gpiolib: rework the wrapper around gpio_chip::set_multiple()

Make the existing wrapper around gpio_chip::set_multiple() consistent
with the one for gpio_chip::set(): make it return int, add a lockdep
assertion, warn on missing set callback and move the code a bit for
better readability.

Add return value checks in all call places.

Reviewed-by: Linus Walleij <[e-mail]>
Acked-by: Uwe Kleine-König <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Bartosz Golaszewski <[e-mail]>

drivers/gpio/gpiolib.c

···
  *        defines which outputs are to be changed
  * @bits: bit value array; one bit per output; BITS_PER_LONG bits per word
  *        defines the values the outputs specified by mask are to be set to
+ *
+ * Returns: 0 on success, negative error number on failure.
  */
-static void gpio_chip_set_multiple(struct gpio_chip *gc,
-				   unsigned long *mask, unsigned long *bits)
+static int gpiochip_set_multiple(struct gpio_chip *gc,
+				 unsigned long *mask, unsigned long *bits)
 {
+	unsigned int i;
+	int ret;
+
 	lockdep_assert_held(&gc->gpiodev->srcu);
+
+	if (WARN_ON(unlikely(!gc->set_multiple && !gc->set)))
+		return -EOPNOTSUPP;
 
 	if (gc->set_multiple) {
 		gc->set_multiple(gc, mask, bits);
-	} else {
-		unsigned int i;
-
-		/* set outputs if the corresponding mask bit is set */
-		for_each_set_bit(i, mask, gc->ngpio)
-			gpiochip_set(gc, i, test_bit(i, bits));
+		return 0;
 	}
+
+	/* set outputs if the corresponding mask bit is set */
+	for_each_set_bit(i, mask, gc->ngpio) {
+		ret = gpiochip_set(gc, i, test_bit(i, bits));
+		if (ret)
+			break;
+	}
+
+	return ret;
 }
 
 int gpiod_set_array_value_complex(bool raw, bool can_sleep,
···
 				  unsigned long *value_bitmap)
 {
 	struct gpio_chip *gc;
-	int i = 0;
+	int i = 0, ret;
 
 	/*
 	 * Validate array_info against desc_array and its size.
···
 			bitmap_xor(value_bitmap, value_bitmap,
 				   array_info->invert_mask, array_size);
 
-		gpio_chip_set_multiple(gc, array_info->set_mask, value_bitmap);
+		ret = gpiochip_set_multiple(gc, array_info->set_mask,
+					    value_bitmap);
+		if (ret)
+			return ret;
 
 		i = find_first_zero_bit(array_info->set_mask, array_size);
 		if (i == array_size)
···
 		} while ((i < array_size) &&
 			 gpio_device_chip_cmp(desc_array[i]->gdev, guard.gc));
 		/* push collected bits to outputs */
-		if (count != 0)
-			gpio_chip_set_multiple(guard.gc, mask, bits);
+		if (count != 0) {
+			ret = gpiochip_set_multiple(guard.gc, mask, bits);
+			if (ret)
+				return ret;
+		}
 
 		if (mask != fastpath_mask)
 			bitmap_free(mask);