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HID: i2c-hid: Skip ELAN power-on command after reset
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For ELAN touchscreen, we found our boot code of IC was not flexible enough
to receive and handle this command.
Once the FW main code of our controller is crashed for some reason,
the controller could not be enumerated successfully to be recognized
by the system host. therefore, it lost touch functionality.

Add quirk for skip send power-on command after reset.
It will impact to ELAN touchscreen and touchpad on HID over I2C projects.

Fixes: 43b7029 ("HID: i2c-hid: Send power-on command after reset").

Cc: stable@vger.kernel.org
Signed-off-by: Johnny Chuang <johnny.chuang.emc@gmail.com>
Reviewed-by: Harry Cutts <hcutts@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
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ElanDriver authored and bentiss committed May 7, 2021
1 parent 6be388f commit ca66a67
Showing 1 changed file with 8 additions and 1 deletion.
9 changes: 8 additions & 1 deletion drivers/hid/i2c-hid/i2c-hid-core.c
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@
#define I2C_HID_QUIRK_BOGUS_IRQ BIT(4)
#define I2C_HID_QUIRK_RESET_ON_RESUME BIT(5)
#define I2C_HID_QUIRK_BAD_INPUT_SIZE BIT(6)
#define I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET BIT(7)


/* flags */
Expand Down Expand Up @@ -178,6 +179,11 @@ static const struct i2c_hid_quirks {
I2C_HID_QUIRK_RESET_ON_RESUME },
{ USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
I2C_HID_QUIRK_BAD_INPUT_SIZE },
/*
* Sending the wakeup after reset actually break ELAN touchscreen controller
*/
{ USB_VENDOR_ID_ELAN, HID_ANY_ID,
I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET },
{ 0, 0 }
};

Expand Down Expand Up @@ -461,7 +467,8 @@ static int i2c_hid_hwreset(struct i2c_client *client)
}

/* At least some SIS devices need this after reset */
ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
if (!(ihid->quirks & I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET))
ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);

out_unlock:
mutex_unlock(&ihid->reset_lock);
Expand Down

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