linux-kernel - [PATCH] input: goodix: Remove setting of RST pin to input

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Message-ID: <20251007102305.445515-1-martyn.welch@collabora.com>
Date: Tue,  7 Oct 2025 11:23:04 +0100
From: Martyn Welch <martyn.welch@...labora.com>
To: Hans de Goede <hansg@...nel.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: kernel@...labora.com,
	Martyn Welch <martyn.welch@...labora.com>,
	linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] input: goodix: Remove setting of RST pin to input

The reset line is being set to input on non-ACPI devices apparently to
save power. This isn't being done on ACPI devices as it's been found
that some ACPI devices don't have a pull-up resistor fitted. This can
also be the case for non-ACPI devices, resulting in:

[  941.672207] Goodix-TS 1-0014: Error reading 10 bytes from 0x814e: -110
[  942.696168] Goodix-TS 1-0014: Error reading 10 bytes from 0x814e: -110
[  945.832208] Goodix-TS 1-0014: Error reading 10 bytes from 0x814e: -110

This behaviour appears to have been initially introduced in ec6e1b4082d9.
This doesn't seem to be based on information in either the GT911 or GT9271
datasheets cited as sources of information for this change. Thus it seems
likely that it is based on functionality in the Android driver which it
also lists. This behaviour may be viable in very specific instances where
the hardware is known to have a pull-up fitted, but seems unwise in the
upstream kernel where such hardware requirements can't be guaranteed.

Remove this over optimisation to improve reliability on non-ACPI
devices.

Signed-off-by: Martyn Welch <martyn.welch@...labora.com>

---
 drivers/input/touchscreen/goodix.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index 252dcae039f8..e7ef744011ad 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -796,17 +796,6 @@ int goodix_reset_no_int_sync(struct goodix_ts_data *ts)

 	usleep_range(6000, 10000);		/* T4: > 5ms */

-	/*
-	 * Put the reset pin back in to input / high-impedance mode to save
-	 * power. Only do this in the non ACPI case since some ACPI boards
-	 * don't have a pull-up, so there the reset pin must stay active-high.
-	 */
-	if (ts->irq_pin_access_method == IRQ_PIN_ACCESS_GPIO) {
-		error = gpiod_direction_input(ts->gpiod_rst);
-		if (error)
-			goto error;
-	}
-
 	return 0;

 error:
-- 
2.39.5