Merge tag 'gpio-fixes-for-v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio fixes from Bartosz Golaszewski:
 "There are two fixes for GPIO core: one adds missing retval checks to
  older code, while the second adds SRCU synchronization to legs in code
  that were missed during the big rework a few cycles back. There's also
  one small driver fix:

   - check the return value of the get_direction() callback in struct
   gpio_chip

   - protect the multi-line get/set legs in GPIO core with SRCU

   - fix a race condition in gpio-vf610"

* tag 'gpio-fixes-for-v6.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
  gpiolib: don't bail out if get_direction() fails in gpiochip_add_data()
  gpiolib: protect gpio_chip with SRCU in array_info paths in multi get/set
  gpio: vf610: add locking to gpio direction functions
  gpiolib: check the return value of gpio_chip::get_direction()

Author: torvalds

drivers/gpio/gpio-vf610.c

@@ -36,6 +36,7 @@ struct vf610_gpio_port {
 	struct clk *clk_port;
 	struct clk *clk_gpio;
 	int irq;
+	spinlock_t lock; /* protect gpio direction registers */
 };
 
 #define GPIO_PDOR		0x00
@@ -124,6 +125,7 @@ static int vf610_gpio_direction_input(struct gpio_chip *chip, unsigned int gpio)
 	u32 val;
 
 	if (port->sdata->have_paddr) {
+		guard(spinlock_irqsave)(&port->lock);
 		val = vf610_gpio_readl(port->gpio_base + GPIO_PDDR);
 		val &= ~mask;
 		vf610_gpio_writel(val, port->gpio_base + GPIO_PDDR);
@@ -142,6 +144,7 @@ static int vf610_gpio_direction_output(struct gpio_chip *chip, unsigned int gpio
 	vf610_gpio_set(chip, gpio, value);
 
 	if (port->sdata->have_paddr) {
+		guard(spinlock_irqsave)(&port->lock);
 		val = vf610_gpio_readl(port->gpio_base + GPIO_PDDR);
 		val |= mask;
 		vf610_gpio_writel(val, port->gpio_base + GPIO_PDDR);
@@ -297,6 +300,7 @@ static int vf610_gpio_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	port->sdata = device_get_match_data(dev);
+	spin_lock_init(&port->lock);
 
 	dual_base = port->sdata->have_dual_base;
 

drivers/gpio/gpiolib.c

@@ -1057,8 +1057,19 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 		desc->gdev = gdev;
 
