On Fri, Jun 04, 2021 at 02:16:02PM +0200, Robert Marko wrote:
[ ... ]

quoted

quoted

+}
+
+static int dps920ab_write_word_data(struct i2c_client *client, int page, int reg,
+                                 u16 word)
+{
+     int ret;
+
+     /*
+      * This masks commands which are not supported.
+      * PSU only has one R/W register and that is
+      * for the fan.
+      */
+     switch (reg) {
+     case PMBUS_FAN_COMMAND_1:
+             break;
+     default:
+             ret = -ENODATA;
+     }
+

Does this work ? It is the wrong error message for a failed write;
it should probably return -EACCES.

It appears to work fine, I was looking at other drivers, and all of them
use -ENODATA for unsupported word registers.

No. They return -ENODATA to tell the PMBus core to use standard PMBus
access functions, ie to handle the access in the core. Please see
_pmbus_write_word_data().

Guenter