings/pwm/pwm-berlin.txt

···
+Berlin PWM controller
+
+Required properties:
+- compatible: should be "marvell,berlin-pwm"
+- reg: physical base address and length of the controller's registers
+- clocks: phandle to the input clock
+- #pwm-cells: should be 3. See pwm.txt in this directory for a description of
+  the cells format.
+
+Example:
+
+pwm: pwm@f7f20000 {
+	compatible = "marvell,berlin-pwm";
+	reg = <0xf7f20000 0x40>;
+	clocks = <&chip_clk CLKID_CFG>;
+	#pwm-cells = <3>;
+}

Documentation/devicetree/bindings/pwm/pwm-mtk-disp.txt

···
+MediaTek display PWM controller
+
+Required properties:
+ - compatible: should be "mediatek,<name>-disp-pwm":
+   - "mediatek,mt8173-disp-pwm": found on mt8173 SoC.
+   - "mediatek,mt6595-disp-pwm": found on mt6595 SoC.
+ - reg: physical base address and length of the controller's registers.
+ - #pwm-cells: must be 2. See pwm.txt in this directory for a description of
+   the cell format.
+ - clocks: phandle and clock specifier of the PWM reference clock.
+ - clock-names: must contain the following:
+   - "main": clock used to generate PWM signals.
+   - "mm": sync signals from the modules of mmsys.
+ - pinctrl-names: Must contain a "default" entry.
+ - pinctrl-0: One property must exist for each entry in pinctrl-names.
+   See pinctrl/pinctrl-bindings.txt for details of the property values.
+
+Example:
+	pwm0: pwm@1401e000 {
+		compatible = "mediatek,mt8173-disp-pwm",
+			     "mediatek,mt6595-disp-pwm";
+		reg = <0 0x1401e000 0 0x1000>;
+		#pwm-cells = <2>;
+		clocks = <&mmsys CLK_MM_DISP_PWM026M>,
+			 <&mmsys CLK_MM_DISP_PWM0MM>;
+		clock-names = "main", "mm";
+		pinctrl-names = "default";
+		pinctrl-0 = <&disp_pwm0_pins>;
+	};
+
+	backlight_lcd: backlight_lcd {
+		compatible = "pwm-backlight";
+		pwms = <&pwm0 0 1000000>;
+		brightness-levels = <
+			  0  16  32  48  64  80  96 112
+			128 144 160 176 192 208 224 240
+			255
+		>;
+		default-brightness-level = <9>;
+		power-supply = <&mt6397_vio18_reg>;
+		enable-gpios = <&pio 95 GPIO_ACTIVE_HIGH>;
+	};

Documentation/devicetree/bindings/pwm/pwm-sun4i.txt

···
 Required properties:
   - compatible: should be one of:
     - "allwinner,sun4i-a10-pwm"
+    - "allwinner,sun5i-a10s-pwm"
+    - "allwinner,sun5i-a13-pwm"
     - "allwinner,sun7i-a20-pwm"
   - reg: physical base address and length of the controller's registers
   - #pwm-cells: should be 3. See pwm.txt in this directory for a description of

Documentation/devicetree/bindings/pwm/renesas,pwm-rcar.txt

···
+* Renesas R-Car PWM Timer Controller
+
+Required Properties:
+- compatible: should be "renesas,pwm-rcar" and one of the following.
+ - "renesas,pwm-r8a7778": for R-Car M1A
+ - "renesas,pwm-r8a7779": for R-Car H1
+ - "renesas,pwm-r8a7790": for R-Car H2
+ - "renesas,pwm-r8a7791": for R-Car M2-W
+ - "renesas,pwm-r8a7794": for R-Car E2
+- reg: base address and length of the registers block for the PWM.
+- #pwm-cells: should be 2. See pwm.txt in this directory for a description of
+  the cells format.
+- clocks: clock phandle and specifier pair.
+- pinctrl-0: phandle, referring to a default pin configuration node.
+- pinctrl-names: Set to "default".
+
+Example: R8A7790 (R-Car H2) PWM Timer node
+
+	pwm0: pwm@e6e30000 {
+		compatible = "renesas,pwm-r8a7790", "renesas,pwm-rcar";
+		reg = <0 0xe6e30000 0 0x8>;
+		#pwm-cells = <2>;
+		clocks = <&mstp5_clks R8A7790_CLK_PWM>;
+		pinctrl-0 = <&pwm0_pins>;
+		pinctrl-names = "default";
+	};

arch/unicore32/kernel/puv3-nb0916.c

···
 #include <linux/reboot.h>
 #include <linux/interrupt.h>
 #include <linux/i2c.h>
+#include <linux/pwm.h>
 #include <linux/pwm_backlight.h>
 #include <linux/gpio.h>
 #include <linux/gpio_keys.h>
···
 	}
 };
 
+static struct pwm_lookup nb0916_pwm_lookup[] = {
+	PWM_LOOKUP("PKUnity-v3-PWM", 0, "pwm-backlight", NULL, 70 * 1024,
+		   PWM_POLARITY_NORMAL),
+};
+
 static struct platform_pwm_backlight_data nb0916_backlight_data = {
-	.pwm_id		= 0,
 	.max_brightness	= 100,
 	.dft_brightness	= 100,
-	.pwm_period_ns	= 70 * 1024,
 	.enable_gpio	= -1,
 };
 
···
 
 	platform_device_register_simple("PKUnity-v3-I2C", -1,
 			puv3_i2c_resources, ARRAY_SIZE(puv3_i2c_resources));
+
+	pwm_add_table(nb0916_pwm_lookup, ARRAY_SIZE(nb0916_pwm_lookup));
 
 	platform_device_register_data(NULL, "pwm-backlight", -1,
 			&nb0916_backlight_data, sizeof(nb0916_backlight_data));

drivers/pwm/Kconfig

···
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-bcm2835.
 
+config PWM_BERLIN
+	tristate "Marvell Berlin PWM support"
+	depends on ARCH_BERLIN
+	help
+	  PWM framework driver for Marvell Berlin SoCs.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-berlin.
+
 config PWM_BFIN
 	tristate "Blackfin PWM support"
 	depends on BFIN_GPTIMERS
···
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-bfin.
+
+config PWM_BRCMSTB
+	tristate "Broadcom STB PWM support"
+	depends on ARCH_BRCMSTB || BMIPS_GENERIC
+	help
+	  Generic PWM framework driver for the Broadcom Set-top-Box
+	  SoCs (BCM7xxx).
+
+	  To compile this driver as a module, choose M Here: the module
+	  will be called pwm-brcmstb.c.
 
 config PWM_CLPS711X
 	tristate "CLPS711X PWM support"
···
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-lpss-platform.
 