 		if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) {
-			assign_bit(FLAG_IS_OUT,
-				   &desc->flags, !gc->get_direction(gc, desc_index));
+			ret = gc->get_direction(gc, desc_index);
+			if (ret < 0)
+				/*
+				 * FIXME: Bail-out here once all GPIO drivers
+				 * are updated to not return errors in
+				 * situations that can be considered normal
+				 * operation.
+				 */
+				dev_warn(&gdev->dev,
+					 "%s: get_direction failed: %d\n",
+					 __func__, ret);
+
+			assign_bit(FLAG_IS_OUT, &desc->flags, !ret);
 		} else {
 			assign_bit(FLAG_IS_OUT,
 				   &desc->flags, !gc->direction_input);
@@ -2728,13 +2739,18 @@ int gpiod_direction_input_nonotify(struct gpio_desc *desc)
 	if (guard.gc->direction_input) {
 		ret = guard.gc->direction_input(guard.gc,
 						gpio_chip_hwgpio(desc));
-	} else if (guard.gc->get_direction &&
-		  (guard.gc->get_direction(guard.gc,
-					   gpio_chip_hwgpio(desc)) != 1)) {
-		gpiod_warn(desc,
-			   "%s: missing direction_input() operation and line is output\n",
-			   __func__);
-		return -EIO;
+	} else if (guard.gc->get_direction) {
+		ret = guard.gc->get_direction(guard.gc,
+					      gpio_chip_hwgpio(desc));
+		if (ret < 0)
+			return ret;
+
+		if (ret != GPIO_LINE_DIRECTION_IN) {
+			gpiod_warn(desc,
+				   "%s: missing direction_input() operation and line is output\n",
+				    __func__);
+			return -EIO;
+		}
 	}
 	if (ret == 0) {
 		clear_bit(FLAG_IS_OUT, &desc->flags);
@@ -2771,12 +2787,18 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value)
 						 gpio_chip_hwgpio(desc), val);
 	} else {
 		/* Check that we are in output mode if we can */
-		if (guard.gc->get_direction &&
-		    guard.gc->get_direction(guard.gc, gpio_chip_hwgpio(desc))) {
-			gpiod_warn(desc,
-				"%s: missing direction_output() operation\n",
-				__func__);
-			return -EIO;
+		if (guard.gc->get_direction) {
+			ret = guard.gc->get_direction(guard.gc,
+						      gpio_chip_hwgpio(desc));
+			if (ret < 0)
+				return ret;
+
+			if (ret != GPIO_LINE_DIRECTION_OUT) {
+				gpiod_warn(desc,
+					   "%s: missing direction_output() operation\n",
+					   __func__);
+				return -EIO;
+			}
 		}
 		/*
 		 * If we can't actively set the direction, we are some
@@ -3129,6 +3151,8 @@ static int gpiod_get_raw_value_commit(const struct gpio_desc *desc)
 static int gpio_chip_get_multiple(struct gpio_chip *gc,
 				  unsigned long *mask, unsigned long *bits)
 {
+	lockdep_assert_held(&gc->gpiodev->srcu);
+
 	if (gc->get_multiple)
 		return gc->get_multiple(gc, mask, bits);
 	if (gc->get) {
@@ -3159,6 +3183,7 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
 				  struct gpio_array *array_info,
 				  unsigned long *value_bitmap)
 {
+	struct gpio_chip *gc;
 	int ret, i = 0;
 
 	/*
@@ -3170,10 +3195,15 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
 	    array_size <= array_info->size &&
 	    (void *)array_info == desc_array + array_info->size) {
 		if (!can_sleep)
-			WARN_ON(array_info->chip->can_sleep);
+			WARN_ON(array_info->gdev->can_sleep);
+
+		guard(srcu)(&array_info->gdev->srcu);
+		gc = srcu_dereference(array_info->gdev->chip,
+				      &array_info->gdev->srcu);
+		if (!gc)
+			return -ENODEV;
 
-		ret = gpio_chip_get_multiple(array_info->chip,
-					     array_info->get_mask,
+		ret = gpio_chip_get_multiple(gc, array_info->get_mask,
 					     value_bitmap);
 		if (ret)
 			return ret;
@@ -3454,6 +3484,8 @@ static void gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value)
 static void gpio_chip_set_multiple(struct gpio_chip *gc,
 				   unsigned long *mask, unsigned long *bits)
 {
+	lockdep_assert_held(&gc->gpiodev->srcu);
+
 	if (gc->set_multiple) {
 		gc->set_multiple(gc, mask, bits);
 	} else {
@@ -3471,6 +3503,7 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
 				  struct gpio_array *array_info,
 				  unsigned long *value_bitmap)
 {
+	struct gpio_chip *gc;
 	int i = 0;
 
 	/*
@@ -3482,14 +3515,19 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
 	    array_size <= array_info->size &&
 	    (void *)array_info == desc_array + array_info->size) {
 		if (!can_sleep)
-			WARN_ON(array_info->chip->can_sleep);
+			WARN_ON(array_info->gdev->can_sleep);
+
+		guard(srcu)(&array_info->gdev->srcu);
+		gc = srcu_dereference(array_info->gdev->chip,
+				      &array_info->gdev->srcu);
+		if (!gc)
+			return -ENODEV;
 
 		if (!raw && !bitmap_empty(array_info->invert_mask, array_size))
 			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);
+		gpio_chip_set_multiple(gc, array_info->set_mask, value_bitmap);
 
 		i = find_first_zero_bit(array_info->set_mask, array_size);
 		if (i == array_size)
@@ -4751,9 +4789,10 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 {
 	struct gpio_desc *desc;
 	struct gpio_descs *descs;
+	struct gpio_device *gdev;
 	struct gpio_array *array_info = NULL;
-	struct gpio_chip *gc;
 	int count, bitmap_size;
+	unsigned long dflags;
 	size_t descs_size;
 
 	count = gpiod_count(dev, con_id);
@@ -4774,16 +4813,16 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 
 		descs->desc[descs->ndescs] = desc;
 
