On Mon, Apr 23, 2018 at 01:58:44PM +0200, Sebastian Reichel wrote:
> The current reset-gpio support triggers an interrupt storm on platforms
> using the maxtouch with level based interrupt. The Motorola Droid 4,
> which I used for some of the tests is not affected, since it uses a edge
> based interrupt.
>
> This change avoids the interrupt storm by enabling the device while its
> interrupt is disabled. Afterwards we wait 100ms. This is important for
> two reasons: The device is unresponsive for some time (~22ms for
> mxt224E) and the CHG (interrupt) line is not working properly for 100ms.
> We don't need to wait for any following interrupts, since the following
> mxt_initialize() checks for bootloader mode anyways.
>
> This fixes a boot issue on GE PPD (watchdog kills device due to
> interrupt storm) and does not cause regression on Motorola Droid 4.
>
> Fixes: f657b00df22e ("Input: atmel_mxt_ts - add support for reset line")
> Signed-off-by: Sebastian Reichel <sebastian.reic...@collabora.co.uk>
Applied, thank you.
> ---
> Changes since PATCHv2:
> * fix patch description
> * use same timeout value for soft and gpio-reset
> ---
> drivers/input/touchscreen/atmel_mxt_ts.c | 18 +++++++-----------
> 1 file changed, 7 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c
> b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 5d9699fe1b55..f97fbb0af020 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -194,6 +194,8 @@ enum t100_type {
>
> /* Delay times */
> #define MXT_BACKUP_TIME 50 /* msec */
> +#define MXT_RESET_GPIO_TIME 20 /* msec */
> +#define MXT_RESET_INVALID_CHG 100 /* msec */
> #define MXT_RESET_TIME 200 /* msec */
> #define MXT_RESET_TIMEOUT 3000 /* msec */
> #define MXT_CRC_TIMEOUT 1000 /* msec */
> @@ -1206,7 +1208,7 @@ static int mxt_soft_reset(struct mxt_data *data)
> return ret;
>
> /* Ignore CHG line for 100ms after reset */
> - msleep(100);
> + msleep(MXT_RESET_INVALID_CHG);
>
> mxt_acquire_irq(data);
>
> @@ -3167,20 +3169,14 @@ static int mxt_probe(struct i2c_client *client, const
> struct i2c_device_id *id)
> return error;
> }
>
> + disable_irq(client->irq);
> +
> if (data->reset_gpio) {
> - data->in_bootloader = true;
> - msleep(MXT_RESET_TIME);
> - reinit_completion(&data->bl_completion);
> + msleep(MXT_RESET_GPIO_TIME);
> gpiod_set_value(data->reset_gpio, 1);
> - error = mxt_wait_for_completion(data, &data->bl_completion,
> - MXT_RESET_TIMEOUT);
> - if (error)
> - return error;
> - data->in_bootloader = false;
> + msleep(MXT_RESET_INVALID_CHG);
> }
>
> - disable_irq(client->irq);
> -
> error = mxt_initialize(data);
> if (error)
> return error;
> --
> 2.17.0
>
--
Dmitry
