Merge tag 'pwm/for-4.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
"This set of changes contains a new driver for OMAP (using the
dual-mode timers) as well as an assortment of fixes all across the
board"

* tag 'pwm/for-4.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
pwm: Mark all devices as "might sleep"
pwm: omap-dmtimer: Potential NULL dereference on error
pwm: add HAS_IOMEM dependency to PWM_FSL_FTM
pwm: Add PWM driver for OMAP using dual-mode timers
pwm: rcar: Improve accuracy of frequency division setting
pwm: lpc32xx: return ERANGE, if requested period is not supported
pwm: lpc32xx: fix and simplify duty cycle and period calculations
pwm: lpc32xx: make device usable with common clock framework
pwm: lpc32xx: correct number of PWM channels from 2 to 1
dt: lpc32xx: pwm: update documentation of LPC32xx PWM device
dt: lpc32xx: pwm: correct LPC32xx PWM device node example
pwm: fsl-ftm: Fix clock enable/disable when using PM
pwm: lpss: Rework the sequence of programming PWM_SW_UPDATE
pwm: lpss: Select core part automatically
pwm: lpss: Update PWM setting for Broxton
pwm: bcm2835: Fix email address specification
pwm: bcm2835: Prevent division by zero
pwm: bcm2835: Calculate scaler in ->config()
pwm: lpss: Remove ->free() callback

Documentation/devicetree/bindings/pwm/lpc32xx-pwm.txt

···
 
 Examples:
 
-pwm@0x4005C000 {
+pwm@4005c000 {
 	compatible = "nxp,lpc3220-pwm";
-	reg = <0x4005C000 0x8>;
+	reg = <0x4005c000 0x4>;
+};
+
+pwm@4005c004 {
+	compatible = "nxp,lpc3220-pwm";
+	reg = <0x4005c004 0x4>;
 };

Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt

···
+* OMAP PWM for dual-mode timers
+
+Required properties:
+- compatible: Shall contain "ti,omap-dmtimer-pwm".
+- ti,timers: phandle to PWM capable OMAP timer. See arm/omap/timer.txt for info
+  about these timers.
+- #pwm-cells: Should be 3. See pwm.txt in this directory for a description of
+  the cells format.
+
+Optional properties:
+- ti,prescaler: Should be a value between 0 and 7, see the timers datasheet
+
+Example:
+	pwm9: dmtimer-pwm@9 {
+		compatible = "ti,omap-dmtimer-pwm";
+		ti,timers = <&timer9>;
+		#pwm-cells = <3>;
+	};

drivers/pwm/Kconfig

···
 
 config PWM_FSL_FTM
 	tristate "Freescale FlexTimer Module (FTM) PWM support"
+	depends on HAS_IOMEM
 	depends on OF
 	select REGMAP_MMIO
 	help
···
 	  will be called pwm-lpc32xx.
 
 config PWM_LPSS
-	tristate "Intel LPSS PWM support"
-	depends on X86
-	help
-	  Generic PWM framework driver for Intel Low Power Subsystem PWM
-	  controller.
-
-	  To compile this driver as a module, choose M here: the module
-	  will be called pwm-lpss.
+	tristate
 
 config PWM_LPSS_PCI
 	tristate "Intel LPSS PWM PCI driver"
-	depends on PWM_LPSS && PCI
+	depends on X86 && PCI
+	select PWM_LPSS
 	help
 	  The PCI driver for Intel Low Power Subsystem PWM controller.
 
···
 
 config PWM_LPSS_PLATFORM
 	tristate "Intel LPSS PWM platform driver"
-	depends on PWM_LPSS && ACPI
+	depends on X86 && ACPI
+	select PWM_LPSS
 	help
 	  The platform driver for Intel Low Power Subsystem PWM controller.
 
