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Date: Fri, 6 Feb 2015 08:54:06 -0800
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
To: Roger Quadros <rogerq@...com>
Cc: rydberg@...math.org, mugunthanvnm@...com, jg1.han@...sung.com,
linux-input@...r.kernel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Input: pixcir_i2c_ts - Add RESET gpio
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@...com>
> ---
> .../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@...00000 {
> 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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