[U-Boot] [PATCH v2] power: regulator: Add support for gpio regulators

[Keerthy]

Add support for gpio regulators. As of now this driver caters
to gpio regulators with one gpio. Supports setting voltage values to gpio
regulators and retrieving the values.

Signed-off-by: Keerthy <j-keerthy at ti.com>
---

Changes in v2:

  * Added states and voltages as part of plat data to have
    a generic state to voltage mapping removing any assumptions.

 drivers/power/regulator/Kconfig          |   8 ++
 drivers/power/regulator/Makefile         |   1 +
 drivers/power/regulator/gpio-regulator.c | 137 +++++++++++++++++++++++++++++++
 include/power/regulator.h                |   1 +
 4 files changed, 147 insertions(+)
 create mode 100644 drivers/power/regulator/gpio-regulator.c

diff --git a/drivers/power/regulator/Kconfig b/drivers/power/regulator/Kconfig
index 2510474..4776011 100644
--- a/drivers/power/regulator/Kconfig
+++ b/drivers/power/regulator/Kconfig
@@ -58,6 +58,14 @@ config DM_REGULATOR_FIXED
 	features for fixed value regulators. The driver implements get/set api
 	for enable and get only for voltage value.
 
+config DM_REGULATOR_GPIO
+	bool "Enable Driver Model for GPIO REGULATOR"
+	depends on DM_REGULATOR
+	---help---
+	This config enables implementation of driver-model regulator uclass
+	features for gpio regulators. The driver implements get/set for
+	voltage value.
+
 config REGULATOR_RK808
 	bool "Enable driver for RK808 regulators"
 	depends on DM_REGULATOR && PMIC_RK808
diff --git a/drivers/power/regulator/Makefile b/drivers/power/regulator/Makefile
index 2093048..2d350cb 100644
--- a/drivers/power/regulator/Makefile
+++ b/drivers/power/regulator/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_REGULATOR_ACT8846) += act8846.o
 obj-$(CONFIG_DM_REGULATOR_MAX77686) += max77686.o
 obj-$(CONFIG_DM_REGULATOR_PFUZE100) += pfuze100.o
 obj-$(CONFIG_$(SPL_)DM_REGULATOR_FIXED) += fixed.o
+obj-$(CONFIG_$(SPL_)DM_REGULATOR_GPIO) += gpio-regulator.o
 obj-$(CONFIG_REGULATOR_RK808) += rk808.o
 obj-$(CONFIG_REGULATOR_S5M8767) += s5m8767.o
 obj-$(CONFIG_DM_REGULATOR_SANDBOX) += sandbox.o
diff --git a/drivers/power/regulator/gpio-regulator.c b/drivers/power/regulator/gpio-regulator.c
new file mode 100644
index 0000000..0a60a9c
--- /dev/null
+++ b/drivers/power/regulator/gpio-regulator.c
@@ -0,0 +1,137 @@
+/*
+ * (C) Copyright 2016 Texas Instruments Incorporated, <www.ti.com>
+ * Keerthy <j-keerthy at ti.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <errno.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm/gpio.h>
+#include <power/pmic.h>
+#include <power/regulator.h>
+
+#define GPIO_REGULATOR_MAX_STATES	2
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct gpio_regulator_platdata {
+	struct gpio_desc gpio; /* GPIO for regulator voltage control */
+	int states[GPIO_REGULATOR_MAX_STATES];
+	int voltages[GPIO_REGULATOR_MAX_STATES];
+};
+
+static int gpio_regulator_ofdata_to_platdata(struct udevice *dev)
+{
+	struct dm_regulator_uclass_platdata *uc_pdata;