···
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-mxs.
+
+config PWM_OMAP_DMTIMER
+	tristate "OMAP Dual-Mode Timer PWM support"
+	depends on OF && ARCH_OMAP && OMAP_DM_TIMER
+	help
+	  Generic PWM framework driver for OMAP Dual-Mode Timer PWM output
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-omap-dmtimer
 
 config PWM_PCA9685
 	tristate "NXP PCA9685 PWM driver"

drivers/pwm/Makefile

···
 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_OMAP_DMTIMER)	+= pwm-omap-dmtimer.o
 obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
 obj-$(CONFIG_PWM_PUV3)		+= pwm-puv3.o
 obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o

drivers/pwm/core.c

···
   */
 bool pwm_can_sleep(struct pwm_device *pwm)
 {
-	return pwm->chip->can_sleep;
+	return true;
 }
 EXPORT_SYMBOL_GPL(pwm_can_sleep);
 

drivers/pwm/pwm-bcm2835.c

···
 struct bcm2835_pwm {
 	struct pwm_chip chip;
 	struct device *dev;
-	unsigned long scaler;
 	void __iomem *base;
 	struct clk *clk;
 };
···
 			      int duty_ns, int period_ns)
 {
 	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
+	unsigned long rate = clk_get_rate(pc->clk);
+	unsigned long scaler;
+
+	if (!rate) {
+		dev_err(pc->dev, "failed to get clock rate\n");
+		return -EINVAL;
+	}
+
+	scaler = NSEC_PER_SEC / rate;
 
 	if (period_ns <= MIN_PERIOD) {
 		dev_err(pc->dev, "period %d not supported, minimum %d\n",
···
 		return -EINVAL;
 	}
 
-	writel(duty_ns / pc->scaler, pc->base + DUTY(pwm->hwpwm));
-	writel(period_ns / pc->scaler, pc->base + PERIOD(pwm->hwpwm));
+	writel(duty_ns / scaler, pc->base + DUTY(pwm->hwpwm));
+	writel(period_ns / scaler, pc->base + PERIOD(pwm->hwpwm));
 
 	return 0;
 }
···
 	if (ret)
 		return ret;
 
-	pc->scaler = NSEC_PER_SEC / clk_get_rate(pc->clk);
-
 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &bcm2835_pwm_ops;
 	pc->chip.npwm = 2;
···
 };
 module_platform_driver(bcm2835_pwm_driver);
 
-MODULE_AUTHOR("Bart Tanghe <[e-mail]");
+MODULE_AUTHOR("Bart Tanghe <[e-mail]>");
 MODULE_DESCRIPTION("Broadcom BCM2835 PWM driver");
 MODULE_LICENSE("GPL v2");

drivers/pwm/pwm-fsl-ftm.c

···
 
 	struct mutex lock;
 
-	unsigned int use_count;
 	unsigned int cnt_select;
 	unsigned int clk_ps;
 
···
 {
 	int ret;
 
-	if (fpc->use_count++ != 0)
-		return 0;
-
 	/* select counter clock source */
 	regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK,
 			   FTM_SC_CLK(fpc->cnt_select));
···
 	return ret;
 }
 
-static void fsl_counter_clock_disable(struct fsl_pwm_chip *fpc)
-{
-	/*
-	 * already disabled, do nothing
-	 */
-	if (fpc->use_count == 0)
-		return;
-
-	/* there are still users, so can't disable yet */
-	if (--fpc->use_count > 0)
-		return;
-
-	/* no users left, disable PWM counter clock */
-	regmap_update_bits(fpc->regmap, FTM_SC, FTM_SC_CLK_MASK, 0);
-
-	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
-	clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
-}
-
 static void fsl_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct fsl_pwm_chip *fpc = to_fsl_chip(chip);
···
 	regmap_update_bits(fpc->regmap, FTM_OUTMASK, BIT(pwm->hwpwm),
 			   BIT(pwm->hwpwm));
 
-	fsl_counter_clock_disable(fpc);
+	clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
+	clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
 
