diff mbox series

[v3,2/2] HID: i2c-hid: goodix: Add support for "goodix,no-reset-during-suspend" property

Message ID 20230426144423.2820826-3-fshao@chromium.org
State Superseded
Headers show
Series Fix Goodix touchscreen power leakage for MT8186 boards | expand

Commit Message

Fei Shao April 26, 2023, 2:44 p.m. UTC
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 <fshao@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>

---

Changes in v3:
- In power-down, only skip the GPIO but not the regulator calls if the
  flag is set

Changes in v2:
- Do not change the regulator_enable logic during power-up.

 drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

Comments

Doug Anderson April 26, 2023, 4:39 p.m. UTC | #1
Hi,

On Wed, Apr 26, 2023 at 7:44 AM Fei Shao <fshao@chromium.org> wrote:
>
> 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 <fshao@chromium.org>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>
> ---
>
> Changes in v3:
> - In power-down, only skip the GPIO but not the regulator calls if the
>   flag is set
>
> Changes in v2:
> - Do not change the regulator_enable logic during power-up.
>
>  drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)

You already carried over my Reviewed-by tag, which is fine. ...but
just sending a quick confirmation that v3 looks good to me. Thanks!

-Doug
diff mbox series

Patch

diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
index 0060e3dcd775..3ed365b50432 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;
 
+	if (ihid_goodix->no_reset_during_suspend) {
+		/*
+		 * 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.
+		 */
+		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);