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Subject[PATCH 5.15 028/230] Input: goodix - try not to touch the reset-pin on x86/ACPI devices
Date
From: Hans de Goede <hdegoede@redhat.com>

[ Upstream commit a2fd46cd3dbb83b373ba74f4043f8dae869c65f1 ]

Unless the controller is not responding at boot or after suspend/resume,
the driver never resets the controller on x86/ACPI platforms. The driver
still requesting the reset pin at probe() though in case it needs it.

Until now the driver has always requested the reset pin with GPIOD_IN
as type. The idea being to put the pin in high-impedance mode to save
power until the driver actually wants to issue a reset.

But this means that just requesting the pin can cause issues, since
requesting it in another mode then GPIOD_ASIS may cause the pinctrl
driver to touch the pin settings. We have already had issues before
due to a bug in the pinctrl-cherryview.c driver which has been fixed in
commit 921daeeca91b ("pinctrl: cherryview: Preserve
CHV_PADCTRL1_INVRXTX_TXDATA flag on GPIOs").

And now it turns out that requesting the reset-pin as GPIOD_IN also stops
the touchscreen from working on the GPD P2 max mini-laptop. The behavior
of putting the pin in high-impedance mode relies on there being some
external pull-up to keep it high and there seems to be no pull-up on the
GPD P2 max, causing things to break.

This commit fixes this by requesting the reset pin as is when using
the x86/ACPI code paths to lookup the GPIOs; and by not dropping it
back into input-mode in case the driver does end up issuing a reset
for error-recovery.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209061
Fixes: a7d4b171660c ("Input: goodix - add support for getting IRQ + reset GPIOs on Cherry Trail devices")
Cc: stable@vger.kernel.org
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20211206091116.44466-2-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/input/touchscreen/goodix.c | 30 +++++++++++++++++++++++++-----
drivers/input/touchscreen/goodix.h | 1 +
2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index 2ca903a8af21..3667f7e51fde 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -640,10 +640,16 @@ int goodix_reset_no_int_sync(struct goodix_ts_data *ts)

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

- /* end select I2C slave addr */
- error = gpiod_direction_input(ts->gpiod_rst);
- if (error)
- goto error;
+ /*
+ * 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;

@@ -777,6 +783,14 @@ static int goodix_add_acpi_gpio_mappings(struct goodix_ts_data *ts)
return -EINVAL;
}

+ /*
+ * Normally we put the reset pin in input / high-impedance mode to save
+ * power. But some x86/ACPI boards don't have a pull-up, so for the ACPI
+ * case, leave the pin as is. This results in the pin not being touched
+ * at all on x86/ACPI boards, except when needed for error-recover.
+ */
+ ts->gpiod_rst_flags = GPIOD_ASIS;
+
return devm_acpi_dev_add_driver_gpios(dev, gpio_mapping);
}
#else
@@ -802,6 +816,12 @@ static int goodix_get_gpio_config(struct goodix_ts_data *ts)
return -EINVAL;
dev = &ts->client->dev;

+ /*
+ * By default we request the reset pin as input, leaving it in
+ * high-impedance when not resetting the controller to save power.
+ */
+ ts->gpiod_rst_flags = GPIOD_IN;
+
ts->avdd28 = devm_regulator_get(dev, "AVDD28");
if (IS_ERR(ts->avdd28)) {
error = PTR_ERR(ts->avdd28);
@@ -839,7 +859,7 @@ static int goodix_get_gpio_config(struct goodix_ts_data *ts)
ts->gpiod_int = gpiod;

/* Get the reset line GPIO pin number */
- gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_RST_NAME, GPIOD_IN);
+ gpiod = devm_gpiod_get_optional(dev, GOODIX_GPIO_RST_NAME, ts->gpiod_rst_flags);
if (IS_ERR(gpiod)) {
error = PTR_ERR(gpiod);
if (error != -EPROBE_DEFER)
diff --git a/drivers/input/touchscreen/goodix.h b/drivers/input/touchscreen/goodix.h
index 0b88554ba2ae..1a1571ad2cd2 100644
--- a/drivers/input/touchscreen/goodix.h
+++ b/drivers/input/touchscreen/goodix.h
@@ -51,6 +51,7 @@ struct goodix_ts_data {
struct gpio_desc *gpiod_rst;
int gpio_count;
int gpio_int_idx;
+ enum gpiod_flags gpiod_rst_flags;
char id[GOODIX_ID_MAX_LEN + 1];
u16 version;
const char *cfg_name;
--
2.35.1


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