+config PWM_MTK_DISP
+	tristate "MediaTek display PWM driver"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  Generic PWM framework driver for MediaTek disp-pwm device.
+	  The PWM is used to control the backlight brightness for display.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-mtk-disp.
+
 config PWM_MXS
 	tristate "Freescale MXS PWM support"
 	depends on ARCH_MXS && OF
···
 
 config PWM_PCA9685
 	tristate "NXP PCA9685 PWM driver"
-	depends on OF && I2C
+	depends on I2C
 	select REGMAP_I2C
 	help
 	  Generic PWM framework driver for NXP PCA9685 LED controller.
···
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-pxa.
+
+config PWM_RCAR
+	tristate "Renesas R-Car PWM support"
+	depends on ARCH_RCAR_GEN1 || ARCH_RCAR_GEN2 || COMPILE_TEST
+	depends on HAS_IOMEM
+	help
+	  This driver exposes the PWM Timer controller found in Renesas
+	  R-Car chips through the PWM API.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-rcar.
 
 config PWM_RENESAS_TPU
 	tristate "Renesas TPU PWM support"
···
 
 config  PWM_TIECAP
 	tristate "ECAP PWM support"
-	depends on SOC_AM33XX || ARCH_DAVINCI_DA8XX
+	depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX
 	help
 	  PWM driver support for the ECAP APWM controller found on AM33XX
 	  TI SOC
···
 
 config  PWM_TIEHRPWM
 	tristate "EHRPWM PWM support"
-	depends on SOC_AM33XX || ARCH_DAVINCI_DA8XX
+	depends on ARCH_OMAP2PLUS || ARCH_DAVINCI_DA8XX
 	help
 	  PWM driver support for the EHRPWM controller found on AM33XX
 	  TI SOC
···
 
 config  PWM_TIPWMSS
 	bool
-	default y if SOC_AM33XX && (PWM_TIECAP || PWM_TIEHRPWM)
+	default y if (ARCH_OMAP2PLUS) && (PWM_TIECAP || PWM_TIEHRPWM)
 	help
 	  PWM Subsystem driver support for AM33xx SOC.
 

drivers/pwm/Makefile

···
 obj-$(CONFIG_PWM_ATMEL_TCB)	+= pwm-atmel-tcb.o
 obj-$(CONFIG_PWM_BCM_KONA)	+= pwm-bcm-kona.o
 obj-$(CONFIG_PWM_BCM2835)	+= pwm-bcm2835.o
+obj-$(CONFIG_PWM_BERLIN)	+= pwm-berlin.o
 obj-$(CONFIG_PWM_BFIN)		+= pwm-bfin.o
+obj-$(CONFIG_PWM_BRCMSTB)	+= pwm-brcmstb.o
 obj-$(CONFIG_PWM_CLPS711X)	+= pwm-clps711x.o
 obj-$(CONFIG_PWM_CRC)		+= pwm-crc.o
 obj-$(CONFIG_PWM_EP93XX)	+= pwm-ep93xx.o
···
 obj-$(CONFIG_PWM_LPSS)		+= pwm-lpss.o
 obj-$(CONFIG_PWM_LPSS_PCI)	+= pwm-lpss-pci.o
 obj-$(CONFIG_PWM_LPSS_PLATFORM)	+= pwm-lpss-platform.o
+obj-$(CONFIG_PWM_MTK_DISP)	+= pwm-mtk-disp.o
 obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
 obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
 obj-$(CONFIG_PWM_PUV3)		+= pwm-puv3.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
+obj-$(CONFIG_PWM_RCAR)		+= pwm-rcar.o
 obj-$(CONFIG_PWM_RENESAS_TPU)	+= pwm-renesas-tpu.o
 obj-$(CONFIG_PWM_ROCKCHIP)	+= pwm-rockchip.o
 obj-$(CONFIG_PWM_SAMSUNG)	+= pwm-samsung.o

drivers/pwm/core.c

···
 		pwm->pwm = chip->base + i;
 		pwm->hwpwm = i;
 		pwm->polarity = polarity;
+		mutex_init(&pwm->lock);
 
 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 	}
···
 	if (!pwm->chip->ops->set_polarity)
 		return -ENOSYS;
 
-	if (pwm_is_enabled(pwm))
-		return -EBUSY;
+	mutex_lock(&pwm->lock);
+
+	if (pwm_is_enabled(pwm)) {
+		err = -EBUSY;
+		goto unlock;
+	}
 
 	err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
 	if (err)
-		return err;
+		goto unlock;
 
 	pwm->polarity = polarity;
 
-	return 0;
+unlock:
+	mutex_unlock(&pwm->lock);
+	return err;
 }
 EXPORT_SYMBOL_GPL(pwm_set_polarity);
 
···
  */
 int pwm_enable(struct pwm_device *pwm)
 {
-	if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
-		return pwm->chip->ops->enable(pwm->chip, pwm);
+	int err = 0;
 
-	return pwm ? 0 : -EINVAL;
+	if (!pwm)
+		return -EINVAL;
+
+	mutex_lock(&pwm->lock);
+
+	if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
+		err = pwm->chip->ops->enable(pwm->chip, pwm);
+		if (err)
+			clear_bit(PWMF_ENABLED, &pwm->flags);
+	}
+
+	mutex_unlock(&pwm->lock);
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(pwm_enable);
 
···
 		}
 	}
 
-	if (!chosen)
+	if (!chosen) {
+		pwm = ERR_PTR(-ENODEV);
 		goto out;
+	}
 
 	chip = pwmchip_find_by_name(chosen->provider);
 	if (!chip)

drivers/pwm/pwm-atmel-hlcdc.c

···
 		.data = &atmel_hlcdc_pwm_at91sam9x5_errata,
 	},
 	{
+		.compatible = "atmel,sama5d2-hlcdc",
+	},
+	{
 		.compatible = "atmel,sama5d3-hlcdc",
 		.data = &atmel_hlcdc_pwm_sama5d3_errata,
 	},
···
 	},
 	{ /* sentinel */ },
 };
+MODULE_DEVICE_TABLE(of, atmel_hlcdc_dt_ids);
 