+	struct gpio_regulator_platdata *dev_pdata;
+	struct gpio_desc *gpio;
+	const void *blob = gd->fdt_blob;
+	int node = dev->of_offset;
+	int ret, count, i, j;
+	u32 states_array[8];
+
+	dev_pdata = dev_get_platdata(dev);
+	uc_pdata = dev_get_uclass_platdata(dev);
+	if (!uc_pdata)
+		return -ENXIO;
+
+	/* Set type to gpio */
+	uc_pdata->type = REGULATOR_TYPE_GPIO;
+
+	/*
+	 * Get gpio regulator gpio desc
+	 * Assuming one GPIO per regulator.
+	 * Can be extended later to multiple GPIOs
+	 * per gpio-regulator. As of now no instance with multiple
+	 * gpios is presnt
+	 */
+	gpio = &dev_pdata->gpio;
+	ret = gpio_request_by_name(dev, "gpios", 0, gpio, GPIOD_IS_OUT);
+	if (ret)
+		debug("regulator gpio - not found! Error: %d", ret);
+
+	count = fdtdec_get_int_array_count(blob, node, "states",
+					   states_array, 8);
+
+	if (!count)
+		return -EINVAL;
+
+	for (i = 0, j = 0; i < count; i += 2) {
+		dev_pdata->voltages[j] = states_array[i];
+		dev_pdata->states[j] = states_array[i + 1];
+		j++;
+	}
+
+	return 0;
+}
+
+static int gpio_regulator_get_value(struct udevice *dev)
+{
+	struct dm_regulator_uclass_platdata *uc_pdata;
+	struct gpio_regulator_platdata *dev_pdata = dev_get_platdata(dev);
+	int enable;
+
+	if (!dev_pdata->gpio.dev)
+		return -ENOSYS;
+
+	uc_pdata = dev_get_uclass_platdata(dev);
+	if (uc_pdata->min_uV > uc_pdata->max_uV) {
+		debug("Invalid constraints for: %s\n", uc_pdata->name);
+		return -EINVAL;
+	}
+
+	enable = dm_gpio_get_value(&dev_pdata->gpio);
+	if (enable == dev_pdata->states[0])
+		return dev_pdata->voltages[0];
+	else
+		return dev_pdata->voltages[1];
+}
+
+static int gpio_regulator_set_value(struct udevice *dev, int uV)
+{
+	struct gpio_regulator_platdata *dev_pdata = dev_get_platdata(dev);
+	int ret;
+	bool enable;
+
+	if (!dev_pdata->gpio.dev)
+		return -ENOSYS;
+
+	if (uV == dev_pdata->voltages[0])
+		enable = dev_pdata->states[0];
+	else if (uV == dev_pdata->voltages[1])
+		enable = dev_pdata->states[1];
+	else
+		return -EINVAL;
+
+	ret = dm_gpio_set_value(&dev_pdata->gpio, enable);
+	if (ret) {
+		error("Can't set regulator : %s gpio to: %d\n", dev->name,
+		      enable);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct dm_regulator_ops gpio_regulator_ops = {
+	.get_value	= gpio_regulator_get_value,
+	.set_value	= gpio_regulator_set_value,
+};
+
+static const struct udevice_id gpio_regulator_ids[] = {
+	{ .compatible = "regulator-gpio" },
+	{ },
+};
+
+U_BOOT_DRIVER(gpio_regulator) = {
+	.name = "gpio regulator",
+	.id = UCLASS_REGULATOR,
+	.ops = &gpio_regulator_ops,
+	.of_match = gpio_regulator_ids,
+	.ofdata_to_platdata = gpio_regulator_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct gpio_regulator_platdata),
+};
diff --git a/include/power/regulator.h b/include/power/regulator.h
index 8ae6b14..5d327e6 100644
--- a/include/power/regulator.h
+++ b/include/power/regulator.h
@@ -108,6 +108,7 @@ enum regulator_type {
 	REGULATOR_TYPE_BUCK,
 	REGULATOR_TYPE_DVS,
 	REGULATOR_TYPE_FIXED,
+	REGULATOR_TYPE_GPIO,
 	REGULATOR_TYPE_OTHER,
 };
 
-- 
1.9.1