On Sat, Sep 12, 2020 at 3:55 AM Jiada Wang [off-list ref] wrote:

From: Nick Dyer <redacted>

Some maXTouch chips (eg mXT1386) will not respond on the first I2C request
when they are in a sleep state. It must be retried after a delay for the
chip to wake up.

Signed-off-by: Nick Dyer <redacted>
[gdavis: Forward port and fix conflicts.]
Signed-off-by: George G. Davis <redacted>
[jiada: return exact errno when i2c_transfer & i2c_master_send fails
        rename "retry" to "retried" and keep its order in length
        set "ret" to correct errno before calling dev_err()

        remove reduntant conditional]

redundant

Signed-off-by: Jiada Wang <redacted>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Dmitry Osipenko <digetx@gmail.com>

...

+       bool retried = false;

I thought Dmitry wants that to be retry

        u8 buf[2];
        int ret;

-       ret = i2c_transfer(client->adapter, xfer, 2);
-       if (ret == 2) {
-               ret = 0;
-       } else {
-               if (ret >= 0)
-                       ret = -EIO;
+retry_read:

+       ret = i2c_transfer(client->adapter, xfer, ARRAY_SIZE(xfer));
+       if (ret != ARRAY_SIZE(xfer)) {

I'm wondering why you can't leave 2 as is and change it to ARRAY_SIZE
in a separate patch?
Also why switch from positive to negative conditional?

+               if (!retried) {
+                       dev_dbg(&client->dev, "i2c retry\n");
+                       msleep(MXT_WAKEUP_TIME);
+                       retried = true;
+                       goto retry_read;
+               }
+               ret = ret < 0 ? ret : -EIO;
                dev_err(&client->dev, "%s: i2c transfer failed (%d)\n",
                        __func__, ret);
+               return ret;
        }

-       return ret;
+       return 0;
 }

..

+       bool retried = false;

Same comments here, in this function.

+retry_write:
        ret = i2c_master_send(client, buf, count);
-       if (ret == count) {
-               ret = 0;
-       } else {
-               if (ret >= 0)
-                       ret = -EIO;
+       if (ret != count) {
+               if (!retried) {
+                       dev_dbg(&client->dev, "i2c retry\n");
+                       msleep(MXT_WAKEUP_TIME);
+                       retried = true;
+                       goto retry_write;
+               }
+               ret = ret < 0 ? ret : -EIO;
                dev_err(&client->dev, "%s: i2c send failed (%d)\n",
                        __func__, ret);
+       } else {
+               ret = 0;
        }

-- 
With Best Regards,
Andy Shevchenko