 static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
 {

drivers/pwm/pwm-berlin.c

···
+/*
+ * Marvell Berlin PWM driver
+ *
+ * Copyright (C) 2015 Marvell Technology Group Ltd.
+ *
+ * Author: Antoine Tenart <[e-mail]>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#define BERLIN_PWM_EN			0x0
+#define  BERLIN_PWM_ENABLE		BIT(0)
+#define BERLIN_PWM_CONTROL		0x4
+#define  BERLIN_PWM_PRESCALE_MASK	0x7
+#define  BERLIN_PWM_PRESCALE_MAX	4096
+#define  BERLIN_PWM_INVERT_POLARITY	BIT(3)
+#define BERLIN_PWM_DUTY			0x8
+#define BERLIN_PWM_TCNT			0xc
+#define  BERLIN_PWM_MAX_TCNT		65535
+
+struct berlin_pwm_chip {
+	struct pwm_chip chip;
+	struct clk *clk;
+	void __iomem *base;
+};
+
+static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct berlin_pwm_chip, chip);
+}
+
+static const u32 prescaler_table[] = {
+	1, 4, 8, 16, 64, 256, 1024, 4096
+};
+
+static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip,
+				   unsigned int channel, unsigned long offset)
+{
+	return readl_relaxed(chip->base + channel * 0x10 + offset);
+}
+
+static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip,
+				     unsigned int channel, u32 value,
+				     unsigned long offset)
+{
+	writel_relaxed(value, chip->base + channel * 0x10 + offset);
+}
+
+static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev,
+			     int duty_ns, int period_ns)
+{
+	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+	unsigned int prescale;
+	u32 value, duty, period;
+	u64 cycles, tmp;
+
+	cycles = clk_get_rate(pwm->clk);
+	cycles *= period_ns;
+	do_div(cycles, NSEC_PER_SEC);
+
+	for (prescale = 0; prescale < ARRAY_SIZE(prescaler_table); prescale++) {
+		tmp = cycles;
+		do_div(tmp, prescaler_table[prescale]);
+
+		if (tmp <= BERLIN_PWM_MAX_TCNT)
+			break;
+	}
+
+	if (tmp > BERLIN_PWM_MAX_TCNT)
+		return -ERANGE;
+
+	period = tmp;
+	cycles = tmp * duty_ns;
+	do_div(cycles, period_ns);
+	duty = cycles;
+
+	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
+	value &= ~BERLIN_PWM_PRESCALE_MASK;
+	value |= prescale;
+	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
+
+	berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY);
+	berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT);
+
+	return 0;
+}
+
+static int berlin_pwm_set_polarity(struct pwm_chip *chip,
+				   struct pwm_device *pwm_dev,
+				   enum pwm_polarity polarity)
+{
+	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+	u32 value;
+
+	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL);
+
+	if (polarity == PWM_POLARITY_NORMAL)
+		value &= ~BERLIN_PWM_INVERT_POLARITY;
+	else
+		value |= BERLIN_PWM_INVERT_POLARITY;
+
+	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL);
+
+	return 0;
+}
+
+static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev)
+{
+	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+	u32 value;
+
+	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
+	value |= BERLIN_PWM_ENABLE;
+	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
+
+	return 0;
+}
+
+static void berlin_pwm_disable(struct pwm_chip *chip,
+			       struct pwm_device *pwm_dev)
+{
+	struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip);
+	u32 value;
+
+	value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN);
+	value &= ~BERLIN_PWM_ENABLE;
+	berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN);
+}
+
+static const struct pwm_ops berlin_pwm_ops = {
+	.config = berlin_pwm_config,
+	.set_polarity = berlin_pwm_set_polarity,
+	.enable = berlin_pwm_enable,
+	.disable = berlin_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static const struct of_device_id berlin_pwm_match[] = {
+	{ .compatible = "marvell,berlin-pwm" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, berlin_pwm_match);
+
+static int berlin_pwm_probe(struct platform_device *pdev)
+{
+	struct berlin_pwm_chip *pwm;
+	struct resource *res;
+	int ret;
+
+	pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
+	if (!pwm)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pwm->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(pwm->base))
+		return PTR_ERR(pwm->base);
+
+	pwm->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(pwm->clk))
+		return PTR_ERR(pwm->clk);
+
+	ret = clk_prepare_enable(pwm->clk);
+	if (ret)
+		return ret;
+
+	pwm->chip.dev = &pdev->dev;
+	pwm->chip.ops = &berlin_pwm_ops;
+	pwm->chip.base = -1;
+	pwm->chip.npwm = 4;
+	pwm->chip.can_sleep = true;
+	pwm->chip.of_xlate = of_pwm_xlate_with_flags;
+	pwm->chip.of_pwm_n_cells = 3;
+
+	ret = pwmchip_add(&pwm->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+		clk_disable_unprepare(pwm->clk);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, pwm);
+
+	return 0;
+}
+
+static int berlin_pwm_remove(struct platform_device *pdev)
+{
+	struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pwmchip_remove(&pwm->chip);
+	clk_disable_unprepare(pwm->clk);
+
+	return ret;
+}
+
+static struct platform_driver berlin_pwm_driver = {
+	.probe = berlin_pwm_probe,
+	.remove = berlin_pwm_remove,
+	.driver = {
+		.name = "berlin-pwm",
+		.of_match_table = berlin_pwm_match,
+	},
+};
+module_platform_driver(berlin_pwm_driver);
+
+MODULE_AUTHOR("Antoine Tenart <[e-mail]>");
+MODULE_DESCRIPTION("Marvell Berlin PWM driver");
+MODULE_LICENSE("GPL v2");

