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 disable 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 v2:
- Do not change the regulator_enable logic during power-up.
drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 26 +++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
index 0060e3dcd775..fc4532fcadcc 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 +38,20 @@ 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) {
+ /*
+ * This is not mandatory, but we assert reset 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.
+ *
+ * Note that in this case we assume the regulators should be
+ * (marked as) always-on, so the regulator core knows what to
+ * do with them in the following regulator_enable() calls
+ * despite regulator_disable() was not called previously.
+ */
+ gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
+ }
ret = regulator_enable(ihid_goodix->vdd);
if (ret)
return ret;
@@ -60,6 +75,14 @@ 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);
+ /*
+ * Don't assert reset GPIO if it's set.
+ * Also, it's okay to skip the following regulator_disable() calls
+ * because the regulators should be always-on in this case.
+ */
+ if (ihid_goodix->no_reset_during_suspend)
+ return;
+
gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
regulator_disable(ihid_goodix->vddio);
regulator_disable(ihid_goodix->vdd);
@@ -91,6 +114,9 @@ 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);
--
2.40.1.495.gc816e09b53d-googHi,
On Wed, Apr 26, 2023 at 2:33 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 disable 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 v2:
> - Do not change the regulator_enable logic during power-up.
>
> drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 26 +++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
> index 0060e3dcd775..fc4532fcadcc 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 +38,20 @@ 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) {
> + /*
> + * This is not mandatory, but we assert reset 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.
> + *
> + * Note that in this case we assume the regulators should be
> + * (marked as) always-on, so the regulator core knows what to
> + * do with them in the following regulator_enable() calls
> + * despite regulator_disable() was not called previously.
> + */
> + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
> + }
> ret = regulator_enable(ihid_goodix->vdd);
> if (ret)
> return ret;
> @@ -60,6 +75,14 @@ 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);
>
> + /*
> + * Don't assert reset GPIO if it's set.
> + * Also, it's okay to skip the following regulator_disable() calls
> + * because the regulators should be always-on in this case.
> + */
> + if (ihid_goodix->no_reset_during_suspend)
> + return;
> +
> gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
> regulator_disable(ihid_goodix->vddio);
> regulator_disable(ihid_goodix->vdd);
I think the above is wrong. You should just skip the GPIO call when
"no_reset_during_suspend", not the regulator calls. As your code is
written, you'll enable the regulators over and over again in
"power_up" and never in "power_down".
-Doug
On Wed, Apr 26, 2023 at 10:05 PM Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Wed, Apr 26, 2023 at 2:33 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 disable 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 v2:
> > - Do not change the regulator_enable logic during power-up.
> >
> > drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 26 +++++++++++++++++++++++++
> > 1 file changed, 26 insertions(+)
> >
> > diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
> > index 0060e3dcd775..fc4532fcadcc 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 +38,20 @@ 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) {
> > + /*
> > + * This is not mandatory, but we assert reset 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.
> > + *
> > + * Note that in this case we assume the regulators should be
> > + * (marked as) always-on, so the regulator core knows what to
> > + * do with them in the following regulator_enable() calls
> > + * despite regulator_disable() was not called previously.
> > + */
> > + gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
> > + }
> > ret = regulator_enable(ihid_goodix->vdd);
> > if (ret)
> > return ret;
> > @@ -60,6 +75,14 @@ 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);
> >
> > + /*
> > + * Don't assert reset GPIO if it's set.
> > + * Also, it's okay to skip the following regulator_disable() calls
> > + * because the regulators should be always-on in this case.
> > + */
> > + if (ihid_goodix->no_reset_during_suspend)
> > + return;
> > +
> > gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
> > regulator_disable(ihid_goodix->vddio);
> > regulator_disable(ihid_goodix->vdd);
>
> I think the above is wrong. You should just skip the GPIO call when
> "no_reset_during_suspend", not the regulator calls. As your code is
> written, you'll enable the regulators over and over again in
> "power_up" and never in "power_down".
Agree, I'll resend v3. Thanks for the feedback!
Regards,
Fei
>
> -Doug
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