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

[Roger Quadros]

Hi Dmitry,

On 06/02/15 18:54, Dmitry Torokhov wrote:
> 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)?
> 

Yes, I'll add a note to set this to -1 for non-OF users.

cheers,
-roger
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