drivers/pwm/pwm-brcmstb.c

···
+/*
+ * Broadcom BCM7038 PWM driver
+ * Author: Florian Fainelli
+ *
+ * Copyright (C) 2015 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/spinlock.h>
+
+#define PWM_CTRL		0x00
+#define  CTRL_START		BIT(0)
+#define  CTRL_OEB		BIT(1)
+#define  CTRL_FORCE_HIGH	BIT(2)
+#define  CTRL_OPENDRAIN		BIT(3)
+#define  CTRL_CHAN_OFFS		4
+
+#define PWM_CTRL2		0x04
+#define  CTRL2_OUT_SELECT	BIT(0)
+
+#define PWM_CH_SIZE		0x8
+
+#define PWM_CWORD_MSB(ch)	(0x08 + ((ch) * PWM_CH_SIZE))
+#define PWM_CWORD_LSB(ch)	(0x0c + ((ch) * PWM_CH_SIZE))
+
+/* Number of bits for the CWORD value */
+#define CWORD_BIT_SIZE		16
+
+/*
+ * Maximum control word value allowed when variable-frequency PWM is used as a
+ * clock for the constant-frequency PMW.
+ */
+#define CONST_VAR_F_MAX		32768
+#define CONST_VAR_F_MIN		1
+
+#define PWM_ON(ch)		(0x18 + ((ch) * PWM_CH_SIZE))
+#define  PWM_ON_MIN		1
+#define PWM_PERIOD(ch)		(0x1c + ((ch) * PWM_CH_SIZE))
+#define  PWM_PERIOD_MIN		0
+
+#define PWM_ON_PERIOD_MAX	0xff
+
+struct brcmstb_pwm {
+	void __iomem *base;
+	spinlock_t lock;
+	struct clk *clk;
+	struct pwm_chip chip;
+};
+
+static inline u32 brcmstb_pwm_readl(struct brcmstb_pwm *p,
+				    unsigned int offset)
+{
+	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+		return __raw_readl(p->base + offset);
+	else
+		return readl_relaxed(p->base + offset);
+}
+
+static inline void brcmstb_pwm_writel(struct brcmstb_pwm *p, u32 value,
+				      unsigned int offset)
+{
+	if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+		__raw_writel(value, p->base + offset);
+	else
+		writel_relaxed(value, p->base + offset);
+}
+
+static inline struct brcmstb_pwm *to_brcmstb_pwm(struct pwm_chip *chip)
+{
+	return container_of(chip, struct brcmstb_pwm, chip);
+}
+
+/*
+ * Fv is derived from the variable frequency output. The variable frequency
+ * output is configured using this formula:
+ *
+ * W = cword, if cword < 2 ^ 15 else 16-bit 2's complement of cword
+ *
+ * Fv = W x 2 ^ -16 x 27Mhz (reference clock)
+ *
+ * The period is: (period + 1) / Fv and "on" time is on / (period + 1)
+ *
+ * The PWM core framework specifies that the "duty_ns" parameter is in fact the
+ * "on" time, so this translates directly into our HW programming here.
+ */
+static int brcmstb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			      int duty_ns, int period_ns)
+{
+	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);
+	unsigned long pc, dc, cword = CONST_VAR_F_MAX;
+	unsigned int channel = pwm->hwpwm;
+	u32 value;
+
+	/*
+	 * If asking for a duty_ns equal to period_ns, we need to substract
+	 * the period value by 1 to make it shorter than the "on" time and
+	 * produce a flat 100% duty cycle signal, and max out the "on" time
+	 */
+	if (duty_ns == period_ns) {
+		dc = PWM_ON_PERIOD_MAX;
+		pc = PWM_ON_PERIOD_MAX - 1;
+		goto done;
+	}
+
+	while (1) {
+		u64 rate, tmp;
+
+		/*
+		 * Calculate the base rate from base frequency and current
+		 * cword
+		 */
+		rate = (u64)clk_get_rate(p->clk) * (u64)cword;
+		do_div(rate, 1 << CWORD_BIT_SIZE);
+
+		tmp = period_ns * rate;
+		do_div(tmp, NSEC_PER_SEC);
+		pc = tmp;
+
+		tmp = (duty_ns + 1) * rate;
+		do_div(tmp, NSEC_PER_SEC);
+		dc = tmp;
+
+		/*
+		 * We can be called with separate duty and period updates,
+		 * so do not reject dc == 0 right away
+		 */
+		if (pc == PWM_PERIOD_MIN || (dc < PWM_ON_MIN && duty_ns))
+			return -EINVAL;
+
+		/* We converged on a calculation */
+		if (pc <= PWM_ON_PERIOD_MAX && dc <= PWM_ON_PERIOD_MAX)
+			break;
+
+		/*
+		 * The cword needs to be a power of 2 for the variable
+		 * frequency generator to output a 50% duty cycle variable
+		 * frequency which is used as input clock to the fixed
+		 * frequency generator.
+		 */
+		cword >>= 1;
+
+		/*
+		 * Desired periods are too large, we do not have a divider
+		 * for them
+		 */
+		if (cword < CONST_VAR_F_MIN)
+			return -EINVAL;
+	}
+
+done:
+	/*
+	 * Configure the defined "cword" value to have the variable frequency
+	 * generator output a base frequency for the constant frequency
+	 * generator to derive from.
+	 */
+	spin_lock(&p->lock);
+	brcmstb_pwm_writel(p, cword >> 8, PWM_CWORD_MSB(channel));
+	brcmstb_pwm_writel(p, cword & 0xff, PWM_CWORD_LSB(channel));
+
+	/* Select constant frequency signal output */
+	value = brcmstb_pwm_readl(p, PWM_CTRL2);
+	value |= CTRL2_OUT_SELECT << (channel * CTRL_CHAN_OFFS);
+	brcmstb_pwm_writel(p, value, PWM_CTRL2);
+
+	/* Configure on and period value */
+	brcmstb_pwm_writel(p, pc, PWM_PERIOD(channel));
+	brcmstb_pwm_writel(p, dc, PWM_ON(channel));
+	spin_unlock(&p->lock);
+
+	return 0;
+}
+
+static inline void brcmstb_pwm_enable_set(struct brcmstb_pwm *p,
+					  unsigned int channel, bool enable)
+{
+	unsigned int shift = channel * CTRL_CHAN_OFFS;
+	u32 value;
+
+	spin_lock(&p->lock);
+	value = brcmstb_pwm_readl(p, PWM_CTRL);
+
+	if (enable) {
+		value &= ~(CTRL_OEB << shift);
+		value |= (CTRL_START | CTRL_OPENDRAIN) << shift;
+	} else {
+		value &= ~((CTRL_START | CTRL_OPENDRAIN) << shift);
+		value |= CTRL_OEB << shift;
+	}
+
+	brcmstb_pwm_writel(p, value, PWM_CTRL);
+	spin_unlock(&p->lock);
+}
+
+static int brcmstb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);
+
+	brcmstb_pwm_enable_set(p, pwm->hwpwm, true);
+
+	return 0;
+}
+
+static void brcmstb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct brcmstb_pwm *p = to_brcmstb_pwm(chip);
+
+	brcmstb_pwm_enable_set(p, pwm->hwpwm, false);
+}
+
+static const struct pwm_ops brcmstb_pwm_ops = {
+	.config = brcmstb_pwm_config,
+	.enable = brcmstb_pwm_enable,
+	.disable = brcmstb_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static const struct of_device_id brcmstb_pwm_of_match[] = {
+	{ .compatible = "brcm,bcm7038-pwm", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, brcmstb_pwm_of_match);
+
+static int brcmstb_pwm_probe(struct platform_device *pdev)
+{
+	struct brcmstb_pwm *p;
+	struct resource *res;
+	int ret;
+
+	p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
+	if (!p)
+		return -ENOMEM;
+
+	spin_lock_init(&p->lock);
+
+	p->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(p->clk)) {
+		dev_err(&pdev->dev, "failed to obtain clock\n");
+		return PTR_ERR(p->clk);
+	}
+
+	ret = clk_prepare_enable(p->clk);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to enable clock: %d\n", ret);
+		return ret;
+	}
+
+	platform_set_drvdata(pdev, p);
+
+	p->chip.dev = &pdev->dev;
+	p->chip.ops = &brcmstb_pwm_ops;
+	p->chip.base = -1;
+	p->chip.npwm = 2;
+	p->chip.can_sleep = true;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	p->base = devm_ioremap_resource(&pdev->dev, res);
+	if (!p->base) {
+		ret = -ENOMEM;
+		goto out_clk;
+	}
+
+	ret = pwmchip_add(&p->chip);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret);
+		goto out_clk;
+	}
+
+	return 0;
+
+out_clk:
+	clk_disable_unprepare(p->clk);
+	return ret;
+}
+
+static int brcmstb_pwm_remove(struct platform_device *pdev)
+{
+	struct brcmstb_pwm *p = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pwmchip_remove(&p->chip);
+	clk_disable_unprepare(p->clk);
+
+	return ret;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int brcmstb_pwm_suspend(struct device *dev)
+{
+	struct brcmstb_pwm *p = dev_get_drvdata(dev);
+
+	clk_disable(p->clk);
+
+	return 0;
+}
+
+static int brcmstb_pwm_resume(struct device *dev)
+{
+	struct brcmstb_pwm *p = dev_get_drvdata(dev);
+
+	clk_enable(p->clk);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(brcmstb_pwm_pm_ops, brcmstb_pwm_suspend,
+			 brcmstb_pwm_resume);
+
+static struct platform_driver brcmstb_pwm_driver = {
+	.probe = brcmstb_pwm_probe,
+	.remove = brcmstb_pwm_remove,
+	.driver = {
+		.name = "pwm-brcmstb",
+		.of_match_table = brcmstb_pwm_of_match,
+		.pm = &brcmstb_pwm_pm_ops,
+	},
+};
+module_platform_driver(brcmstb_pwm_driver);
+
+MODULE_AUTHOR("Florian Fainelli <[e-mail]>");
+MODULE_DESCRIPTION("Broadcom STB PWM driver");
+MODULE_ALIAS("platform:pwm-brcmstb");
+MODULE_LICENSE("GPL");

drivers/pwm/pwm-lpss-pci.c

···
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pci.h>
+#include <linux/pm_runtime.h>
 
 #include "pwm-lpss.h"
 
···
 		return PTR_ERR(lpwm);
 
 	pci_set_drvdata(pdev, lpwm);
+
+	pm_runtime_put(&pdev->dev);
+	pm_runtime_allow(&pdev->dev);
+
 	return 0;
 }
 
···
 {
 	struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);
 
+	pm_runtime_forbid(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+
 	pwm_lpss_remove(lpwm);
 }
 
+#ifdef CONFIG_PM
+static int pwm_lpss_runtime_suspend_pci(struct device *dev)
+{
+	/*
+	 * The PCI core will handle transition to D3 automatically. We only
+	 * need to provide runtime PM hooks for that to happen.
+	 */
+	return 0;
+}
+
+static int pwm_lpss_runtime_resume_pci(struct device *dev)
+{
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops pwm_lpss_pci_pm = {
+	SET_RUNTIME_PM_OPS(pwm_lpss_runtime_suspend_pci,
+			   pwm_lpss_runtime_resume_pci, NULL)
+};
+
 static const struct pci_device_id pwm_lpss_pci_ids[] = {
-	{ PCI_VDEVICE(INTEL, 0x0ac8), (unsigned long)&pwm_lpss_bsw_info},
+	{ PCI_VDEVICE(INTEL, 0x0ac8), (unsigned long)&pwm_lpss_bxt_info},
 	{ PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&pwm_lpss_byt_info},
 	{ PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&pwm_lpss_byt_info},
-	{ PCI_VDEVICE(INTEL, 0x1ac8), (unsigned long)&pwm_lpss_bsw_info},
+	{ PCI_VDEVICE(INTEL, 0x1ac8), (unsigned long)&pwm_lpss_bxt_info},
 	{ PCI_VDEVICE(INTEL, 0x2288), (unsigned long)&pwm_lpss_bsw_info},
 	{ PCI_VDEVICE(INTEL, 0x2289), (unsigned long)&pwm_lpss_bsw_info},
+	{ PCI_VDEVICE(INTEL, 0x5ac8), (unsigned long)&pwm_lpss_bxt_info},
 	{ },
 };
 MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids);
···
 	.id_table = pwm_lpss_pci_ids,
 	.probe = pwm_lpss_probe_pci,
 	.remove = pwm_lpss_remove_pci,
+	.driver = {
+		.pm = &pwm_lpss_pci_pm,
+	},
 };
 module_pci_driver(pwm_lpss_driver_pci);
 

drivers/pwm/pwm-lpss-platform.c

···
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #include "pwm-lpss.h"
 
