From 359ed24a0dd3802e703ec8071dc3b6ed446de5f0 Mon Sep 17 00:00:00 2001 From: Fei Shao Date: Wed, 24 May 2023 11:42:36 +0800 Subject: dt-bindings: input: goodix: Add "goodix,no-reset-during-suspend" property We observed that on Chromebook device Steelix, if Goodix GT7375P touchscreen is powered in suspend (because, for example, it connects to an always-on regulator) and with the reset GPIO asserted, it will introduce about 14mW power leakage. To address that, we add this property to skip reset during suspend. If it's set, the driver will stop asserting the reset GPIO during power-down. Refer to the comments in the driver for details. Signed-off-by: Fei Shao Suggested-by: Jeff LaBundy Reviewed-by: Douglas Anderson Reviewed-by: Matthias Brugger Reviewed-by: Jeff LaBundy Acked-by: Rob Herring Signed-off-by: Jiri Kosina --- Documentation/devicetree/bindings/input/goodix,gt7375p.yaml | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml index ce18d7dadae2..1edad1da1196 100644 --- a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml +++ b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml @@ -43,6 +43,15 @@ properties: itself as long as it allows the main board to make signals compatible with what the touchscreen is expecting for its IO rails. + goodix,no-reset-during-suspend: + description: + Set this to true to enforce the driver to not assert the reset GPIO + during suspend. + Due to potential touchscreen hardware flaw, back-powering could happen in + suspend if the power supply is on and with active-low reset GPIO asserted. + This property is used to avoid the back-powering issue. + type: boolean + required: - compatible - reg -- cgit v1.2.3 From 7607f12ba735f04e0ef8718dabadf3a765c9a477 Mon Sep 17 00:00:00 2001 From: Fei Shao Date: Wed, 24 May 2023 11:42:37 +0800 Subject: HID: i2c-hid: goodix: Add support for "goodix,no-reset-during-suspend" property In the beginning, commit 18eeef46d359 ("HID: i2c-hid: goodix: Tie the reset line to true state of the regulator") introduced a change to tie the reset line of the Goodix touchscreen to the state of the regulator to fix a power leakage issue in suspend. After some time, the change was deemed unnecessary and was reverted in commit 557e05fa9fdd ("HID: i2c-hid: goodix: Stop tying the reset line to the regulator") due to difficulties in managing regulator notifiers for designs like Evoker, which provides a second power rail to touchscreen. However, the revert caused a power regression on another Chromebook device Steelix in the field, which has a dedicated always-on regulator for touchscreen and was covered by the workaround in the first commit. To address both cases, this patch adds the support for the new "goodix,no-reset-during-suspend" property in the driver: - When set to true, the driver does not assert the reset GPIO during power-down. Instead, the GPIO will be asserted during power-up to ensure the touchscreen always has a clean start and consistent behavior after resuming. This is for designs with a dedicated always-on regulator. - When set to false or unset, the driver uses the original control flow and asserts GPIO and disables regulators normally. This is for the two-regulator and shared-regulator designs. Signed-off-by: Fei Shao Suggested-by: Douglas Anderson Reviewed-by: Douglas Anderson Reviewed-by: Jeff LaBundy Signed-off-by: Jiri Kosina --- drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c index 0060e3dcd775..db4639db9840 100644 --- a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c +++ b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c @@ -28,6 +28,7 @@ struct i2c_hid_of_goodix { struct regulator *vdd; struct regulator *vddio; struct gpio_desc *reset_gpio; + bool no_reset_during_suspend; const struct goodix_i2c_hid_timing_data *timings; }; @@ -37,6 +38,14 @@ static int goodix_i2c_hid_power_up(struct i2chid_ops *ops) container_of(ops, struct i2c_hid_of_goodix, ops); int ret; + /* + * We assert reset GPIO here (instead of during power-down) to ensure + * the device will have a clean state after powering up, just like the + * normal scenarios will have. + */ + if (ihid_goodix->no_reset_during_suspend) + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1); + ret = regulator_enable(ihid_goodix->vdd); if (ret) return ret; @@ -60,7 +69,9 @@ static void goodix_i2c_hid_power_down(struct i2chid_ops *ops) struct i2c_hid_of_goodix *ihid_goodix = container_of(ops, struct i2c_hid_of_goodix, ops); - gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1); + if (!ihid_goodix->no_reset_during_suspend) + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1); + regulator_disable(ihid_goodix->vddio); regulator_disable(ihid_goodix->vdd); } @@ -91,6 +102,9 @@ static int i2c_hid_of_goodix_probe(struct i2c_client *client) if (IS_ERR(ihid_goodix->vddio)) return PTR_ERR(ihid_goodix->vddio); + ihid_goodix->no_reset_during_suspend = + of_property_read_bool(client->dev.of_node, "goodix,no-reset-during-suspend"); + ihid_goodix->timings = device_get_match_data(&client->dev); return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001, 0); -- cgit v1.2.3