Input: goodix - try not to touch the reset-pin on x86/ACPI devices

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>

diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index 906b5a6..e7efc32 100644 (file)
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -695,10 +695,16 @@ 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;
 
@@ -832,6 +838,14 @@ 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
@@ -857,6 +871,12 @@ 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);
@@ -894,7 +914,7 @@ retry_get_irq_gpio:
        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 62138f9..02065d1 100644 (file)
--- a/drivers/input/touchscreen/goodix.h
+++ b/drivers/input/touchscreen/goodix.h
@@ -87,6 +87,7 @@ 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];
        char cfg_name[64];
        u16 version;