···
 		return PTR_ERR(lpwm);
 
 	platform_set_drvdata(pdev, lpwm);
+
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
 	return 0;
 }
 
···
 {
 	struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
 
+	pm_runtime_disable(&pdev->dev);
 	return pwm_lpss_remove(lpwm);
 }
 
 static const struct acpi_device_id pwm_lpss_acpi_match[] = {
 	{ "80860F09", (unsigned long)&pwm_lpss_byt_info },
 	{ "80862288", (unsigned long)&pwm_lpss_bsw_info },
+	{ "80865AC8", (unsigned long)&pwm_lpss_bxt_info },
 	{ },
 };
 MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);

drivers/pwm/pwm-lpss.c

···
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/pm_runtime.h>
 
 #include "pwm-lpss.h"
 
···
 #define PWM_LIMIT			(0x8000 + PWM_DIVISION_CORRECTION)
 #define NSECS_PER_SEC			1000000000UL
 
+/* Size of each PWM register space if multiple */
+#define PWM_SIZE			0x400
+
 struct pwm_lpss_chip {
 	struct pwm_chip chip;
 	void __iomem *regs;
···
 
 /* BayTrail */
 const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
-	.clk_rate = 25000000
+	.clk_rate = 25000000,
+	.npwm = 1,
 };
 EXPORT_SYMBOL_GPL(pwm_lpss_byt_info);
 
 /* Braswell */
 const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
-	.clk_rate = 19200000
+	.clk_rate = 19200000,
+	.npwm = 1,
 };
 EXPORT_SYMBOL_GPL(pwm_lpss_bsw_info);
+
+/* Broxton */
+const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
+	.clk_rate = 19200000,
+	.npwm = 4,
+};
+EXPORT_SYMBOL_GPL(pwm_lpss_bxt_info);
 
 static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
 {
 	return container_of(chip, struct pwm_lpss_chip, chip);
+}
+
+static inline u32 pwm_lpss_read(const struct pwm_device *pwm)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip);
+
+	return readl(lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
+}
+
+static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value)
+{
+	struct pwm_lpss_chip *lpwm = to_lpwm(pwm->chip);
+
+	writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
 }
 
 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
···
 		duty_ns = 1;
 	on_time_div = 255 - (255 * duty_ns / period_ns);
 
-	ctrl = readl(lpwm->regs + PWM);
+	pm_runtime_get_sync(chip->dev);
+
+	ctrl = pwm_lpss_read(pwm);
 	ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK);
 	ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT;
 	ctrl |= on_time_div;
 	/* request PWM to update on next cycle */
 	ctrl |= PWM_SW_UPDATE;
-	writel(ctrl, lpwm->regs + PWM);
+	pwm_lpss_write(pwm, ctrl);
+
+	pm_runtime_put(chip->dev);
 
 	return 0;
 }
 
 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
-	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
-	u32 ctrl;
-
-	ctrl = readl(lpwm->regs + PWM);
-	writel(ctrl | PWM_ENABLE, lpwm->regs + PWM);
-
+	pm_runtime_get_sync(chip->dev);
+	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
 	return 0;
 }
 
 static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
-	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
-	u32 ctrl;
-
-	ctrl = readl(lpwm->regs + PWM);
-	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
+	pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
+	pm_runtime_put(chip->dev);
 }
 
 static const struct pwm_ops pwm_lpss_ops = {
+	.free = pwm_lpss_disable,
 	.config = pwm_lpss_config,
 	.enable = pwm_lpss_enable,
 	.disable = pwm_lpss_disable,
···
 	lpwm->chip.dev = dev;
 	lpwm->chip.ops = &pwm_lpss_ops;
 	lpwm->chip.base = -1;
-	lpwm->chip.npwm = 1;
+	lpwm->chip.npwm = info->npwm;
 
 	ret = pwmchip_add(&lpwm->chip);
 	if (ret) {
···
 
 int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
 {
-	u32 ctrl;
-
-	ctrl = readl(lpwm->regs + PWM);
-	writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
-
 	return pwmchip_remove(&lpwm->chip);
 }
 EXPORT_SYMBOL_GPL(pwm_lpss_remove);

drivers/pwm/pwm-lpss.h

···
 
 struct pwm_lpss_boardinfo {
 	unsigned long clk_rate;
+	unsigned int npwm;
 };
 
 extern const struct pwm_lpss_boardinfo pwm_lpss_byt_info;
 extern const struct pwm_lpss_boardinfo pwm_lpss_bsw_info;
+extern const struct pwm_lpss_boardinfo pwm_lpss_bxt_info;
 
 struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
 				     const struct pwm_lpss_boardinfo *info);