 	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
 	if ((val & 0xFF) == 0xFF)
···
 static int fsl_pwm_suspend(struct device *dev)
 {
 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
-	u32 val;
+	int i;
 
 	regcache_cache_only(fpc->regmap, true);
 	regcache_mark_dirty(fpc->regmap);
 
-	/* read from cache */
-	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
-	if ((val & 0xFF) != 0xFF) {
+	for (i = 0; i < fpc->chip.npwm; i++) {
+		struct pwm_device *pwm = &fpc->chip.pwms[i];
+
+		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
+			continue;
+
+		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
+
+		if (!pwm_is_enabled(pwm))
+			continue;
+
 		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_CNTEN]);
 		clk_disable_unprepare(fpc->clk[fpc->cnt_select]);
-		clk_disable_unprepare(fpc->clk[FSL_PWM_CLK_SYS]);
 	}
 
 	return 0;
···
 static int fsl_pwm_resume(struct device *dev)
 {
 	struct fsl_pwm_chip *fpc = dev_get_drvdata(dev);
-	u32 val;
+	int i;
 
-	/* read from cache */
-	regmap_read(fpc->regmap, FTM_OUTMASK, &val);
-	if ((val & 0xFF) != 0xFF) {
+	for (i = 0; i < fpc->chip.npwm; i++) {
+		struct pwm_device *pwm = &fpc->chip.pwms[i];
+
+		if (!test_bit(PWMF_REQUESTED, &pwm->flags))
+			continue;
+
 		clk_prepare_enable(fpc->clk[FSL_PWM_CLK_SYS]);
+
+		if (!pwm_is_enabled(pwm))
+			continue;
+
 		clk_prepare_enable(fpc->clk[fpc->cnt_select]);
 		clk_prepare_enable(fpc->clk[FSL_PWM_CLK_CNTEN]);
 	}

drivers/pwm/pwm-lpc32xx.c

···
 	void __iomem *base;
 };
 
-#define PWM_ENABLE	(1 << 31)
-#define PWM_RELOADV(x)	(((x) & 0xFF) << 8)
-#define PWM_DUTY(x)	((x) & 0xFF)
+#define PWM_ENABLE	BIT(31)
 
 #define to_lpc32xx_pwm_chip(_chip) \
 	container_of(_chip, struct lpc32xx_pwm_chip, chip)
···
 	unsigned long long c;
 	int period_cycles, duty_cycles;
 	u32 val;
+	c = clk_get_rate(lpc32xx->clk);
 
-	c = clk_get_rate(lpc32xx->clk) / 256;
-	c = c * period_ns;
-	do_div(c, NSEC_PER_SEC);
+	/* The highest acceptable divisor is 256, which is represented by 0 */
+	period_cycles = div64_u64(c * period_ns,
+			       (unsigned long long)NSEC_PER_SEC * 256);
+	if (!period_cycles || period_cycles > 256)
+		return -ERANGE;
+	if (period_cycles == 256)
+		period_cycles = 0;
 
-	/* Handle high and low extremes */
-	if (c == 0)
-		c = 1;
-	if (c > 255)
-		c = 0; /* 0 set division by 256 */
-	period_cycles = c;
-
-	/* The duty-cycle value is as follows:
-	 *
-	 *  DUTY-CYCLE     HIGH LEVEL
-	 *      1            99.9%
-	 *      25           90.0%
-	 *      128          50.0%
-	 *      220          10.0%
-	 *      255           0.1%
-	 *      0             0.0%
-	 *
-	 * In other words, the register value is duty-cycle % 256 with
-	 * duty-cycle in the range 1-256.
-	 */
-	c = 256 * duty_ns;
-	do_div(c, period_ns);
-	if (c > 255)
-		c = 255;
-	duty_cycles = 256 - c;
+	/* Compute 256 x #duty/period value and care for corner cases */
+	duty_cycles = div64_u64((unsigned long long)(period_ns - duty_ns) * 256,
+				period_ns);
+	if (!duty_cycles)
+		duty_cycles = 1;
+	if (duty_cycles > 255)
+		duty_cycles = 255;
 
 	val = readl(lpc32xx->base + (pwm->hwpwm << 2));
 	val &= ~0xFFFF;
-	val |= PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles);
+	val |= (period_cycles << 8) | duty_cycles;
 	writel(val, lpc32xx->base + (pwm->hwpwm << 2));
 
 	return 0;
···
 	u32 val;
 	int ret;
 
