regulator: TPS6238X0: Add tps6238X0 regulator driver

The regulator module consists of 1 DCDC. The output voltage
is configurable and is meant for supply power to the core
voltage of Soc.

Change-Id: Ic62d100a588f7b6f1b30c11fd44a925c97393069
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-on: http://git-master/r/100653
Reviewed-by: Automatic_Commit_Validation_User
Tested-by: Pradeep Goudagunta <pgoudagunta@nvidia.com>
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>

3 files changed, 499 insertions, 0 deletions

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index d3cb8e6ff099..8d7161b3313f 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -345,6 +345,16 @@ config REGULATOR_TPS62360
 	  high-frequency synchronous step down dc-dc converter optimized
 	  for battery-powered portable applications.
 
+config REGULATOR_TPS6238X0
+	tristate "TI TPS623850/TPS623860/TPS623870 Power Regulator"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  This driver supports TPS6238X0 voltage regulator chip. This
+	  regulator is meant for processor core supply. This chip is
+	  high-frequency synchronous step down dc-dc converter optimized
+	  for battery-powered portable applications.
+
 config REGULATOR_AAT2870
 	tristate "AnalogicTech AAT2870 Regulators"
 	depends on MFD_AAT2870_CORE
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 4fc5c3f275ab..7cca6bd64d6c 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_REGULATOR_AB8500)	+= ab8500.o
 obj-$(CONFIG_REGULATOR_DB8500_PRCMU) += db8500-prcmu.o
 obj-$(CONFIG_REGULATOR_TPS65910) += tps65910-regulator.o
 obj-$(CONFIG_REGULATOR_TPS62360) += tps62360-regulator.o
+obj-$(CONFIG_REGULATOR_TPS6238X0) += tps6238x0-regulator.o
 obj-$(CONFIG_REGULATOR_AAT2870) += aat2870-regulator.o
 obj-$(CONFIG_REGULATOR_FAN53555) += fan53555-regulator.o
 ccflags-$(CONFIG_REGULATOR_DEBUG) += -DDEBUG
diff --git a/drivers/regulator/tps6238x0-regulator.c b/drivers/regulator/tps6238x0-regulator.c
new file mode 100644
index 000000000000..880249627ab6
--- /dev/null
+++ b/drivers/regulator/tps6238x0-regulator.c
@@ -0,0 +1,488 @@
+/*
+ * tps6238x0-regulator.c -- TI tps623850/tps623860/tps623870
+ *
+ * Driver for processor core supply tps623850, tps623860 and tps623870
+ *
+ * Copyright (c) 2012, NVIDIA Corporation.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.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.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA
+ * 02111-1307, USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/tps6238x0-regulator.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+/* Register definitions */
+#define REG_VSET0		0
+#define REG_VSET1		1
+#define REG_MODE0		2
+#define REG_MODE1		3
+#define REG_CONTROL		4
+#define REG_EXCEPTION		5
+#define REG_RAMPCTRL		6
+#define REG_IOUT		7
+#define REG_CHIPID		8
+
+#define TPS6238X0_BASE_VOLTAGE	500000
+#define TPS6238X0_N_VOLTAGES	128
+#define TPS6238X0_MAX_VSET	2
+#define TPS6238X0_VOUT_MASK	0x7F
+
+/* tps 6238x0 chip information */
+struct tps6238x0_chip {
+	const char *name;
+	struct device *dev;
+	struct regulator_desc desc;
+	struct regulator_dev *rdev;
+	struct regmap *regmap;
+	int vsel_gpio;
+	int change_uv_per_us;
+	bool en_internal_pulldn;
+	bool en_discharge;
+	bool valid_gpios;
+	int lru_index[TPS6238X0_MAX_VSET];
+	int curr_vset_vsel[TPS6238X0_MAX_VSET];
+	int curr_vset_id;
+};
+
+/*
+ * find_voltage_set_register: Find new voltage configuration register
+ * (VSET) id.
+ * The finding of the new VSET register will be based on the LRU mechanism.
+ * Each VSET register will have different voltage configured . This
+ * Function will look if any of the VSET register have requested voltage set
+ * or not.
+ *     - If it is already there then it will make that register as most
+ *       recently used and return as found so that caller need not to set
+ *       the VSET register but need to set the proper gpios to select this
+ *       VSET register.
+ *     - If requested voltage is not found then it will use the least
+ *       recently mechanism to get new VSET register for new configuration
+ *       and will return not_found so that caller need to set new VSET
+ *       register and then gpios (both).