drivers/pwm/pwm-mtk-disp.c

···
+/*
+ * MediaTek display pulse-width-modulation controller driver.
+ * Copyright (c) 2015 MediaTek Inc.
+ * Author: YH Huang <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define DISP_PWM_EN		0x00
+#define PWM_ENABLE_MASK		BIT(0)
+
+#define DISP_PWM_COMMIT		0x08
+#define PWM_COMMIT_MASK		BIT(0)
+
+#define DISP_PWM_CON_0		0x10
+#define PWM_CLKDIV_SHIFT	16
+#define PWM_CLKDIV_MAX		0x3ff
+#define PWM_CLKDIV_MASK		(PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT)
+
+#define DISP_PWM_CON_1		0x14
+#define PWM_PERIOD_BIT_WIDTH	12
+#define PWM_PERIOD_MASK		((1 << PWM_PERIOD_BIT_WIDTH) - 1)
+
+#define PWM_HIGH_WIDTH_SHIFT	16
+#define PWM_HIGH_WIDTH_MASK	(0x1fff << PWM_HIGH_WIDTH_SHIFT)
+
+struct mtk_disp_pwm {
+	struct pwm_chip chip;
+	struct clk *clk_main;
+	struct clk *clk_mm;
+	void __iomem *base;
+};
+
+static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip)
+{
+	return container_of(chip, struct mtk_disp_pwm, chip);
+}
+
+static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset,
+				     u32 mask, u32 data)
+{
+	void __iomem *address = mdp->base + offset;
+	u32 value;
+
+	value = readl(address);
+	value &= ~mask;
+	value |= data;
+	writel(value, address);
+}
+
+static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			       int duty_ns, int period_ns)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	u32 clk_div, period, high_width, value;
+	u64 div, rate;
+	int err;
+
+	/*
+	 * Find period, high_width and clk_div to suit duty_ns and period_ns.
+	 * Calculate proper div value to keep period value in the bound.
+	 *
+	 * period_ns = 10^9 * (clk_div + 1) * (period + 1) / PWM_CLK_RATE
+	 * duty_ns = 10^9 * (clk_div + 1) * high_width / PWM_CLK_RATE
+	 *
+	 * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1
+	 * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1))
+	 */
+	rate = clk_get_rate(mdp->clk_main);
+	clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >>
+			  PWM_PERIOD_BIT_WIDTH;
+	if (clk_div > PWM_CLKDIV_MAX)
+		return -EINVAL;
+
+	div = NSEC_PER_SEC * (clk_div + 1);
+	period = div64_u64(rate * period_ns, div);
+	if (period > 0)
+		period--;
+
+	high_width = div64_u64(rate * duty_ns, div);
+	value = period | (high_width << PWM_HIGH_WIDTH_SHIFT);
+
+	err = clk_enable(mdp->clk_main);
+	if (err < 0)
+		return err;
+
+	err = clk_enable(mdp->clk_mm);
+	if (err < 0) {
+		clk_disable(mdp->clk_main);
+		return err;
+	}
+
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_0, PWM_CLKDIV_MASK,
+				 clk_div << PWM_CLKDIV_SHIFT);
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_1,
+				 PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value);
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 1);
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, PWM_COMMIT_MASK, 0);
+
+	clk_disable(mdp->clk_mm);
+	clk_disable(mdp->clk_main);
+
+	return 0;
+}
+
+static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+	int err;
+
+	err = clk_enable(mdp->clk_main);
+	if (err < 0)
+		return err;
+
+	err = clk_enable(mdp->clk_mm);
+	if (err < 0) {
+		clk_disable(mdp->clk_main);
+		return err;
+	}
+
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 1);
+
+	return 0;
+}
+
+static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip);
+
+	mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, PWM_ENABLE_MASK, 0);
+
+	clk_disable(mdp->clk_mm);
+	clk_disable(mdp->clk_main);
+}
+
+static const struct pwm_ops mtk_disp_pwm_ops = {
+	.config = mtk_disp_pwm_config,
+	.enable = mtk_disp_pwm_enable,
+	.disable = mtk_disp_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int mtk_disp_pwm_probe(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp;
+	struct resource *r;
+	int ret;
+
+	mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL);
+	if (!mdp)
+		return -ENOMEM;
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	mdp->base = devm_ioremap_resource(&pdev->dev, r);
+	if (IS_ERR(mdp->base))
+		return PTR_ERR(mdp->base);
+
+	mdp->clk_main = devm_clk_get(&pdev->dev, "main");
+	if (IS_ERR(mdp->clk_main))
+		return PTR_ERR(mdp->clk_main);
+
+	mdp->clk_mm = devm_clk_get(&pdev->dev, "mm");
+	if (IS_ERR(mdp->clk_mm))
+		return PTR_ERR(mdp->clk_mm);
+
+	ret = clk_prepare(mdp->clk_main);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_prepare(mdp->clk_mm);
+	if (ret < 0)
+		goto disable_clk_main;
+
+	mdp->chip.dev = &pdev->dev;
+	mdp->chip.ops = &mtk_disp_pwm_ops;
+	mdp->chip.base = -1;
+	mdp->chip.npwm = 1;
+
+	ret = pwmchip_add(&mdp->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
+		goto disable_clk_mm;
+	}
+
+	platform_set_drvdata(pdev, mdp);
+
+	return 0;
+
+disable_clk_mm:
+	clk_unprepare(mdp->clk_mm);
+disable_clk_main:
+	clk_unprepare(mdp->clk_main);
+	return ret;
+}
+
+static int mtk_disp_pwm_remove(struct platform_device *pdev)
+{
+	struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = pwmchip_remove(&mdp->chip);
+	clk_unprepare(mdp->clk_mm);
+	clk_unprepare(mdp->clk_main);
+
+	return ret;
+}
+
+static const struct of_device_id mtk_disp_pwm_of_match[] = {
+	{ .compatible = "mediatek,mt8173-disp-pwm" },
+	{ .compatible = "mediatek,mt6595-disp-pwm" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match);
+
+static struct platform_driver mtk_disp_pwm_driver = {
+	.driver = {
+		.name = "mediatek-disp-pwm",
+		.of_match_table = mtk_disp_pwm_of_match,
+	},
+	.probe = mtk_disp_pwm_probe,
+	.remove = mtk_disp_pwm_remove,
+};
+module_platform_driver(mtk_disp_pwm_driver);
+
+MODULE_AUTHOR("YH Huang <[e-mail]>");
+MODULE_DESCRIPTION("MediaTek SoC display PWM driver");
+MODULE_LICENSE("GPL v2");

drivers/pwm/pwm-pca9685.c

···
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <linux/acpi.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/property.h>
 #include <linux/pwm.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
···
 static int pca9685_pwm_probe(struct i2c_client *client,
 				const struct i2c_device_id *id)
 {
-	struct device_node *np = client->dev.of_node;
 	struct pca9685 *pca;
 	int ret;
 	int mode2;
···
 
 	regmap_read(pca->regmap, PCA9685_MODE2, &mode2);
 
-	if (of_property_read_bool(np, "invert"))
+	if (device_property_read_bool(&client->dev, "invert"))
 		mode2 |= MODE2_INVRT;
 	else
 		mode2 &= ~MODE2_INVRT;
 
-	if (of_property_read_bool(np, "open-drain"))
+	if (device_property_read_bool(&client->dev, "open-drain"))
 		mode2 &= ~MODE2_OUTDRV;
 	else
 		mode2 |= MODE2_OUTDRV;
···
 };
 MODULE_DEVICE_TABLE(i2c, pca9685_id);
 
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id pca9685_acpi_ids[] = {
+	{ "INT3492", 0 },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(acpi, pca9685_acpi_ids);
+#endif
+
+#ifdef CONFIG_OF
 static const struct of_device_id pca9685_dt_ids[] = {
 	{ .compatible = "nxp,pca9685-pwm", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, pca9685_dt_ids);
+#endif
 
 static struct i2c_driver pca9685_i2c_driver = {
 	.driver = {
 		.name = "pca9685-pwm",
-		.of_match_table = pca9685_dt_ids,
+		.acpi_match_table = ACPI_PTR(pca9685_acpi_ids),
+		.of_match_table = of_match_ptr(pca9685_dt_ids),
 	},
 	.probe = pca9685_pwm_probe,
 	.remove = pca9685_pwm_remove,

