+static inline u8 pef2256_read8(struct pef2256 *pef2256, int offset)
+{
+	int val;
+
+	regmap_read(pef2256->regmap, offset, &val);
+	return val;
+}
+
+static inline void pef2256_write8(struct pef2256 *pef2256, int offset, u8 val)
+{
+	regmap_write(pef2256->regmap, offset, val);
+}

More cases of inline functions in .C files. Please let the compiler
decide.

+static void pef2256_isr_default_handler(struct pef2256 *pef2256, u8 nbr, u8 isr)
+{
+	dev_warn(pef2256->dev, "ISR%u: 0x%02x not handled\n", nbr, isr);
+}

Should this be rate limited? It is going to be very noise if it gets
called once per frame time.

       Andrew