[PATCH v3] HID: i2c-hid: Skip ELAN power-on command after reset

[Johnny Chuang]

Fixes: 43b7029f475e ("HID: i2c-hid: Send power-on command after reset").

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.

Signed-off-by: Johnny Chuang <johnny.chuang.emc@xxxxxxxxx>
---
Changes in V3:
    - intent the comment at qurik entry
    - add Fixes:flag for previous commit id

Changes in v2:
    - move comment to quirk entry
---
 drivers/hid/i2c-hid/i2c-hid-core.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index 9993133..32e3287 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -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 */
@@ -178,6 +179,12 @@ 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
+	 * Add I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET to skip wakeup after reset
+	 */
+	{ USB_VENDOR_ID_ELAN, HID_ANY_ID,
+		 I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET },
 	{ 0, 0 }
 };
 
@@ -461,7 +468,8 @@ 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);
-- 
2.7.4