Hello Keerthy,

On 09/15/2016 10:25 AM, Keerthy wrote:
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-keer...@ti.com>
---
  drivers/power/regulator/Kconfig          |   8 ++
  drivers/power/regulator/Makefile         |   1 +
  drivers/power/regulator/gpio-regulator.c | 136 +++++++++++++++++++++++++++++++
  include/power/regulator.h                |   1 +
  4 files changed, 146 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..9c8832e
--- /dev/null
+++ b/drivers/power/regulator/gpio-regulator.c
@@ -0,0 +1,136 @@
+/*
+ * (C) Copyright 2016 Texas Instruments Incorporated, <www.ti.com>
+ * Keerthy <j-keer...@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>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct gpio_regulator_platdata {
+       struct gpio_desc gpio; /* GPIO for regulator voltage control */
+       int gpio_low_uV;
+       int gpio_high_uV;
+};

The low/high values can be provided by regulator's uclass driver in struct of type "dm_regulator_uclass_platdata", as for other regulators.

But as I can see in the Linux, this driver should provide a structure for the gpio 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;
+       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; i < count; i += 2) {
The below condition is valid for most devices.

In Linux we can find dts for some ARMs in which I can find at least two boards, with inverted meaning of state/voltage, so "0", can be also valid for the high uV.

I think, this driver should keep possible states in platdata.

+               if (states_array[i + 1] == 0)
+                       dev_pdata->gpio_low_uV = states_array[i];
+               else
+                       dev_pdata->gpio_high_uV = states_array[i];
+       }
+
+       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);
The returned value (enable) should be compared to the states kept in platdata.

+       if (enable)
+               return dev_pdata->gpio_high_uV;
+       else
+               return dev_pdata->gpio_low_uV;
+}
+
+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->gpio_high_uV)
+               enable = 1;
+       else if (uV == dev_pdata->gpio_low_uV)
+               enable = 0;
+       else
+               return -EINVAL;
+

And also here you should get the "enable" value from states kept in platdata.

+       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,
  };

Best regards,

--
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marc...@samsung.com

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