Messages in this thread | | | From | Doug Anderson <> | Date | Sun, 7 Apr 2024 20:18:10 -0700 | Subject | Re: [PATCH v2] HID: i2c-hid: wait for i2c touchpad deep-sleep to power-up transition |
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Hi,
On Fri, Apr 5, 2024 at 3:24 AM Lukasz Majczak <lma@chromium.org> wrote: > > This patch extends the early bailout for probing procedure introduced in > commit b3a81b6c4fc6 ("HID: i2c-hid: check if device is there before > really probing"), in order to cover devices > based on STM microcontrollers. For touchpads based on STM uC, > the probe sequence needs to take into account the increased response time > for i2c transaction if the device already entered a deep power state. > STM specify the wakeup time as 400us between positive strobe of > the clock line. Deep sleep is controlled by Touchpad FW, > though some devices enter it pretty early to conserve power > in case of lack of activity on the i2c bus. > Failing to follow this requirement will result in touchpad device not being > detected due initial transaction being dropped by STM i2c slave controller. > By adding additional try, first transaction will wake up the touchpad > STM controller, and the second will produce proper detection response. > > v1->v2: > * Updated commit message with short sha of a base commit and proper tags > * Rearranged while loop to perform check only once > * Loosened sleeping range > > Co-developed-by: Radoslaw Biernacki <rad@chromium.org> > Signed-off-by: Radoslaw Biernacki <rad@chromium.org> > Signed-off-by: Lukasz Majczak <lma@chromium.org> > --- > drivers/hid/i2c-hid/i2c-hid-core.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-)
As per my review comments in response to your v1 [1], this seems reasonable to me.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
[1] https://lore.kernel.org/r/20240325105452.529921-1-lma@chromium.org
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