Re: [PATCH] Input: pixcir_i2c_ts - Add RESET gpio

[Dmitry Torokhov]

Hi Roger,

On Fri, Feb 06, 2015 at 02:53:10PM +0200, Roger Quadros wrote:
> The controller has a RESET pin which is usually controlled over
> a GPIO line. If such a GPIO is provided, perform a RESET
> during probe.
> 
> Signed-off-by: Roger Quadros <rogerq@xxxxxx>
> ---
>  .../bindings/input/touchscreen/pixcir_i2c_ts.txt   |  3 ++
>  drivers/input/touchscreen/pixcir_i2c_ts.c          | 37 ++++++++++++++++++++--
>  include/linux/input/pixcir_ts.h                    |  1 +
>  3 files changed, 38 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt
> index 6e55109..8eb240a 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/pixcir_i2c_ts.txt
> @@ -8,6 +8,9 @@ Required properties:
>  - touchscreen-size-x: horizontal resolution of touchscreen (in pixels)
>  - touchscreen-size-y: vertical resolution of touchscreen (in pixels)
>  
> +Optional properties:
> +- reset-gpio: GPIO connected to the RESET line of the chip
> +
>  Example:
>  
>  	i2c@00000000 {
> diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
> index 4fb5537..610ce0b 100644
> --- a/drivers/input/touchscreen/pixcir_i2c_ts.c
> +++ b/drivers/input/touchscreen/pixcir_i2c_ts.c
> @@ -51,6 +51,19 @@ struct pixcir_report_data {
>  	struct pixcir_touch touches[PIXCIR_MAX_SLOTS];
>  };
>  
> +static void pixcir_reset(struct pixcir_i2c_ts_data *tsdata)
> +{
> +	const struct pixcir_ts_platform_data *pdata = tsdata->pdata;
> +
> +	if (gpio_is_valid(pdata->gpio_reset)) {
> +		gpio_set_value(pdata->gpio_reset, 1);
> +		ndelay(80);
> +		gpio_set_value(pdata->gpio_reset, 0);
> +		/* wait as controller might not immediately respond */
> +		msleep(100);
> +	}
> +}
> +
>  static void pixcir_ts_parse(struct pixcir_i2c_ts_data *tsdata,
>  			    struct pixcir_report_data *report)
>  {
> @@ -428,7 +441,8 @@ static struct pixcir_ts_platform_data *pixcir_parse_dt(struct device *dev)
>  	pdata->chip = *(const struct pixcir_i2c_chip_data *)match->data;
>  
>  	pdata->gpio_attb = of_get_named_gpio(np, "attb-gpio", 0);
> -	/* gpio_attb validity is checked in probe */
> +	pdata->gpio_reset = of_get_named_gpio(np, "reset-gpio", 0);
> +	/* gpio validity is checked in probe */
>  
>  	if (of_property_read_u32(np, "touchscreen-size-x", &pdata->x_max)) {
>  		dev_err(dev, "Failed to get touchscreen-size-x property\n");
> @@ -442,8 +456,9 @@ static struct pixcir_ts_platform_data *pixcir_parse_dt(struct device *dev)
>  	}
>  	pdata->y_max -= 1;
>  
> -	dev_dbg(dev, "%s: x %d, y %d, gpio %d\n", __func__,
> -		pdata->x_max + 1, pdata->y_max + 1, pdata->gpio_attb);
> +	dev_dbg(dev, "%s: x %d, y %d, ATTB gpio %d, RESET gpio %d\n", __func__,
> +		pdata->x_max + 1, pdata->y_max + 1, pdata->gpio_attb,
> +		pdata->gpio_reset);
>  
>  	return pdata;
>  }
> @@ -481,6 +496,10 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
>  		return -EINVAL;
>  	}
>  
> +	/* RESET gpio is optional */
> +	if (!gpio_is_valid(pdata->gpio_reset))
> +		dev_info(dev, "Invalid gpio_reset in pdata\n");
> +
>  	if (!pdata->chip.max_fingers) {
>  		dev_err(dev, "Invalid max_fingers in pdata\n");
>  		return -EINVAL;
> @@ -530,6 +549,16 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
>  
>  	input_set_drvdata(input, tsdata);
>  
> +	if (gpio_is_valid(pdata->gpio_reset)) {
> +		error = devm_gpio_request_one(dev, pdata->gpio_reset,
> +					      GPIOF_OUT_INIT_LOW,
> +					      "pixcir_i2c_reset");
> +		if (error) {
> +			dev_err(dev, "Failed to request RESET gpio\n");
> +			return error;
> +		}
> +	}
> +
>  	error = devm_gpio_request_one(dev, pdata->gpio_attb,
>  				      GPIOF_DIR_IN, "pixcir_i2c_attb");
>  	if (error) {
> @@ -545,6 +574,8 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
>  		return error;
>  	}
>  
> +	pixcir_reset(tsdata);
> +
>  	/* Always be in IDLE mode to save power, device supports auto wake */
>  	error = pixcir_set_power_mode(tsdata, PIXCIR_POWER_IDLE);
>  	if (error) {
> diff --git a/include/linux/input/pixcir_ts.h b/include/linux/input/pixcir_ts.h
> index 7bae83b..9e91fd3 100644
> --- a/include/linux/input/pixcir_ts.h
> +++ b/include/linux/input/pixcir_ts.h
> @@ -58,6 +58,7 @@ struct pixcir_ts_platform_data {
>  	int x_max;
>  	int y_max;
>  	int gpio_attb;		/* GPIO connected to ATTB line */
> +	int gpio_reset;		/* GPIO connected to RESET line */
>  	struct pixcir_i2c_chip_data chip;

Declaring gpio_reset like this means that non-OF platforms will have it
as 0, which is usually a valid gpio number, which means they'll get a
nasty surprise when they update the driver.

Maybe we should add a flag, or at least document that it should be set
to -1 if not available (since I do not see non-OF users in the tree)?

Thanks.

-- 
Dmitry
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