-		gc = gpiod_to_chip(desc);
+		gdev = gpiod_to_gpio_device(desc);
 		/*
 		 * If pin hardware number of array member 0 is also 0, select
 		 * its chip as a candidate for fast bitmap processing path.
 		 */
 		if (descs->ndescs == 0 && gpio_chip_hwgpio(desc) == 0) {
 			struct gpio_descs *array;
 
-			bitmap_size = BITS_TO_LONGS(gc->ngpio > count ?
-						    gc->ngpio : count);
+			bitmap_size = BITS_TO_LONGS(gdev->ngpio > count ?
+						    gdev->ngpio : count);
 
 			array = krealloc(descs, descs_size +
 					 struct_size(array_info, invert_mask, 3 * bitmap_size),
@@ -4803,7 +4842,7 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 
 			array_info->desc = descs->desc;
 			array_info->size = count;
-			array_info->chip = gc;
+			array_info->gdev = gdev;
 			bitmap_set(array_info->get_mask, descs->ndescs,
 				   count - descs->ndescs);
 			bitmap_set(array_info->set_mask, descs->ndescs,
@@ -4816,7 +4855,7 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 			continue;
 
 		/* Unmark array members which don't belong to the 'fast' chip */
-		if (array_info->chip != gc) {
+		if (array_info->gdev != gdev) {
 			__clear_bit(descs->ndescs, array_info->get_mask);
 			__clear_bit(descs->ndescs, array_info->set_mask);
 		}
@@ -4839,9 +4878,10 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 					    array_info->set_mask);
 			}
 		} else {
+			dflags = READ_ONCE(desc->flags);
 			/* Exclude open drain or open source from fast output */
-			if (gpiochip_line_is_open_drain(gc, descs->ndescs) ||
-			    gpiochip_line_is_open_source(gc, descs->ndescs))
+			if (test_bit(FLAG_OPEN_DRAIN, &dflags) ||
+			    test_bit(FLAG_OPEN_SOURCE, &dflags))
 				__clear_bit(descs->ndescs,
 					    array_info->set_mask);
 			/* Identify 'fast' pins which require invertion */
@@ -4853,7 +4893,7 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 	if (array_info)
 		dev_dbg(dev,
 			"GPIO array info: chip=%s, size=%d, get_mask=%lx, set_mask=%lx, invert_mask=%lx\n",
-			array_info->chip->label, array_info->size,
+			array_info->gdev->label, array_info->size,
 			*array_info->get_mask, *array_info->set_mask,
 			*array_info->invert_mask);
 	return descs;

drivers/gpio/gpiolib.h

@@ -114,7 +114,7 @@ extern const char *const gpio_suffixes[];
  *
  * @desc:		Array of pointers to the GPIO descriptors
  * @size:		Number of elements in desc
- * @chip:		Parent GPIO chip
+ * @gdev:		Parent GPIO device
  * @get_mask:		Get mask used in fastpath
  * @set_mask:		Set mask used in fastpath
  * @invert_mask:	Invert mask used in fastpath
@@ -126,7 +126,7 @@ extern const char *const gpio_suffixes[];
 struct gpio_array {
 	struct gpio_desc	**desc;
 	unsigned int		size;
-	struct gpio_chip	*chip;
+	struct gpio_device	*gdev;
 	unsigned long		*get_mask;
 	unsigned long		*set_mask;
 	unsigned long		invert_mask[];