regulator: add pbias regulator support

pbias register controls internal power supply to sd card i/o pads
in most OMAPs (OMAP2-5, DRA7).
Control bits for selecting voltage level and
enabling/disabling are in the same PBIAS register.
Signed-off-by: Balaji T K <balajitk@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Mark Brown <broonie@linaro.org>
Tested-by: Florian Vaussard <florian.vaussard@epfl.ch>
Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Chris Ball <chris@printf.net>

Documentation/devicetree/bindings/regulator/pbias-regulator.txt

+PBIAS internal regulator for SD card dual voltage i/o pads on OMAP SoCs.
+
+Required properties:
+- compatible:
+  - "ti,pbias-omap" for OMAP2, OMAP3, OMAP4, OMAP5, DRA7.
+- reg: pbias register offset from syscon base and size of pbias register.
+- syscon : phandle of the system control module
+- regulator-name : should be
+			pbias_mmc_omap2430 for OMAP2430, OMAP3 SoCs
+			pbias_sim_omap3 for OMAP3 SoCs
+			pbias_mmc_omap4 for OMAP4 SoCs
+			pbias_mmc_omap5 for OMAP5 and DRA7 SoC
+
+Optional properties:
+- Any optional property defined in bindings/regulator/regulator.txt
+
+Example:
+
+		pbias_regulator: pbias_regulator {
+			compatible = "ti,pbias-omap";
+			reg = <0 0x4>;
+			syscon = <&omap5_padconf_global>;
+			pbias_mmc_reg: pbias_mmc_omap5 {
+				regulator-name = "pbias_mmc_omap5";
+				regulator-min-microvolt = <1800000>;
+				regulator-max-microvolt = <3000000>;
+			};

drivers/regulator/Kconfig

@@ -384,6 +384,15 @@ config REGULATOR_PALMAS
 	  on the muxing. This is handled automatically in the driver by
 	  reading the mux info from OTP.
 
+config REGULATOR_PBIAS
+	tristate "PBIAS OMAP regulator driver"
+	depends on (ARCH_OMAP || COMPILE_TEST) && MFD_SYSCON
+	help
+	 Say y here to support pbias regulator for mmc1:SD card i/o
+	 on OMAP SoCs.
+	 This driver provides support for OMAP pbias modelled
+	 regulators.
+
 config REGULATOR_PCAP
 	tristate "Motorola PCAP2 regulator driver"
 	depends on EZX_PCAP

drivers/regulator/Makefile

@@ -54,6 +54,7 @@ obj-$(CONFIG_REGULATOR_MC13XXX_CORE) +=  mc13xxx-regulator-core.o
 obj-$(CONFIG_REGULATOR_PALMAS) += palmas-regulator.o
 obj-$(CONFIG_REGULATOR_PFUZE100) += pfuze100-regulator.o
 obj-$(CONFIG_REGULATOR_TPS51632) += tps51632-regulator.o
+obj-$(CONFIG_REGULATOR_PBIAS) += pbias-regulator.o
 obj-$(CONFIG_REGULATOR_PCAP) += pcap-regulator.o
 obj-$(CONFIG_REGULATOR_PCF50633) += pcf50633-regulator.o
 obj-$(CONFIG_REGULATOR_RC5T583)  += rc5t583-regulator.o

