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| /openbmc/linux/arch/arm64/boot/dts/qcom/ |
| H A D | sc7180-trogdor.dtsi | 9506a366 Fri Dec 09 11:12:37 CST 2022 Douglas Anderson <dianders@chromium.org> arm64: dts: qcom: sc7180: Bump up trogdor ts_reset_l drive strength
On at least one board (pazquel360) the reset line for the touchscreen
was scoped and found to take almost 2 ms to fall when we drove it
low. This wasn't great because the Linux driver for the touchscreen
(the elants_i2c driver) thinks it can do a 500 us reset pulse. If we
bump the drive strength to 8 mA then the reset line went down in ~421
us.
NOTE: we could apply this fix just for pazquel360, but:
* Probably other trogdor devices have similar timings and it's just
that nobody has noticed it before.
* There are other trogdor boards using the same elan driver that tries
to do 500 us reset pulses.
* Bumping the drive strength to 8mA across the board won't hurt. This
isn't a high speed signal or anything.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20221209091234.v3.1.I39c387f1e3176fcf340039ec12d54047de9f8526@changeid
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