drivers/pwm/pwm-rcar.c

···
+/*
+ * R-Car PWM Timer driver
+ *
+ * Copyright (C) 2015 Renesas Electronics Corporation
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+
+#define RCAR_PWM_MAX_DIVISION	24
+#define RCAR_PWM_MAX_CYCLE	1023
+
+#define RCAR_PWMCR		0x00
+#define  RCAR_PWMCR_CC0_MASK	0x000f0000
+#define  RCAR_PWMCR_CC0_SHIFT	16
+#define  RCAR_PWMCR_CCMD	BIT(15)
+#define  RCAR_PWMCR_SYNC	BIT(11)
+#define  RCAR_PWMCR_SS0		BIT(4)
+#define  RCAR_PWMCR_EN0		BIT(0)
+
+#define RCAR_PWMCNT		0x04
+#define  RCAR_PWMCNT_CYC0_MASK	0x03ff0000
+#define  RCAR_PWMCNT_CYC0_SHIFT	16
+#define  RCAR_PWMCNT_PH0_MASK	0x000003ff
+#define  RCAR_PWMCNT_PH0_SHIFT	0
+
+struct rcar_pwm_chip {
+	struct pwm_chip chip;
+	void __iomem *base;
+	struct clk *clk;
+};
+
+static inline struct rcar_pwm_chip *to_rcar_pwm_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct rcar_pwm_chip, chip);
+}
+
+static void rcar_pwm_write(struct rcar_pwm_chip *rp, u32 data,
+			   unsigned int offset)
+{
+	writel(data, rp->base + offset);
+}
+
+static u32 rcar_pwm_read(struct rcar_pwm_chip *rp, unsigned int offset)
+{
+	return readl(rp->base + offset);
+}
+
+static void rcar_pwm_update(struct rcar_pwm_chip *rp, u32 mask, u32 data,
+			    unsigned int offset)
+{
+	u32 value;
+
+	value = rcar_pwm_read(rp, offset);
+	value &= ~mask;
+	value |= data & mask;
+	rcar_pwm_write(rp, value, offset);
+}
+
+static int rcar_pwm_get_clock_division(struct rcar_pwm_chip *rp, int period_ns)
+{
+	unsigned long clk_rate = clk_get_rate(rp->clk);
+	unsigned long long max; /* max cycle / nanoseconds */
+	unsigned int div;
+
+	if (clk_rate == 0)
+		return -EINVAL;
+
+	for (div = 0; div <= RCAR_PWM_MAX_DIVISION; div++) {
+		max = (unsigned long long)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE *
+			(1 << div);
+		do_div(max, clk_rate);
+		if (period_ns < max)
+			break;
+	}
+
+	return (div <= RCAR_PWM_MAX_DIVISION) ? div : -ERANGE;
+}
+
+static void rcar_pwm_set_clock_control(struct rcar_pwm_chip *rp,
+				       unsigned int div)
+{
+	u32 value;
+
+	value = rcar_pwm_read(rp, RCAR_PWMCR);
+	value &= ~(RCAR_PWMCR_CCMD | RCAR_PWMCR_CC0_MASK);
+
+	if (div & 1)
+		value |= RCAR_PWMCR_CCMD;
+
+	div >>= 1;
+
+	value |= div << RCAR_PWMCR_CC0_SHIFT;
+	rcar_pwm_write(rp, value, RCAR_PWMCR);
+}
+
+static int rcar_pwm_set_counter(struct rcar_pwm_chip *rp, int div, int duty_ns,
+				int period_ns)
+{
+	unsigned long long one_cycle, tmp;	/* 0.01 nanoseconds */
+	unsigned long clk_rate = clk_get_rate(rp->clk);
+	u32 cyc, ph;
+
+	one_cycle = (unsigned long long)NSEC_PER_SEC * 100ULL * (1 << div);
+	do_div(one_cycle, clk_rate);
+
+	tmp = period_ns * 100ULL;
+	do_div(tmp, one_cycle);
+	cyc = (tmp << RCAR_PWMCNT_CYC0_SHIFT) & RCAR_PWMCNT_CYC0_MASK;
+
+	tmp = duty_ns * 100ULL;
+	do_div(tmp, one_cycle);
+	ph = tmp & RCAR_PWMCNT_PH0_MASK;
+
+	/* Avoid prohibited setting */
+	if (cyc == 0 || ph == 0)
+		return -EINVAL;
+
+	rcar_pwm_write(rp, cyc | ph, RCAR_PWMCNT);
+
+	return 0;
+}
+
+static int rcar_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+
+	return clk_prepare_enable(rp->clk);
+}
+
+static void rcar_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+
+	clk_disable_unprepare(rp->clk);
+}
+
+static int rcar_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+			   int duty_ns, int period_ns)
+{
+	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+	int div, ret;
+
+	div = rcar_pwm_get_clock_division(rp, period_ns);
+	if (div < 0)
+		return div;
+
+	/* Let the core driver set pwm->period if disabled and duty_ns == 0 */
+	if (!test_bit(PWMF_ENABLED, &pwm->flags) && !duty_ns)
+		return 0;
+
+	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, RCAR_PWMCR_SYNC, RCAR_PWMCR);
+
+	ret = rcar_pwm_set_counter(rp, div, duty_ns, period_ns);
+	if (!ret)
+		rcar_pwm_set_clock_control(rp, div);
+
+	/* The SYNC should be set to 0 even if rcar_pwm_set_counter failed */
+	rcar_pwm_update(rp, RCAR_PWMCR_SYNC, 0, RCAR_PWMCR);
+
+	return ret;
+}
+
+static int rcar_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+	u32 value;
+
+	/* Don't enable the PWM device if CYC0 or PH0 is 0 */
+	value = rcar_pwm_read(rp, RCAR_PWMCNT);
+	if ((value & RCAR_PWMCNT_CYC0_MASK) == 0 ||
+	    (value & RCAR_PWMCNT_PH0_MASK) == 0)
+		return -EINVAL;
+
+	rcar_pwm_update(rp, RCAR_PWMCR_EN0, RCAR_PWMCR_EN0, RCAR_PWMCR);
+
+	return 0;
+}
+
+static void rcar_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct rcar_pwm_chip *rp = to_rcar_pwm_chip(chip);
+
+	rcar_pwm_update(rp, RCAR_PWMCR_EN0, 0, RCAR_PWMCR);
+}
+
+static const struct pwm_ops rcar_pwm_ops = {
+	.request = rcar_pwm_request,
+	.free = rcar_pwm_free,
+	.config = rcar_pwm_config,
+	.enable = rcar_pwm_enable,
+	.disable = rcar_pwm_disable,
+	.owner = THIS_MODULE,
+};
+
+static int rcar_pwm_probe(struct platform_device *pdev)
+{
+	struct rcar_pwm_chip *rcar_pwm;
+	struct resource *res;
+	int ret;
+
+	rcar_pwm = devm_kzalloc(&pdev->dev, sizeof(*rcar_pwm), GFP_KERNEL);
+	if (rcar_pwm == NULL)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rcar_pwm->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rcar_pwm->base))
+		return PTR_ERR(rcar_pwm->base);
+
+	rcar_pwm->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(rcar_pwm->clk)) {
+		dev_err(&pdev->dev, "cannot get clock\n");
+		return PTR_ERR(rcar_pwm->clk);
+	}
+
+	platform_set_drvdata(pdev, rcar_pwm);
+
+	rcar_pwm->chip.dev = &pdev->dev;
+	rcar_pwm->chip.ops = &rcar_pwm_ops;
+	rcar_pwm->chip.base = -1;
+	rcar_pwm->chip.npwm = 1;
+
+	ret = pwmchip_add(&rcar_pwm->chip);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to register PWM chip: %d\n", ret);
+		return ret;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+}
+
+static int rcar_pwm_remove(struct platform_device *pdev)
+{
+	struct rcar_pwm_chip *rcar_pwm = platform_get_drvdata(pdev);
+
+	pm_runtime_disable(&pdev->dev);
+
+	return pwmchip_remove(&rcar_pwm->chip);
+}
+
+static const struct of_device_id rcar_pwm_of_table[] = {
+	{ .compatible = "renesas,pwm-rcar", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, rcar_pwm_of_table);
+
+static struct platform_driver rcar_pwm_driver = {
+	.probe = rcar_pwm_probe,
+	.remove = rcar_pwm_remove,
+	.driver = {
+		.name = "pwm-rcar",
+		.of_match_table = of_match_ptr(rcar_pwm_of_table),
+	}
+};
+module_platform_driver(rcar_pwm_driver);
+
+MODULE_AUTHOR("Yoshihiro Shimoda <[e-mail]>");
+MODULE_DESCRIPTION("Renesas PWM Timer Driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:pwm-rcar");

drivers/pwm/pwm-sun4i.c

···
 struct sun4i_pwm_data {
 	bool has_prescaler_bypass;
 	bool has_rdy;
+	unsigned int npwm;
 };
 
 struct sun4i_pwm_chip {
···
 		 * is not an integer so round it half up instead of
 		 * truncating to get less surprising values.
 		 */
-		div = clk_rate * period_ns + NSEC_PER_SEC/2;
+		div = clk_rate * period_ns + NSEC_PER_SEC / 2;
 		do_div(div, NSEC_PER_SEC);
 		if (div - 1 > PWM_PRD_MASK)
 			prescaler = 0;
···
 static const struct sun4i_pwm_data sun4i_pwm_data_a10 = {
 	.has_prescaler_bypass = false,
 	.has_rdy = false,
+	.npwm = 2,
+};
+
+static const struct sun4i_pwm_data sun4i_pwm_data_a10s = {
+	.has_prescaler_bypass = true,
+	.has_rdy = true,
+	.npwm = 2,
+};
+
+static const struct sun4i_pwm_data sun4i_pwm_data_a13 = {
+	.has_prescaler_bypass = true,
+	.has_rdy = true,
+	.npwm = 1,
 };
 
 static const struct sun4i_pwm_data sun4i_pwm_data_a20 = {
 	.has_prescaler_bypass = true,
 	.has_rdy = true,
+	.npwm = 2,
 };
 
 static const struct of_device_id sun4i_pwm_dt_ids[] = {
 	{
 		.compatible = "allwinner,sun4i-a10-pwm",
 		.data = &sun4i_pwm_data_a10,
+	}, {
+		.compatible = "allwinner,sun5i-a10s-pwm",
+		.data = &sun4i_pwm_data_a10s,
+	}, {
+		.compatible = "allwinner,sun5i-a13-pwm",
+		.data = &sun4i_pwm_data_a13,
 	}, {
 		.compatible = "allwinner,sun7i-a20-pwm",
 		.data = &sun4i_pwm_data_a20,
···
 	if (IS_ERR(pwm->clk))
 		return PTR_ERR(pwm->clk);
 
