Hi,
On Thu, Apr 27, 2023 at 9:08 AM Jeff LaBundy <jeff@xxxxxxxxxxx> wrote:
>
> Hi Fei,
>
> On Wed, Apr 26, 2023 at 10:44:22PM +0800, Fei Shao 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@xxxxxxxxxxxx>
> > Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
>
> Great work; one tiny nit below. If you do not agree with it or have found
> precedent that suggests it is OK, feel free to ignore it. Either way:
>
> Reviewed-by: Jeff LaBundy <jeff@xxxxxxxxxxx>
>
> >
> > ---
> >
> > 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(-)
> >
> > 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);
> > + }
>
> I don't think curly braces are technically required here, as there is only
> one statement within the conditional despite the comments making it appear
> otherwise. Maybe this would work too:
>
> /* ... */
> if (...)
> gpiod_set_value_cansleep(...);
>
> Again however, I do not feel strongly about this.
Oops, I just carried it over from v1 and didn't think that much at the
moment, but indeed I should have cleaned that up.
V4 is on the way, thanks for pointing that out. :)
Regards,
Fei
>
> > 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);
> > --
> > 2.40.1.495.gc816e09b53d-goog
> >
>
> Kind regards,
> Jeff LaBundy
