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Message-ID: <74d0deb30907311003offfc1el7c2a28cdb23cb388@mail.gmail.com>
Date: Fri, 31 Jul 2009 19:03:28 +0200
From: pHilipp Zabel <philipp.zabel@...il.com>
To: Roger Quadros <quadros.roger@...il.com>
Cc: broonie@...nsource.wolfsonmicro.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] regulator: Add GPIO enable control to fixed voltage
regulator driver
On Fri, Jul 31, 2009 at 6:19 PM, Roger Quadros<quadros.roger@...il.com> wrote:
> From: Roger Quadros <ext-roger.quadros@...ia.com>
>
> Now fixed regulators that have their enable pin connected to a GPIO line
> can use the fixed regulator driver. The GPIO number and polarity
> information is passed through platform data. GPIO enable control
> is acheived using gpiolib.
>
> Signed-off-by: Roger Quadros <ext-roger.quadros@...ia.com>
> Reviewed-by: Mark Brown <broonie@...nsource.wolfsonmicro.com>
> Reviewed-by: Philipp Zabel <philipp.zabel@...il.com>
>
> ---
> drivers/regulator/fixed.c | 66 +++++++++++++++++++++++++++++++++++++-
> include/linux/regulator/fixed.h | 17 ++++++++++
> 2 files changed, 81 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/regulator/fixed.c b/drivers/regulator/fixed.c
> index cdc674f..bcebb0c 100644
> --- a/drivers/regulator/fixed.c
> +++ b/drivers/regulator/fixed.c
> @@ -20,20 +20,50 @@
> #include <linux/platform_device.h>
> #include <linux/regulator/driver.h>
> #include <linux/regulator/fixed.h>
> +#include <linux/gpio.h>
>
> struct fixed_voltage_data {
> struct regulator_desc desc;
> struct regulator_dev *dev;
> int microvolts;
> + int gpio;
> + int enable_high;
> + int is_enabled;
> };
>
> static int fixed_voltage_is_enabled(struct regulator_dev *dev)
> {
> - return 1;
> + struct fixed_voltage_data *data = rdev_get_drvdata(dev);
> +
> + if (data->gpio)
if (gpio_is_valid(data->gpio))
> + return data->is_enabled;
> + else
> + return 1;
> }
Or this function could just unconditionally return data->is_enabled if
you set it to 1 in _probe for gpio-less regulators.
>
> static int fixed_voltage_enable(struct regulator_dev *dev)
> {
> + struct fixed_voltage_data *data = rdev_get_drvdata(dev);
> +
> + if (data->gpio) {
if (gpio_is_valid(data->gpio)) {
> + gpio_set_value(data->gpio,
> + data->enable_high ? 1 : 0);
> + data->is_enabled = 1;
> + }
> +
> + return 0;
> +}
> +
> +static int fixed_voltage_disable(struct regulator_dev *dev)
> +{
> + struct fixed_voltage_data *data = rdev_get_drvdata(dev);
> +
> + if (data->gpio) {
> + gpio_set_value(data->gpio,
> + data->enable_high ? 0 : 1);
> + data->is_enabled = 0;
> + }
> +
> return 0;
> }
>
> @@ -58,6 +88,7 @@ static int fixed_voltage_list_voltage(struct regulator_dev *dev,
> static struct regulator_ops fixed_voltage_ops = {
> .is_enabled = fixed_voltage_is_enabled,
> .enable = fixed_voltage_enable,
> + .disable = fixed_voltage_disable,
> .get_voltage = fixed_voltage_get_voltage,
> .list_voltage = fixed_voltage_list_voltage,
> };
> @@ -85,12 +116,37 @@ static int regulator_fixed_voltage_probe(struct platform_device *pdev)
> drvdata->desc.n_voltages = 1;
>
> drvdata->microvolts = config->microvolts;
> + if (config->gpio) {
That should be more like
if (gpio_is_valid(config->gpio) && config->gpio) {
People are going to set config->gpio to negative values to disable the gpio.
(And I think eventually GPIO0 should be allowed here.)
> + drvdata->gpio = config->gpio;
> + drvdata->enable_high = config->enable_high;
> +
> + ret = gpio_request(config->gpio,
> + config->supply_name);
> + if (ret) {
> + dev_err(&pdev->dev, "Could not obtain regulator"
> + "enable GPIO %d: %d\n", config->gpio, ret);
> + goto err_name;
> + }
> +
> + /* set output direction without changing state
> + * to prevent glitch
> + */
> + ret = gpio_get_value(config->gpio);
> + ret = gpio_direction_output(config->gpio, ret);
> + if (ret) {
> + dev_err(&pdev->dev, "Could not configure "
> + "enable GPIO %d direction: %d\n",
> + config->gpio, ret);
> + goto err_gpio;
> + }
> + } else
> + dev_warn(&pdev->dev, "Not using GPIO 0 for enable control\n");
>
> drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
> config->init_data, drvdata);
> if (IS_ERR(drvdata->dev)) {
> ret = PTR_ERR(drvdata->dev);
> - goto err_name;
> + goto err_gpio;
> }
>
> platform_set_drvdata(pdev, drvdata);
> @@ -100,6 +156,9 @@ static int regulator_fixed_voltage_probe(struct platform_device *pdev)
>
> return 0;
>
> +err_gpio:
> + if (config->gpio)
> + gpio_free(config->gpio);
gpio_is_valid(config->gpio)
> err_name:
> kfree(drvdata->desc.name);
> err:
> @@ -115,6 +174,9 @@ static int regulator_fixed_voltage_remove(struct platform_device *pdev)
> kfree(drvdata->desc.name);
> kfree(drvdata);
>
> + if (drvdata->gpio)
> + gpio_free(drvdata->gpio);
> +
dito
> return 0;
> }
>
> diff --git a/include/linux/regulator/fixed.h b/include/linux/regulator/fixed.h
> index 91b4da3..b40e06b 100644
> --- a/include/linux/regulator/fixed.h
> +++ b/include/linux/regulator/fixed.h
> @@ -16,9 +16,26 @@
>
> struct regulator_init_data;
>
> +/**
> + * struct fixed_voltage_config - fixed_voltage_config structure
> + * @supply_name: Name of the regulator supply
> + * @microvolts: Output voltage of regulator
> + * @use_gpio_control: Use GPIO enable control
> + * @gpio: GPIO to use for enable control
> + * @enable_high: Polarity of enable GPIO
> + * 1 = Active high, 0 = Active low
> + * @init_data: regulator_init_data
> + *
> + * This structure contains fixed voltage regulator configuration
> + * information that must be passed by platform code to the fixed
> + * voltage regulator driver.
> + */
> struct fixed_voltage_config {
> const char *supply_name;
> int microvolts;
> + int use_gpio_control;
You wanted to drop that, it's not used anymore.
> + int gpio;
> + int enable_high;
> struct regulator_init_data *init_data;
> };
>
> --
> 1.6.0.4
>
>
regards
Philipp
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