drivers/regulator/pbias-regulator.c

+/*
+ * pbias-regulator.c
+ *
+ * Copyright (C) 2014 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Balaji T K <balajitk@ti.com>
+ *
+ * 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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+struct pbias_reg_info {
+	u32 enable;
+	u32 enable_mask;
+	u32 vmode;
+	unsigned int enable_time;
+	char *name;
+};
+
+struct pbias_regulator_data {
+	struct regulator_desc desc;
+	void __iomem *pbias_addr;
+	unsigned int pbias_reg;
+	struct regulator_dev *dev;
+	struct regmap *syscon;
+	const struct pbias_reg_info *info;
+	int voltage;
+};
+
+static int pbias_regulator_set_voltage(struct regulator_dev *dev,
+			int min_uV, int max_uV, unsigned *selector)
+{
+	struct pbias_regulator_data *data = rdev_get_drvdata(dev);
+	const struct pbias_reg_info *info = data->info;
+	int ret, vmode;
+
+	if (min_uV <= 1800000)
+		vmode = 0;
+	else if (min_uV > 1800000)
+		vmode = info->vmode;
+
+	ret = regmap_update_bits(data->syscon, data->pbias_reg,
+						info->vmode, vmode);
+
+	return ret;
+}
+
+static int pbias_regulator_get_voltage(struct regulator_dev *rdev)
+{
+	struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+	const struct pbias_reg_info *info = data->info;
+	int value, voltage;
+
+	regmap_read(data->syscon, data->pbias_reg, &value);
+	value &= info->vmode;
+
+	voltage = value ? 3000000 : 1800000;
+
+	return voltage;
+}
+
+static int pbias_regulator_enable(struct regulator_dev *rdev)
+{
+	struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+	const struct pbias_reg_info *info = data->info;
+	int ret;
+
+	ret = regmap_update_bits(data->syscon, data->pbias_reg,
+					info->enable_mask, info->enable);
+
+	return ret;
+}
+
+static int pbias_regulator_disable(struct regulator_dev *rdev)
+{
+	struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+	const struct pbias_reg_info *info = data->info;
+	int ret;
+
+	ret = regmap_update_bits(data->syscon, data->pbias_reg,
+						info->enable_mask, 0);
+	return ret;
+}
+
+static int pbias_regulator_is_enable(struct regulator_dev *rdev)
+{
+	struct pbias_regulator_data *data = rdev_get_drvdata(rdev);
+	const struct pbias_reg_info *info = data->info;
+	int value;
+
+	regmap_read(data->syscon, data->pbias_reg, &value);
+
+	return (value & info->enable_mask) == info->enable_mask;
+}
+
+static struct regulator_ops pbias_regulator_voltage_ops = {
+	.set_voltage	= pbias_regulator_set_voltage,
+	.get_voltage	= pbias_regulator_get_voltage,
+	.enable		= pbias_regulator_enable,
+	.disable	= pbias_regulator_disable,
+	.is_enabled	= pbias_regulator_is_enable,
+};
+
+static const struct pbias_reg_info pbias_mmc_omap2430 = {
+	.enable = BIT(1),
+	.enable_mask = BIT(1),
+	.vmode = BIT(0),
+	.enable_time = 100,
+	.name = "pbias_mmc_omap2430"
+};
+
+static const struct pbias_reg_info pbias_sim_omap3 = {
+	.enable = BIT(9),
+	.enable_mask = BIT(9),
+	.vmode = BIT(8),
+	.enable_time = 100,
+	.name = "pbias_sim_omap3"
+};
+
+static const struct pbias_reg_info pbias_mmc_omap4 = {
+	.enable = BIT(26) | BIT(22),
+	.enable_mask = BIT(26) | BIT(25) | BIT(22),
+	.vmode = BIT(21),
+	.enable_time = 100,
+	.name = "pbias_mmc_omap4"
+};
+
+static const struct pbias_reg_info pbias_mmc_omap5 = {
+	.enable = BIT(27) | BIT(26),
+	.enable_mask = BIT(27) | BIT(25) | BIT(26),
+	.vmode = BIT(21),
+	.enable_time = 100,
+	.name = "pbias_mmc_omap5"
+};
+
+static struct of_regulator_match pbias_matches[] = {
+	{ .name = "pbias_mmc_omap2430", .driver_data = (void *)&pbias_mmc_omap2430},
+	{ .name = "pbias_sim_omap3", .driver_data = (void *)&pbias_sim_omap3},
+	{ .name = "pbias_mmc_omap4", .driver_data = (void *)&pbias_mmc_omap4},
+	{ .name = "pbias_mmc_omap5", .driver_data = (void *)&pbias_mmc_omap5},
+};
+#define PBIAS_NUM_REGS	ARRAY_SIZE(pbias_matches)
+
+static const struct of_device_id pbias_of_match[] = {
+	{ .compatible = "ti,pbias-omap", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, pbias_of_match);
+
+static int pbias_regulator_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct pbias_regulator_data *drvdata;
+	struct resource *res;
+	struct regulator_config cfg = { };
+	struct regmap *syscon;
+	const struct pbias_reg_info *info;
+	int ret = 0;
+	int count, idx, data_idx = 0;
+
+	count = of_regulator_match(&pdev->dev, np, pbias_matches,
+						PBIAS_NUM_REGS);
+	if (count < 0)
+		return count;
+
+	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct pbias_regulator_data)
+			       * count, GFP_KERNEL);
+	if (drvdata == NULL) {
+		dev_err(&pdev->dev, "Failed to allocate device data\n");
+		return -ENOMEM;
+	}
+
+	syscon = syscon_regmap_lookup_by_phandle(np, "syscon");
+	if (IS_ERR(syscon))
+		return PTR_ERR(syscon);
+
+	cfg.dev = &pdev->dev;
+
+	for (idx = 0; idx < PBIAS_NUM_REGS && data_idx < count; idx++) {
+		if (!pbias_matches[idx].init_data ||
+			!pbias_matches[idx].of_node)
+			continue;
+
+		info = pbias_matches[idx].driver_data;
+		if (!info)
+			return -ENODEV;
+
+		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+		if (!res)
+			return -EINVAL;
+
+		drvdata[data_idx].pbias_reg = res->start;
+		drvdata[data_idx].syscon = syscon;
+		drvdata[data_idx].info = info;
+		drvdata[data_idx].desc.name = info->name;
+		drvdata[data_idx].desc.owner = THIS_MODULE;
+		drvdata[data_idx].desc.type = REGULATOR_VOLTAGE;
+		drvdata[data_idx].desc.ops = &pbias_regulator_voltage_ops;
+		drvdata[data_idx].desc.n_voltages = 2;
+		drvdata[data_idx].desc.enable_time = info->enable_time;
+
+		cfg.init_data = pbias_matches[idx].init_data;
+		cfg.driver_data = &drvdata[data_idx];
+		cfg.of_node = pbias_matches[idx].of_node;
+
+		drvdata[data_idx].dev = devm_regulator_register(&pdev->dev,
+					&drvdata[data_idx].desc, &cfg);
+		if (IS_ERR(drvdata[data_idx].dev)) {
+			ret = PTR_ERR(drvdata[data_idx].dev);
+			dev_err(&pdev->dev,
+				"Failed to register regulator: %d\n", ret);
+			goto err_regulator;
+		}
+		data_idx++;
+	}
+
+	platform_set_drvdata(pdev, drvdata);
+
+err_regulator:
+	return ret;
+}
+
+static struct platform_driver pbias_regulator_driver = {
+	.probe		= pbias_regulator_probe,
+	.driver		= {
+		.name		= "pbias-regulator",
+		.owner		= THIS_MODULE,
+		.of_match_table = of_match_ptr(pbias_of_match),
+	},
+};
+
+module_platform_driver(pbias_regulator_driver);
+
+MODULE_AUTHOR("Balaji T K <balajitk@ti.com>");
+MODULE_DESCRIPTION("pbias voltage regulator");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pbias-regulator");