On Wed, Jan 02, 2019 at 06:38:39PM -0800, Yizhuo wrote:

int ret;

• unsigned int val;

• unsigned int val = ~0;

This just shuts warnings up which may mask further problem, it is better to just leave it and fix the users.

• regmap_read(rt274->regmap,

• ret = regmap_read(rt274->regmap, RT274_GET_PARAM(AC_NODE_ROOT, AC_PAR_VENDOR_ID), &val);

• if (val != RT274_VENDOR_ID) {

• if (ret || val != RT274_VENDOR_ID) { dev_err(&i2c->dev, "Device with ID register %#x is not rt274\n", val); return -ENODEV;

If the read returned an error we should pass back the error code we got from it, not mask it with another error code. This is especially true here where the error message would be very misleading if there's a problem with I/O.