linux-kernel - [PATCH 03/14] gpiolib: rework the wrapper around gpio_chip::set

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Message-Id: <20250211-gpio-set-retval-v1-3-52d3d613d7d3@linaro.org>
Date: Tue, 11 Feb 2025 13:09:37 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Linus Walleij <linus.walleij@...aro.org>, 
 Bartosz Golaszewski <brgl@...ev.pl>, Michael Walle <mwalle@...nel.org>, 
 Bamvor Jian Zhang <bamv2005@...il.com>, 
 Geert Uytterhoeven <geert+renesas@...der.be>, Keerthy <j-keerthy@...com>, 
 Uwe Kleine-König <ukleinek@...nel.org>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-pwm@...r.kernel.org, 
 Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH 03/14] gpiolib: rework the wrapper around
 gpio_chip::set_multiple()

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

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.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 drivers/gpio/gpiolib.c | 45 ++++++++++++++++++++++++++++++++-------------
 1 file changed, 32 insertions(+), 13 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 7826bfb72104..1f078a20ce3d 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -3468,19 +3468,32 @@ static int gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value)
  *        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;
+
+	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,
@@ -3489,7 +3502,7 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
 				  struct gpio_array *array_info,
 				  unsigned long *value_bitmap)
 {
-	int i = 0;
+	int i = 0, ret;
 
 	/*
 	 * Validate array_info against desc_array and its size.
@@ -3506,8 +3519,11 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
 			bitmap_xor(value_bitmap, value_bitmap,
 				   array_info->invert_mask, array_size);
 
-		gpio_chip_set_multiple(array_info->chip, array_info->set_mask,
-				       value_bitmap);
+		ret = gpiochip_set_multiple(array_info->chip,
+					    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)
@@ -3584,8 +3600,11 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
 		} 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);

-- 
2.45.2