-	ret = clk_enable(lpc32xx->clk);
+	ret = clk_prepare_enable(lpc32xx->clk);
 	if (ret)
 		return ret;
 
···
 	val &= ~PWM_ENABLE;
 	writel(val, lpc32xx->base + (pwm->hwpwm << 2));
 
-	clk_disable(lpc32xx->clk);
+	clk_disable_unprepare(lpc32xx->clk);
 }
 
 static const struct pwm_ops lpc32xx_pwm_ops = {
···
 
 	lpc32xx->chip.dev = &pdev->dev;
 	lpc32xx->chip.ops = &lpc32xx_pwm_ops;
-	lpc32xx->chip.npwm = 2;
+	lpc32xx->chip.npwm = 1;
 	lpc32xx->chip.base = -1;
 
 	ret = pwmchip_add(&lpc32xx->chip);

drivers/pwm/pwm-lpss.c

···
  * published by the Free Software Foundation.
  */
 
+#include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/time.h>
 
 #include "pwm-lpss.h"
 
···
 #define PWM_ENABLE			BIT(31)
 #define PWM_SW_UPDATE			BIT(30)
 #define PWM_BASE_UNIT_SHIFT		8
-#define PWM_BASE_UNIT_MASK		0x00ffff00
 #define PWM_ON_TIME_DIV_MASK		0x000000ff
 #define PWM_DIVISION_CORRECTION		0x2
-#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;
-	unsigned long clk_rate;
+	const struct pwm_lpss_boardinfo *info;
 };
 
 /* BayTrail */
 const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
 	.clk_rate = 25000000,
 	.npwm = 1,
+	.base_unit_bits = 16,
 };
 EXPORT_SYMBOL_GPL(pwm_lpss_byt_info);
 
···
 const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
 	.clk_rate = 19200000,
 	.npwm = 1,
+	.base_unit_bits = 16,
 };
 EXPORT_SYMBOL_GPL(pwm_lpss_bsw_info);
 
···
 const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
 	.clk_rate = 19200000,
 	.npwm = 4,
+	.base_unit_bits = 22,
 };
 EXPORT_SYMBOL_GPL(pwm_lpss_bxt_info);
 
···
 	writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
 }
 
+static void pwm_lpss_update(struct pwm_device *pwm)
+{
+	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
+	/* Give it some time to propagate */
+	usleep_range(10, 50);
+}
+
 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			   int duty_ns, int period_ns)
 {
 	struct pwm_lpss_chip *lpwm = to_lpwm(chip);
 	u8 on_time_div;
-	unsigned long c;
-	unsigned long long base_unit, freq = NSECS_PER_SEC;
+	unsigned long c, base_unit_range;
+	unsigned long long base_unit, freq = NSEC_PER_SEC;
 	u32 ctrl;
 
 	do_div(freq, period_ns);
 
-	/* The equation is: base_unit = ((freq / c) * 65536) + correction */
-	base_unit = freq * 65536;
+	/*
+	 * The equation is:
+	 * base_unit = ((freq / c) * base_unit_range) + correction
+	 */
+	base_unit_range = BIT(lpwm->info->base_unit_bits);
+	base_unit = freq * base_unit_range;
 