+ */
+static bool find_voltage_set_register(struct tps6238x0_chip *tps,
+		int req_vsel, int *vset_reg_id)
+{
+	int i;
+	bool found = false;
+	int new_vset_reg = tps->lru_index[1];
+	int found_index = 1;
+	for (i = 0; i < TPS6238X0_MAX_VSET; ++i) {
+		if (tps->curr_vset_vsel[tps->lru_index[i]] == req_vsel) {
+			new_vset_reg = tps->lru_index[i];
+			found_index = i;
+			found = true;
+			goto update_lru_index;
+		}
+	}
+
+update_lru_index:
+	for (i = found_index; i > 0; i--)
+		tps->lru_index[i] = tps->lru_index[i - 1];
+
+	tps->lru_index[0] = new_vset_reg;
+	*vset_reg_id = new_vset_reg;
+	return found;
+}
+
+static int tps6238x0_get_voltage_sel(struct regulator_dev *dev)
+{
+	struct tps6238x0_chip *tps = rdev_get_drvdata(dev);
+	unsigned int data;
+	int ret;
+
+	ret = regmap_read(tps->regmap, REG_VSET0 + tps->curr_vset_id, &data);
+	if (ret < 0) {
+		dev_err(tps->dev, "%s: Error in reading register %d\n",
+			__func__, REG_VSET0 + tps->curr_vset_id);
+		return ret;
+	}
+	return data & TPS6238X0_VOUT_MASK;
+}
+
+static int tps6238x0_set_voltage(struct regulator_dev *dev,
+	     int min_uV, int max_uV, unsigned *selector)
+{
+	struct tps6238x0_chip *tps = rdev_get_drvdata(dev);
+	int vsel;
+	int ret;
+	bool found = false;
+	int new_vset_id = tps->curr_vset_id;
+
+	if (min_uV >
+		((TPS6238X0_BASE_VOLTAGE + (TPS6238X0_N_VOLTAGES - 1) * 10000)))
+		return -EINVAL;
+
+	if ((max_uV < min_uV) || (max_uV < TPS6238X0_BASE_VOLTAGE))
+		return -EINVAL;
+
+	vsel = DIV_ROUND_UP(min_uV - TPS6238X0_BASE_VOLTAGE, 10000);
+	if (selector)
+		*selector = (vsel & TPS6238X0_VOUT_MASK);
+
+	/*
+	 * If gpios are available to select the VSET register then least
+	 * recently used register for new configuration.
+	 */
+	if (tps->valid_gpios)
+		found = find_voltage_set_register(tps, vsel, &new_vset_id);
+
+	if (!found) {
+		ret = regmap_update_bits(tps->regmap, REG_VSET0 + new_vset_id,
+				TPS6238X0_VOUT_MASK, vsel);
+		if (ret < 0) {
+			dev_err(tps->dev, "%s: Error in updating register %d\n",
+				 __func__, REG_VSET0 + new_vset_id);
+			return ret;
+		}
+		tps->curr_vset_id = new_vset_id;
+		tps->curr_vset_vsel[new_vset_id] = vsel;
+	}
+
+	/* Select proper VSET register vio gpios */
+	if (tps->valid_gpios)
+		gpio_set_value_cansleep(tps->vsel_gpio, new_vset_id & 0x1);
+	return 0;
+}
+
+static int tps6238x0_list_voltage(struct regulator_dev *dev,
+			unsigned selector)
+{
+	struct tps6238x0_chip *tps = rdev_get_drvdata(dev);
+
+	if ((selector < 0) || (selector >= tps->desc.n_voltages))
+		return -EINVAL;
+
+	return TPS6238X0_BASE_VOLTAGE + selector * 10000;
+}
+
+static int tps6238x0_regulator_enable_time(struct regulator_dev *rdev)
+{
+	return 300;
+}
+
+static int tps6238x0_set_voltage_time_sel(struct regulator_dev *rdev,
+		unsigned int old_selector, unsigned int new_selector)
+{
+	struct tps6238x0_chip *tps = rdev_get_drvdata(rdev);
+	int old_uV, new_uV;
+	old_uV = tps6238x0_list_voltage(rdev, old_selector);
+
+	if (old_uV < 0)
+		return old_uV;
+
+	new_uV = tps6238x0_list_voltage(rdev, new_selector);
+	if (new_uV < 0)
+		return new_uV;
+
+	return DIV_ROUND_UP(abs(old_uV - new_uV),
+				tps->change_uv_per_us);
+}
+
+static int tps6238x0_is_enable(struct regulator_dev *rdev)
+{
+	struct tps6238x0_chip *tps = rdev_get_drvdata(rdev);
+	unsigned int data;
+	int ret;
+
+	ret = regmap_read(tps->regmap, REG_VSET0 + tps->curr_vset_id, &data);
+	if (ret < 0) {
+		dev_err(tps->dev, "%s: Error in reading register %d\n",
+			__func__, REG_VSET0 + tps->curr_vset_id);
+		return ret;
+	}
+	return !!(data & BIT(7));
+}
+
+static int tps6238x0_enable(struct regulator_dev *rdev)
+{
+	struct tps6238x0_chip *tps = rdev_get_drvdata(rdev);
+	int ret;
+	int i;
+
+	/* Enable required VSET configuration */
+	for (i = 0; i < TPS6238X0_MAX_VSET; ++i) {
+		unsigned int en = 0;
+		if (tps->valid_gpios || (i == tps->curr_vset_id))
+			en = BIT(7);
