linux-kernel - Re: [PATCH 29/38] iio: pressure-core: st: Provide support for the Vdd power supply

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Message-ID: <52349CC2.2060505@kernel.org>
Date:	Sat, 14 Sep 2013 18:28:34 +0100
From:	Jonathan Cameron <jic23@...nel.org>
To:	Lee Jones <lee.jones@...aro.org>
CC:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	arnd@...db.de, linus.walleij@...aro.org, denis.ciocca@...com,
	linux-iio@...r.kernel.org
Subject: Re: [PATCH 29/38] iio: pressure-core: st: Provide support for the
 Vdd power supply

On 09/10/13 13:49, Lee Jones wrote:
> The power to some of the sensors are controlled by regulators. In most
> cases these are 'always on', but if not they will fail to work until
> the regulator is enabled using the relevant APIs. This patch allows for
> the Vdd power supply to be specified by either platform data or Device
> Tree.
> 
> Signed-off-by: Lee Jones <lee.jones@...aro.org>
Fine, will pick up with the rest.  This optional regulator stuff is nice as
it gets around the annoying platform specific callbacks that tend to do stuff
like this.

If anyone is bored, I suspect there are quite a few cases where this makes sense
in other IIO drivers!
> ---
>  drivers/iio/pressure/st_pressure_core.c | 28 ++++++++++++++++++++++++++++
>  include/linux/iio/common/st_sensors.h   |  3 +++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/iio/pressure/st_pressure_core.c b/drivers/iio/pressure/st_pressure_core.c
> index b42614a..d52b487 100644
> --- a/drivers/iio/pressure/st_pressure_core.c
> +++ b/drivers/iio/pressure/st_pressure_core.c
> @@ -23,6 +23,7 @@
>  #include <linux/iio/sysfs.h>
>  #include <linux/iio/trigger.h>
>  #include <linux/iio/buffer.h>
> +#include <linux/regulator/consumer.h>
>  #include <asm/unaligned.h>
>  
>  #include <linux/iio/common/st_sensors.h>
> @@ -313,6 +314,29 @@ static const struct iio_trigger_ops st_press_trigger_ops = {
>  #define ST_PRESS_TRIGGER_OPS NULL
>  #endif
>  
> +void st_press_power_enable(struct iio_dev *indio_dev)
> +{
> +	struct st_sensor_data *pdata = iio_priv(indio_dev);
> +	int err;
> +
> +	/* Regulators not mandatory, but if requested we should enable it. */
> +	pdata->vdd = devm_regulator_get_optional(&indio_dev->dev, "vdd");
> +	if (!IS_ERR(pdata->vdd)) {
> +		err = regulator_enable(pdata->vdd);
> +		if (err != 0)
> +			dev_warn(&indio_dev->dev,
> +				 "Failed to enable specified Vdd supply\n");
> +	}
> +}
> +
> +void st_press_power_disable(struct iio_dev *indio_dev)
> +{
> +	struct st_sensor_data *pdata = iio_priv(indio_dev);
> +
> +	if (!IS_ERR(pdata->vdd))
> +		regulator_disable(pdata->vdd);
> +}
> +
>  int st_press_common_probe(struct iio_dev *indio_dev,
>  				struct st_sensors_platform_data *plat_data)
>  {
> @@ -323,6 +347,8 @@ int st_press_common_probe(struct iio_dev *indio_dev,
>  	indio_dev->modes = INDIO_DIRECT_MODE;
>  	indio_dev->info = &press_info;
>  
> +	st_press_power_enable(indio_dev);
> +
>  	err = st_sensors_check_device_support(indio_dev,
>  					      ARRAY_SIZE(st_press_sensors),
>  					      st_press_sensors);
> @@ -382,6 +408,8 @@ void st_press_common_remove(struct iio_dev *indio_dev)
>  {
>  	struct st_sensor_data *pdata = iio_priv(indio_dev);
>  
> +	st_press_power_disable(indio_dev);
> +
>  	iio_device_unregister(indio_dev);
>  	if (pdata->get_irq_data_ready(indio_dev) > 0) {
>  		st_sensors_deallocate_trigger(indio_dev);
> diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
> index e732fda..968b84e 100644
> --- a/include/linux/iio/common/st_sensors.h
> +++ b/include/linux/iio/common/st_sensors.h
> @@ -16,6 +16,7 @@
>  #include <linux/irqreturn.h>
>  #include <linux/iio/trigger.h>
>  #include <linux/bitops.h>
> +#include <linux/regulator/consumer.h>
>  
>  #include <linux/platform_data/st_sensors_pdata.h>
>  
> @@ -201,6 +202,7 @@ struct st_sensors {
>   * @trig: The trigger in use by the core driver.
>   * @sensor: Pointer to the current sensor struct in use.
>   * @current_fullscale: Maximum range of measure by the sensor.
> + * @vdd: Pointer to sensor's Vdd power supply
>   * @enabled: Status of the sensor (false->off, true->on).
>   * @multiread_bit: Use or not particular bit for [I2C/SPI] multiread.
>   * @buffer_data: Data used by buffer part.
> @@ -216,6 +218,7 @@ struct st_sensor_data {
>  	struct iio_trigger *trig;
>  	struct st_sensors *sensor;
>  	struct st_sensor_fullscale_avl *current_fullscale;
> +	struct regulator *vdd;
>  
>  	bool enabled;
>  	bool multiread_bit;
> 
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