+	pwm->data = match->data;
 	pwm->chip.dev = &pdev->dev;
 	pwm->chip.ops = &sun4i_pwm_ops;
 	pwm->chip.base = -1;
-	pwm->chip.npwm = 2;
+	pwm->chip.npwm = pwm->data->npwm;
 	pwm->chip.can_sleep = true;
 	pwm->chip.of_xlate = of_pwm_xlate_with_flags;
 	pwm->chip.of_pwm_n_cells = 3;
-	pwm->data = match->data;
 
 	spin_lock_init(&pwm->ctrl_lock);
 

drivers/pwm/sysfs.c

···
 	return export->pwm;
 }
 
-static ssize_t pwm_period_show(struct device *child,
-			       struct device_attribute *attr,
-			       char *buf)
+static ssize_t period_show(struct device *child,
+			   struct device_attribute *attr,
+			   char *buf)
 {
 	const struct pwm_device *pwm = child_to_pwm_device(child);
 
 	return sprintf(buf, "%u\n", pwm_get_period(pwm));
 }
 
-static ssize_t pwm_period_store(struct device *child,
-				struct device_attribute *attr,
-				const char *buf, size_t size)
+static ssize_t period_store(struct device *child,
+			    struct device_attribute *attr,
+			    const char *buf, size_t size)
 {
 	struct pwm_device *pwm = child_to_pwm_device(child);
 	unsigned int val;
···
 	return ret ? : size;
 }
 
-static ssize_t pwm_duty_cycle_show(struct device *child,
-				   struct device_attribute *attr,
-				   char *buf)
+static ssize_t duty_cycle_show(struct device *child,
+			       struct device_attribute *attr,
+			       char *buf)
 {
 	const struct pwm_device *pwm = child_to_pwm_device(child);
 
 	return sprintf(buf, "%u\n", pwm_get_duty_cycle(pwm));
 }
 
-static ssize_t pwm_duty_cycle_store(struct device *child,
-				    struct device_attribute *attr,
-				    const char *buf, size_t size)
+static ssize_t duty_cycle_store(struct device *child,
+				struct device_attribute *attr,
+				const char *buf, size_t size)
 {
 	struct pwm_device *pwm = child_to_pwm_device(child);
 	unsigned int val;
···
 	return ret ? : size;
 }
 
-static ssize_t pwm_enable_show(struct device *child,
-			       struct device_attribute *attr,
-			       char *buf)
+static ssize_t enable_show(struct device *child,
+			   struct device_attribute *attr,
+			   char *buf)
 {
 	const struct pwm_device *pwm = child_to_pwm_device(child);
-	int enabled = pwm_is_enabled(pwm);
 
-	return sprintf(buf, "%d\n", enabled);
+	return sprintf(buf, "%d\n", pwm_is_enabled(pwm));
 }
 
-static ssize_t pwm_enable_store(struct device *child,
-				struct device_attribute *attr,
-				const char *buf, size_t size)
+static ssize_t enable_store(struct device *child,
+			    struct device_attribute *attr,
+			    const char *buf, size_t size)
 {
 	struct pwm_device *pwm = child_to_pwm_device(child);
 	int val, ret;
···
 	return ret ? : size;
 }
 
-static ssize_t pwm_polarity_show(struct device *child,
-				 struct device_attribute *attr,
-				 char *buf)
+static ssize_t polarity_show(struct device *child,
+			     struct device_attribute *attr,
+			     char *buf)
 {
 	const struct pwm_device *pwm = child_to_pwm_device(child);
 	const char *polarity = "unknown";
···
 	return sprintf(buf, "%s\n", polarity);
 }
 
-static ssize_t pwm_polarity_store(struct device *child,
-				  struct device_attribute *attr,
-				  const char *buf, size_t size)
+static ssize_t polarity_store(struct device *child,
+			      struct device_attribute *attr,
+			      const char *buf, size_t size)
 {
 	struct pwm_device *pwm = child_to_pwm_device(child);
 	enum pwm_polarity polarity;
···
 	return ret ? : size;
 }
 
-static DEVICE_ATTR(period, 0644, pwm_period_show, pwm_period_store);
-static DEVICE_ATTR(duty_cycle, 0644, pwm_duty_cycle_show, pwm_duty_cycle_store);
-static DEVICE_ATTR(enable, 0644, pwm_enable_show, pwm_enable_store);
-static DEVICE_ATTR(polarity, 0644, pwm_polarity_show, pwm_polarity_store);
+static DEVICE_ATTR_RW(period);
+static DEVICE_ATTR_RW(duty_cycle);
+static DEVICE_ATTR_RW(enable);
+static DEVICE_ATTR_RW(polarity);
 
 static struct attribute *pwm_attrs[] = {
 	&dev_attr_period.attr,
···
 	return 0;
 }
 
-static ssize_t pwm_export_store(struct device *parent,
-				struct device_attribute *attr,
-				const char *buf, size_t len)
+static ssize_t export_store(struct device *parent,
+			    struct device_attribute *attr,
+			    const char *buf, size_t len)
 {
 	struct pwm_chip *chip = dev_get_drvdata(parent);
 	struct pwm_device *pwm;
···
 
 	return ret ? : len;
 }
-static DEVICE_ATTR(export, 0200, NULL, pwm_export_store);
+static DEVICE_ATTR_WO(export);
 
-static ssize_t pwm_unexport_store(struct device *parent,
-				  struct device_attribute *attr,
-				  const char *buf, size_t len)
+static ssize_t unexport_store(struct device *parent,
+			      struct device_attribute *attr,
+			      const char *buf, size_t len)
 {
 	struct pwm_chip *chip = dev_get_drvdata(parent);
 	unsigned int hwpwm;
···
 
 	return ret ? : len;
 }
-static DEVICE_ATTR(unexport, 0200, NULL, pwm_unexport_store);
+static DEVICE_ATTR_WO(unexport);
 
 static ssize_t npwm_show(struct device *parent, struct device_attribute *attr,
 			 char *buf)

include/linux/pwm.h

···
 #define __LINUX_PWM_H
 
 #include <linux/err.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 
 struct pwm_device;
···
  * @pwm: global index of the PWM device
  * @chip: PWM chip providing this PWM device
  * @chip_data: chip-private data associated with the PWM device
+ * @lock: used to serialize accesses to the PWM device where necessary
  * @period: period of the PWM signal (in nanoseconds)
  * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
  * @polarity: polarity of the PWM signal
···
 	unsigned int pwm;
 	struct pwm_chip *chip;
 	void *chip_data;
+	struct mutex lock;
 
 	unsigned int period;
 	unsigned int duty_cycle;