Thread (9 messages) 9 messages, 5 authors, 2020-11-23

Re: [PATCH 1/3 v2] Input: atmel_mxt_ts - Fix up inverted RESET handler

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Date: 2020-11-23 06:49:51
Also in: linux-arm-kernel, linux-samsung-soc, linux-tegra

On Wed, Nov 04, 2020 at 04:30:30PM +0100, Linus Walleij wrote:
This driver uses GPIO descriptors to drive the touchscreen
RESET line. In the existing device trees this has in
conflict with intution been flagged as GPIO_ACTIVE_HIGH
and the driver then applies the reverse action by
driving the line low (setting to 0) to enter
reset state and driving the line high (setting to 1) to
get out of reset state.

The correct way to handle active low GPIO lines is to
provide the GPIO_ACTIVE_LOW in the device tree (thus
properly describing the hardware) and letting the GPIO
framework invert the assertion (driving high) to a low
level and vice versa.

This is considered a bug since the device trees are
incorrectly mis-specifying the line as active high.

Fix the driver and all device trees specifying a reset
line.

Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-tegra@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: NXP Linux Team <redacted>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Signed-off-by: Linus Walleij <redacted>
Applied, thank you.

-- 
Dmitry
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