-	c = lpwm->clk_rate;
+	c = lpwm->info->clk_rate;
 	if (!c)
 		return -EINVAL;
 
 	do_div(base_unit, c);
 	base_unit += PWM_DIVISION_CORRECTION;
-	if (base_unit > PWM_LIMIT)
-		return -EINVAL;
 
 	if (duty_ns <= 0)
 		duty_ns = 1;
···
 	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 &= ~PWM_ON_TIME_DIV_MASK;
+	ctrl &= ~((base_unit_range - 1) << PWM_BASE_UNIT_SHIFT);
+	base_unit &= (base_unit_range - 1);
+	ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT;
 	ctrl |= on_time_div;
-	/* request PWM to update on next cycle */
-	ctrl |= PWM_SW_UPDATE;
 	pwm_lpss_write(pwm, ctrl);
+
+	/*
+	 * If the PWM is already enabled we need to notify the hardware
+	 * about the change by setting PWM_SW_UPDATE.
+	 */
+	if (pwm_is_enabled(pwm))
+		pwm_lpss_update(pwm);
 
 	pm_runtime_put(chip->dev);
 
···
 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	pm_runtime_get_sync(chip->dev);
+
+	/*
+	 * Hardware must first see PWM_SW_UPDATE before the PWM can be
+	 * enabled.
+	 */
+	pwm_lpss_update(pwm);
 	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
 	return 0;
 }
···
 }
 
 static const struct pwm_ops pwm_lpss_ops = {
-	.free = pwm_lpss_disable,
 	.config = pwm_lpss_config,
 	.enable = pwm_lpss_enable,
 	.disable = pwm_lpss_disable,
···
 	if (IS_ERR(lpwm->regs))
 		return ERR_CAST(lpwm->regs);
 
-	lpwm->clk_rate = info->clk_rate;
+	lpwm->info = info;
 	lpwm->chip.dev = dev;
 	lpwm->chip.ops = &pwm_lpss_ops;
 	lpwm->chip.base = -1;

drivers/pwm/pwm-lpss.h

···
 struct pwm_lpss_boardinfo {
 	unsigned long clk_rate;
 	unsigned int npwm;
+	unsigned long base_unit_bits;
 };
 
 extern const struct pwm_lpss_boardinfo pwm_lpss_byt_info;

