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
`powered-in-suspend` property in the driver that allows the driver to
determine whether the touchscreen is still powered in suspend, and
handle the reset GPIO accordingly as below:
- When set to true, the driver does not assert the reset GPIO in power
down. To ensure a clean start and the consistent behavior, it does the
assertion in power up instead.
This is for designs with a dedicated always-on regulator.
- When set to false, 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@xxxxxxxxxxxx>
---
drivers/hid/i2c-hid/i2c-hid-of-goodix.c | 46 +++++++++++++++++++++----
1 file changed, 39 insertions(+), 7 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid-of-goodix.c b/drivers/hid/i2c-hid/i2c-hid-of-goodix.c
index 0060e3dcd775..b438db8ca6f4 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 powered_in_suspend;
const struct goodix_i2c_hid_timing_data *timings;
};
@@ -37,13 +38,34 @@ static int goodix_i2c_hid_power_up(struct i2chid_ops *ops)
container_of(ops, struct i2c_hid_of_goodix, ops);
int ret;
- ret = regulator_enable(ihid_goodix->vdd);
- if (ret)
- return ret;
-
- ret = regulator_enable(ihid_goodix->vddio);
- if (ret)
- return ret;
+ /*
+ * This is to ensure that the reset GPIO will be asserted and the
+ * regulators will be enabled for all cases.
+ */
+ if (ihid_goodix->powered_in_suspend) {
+ /*
+ * This is not mandatory, but we assert reset here (instead of
+ * in power-down) to ensure that the device will have a clean
+ * state later on just like the normal scenarios would have.
+ *
+ * Also, since the regulators were not disabled in power-down,
+ * we don't need to enable them here.
+ */
+ gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
+ } else {
+ /*
+ * In this case, the reset is already asserted (either in
+ * probe or power-down).
+ * All we need is to enable the regulators.
+ */
+ ret = regulator_enable(ihid_goodix->vdd);
+ if (ret)
+ return ret;
+
+ ret = regulator_enable(ihid_goodix->vddio);
+ if (ret)
+ return ret;
+ }
if (ihid_goodix->timings->post_power_delay_ms)
msleep(ihid_goodix->timings->post_power_delay_ms);
@@ -60,6 +82,13 @@ 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 or disable regulators if we're keeping the
+ * device powered in suspend.
+ */
+ if (ihid_goodix->powered_in_suspend)
+ return;
+
gpiod_set_value_cansleep(ihid_goodix->reset_gpio, 1);
regulator_disable(ihid_goodix->vddio);
regulator_disable(ihid_goodix->vdd);
@@ -91,6 +120,9 @@ 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->powered_in_suspend =
+ of_property_read_bool(client->dev.of_node, "powered-in-suspend");
+
ihid_goodix->timings = device_get_match_data(&client->dev);
return i2c_hid_core_probe(client, &ihid_goodix->ops, 0x0001, 0);
--
2.40.0.634.g4ca3ef3211-goog