+
+		ret = regmap_update_bits(tps->regmap, REG_VSET0 + i,
+				BIT(7), en);
+		if (ret < 0) {
+			dev_err(tps->dev, "%s() fails in updating reg %d\n",
+					__func__, REG_VSET0 + i);
+			return ret;
+		}
+	}
+	return ret;
+}
+
+static int tps6238x0_disable(struct regulator_dev *rdev)
+{
+	struct tps6238x0_chip *tps = rdev_get_drvdata(rdev);
+	int ret;
+	int i;
+
+	/* Disable required VSET configuration */
+	for (i = 0; i < TPS6238X0_MAX_VSET; ++i) {
+		ret = regmap_update_bits(tps->regmap, REG_VSET0 + i,
+				BIT(7), 0);
+		if (ret < 0) {
+			dev_err(tps->dev, "%s() fails in updating reg %d\n",
+					__func__, REG_VSET0 + i);
+			return ret;
+		}
+	}
+	return ret;
+}
+
+static struct regulator_ops tps6238x0_ops = {
+	.is_enabled		= tps6238x0_is_enable,
+	.enable			= tps6238x0_enable,
+	.disable		= tps6238x0_disable,
+	.enable_time		= tps6238x0_regulator_enable_time,
+	.set_voltage_time_sel	= tps6238x0_set_voltage_time_sel,
+	.get_voltage_sel	= tps6238x0_get_voltage_sel,
+	.set_voltage		= tps6238x0_set_voltage,
+	.list_voltage		= tps6238x0_list_voltage,
+};
+
+static int __devinit tps6238x0_configure(struct tps6238x0_chip *tps,
+		struct tps6238x0_regulator_platform_data *pdata)
+{
+	int ret;
+	int i;
+
+	/* Initailize internal pull up/down control */
+	if (tps->en_internal_pulldn)
+		ret = regmap_write(tps->regmap, REG_CONTROL, 0xC0);
+	else
+		ret = regmap_write(tps->regmap, REG_CONTROL, 0x0);
+	if (ret < 0) {
+		dev_err(tps->dev, "%s() fails in writing reg %d\n",
+			__func__, REG_CONTROL);
+		return ret;
+	}
+
+	/* Enable required VSET configuration */
+	for (i = 0; i < TPS6238X0_MAX_VSET; ++i) {
+		unsigned int en = 0;
+		if (tps->valid_gpios || (i == tps->curr_vset_id))
+			en = BIT(7);
+
+		ret = regmap_update_bits(tps->regmap, REG_VSET0 + i,
+				BIT(7), en);
+		if (ret < 0) {
+			dev_err(tps->dev, "%s() fails in updating reg %d\n",
+					__func__, REG_VSET0 + i);
+			return ret;
+		}
+	}
+
+	/* Reset output discharge path to reduce power consumption */
+	ret = regmap_update_bits(tps->regmap, REG_RAMPCTRL, BIT(2), 0);
+	if (ret < 0)
+		dev_err(tps->dev, "%s() fails in updating reg %d\n",
+			__func__, REG_RAMPCTRL);
+	tps->change_uv_per_us = 312;
+	return ret;
+}
+
+static const struct regmap_config tps6238x0_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = REG_CHIPID,
+	.num_reg_defaults_raw = REG_CHIPID + 1,
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static int __devinit tps6238x0_probe(struct i2c_client *client,
+				     const struct i2c_device_id *id)
+{
+	struct tps6238x0_regulator_platform_data *pdata;
+	struct regulator_dev *rdev;
+	struct tps6238x0_chip *tps;
+	int ret;
+	int i;
+
+	pdata = client->dev.platform_data;
+	if (!pdata) {
+		dev_err(&client->dev, "%s() Err: Platform data not found\n",
+						__func__);
+		return -EIO;
+	}
+
+	tps = devm_kzalloc(&client->dev, sizeof(*tps), GFP_KERNEL);
+	if (!tps) {
+		dev_err(&client->dev, "%s() Err: Memory allocation fails\n",
+						__func__);
+		return -ENOMEM;
+	}
+
+	tps->en_discharge = pdata->en_discharge;
+	tps->en_internal_pulldn = pdata->en_internal_pulldn;
+	tps->vsel_gpio = pdata->vsel_gpio;
+	tps->dev = &client->dev;
+
+	tps->desc.name = id->name;
+	tps->desc.id = 0;
+	tps->desc.n_voltages = TPS6238X0_N_VOLTAGES;
+	tps->desc.ops = &tps6238x0_ops;
+	tps->desc.type = REGULATOR_VOLTAGE;
+	tps->desc.owner = THIS_MODULE;
+	tps->regmap = devm_regmap_init_i2c(client, &tps6238x0_regmap_config);
+	if (IS_ERR(tps->regmap)) {
+		ret = PTR_ERR(tps->regmap);
+		dev_err(&client->dev, "%s() Err: Failed to allocate register"
+			"map: %d\n", __func__, ret);
+		return ret;
+	}
+	i2c_set_clientdata(client, tps);
+
+	tps->curr_vset_id = (pdata->vsel_def_state & 1);
+	tps->lru_index[0] = tps->curr_vset_id;
+	tps->valid_gpios = false;
+
+	if (gpio_is_valid(tps->vsel_gpio)) {
+		int gpio_flag;
+		gpio_flag = (tps->curr_vset_id) ?