drivers/pwm/pwm-omap-dmtimer.c

···
+/*
+ * Copyright (c) 2015 Neil Armstrong <[e-mail]>
+ * Copyright (c) 2014 Joachim Eastwood <[e-mail]>
+ * Copyright (c) 2012 NeilBrown <[e-mail]>
+ * Heavily based on earlier code which is:
+ * Copyright (c) 2010 Grant Erickson <[e-mail]>
+ *
+ * Also based on pwm-samsung.c
+ *
+ * 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.
+ *
+ * Description:
+ *   This file is the core OMAP support for the generic, Linux
+ *   PWM driver / controller, using the OMAP's dual-mode timers.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_data/pwm_omap_dmtimer.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+
+#define DM_TIMER_LOAD_MIN 0xfffffffe
+
+struct pwm_omap_dmtimer_chip {
+	struct pwm_chip chip;
+	struct mutex mutex;
+	pwm_omap_dmtimer *dm_timer;
+	struct pwm_omap_dmtimer_pdata *pdata;
+	struct platform_device *dm_timer_pdev;
+};
+
+static inline struct pwm_omap_dmtimer_chip *
+to_pwm_omap_dmtimer_chip(struct pwm_chip *chip)
+{
+	return container_of(chip, struct pwm_omap_dmtimer_chip, chip);
+}
+
+static int pwm_omap_dmtimer_calc_value(unsigned long clk_rate, int ns)
+{
+	u64 c = (u64)clk_rate * ns;
+
+	do_div(c, NSEC_PER_SEC);
+
+	return DM_TIMER_LOAD_MIN - c;
+}
+
+static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap)
+{
+	/*
+	 * According to OMAP 4 TRM section 22.2.4.10 the counter should be
+	 * started at 0xFFFFFFFE when overflow and match is used to ensure
+	 * that the PWM line is toggled on the first event.
+	 *
+	 * Note that omap_dm_timer_enable/disable is for register access and
+	 * not the timer counter itself.
+	 */
+	omap->pdata->enable(omap->dm_timer);
+	omap->pdata->write_counter(omap->dm_timer, DM_TIMER_LOAD_MIN);
+	omap->pdata->disable(omap->dm_timer);
+
+	omap->pdata->start(omap->dm_timer);
+}
+
+static int pwm_omap_dmtimer_enable(struct pwm_chip *chip,
+				   struct pwm_device *pwm)
+{
+	struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
+
+	mutex_lock(&omap->mutex);
+	pwm_omap_dmtimer_start(omap);
+	mutex_unlock(&omap->mutex);
+
+	return 0;
+}
+
+static void pwm_omap_dmtimer_disable(struct pwm_chip *chip,
+				     struct pwm_device *pwm)
+{
+	struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
+
+	mutex_lock(&omap->mutex);
+	omap->pdata->stop(omap->dm_timer);
+	mutex_unlock(&omap->mutex);
+}
+
+static int pwm_omap_dmtimer_config(struct pwm_chip *chip,
+				   struct pwm_device *pwm,
+				   int duty_ns, int period_ns)
+{
+	struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
+	int load_value, match_value;
+	struct clk *fclk;
+	unsigned long clk_rate;
+	bool timer_active;
+
+	dev_dbg(chip->dev, "duty cycle: %d, period %d\n", duty_ns, period_ns);
+
+	mutex_lock(&omap->mutex);
+	if (duty_ns == pwm_get_duty_cycle(pwm) &&
+	    period_ns == pwm_get_period(pwm)) {
+		/* No change - don't cause any transients. */
+		mutex_unlock(&omap->mutex);
+		return 0;
+	}
+
+	fclk = omap->pdata->get_fclk(omap->dm_timer);
+	if (!fclk) {
+		dev_err(chip->dev, "invalid pmtimer fclk\n");
+		mutex_unlock(&omap->mutex);
+		return -EINVAL;
+	}
+
+	clk_rate = clk_get_rate(fclk);
+	if (!clk_rate) {
+		dev_err(chip->dev, "invalid pmtimer fclk rate\n");
+		mutex_unlock(&omap->mutex);
+		return -EINVAL;
+	}
+
+	dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate);
+
+	/*
+	 * Calculate the appropriate load and match values based on the
+	 * specified period and duty cycle. The load value determines the
+	 * cycle time and the match value determines the duty cycle.
+	 */
+	load_value = pwm_omap_dmtimer_calc_value(clk_rate, period_ns);
+	match_value = pwm_omap_dmtimer_calc_value(clk_rate,
+						  period_ns - duty_ns);
+
+	/*
+	 * We MUST stop the associated dual-mode timer before attempting to
+	 * write its registers, but calls to omap_dm_timer_start/stop must
+	 * be balanced so check if timer is active before calling timer_stop.
+	 */
+	timer_active = pm_runtime_active(&omap->dm_timer_pdev->dev);
+	if (timer_active)
+		omap->pdata->stop(omap->dm_timer);
+
+	omap->pdata->set_load(omap->dm_timer, true, load_value);
+	omap->pdata->set_match(omap->dm_timer, true, match_value);
+
+	dev_dbg(chip->dev, "load value: %#08x (%d), match value: %#08x (%d)\n",
+		load_value, load_value,	match_value, match_value);
+
+	omap->pdata->set_pwm(omap->dm_timer,
+			      pwm->polarity == PWM_POLARITY_INVERSED,
+			      true,
