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

[Przemyslaw Marczak <p.marczak@samsung.com>]

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-keerthy@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-keerthy@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@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.marczak at samsung.com