On 5/18/22 21:09, Dmitry Torokhov wrote:
On Wed, May 18, 2022 at 06:34:30PM +0200, Marek Vasut wrote:
According to Ilitek "231x & ILI251x Programming Guide" Version: 2.30 "2.1. Power Sequence", "T4 Chip Reset and discharge time" is minimum 10ms and "T2 Chip initial time" is maximum 150ms. Adjust the reset timings such that T4 is 15ms and T2 is 160ms to fit those figures.
This prevents sporadic touch controller start up failures when some systems with at least ILI251x controller boot, without this patch the systems sometimes fail to communicate with the touch controller.
Fixes: 201f3c803544c ("Input: ili210x - add reset GPIO support") Signed-off-by: Marek Vasut marex@denx.de Cc: Dmitry Torokhov dmitry.torokhov@gmail.com
drivers/input/touchscreen/ili210x.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/input/touchscreen/ili210x.c b/drivers/input/touchscreen/ili210x.c index 2bd407d86bae5..131cb648a82ae 100644 --- a/drivers/input/touchscreen/ili210x.c +++ b/drivers/input/touchscreen/ili210x.c @@ -951,9 +951,9 @@ static int ili210x_i2c_probe(struct i2c_client *client, if (error) return error;
usleep_range(50, 100);
msleep(15);WARNING: msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.rst #38: FILE: drivers/input/touchscreen/ili210x.c:954:
msleep(15);
Sigh, yes, fixed in V2 to be 12..15ms .
Should this be usleep_range(10000, 15000) like in ili251x_hardware_reset()? Actually, should we adopt ili251x_hardware_reset() to be used there?
I'll send a separate patch for that, it is indeed a good idea, but I think we should keep the fix as simple as possible for backporting ?