+			      PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE);
+
+	/* If config was called while timer was running it must be reenabled. */
+	if (timer_active)
+		pwm_omap_dmtimer_start(omap);
+
+	mutex_unlock(&omap->mutex);
+
+	return 0;
+}
+
+static int pwm_omap_dmtimer_set_polarity(struct pwm_chip *chip,
+					 struct pwm_device *pwm,
+					 enum pwm_polarity polarity)
+{
+	struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip);
+
+	/*
+	 * PWM core will not call set_polarity while PWM is enabled so it's
+	 * safe to reconfigure the timer here without stopping it first.
+	 */
+	mutex_lock(&omap->mutex);
+	omap->pdata->set_pwm(omap->dm_timer,
+			      polarity == PWM_POLARITY_INVERSED,
+			      true,
+			      PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE);
+	mutex_unlock(&omap->mutex);
+
+	return 0;
+}
+
+static const struct pwm_ops pwm_omap_dmtimer_ops = {
+	.enable	= pwm_omap_dmtimer_enable,
+	.disable = pwm_omap_dmtimer_disable,
+	.config	= pwm_omap_dmtimer_config,
+	.set_polarity = pwm_omap_dmtimer_set_polarity,
+	.owner = THIS_MODULE,
+};
+
+static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct device_node *timer;
+	struct pwm_omap_dmtimer_chip *omap;
+	struct pwm_omap_dmtimer_pdata *pdata;
+	pwm_omap_dmtimer *dm_timer;
+	u32 prescaler;
+	int status;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata) {
+		dev_err(&pdev->dev, "Missing dmtimer platform data\n");
+		return -EINVAL;
+	}
+
+	if (!pdata->request_by_node ||
+	    !pdata->free ||
+	    !pdata->enable ||
+	    !pdata->disable ||
+	    !pdata->get_fclk ||
+	    !pdata->start ||
+	    !pdata->stop ||
+	    !pdata->set_load ||
+	    !pdata->set_match ||
+	    !pdata->set_pwm ||
+	    !pdata->set_prescaler ||
+	    !pdata->write_counter) {
+		dev_err(&pdev->dev, "Incomplete dmtimer pdata structure\n");
+		return -EINVAL;
+	}
+
+	timer = of_parse_phandle(np, "ti,timers", 0);
+	if (!timer)
+		return -ENODEV;
+
+	if (!of_get_property(timer, "ti,timer-pwm", NULL)) {
+		dev_err(&pdev->dev, "Missing ti,timer-pwm capability\n");
+		return -ENODEV;
+	}
+
+	dm_timer = pdata->request_by_node(timer);
+	if (!dm_timer)
+		return -EPROBE_DEFER;
+
+	omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL);
+	if (!omap) {
+		pdata->free(dm_timer);
+		return -ENOMEM;
+	}
+
+	omap->pdata = pdata;
+	omap->dm_timer = dm_timer;
+
+	omap->dm_timer_pdev = of_find_device_by_node(timer);
+	if (!omap->dm_timer_pdev) {
+		dev_err(&pdev->dev, "Unable to find timer pdev\n");
+		omap->pdata->free(dm_timer);
+		return -EINVAL;
+	}
+
+	/*
+	 * Ensure that the timer is stopped before we allow PWM core to call
+	 * pwm_enable.
+	 */
+	if (pm_runtime_active(&omap->dm_timer_pdev->dev))
+		omap->pdata->stop(omap->dm_timer);
+
+	/* setup dmtimer prescaler */
+	if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler",
+				&prescaler))
+		omap->pdata->set_prescaler(omap->dm_timer, prescaler);
+
+	omap->chip.dev = &pdev->dev;
+	omap->chip.ops = &pwm_omap_dmtimer_ops;
+	omap->chip.base = -1;
+	omap->chip.npwm = 1;
+	omap->chip.of_xlate = of_pwm_xlate_with_flags;
+	omap->chip.of_pwm_n_cells = 3;
+
+	mutex_init(&omap->mutex);
+
+	status = pwmchip_add(&omap->chip);
+	if (status < 0) {
+		dev_err(&pdev->dev, "failed to register PWM\n");
+		omap->pdata->free(omap->dm_timer);
+		return status;
+	}
+
+	platform_set_drvdata(pdev, omap);
+
+	return 0;
+}
+
+static int pwm_omap_dmtimer_remove(struct platform_device *pdev)
+{
+	struct pwm_omap_dmtimer_chip *omap = platform_get_drvdata(pdev);
+
+	if (pm_runtime_active(&omap->dm_timer_pdev->dev))
+		omap->pdata->stop(omap->dm_timer);
+
+	omap->pdata->free(omap->dm_timer);
+
+	mutex_destroy(&omap->mutex);
+
+	return pwmchip_remove(&omap->chip);
+}
+
+static const struct of_device_id pwm_omap_dmtimer_of_match[] = {
+	{.compatible = "ti,omap-dmtimer-pwm"},
+	{}
+};
+MODULE_DEVICE_TABLE(of, pwm_omap_dmtimer_of_match);
+
+static struct platform_driver pwm_omap_dmtimer_driver = {
+	.driver = {
+		.name = "omap-dmtimer-pwm",
+		.of_match_table = of_match_ptr(pwm_omap_dmtimer_of_match),
+	},
+	.probe = pwm_omap_dmtimer_probe,
+	.remove	= pwm_omap_dmtimer_remove,
+};
+module_platform_driver(pwm_omap_dmtimer_driver);
+
+MODULE_AUTHOR("Grant Erickson <[e-mail]>");
+MODULE_AUTHOR("NeilBrown <[e-mail]>");
+MODULE_AUTHOR("Neil Armstrong <[e-mail]>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("OMAP PWM Driver using Dual-mode Timers");

