mfd: Add HI6421 PMIC Core driver

This adds driver to support HiSilicon Hi6421 PMIC. Hi6421 includes multi-
functions, such as regulators, codec, ADCs, Coulomb counter, etc.
This driver includes core APIs _only_.

Drivers for individul components, like voltage regulators, are
implemented in corresponding driver directories and files.

Registers in Hi6421 are memory mapped, so using regmap-mmio API.

Signed-off-by: Guodong Xu <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/Kconfig

···
 	help
 	  Select this if your MC13xxx is connected via an I2C bus.
 
+config MFD_HI6421_PMIC
+	tristate "HiSilicon Hi6421 PMU/Codec IC"
+	depends on OF
+	select MFD_CORE
+	select REGMAP_MMIO
+	help
+	  Add support for HiSilicon Hi6421 PMIC. Hi6421 includes multi-
+	  functions, such as regulators, RTC, codec, Coulomb counter, etc.
+	  This driver includes core APIs _only_. You have to select
+	  individul components like voltage regulators under corresponding
+	  menus in order to enable them.
+	  We communicate with the Hi6421 via memory-mapped I/O.
+
 config HTC_EGPIO
 	bool "HTC EGPIO support"
 	depends on GPIOLIB && ARM

drivers/mfd/Makefile

···
 obj-$(CONFIG_MFD_STW481X)	+= stw481x.o
 obj-$(CONFIG_MFD_IPAQ_MICRO)	+= ipaq-micro.o
 obj-$(CONFIG_MFD_MENF21BMC)	+= menf21bmc.o
+obj-$(CONFIG_MFD_HI6421_PMIC)	+= hi6421-pmic-core.o
 
 intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
 obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o

drivers/mfd/hi6421-pmic-core.c

···
+/*
+ * Device driver for Hi6421 IC
+ *
+ * Copyright (c) <2011-2014> HiSilicon Technologies Co., Ltd.
+ *              http://www.hisilicon.com
+ * Copyright (c) <2013-2014> Linaro Ltd.
+ *              http://www.linaro.org
+ *
+ * Author: Guodong Xu <[e-mail]>
+ *
+ * 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 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/mfd/hi6421-pmic.h>
+
+static const struct mfd_cell hi6421_devs[] = {
+	{ .name = "hi6421-regulator", },
+};
+
+static struct regmap_config hi6421_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 8,
+	.max_register = HI6421_REG_TO_BUS_ADDR(HI6421_REG_MAX),
+};
+
+static int hi6421_pmic_probe(struct platform_device *pdev)
+{
+	struct hi6421_pmic *pmic;
+	struct resource *res;
+	void __iomem *base;
+	int ret;
+
+	pmic = devm_kzalloc(&pdev->dev, sizeof(*pmic), GFP_KERNEL);
+	if (!pmic)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	pmic->regmap = devm_regmap_init_mmio_clk(&pdev->dev, NULL, base,
+						 &hi6421_regmap_config);
+	if (IS_ERR(pmic->regmap)) {
+		dev_err(&pdev->dev,
+			"regmap init failed: %ld\n", PTR_ERR(pmic->regmap));
+		return PTR_ERR(pmic->regmap);
+	}
+
+	/* set over-current protection debounce 8ms */
+	regmap_update_bits(pmic->regmap, HI6421_OCP_DEB_CTRL_REG,
+				(HI6421_OCP_DEB_SEL_MASK
+				 | HI6421_OCP_EN_DEBOUNCE_MASK
+				 | HI6421_OCP_AUTO_STOP_MASK),
+				(HI6421_OCP_DEB_SEL_8MS
+				 | HI6421_OCP_EN_DEBOUNCE_ENABLE));
+
+	platform_set_drvdata(pdev, pmic);
+
+	ret = mfd_add_devices(&pdev->dev, 0, hi6421_devs,
+			ARRAY_SIZE(hi6421_devs), NULL, 0, NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "add mfd devices failed: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int hi6421_pmic_remove(struct platform_device *pdev)
+{
+	mfd_remove_devices(&pdev->dev);
+
+	return 0;
+}
+
+static struct of_device_id of_hi6421_pmic_match_tbl[] = {
+	{ .compatible = "hisilicon,hi6421-pmic", },
+	{ },
+};
+
+static struct platform_driver hi6421_pmic_driver = {
+	.driver = {
+		.name	= "hi6421_pmic",
+		.of_match_table = of_hi6421_pmic_match_tbl,
+	},
+	.probe	= hi6421_pmic_probe,
+	.remove	= hi6421_pmic_remove,
+};
+module_platform_driver(hi6421_pmic_driver);
+
+MODULE_AUTHOR("Guodong Xu <[e-mail]>");
+MODULE_DESCRIPTION("Hi6421 PMIC driver");
+MODULE_LICENSE("GPL v2");

include/linux/mfd/hi6421-pmic.h

···
+/*
+ * Header file for device driver Hi6421 PMIC
+ *
+ * Copyright (c) <2011-2014> HiSilicon Technologies Co., Ltd.
+ *              http://www.hisilicon.com
+ * Copyright (c) <2013-2014> Linaro Ltd.
+ *              http://www.linaro.org
+ *
+ * Author: Guodong Xu <[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.
+ */
+
+#ifndef	__HI6421_PMIC_H
+#define	__HI6421_PMIC_H
+
+/* Hi6421 registers are mapped to memory bus in 4 bytes stride */
+#define HI6421_REG_TO_BUS_ADDR(x)	(x << 2)
+
+/* Hi6421 maximum register number */
+#define HI6421_REG_MAX			0xFF
+
+/* Hi6421 OCP (over current protection) and DEB (debounce) control register */
+#define	HI6421_OCP_DEB_CTRL_REG		HI6421_REG_TO_BUS_ADDR(0x51)
+#define	HI6421_OCP_DEB_SEL_MASK		0x0C
+#define HI6421_OCP_DEB_SEL_8MS		0x00
+#define HI6421_OCP_DEB_SEL_16MS		0x04
+#define HI6421_OCP_DEB_SEL_32MS		0x08
+#define HI6421_OCP_DEB_SEL_64MS		0x0C
+#define HI6421_OCP_EN_DEBOUNCE_MASK	0x02
+#define HI6421_OCP_EN_DEBOUNCE_ENABLE	0x02
+#define HI6421_OCP_AUTO_STOP_MASK	0x01
+#define HI6421_OCP_AUTO_STOP_ENABLE	0x01
+
+struct hi6421_pmic {
+	struct regmap		*regmap;
+};
+
+#endif		/* __HI6421_PMIC_H */