media: ccs: Add debug prints for MSR registers

Also print out MSR registers written to the sensor. This isn't entirely
optimal as the debug strings are produced even if they're not used but
that isn't really a grave issue --- the I²C bus is very slow anyway.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/i2c/ccs/ccs-reg-access.c

@@ -387,12 +387,20 @@ int ccs_write_data_regs(struct ccs_sensor *sensor, struct ccs_reg *regs,
 
 		for (j = 0; j < regs->len;
 		     j += msg.len - 2, regdata += msg.len - 2) {
+			char printbuf[(MAX_WRITE_LEN << 1) +
+				      1 /* \0 */] = { 0 };
 			int rval;
 
 			msg.len = min(regs->len - j, MAX_WRITE_LEN);
 
+			bin2hex(printbuf, regdata, msg.len);
+			dev_dbg(&client->dev,
+				"writing msr reg 0x%4.4x value 0x%s\n",
+				regs->addr + j, printbuf);
+
 			put_unaligned_be16(regs->addr + j, buf);
 			memcpy(buf + 2, regdata, msg.len);
+
 			msg.len += 2;
 
 			rval = ccs_write_retry(client, &msg);