+				GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
+		ret = gpio_request_one(tps->vsel_gpio,
+					gpio_flag, "tps6238x0-vsel0");
+		if (ret) {
+			dev_err(&client->dev,
+				"Err: Could not obtain vsel GPIO %d: %d\n",
+						tps->vsel_gpio, ret);
+			return ret;
+		}
+		tps->valid_gpios = true;
+
+		/*
+		 * Initialize the lru index with vset_reg id
+		 * The index 0 will be most recently used and
+		 * set with the tps->curr_vset_id */
+		for (i = 0; i < TPS6238X0_MAX_VSET; ++i)
+			tps->lru_index[i] = i;
+		tps->lru_index[0] = tps->curr_vset_id;
+		tps->lru_index[tps->curr_vset_id] = 0;
+	}
+
+	ret = tps6238x0_configure(tps, pdata);
+	if (ret < 0) {
+		dev_err(tps->dev, "%s() Err: Init fails with = %d\n",
+				__func__, ret);
+		goto err_init;
+	}
+
+	/* Register the regulators */
+	rdev = regulator_register(&tps->desc, &client->dev,
+				pdata->init_data, tps);
+	if (IS_ERR(rdev)) {
+		dev_err(tps->dev, "%s() Err: Failed to register %s\n",
+				__func__, id->name);
+		ret = PTR_ERR(rdev);
+		goto err_init;
+	}
+
+	tps->rdev = rdev;
+	return 0;
+
+err_init:
+	if (gpio_is_valid(tps->vsel_gpio))
+		gpio_free(tps->vsel_gpio);
+
+	return ret;
+}
+
+/**
+ * tps6238x0_remove - tps62360 driver i2c remove handler
+ * @client: i2c driver client device structure
+ *
+ * Unregister TPS driver as an i2c client device driver
+ */
+static int __devexit tps6238x0_remove(struct i2c_client *client)
+{
+	struct tps6238x0_chip *tps = i2c_get_clientdata(client);
+
+	if (gpio_is_valid(tps->vsel_gpio))
+		gpio_free(tps->vsel_gpio);
+
+	regulator_unregister(tps->rdev);
+	return 0;
+}
+
+static void tps6238x0_shutdown(struct i2c_client *client)
+{
+	struct tps6238x0_chip *tps = i2c_get_clientdata(client);
+	int st;
+
+	if (!tps->en_discharge)
+		return;
+
+	/* Configure the output discharge path */
+	st = regmap_update_bits(tps->regmap, REG_RAMPCTRL, BIT(2), BIT(2));
+	if (st < 0)
+		dev_err(tps->dev, "%s() fails in updating reg %d\n",
+			__func__, REG_RAMPCTRL);
+}
+
+static const struct i2c_device_id tps6238x0_id[] = {
+	{.name = "tps623850", },
+	{.name = "tps623860", },
+	{.name = "tps623870", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(i2c, tps6238x0_id);
+
+static struct i2c_driver tps6238x0_i2c_driver = {
+	.driver = {
+		.name = "tps6238x0",
+		.owner = THIS_MODULE,
+	},
+	.probe = tps6238x0_probe,
+	.remove = __devexit_p(tps6238x0_remove),
+	.shutdown = tps6238x0_shutdown,
+	.id_table = tps6238x0_id,
+};
+
+static int __init tps6238x0_init(void)
+{
+	return i2c_add_driver(&tps6238x0_i2c_driver);
+}
+subsys_initcall(tps6238x0_init);
+
+static void __exit tps6238x0_cleanup(void)
+{
+	i2c_del_driver(&tps6238x0_i2c_driver);
+}
+module_exit(tps6238x0_cleanup);
+
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_DESCRIPTION("TPS623850/TPS623860/TPS623870 voltage regulator driver");
+MODULE_LICENSE("GPL v2");