Re: [PATCH v2] input: touchscreen: silead: Add regulator support

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Wed, Nov 16, 2016 at 12:55:07PM +0100, Hans de Goede wrote:
> On some tablets the touchscreen controller is powered by separate
> regulators, add support for this.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> Acked-by: Rob Herring <robh@kernel.org>
> ---
> Changes in v2:
> -Use devm_regulator_bulk_get() and friends
> -Use devm_add_action_or_reset() to disable the regulator
> ---
>  .../bindings/input/touchscreen/silead_gsl1680.txt  |  2 ++
>  drivers/input/touchscreen/silead.c                 | 29 ++++++++++++++++++++++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> index e844c3f..b726823 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
> @@ -22,6 +22,8 @@ Optional properties:
>  - touchscreen-inverted-y  : See touchscreen.txt
>  - touchscreen-swapped-x-y : See touchscreen.txt
>  - silead,max-fingers	  : maximum number of fingers the touchscreen can detect
> +- vddio-supply		  : regulator phandle for controller VDDIO
> +- avdd-supply		  : regulator phandle for controller AVDD
>  
>  Example:
>  
> diff --git a/drivers/input/touchscreen/silead.c b/drivers/input/touchscreen/silead.c
> index f502c84..404830a 100644
> --- a/drivers/input/touchscreen/silead.c
> +++ b/drivers/input/touchscreen/silead.c
> @@ -29,6 +29,7 @@
>  #include <linux/input/touchscreen.h>
>  #include <linux/pm.h>
>  #include <linux/irq.h>
> +#include <linux/regulator/consumer.h>
>  
>  #include <asm/unaligned.h>
>  
> @@ -73,6 +74,7 @@ struct silead_ts_data {
>  	struct i2c_client *client;
>  	struct gpio_desc *gpio_power;
>  	struct input_dev *input;
> +	struct regulator_bulk_data regulators[2];
>  	char fw_name[64];
>  	struct touchscreen_properties prop;
>  	u32 max_fingers;
> @@ -433,6 +435,13 @@ static int silead_ts_set_default_fw_name(struct silead_ts_data *data,
>  }
>  #endif
>  
> +static void silead_disable_regulator(void *arg)
> +{
> +	struct silead_ts_data *data = arg;
> +
> +	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
> +}
> +
>  static int silead_ts_probe(struct i2c_client *client,
>  			   const struct i2c_device_id *id)
>  {
> @@ -465,6 +474,26 @@ static int silead_ts_probe(struct i2c_client *client,
>  	if (client->irq <= 0)
>  		return -ENODEV;
>  
> +	data->regulators[0].supply = "vddio";
> +	data->regulators[1].supply = "avdd";
> +	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->regulators),
> +					data->regulators);
> +	if (error)
> +		return error;
> +
> +	/*
> +	 * Enable regulators at probe and disable them at remove, we need
> +	 * to keep the chip powered otherwise it forgets its firmware.
> +	 */

Hmm, this burns power though. Why can't we reload firmware on resume (it
should be already cached)? Does it take too long?

Thanks.

> +	error = regulator_bulk_enable(ARRAY_SIZE(data->regulators),
> +				      data->regulators);
> +	if (error)
> +		return error;
> +
> +	error = devm_add_action_or_reset(dev, silead_disable_regulator, data);
> +	if (error)
> +		return error;
> +
>  	/* Power GPIO pin */
>  	data->gpio_power = devm_gpiod_get_optional(dev, "power", GPIOD_OUT_LOW);
>  	if (IS_ERR(data->gpio_power)) {
> -- 
> 2.9.3
> 

-- 
Dmitry