After releasing the reset line stmfts_reset() sleeps a fixed 50 ms and
stmfts_power_on() another 50 ms before the first I2C access. That is
enough for a warm reset, but when both supplies were really cut during
system suspend the controller boots from cold and can need longer. If
it does, the first read fails, stmfts_resume() returns an error and the
touchscreen is left powered off with its interrupt disabled.
The controller posts a controller ready event once it has booted, and
the event parser already completes cmd_done on it. Enable the interrupt
right after releasing reset and wait for that event instead of sleeping,
giving the controller 300 ms, the total budget the vendor driver allows.
Boards without a reset line keep the old timing.
Usually phones such as Pixel 4a and Xiaomi Mi 8 needs longer delay, so
without this change touchscreen stops working.
Fixes: 8a1f9de80e45 ("Input: stmfts - add optional reset GPIO support")
Cc: stable@vger.kernel.org
Co-developed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
David Heidelberg
36fa0b8913