drivers/pwm/pwm-rcar.c

···
 		max = (unsigned long long)NSEC_PER_SEC * RCAR_PWM_MAX_CYCLE *
 			(1 << div);
 		do_div(max, clk_rate);
-		if (period_ns < max)
+		if (period_ns <= max)
 			break;
 	}
 

include/linux/platform_data/pwm_omap_dmtimer.h

···
+/*
+ * include/linux/platform_data/pwm_omap_dmtimer.h
+ *
+ * OMAP Dual-Mode Timer PWM platform data
+ *
+ * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/
+ * Tarun Kanti DebBarma <[e-mail]>
+ * Thara Gopinath <[e-mail]>
+ *
+ * Platform device conversion and hwmod support.
+ *
+ * Copyright (C) 2005 Nokia Corporation
+ * Author: Lauri Leukkunen <[e-mail]>
+ * PWM and clock framework support by Timo Teras.
+ *
+ * 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
+ * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * You should have received a copy of the  GNU General Public License along
+ * with this program; if not, write  to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef __PWM_OMAP_DMTIMER_PDATA_H
+#define __PWM_OMAP_DMTIMER_PDATA_H
+
+/* trigger types */
+#define PWM_OMAP_DMTIMER_TRIGGER_NONE			0x00
+#define PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW		0x01
+#define PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE	0x02
+
+struct omap_dm_timer;
+typedef struct omap_dm_timer pwm_omap_dmtimer;
+
+struct pwm_omap_dmtimer_pdata {
+	pwm_omap_dmtimer *(*request_by_node)(struct device_node *np);
+	int	(*free)(pwm_omap_dmtimer *timer);
+
+	void	(*enable)(pwm_omap_dmtimer *timer);
+	void	(*disable)(pwm_omap_dmtimer *timer);
+
+	struct clk *(*get_fclk)(pwm_omap_dmtimer *timer);
+
+	int	(*start)(pwm_omap_dmtimer *timer);
+	int	(*stop)(pwm_omap_dmtimer *timer);
+
+	int	(*set_load)(pwm_omap_dmtimer *timer, int autoreload,
+			unsigned int value);
+	int	(*set_match)(pwm_omap_dmtimer *timer, int enable,
+			unsigned int match);
+	int	(*set_pwm)(pwm_omap_dmtimer *timer, int def_on,
+			int toggle, int trigger);
+	int	(*set_prescaler)(pwm_omap_dmtimer *timer, int prescaler);
+
+	int	(*write_counter)(pwm_omap_dmtimer *timer, unsigned int value);
+};
+
+#endif /* __PWM_OMAP_DMTIMER_PDATA_H */