HID: i2c-hid: add retry in set power for fixing resume issue(send again) Weida's controllers(WDT8752/WDT8755) require 2 steps to wakeup from SLEEP mode. The first command will wakeup the controller but will be ignored. The second command will be executed

Commit Message

HungNien Chen Nov. 7, 2016, 10:45 a.m. UTC

From: HungNien Chen <[e-mail]>

Signed-off-by: HungNien Chen <[e-mail]>
---
 drivers/hid/i2c-hid/i2c-hid.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

Patch

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index b3ec4f2..d7423d9 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -49,6 +49,8 @@ 
 #define I2C_HID_PWR_ON		0x00
 #define I2C_HID_PWR_SLEEP	0x01
 
+#define	SET_PWR_RETRIES		2
+
 /* debug option */
 static bool debug;
 module_param(debug, bool, 0444);
@@ -343,14 +345,26 @@  static int i2c_hid_set_power(struct i2c_client *client, int power_state)
 {
 	struct i2c_hid *ihid = i2c_get_clientdata(client);
 	int ret;
+	int retry;
 
 	i2c_hid_dbg(ihid, "%s\n", __func__);
 
-	ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
-		0, NULL, 0, NULL, 0);
-	if (ret)
-		dev_err(&client->dev, "failed to change power setting.\n");
+       /*
+	* Some Weida's controllers require Set_Power twice on resume.
+	* The 1st cmd wakeup the controller and the 2nd cmd will be executed.
+	* It should be safe to controllers of other vendors.
+	*/
+	for (retry = 0; retry < SET_PWR_RETRIES; retry++) {
+		ret = __i2c_hid_command(client, &hid_set_power_cmd,
+			power_state, 0, NULL, 0, NULL, 0);
+
+		if (!ret)
+			goto set_power_exit;
+	}
+
+	dev_err(&client->dev, "failed to change power setting.\n");
 
+set_power_exit:
 	return ret;
 }