Merge tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux

Pull second round of GPIO changes from Grant Likely:
 "This branch contains a few bug fixes that I missed the first time
  around and updates to the gpio_desc series included in the first pull
  request.  This tag has been retagged to drop the 2 head commits
  because the one of them caused a build failure."

* tag 'gpio-for-linus' of git://git.secretlab.ca/git/linux:
  gpio/gpio-ich: fix ichx_gpio_check_available() return what callers expect
  gpiolib: move comment to right function
  gpiolib: use const parameters when possible
  gpiolib: check descriptors validity before use

2 files changed, 84 insertions, 63 deletions

diff --git a/drivers/gpio/gpio-ich.c b/drivers/gpio/gpio-ich.c
index 6f2306db8591..f9dbd503fc40 100644
--- a/drivers/gpio/gpio-ich.c
+++ b/drivers/gpio/gpio-ich.c
@@ -128,9 +128,9 @@ static int ichx_read_bit(int reg, unsigned nr)
 	return data & (1 << bit) ? 1 : 0;
 }
 
-static int ichx_gpio_check_available(struct gpio_chip *gpio, unsigned nr)
+static bool ichx_gpio_check_available(struct gpio_chip *gpio, unsigned nr)
 {
-	return (ichx_priv.use_gpio & (1 << (nr / 32))) ? 0 : -ENXIO;
+	return ichx_priv.use_gpio & (1 << (nr / 32));
 }
 
 static int ichx_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index fff9786cdc64..c2534d62911c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -88,13 +88,14 @@ static int gpiod_request(struct gpio_desc *desc, const char *label);
 static void gpiod_free(struct gpio_desc *desc);
 static int gpiod_direction_input(struct gpio_desc *desc);
 static int gpiod_direction_output(struct gpio_desc *desc, int value);
+static int gpiod_get_direction(const struct gpio_desc *desc);
 static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
-static int gpiod_get_value_cansleep(struct gpio_desc *desc);
+static int gpiod_get_value_cansleep(const struct gpio_desc *desc);
 static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
-static int gpiod_get_value(struct gpio_desc *desc);
+static int gpiod_get_value(const struct gpio_desc *desc);
 static void gpiod_set_value(struct gpio_desc *desc, int value);
-static int gpiod_cansleep(struct gpio_desc *desc);
-static int gpiod_to_irq(struct gpio_desc *desc);
+static int gpiod_cansleep(const struct gpio_desc *desc);
+static int gpiod_to_irq(const struct gpio_desc *desc);
 static int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
 static int gpiod_export_link(struct device *dev, const char *name,
 			     struct gpio_desc *desc);
@@ -171,12 +172,12 @@ static int gpio_ensure_requested(struct gpio_desc *desc)
 	return 0;
 }
 
-/* caller holds gpio_lock *OR* gpio is marked as requested */
-static struct gpio_chip *gpiod_to_chip(struct gpio_desc *desc)
+static struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 {
-	return desc->chip;
+	return desc ? desc->chip : NULL;
 }
 
+/* caller holds gpio_lock *OR* gpio is marked as requested */
 struct gpio_chip *gpio_to_chip(unsigned gpio)
 {
 	return gpiod_to_chip(gpio_to_desc(gpio));
@@ -207,7 +208,7 @@ static int gpiochip_find_base(int ngpio)
 }
 
 /* caller ensures gpio is valid and requested, chip->get_direction may sleep  */
-static int gpiod_get_direction(struct gpio_desc *desc)
+static int gpiod_get_direction(const struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
 	unsigned		offset;
@@ -223,11 +224,13 @@ static int gpiod_get_direction(struct gpio_desc *desc)
 	if (status > 0) {
 		/* GPIOF_DIR_IN, or other positive */
 		status = 1;
-		clear_bit(FLAG_IS_OUT, &desc->flags);
+		/* FLAG_IS_OUT is just a cache of the result of get_direction(),
+		 * so it does not affect constness per se */
+		clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
 	}
 	if (status == 0) {
 		/* GPIOF_DIR_OUT */
-		set_bit(FLAG_IS_OUT, &desc->flags);
+		set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
 	}
 	return status;
 }
@@ -263,7 +266,7 @@ static DEFINE_MUTEX(sysfs_lock);
 static ssize_t gpio_direction_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
-	struct gpio_desc	*desc = dev_get_drvdata(dev);
+	const struct gpio_desc	*desc = dev_get_drvdata(dev);
 	ssize_t			status;
 
 	mutex_lock(&sysfs_lock);
@@ -654,6 +657,11 @@ static ssize_t export_store(struct class *class,
 		goto done;
 
 	desc = gpio_to_desc(gpio);
+	/* reject invalid GPIOs */
+	if (!desc) {
+		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+		return -EINVAL;
+	}
 
 	/* No extra locking here; FLAG_SYSFS just signifies that the
 	 * request and export were done by on behalf of userspace, so
@@ -690,12 +698,14 @@ static ssize_t unexport_store(struct class *class,
 	if (status < 0)
 		goto done;
 
-	status = -EINVAL;
-
 	desc = gpio_to_desc(gpio);
 	/* reject bogus commands (gpio_unexport ignores them) */
-	if (!desc)
-		goto done;
+	if (!desc) {
+		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
+		return -EINVAL;
+	}
+
+	status = -EINVAL;
 
 	/* No extra locking here; FLAG_SYSFS just signifies that the
 	 * request and export were done by on behalf of userspace, so
@@ -846,8 +856,10 @@ static int gpiod_export_link(struct device *dev, const char *name,
 {
 	int			status = -EINVAL;
 
-	if (!desc)
-		goto done;
+	if (!desc) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
 
 	mutex_lock(&sysfs_lock);
 
@@ -865,7 +877,6 @@ static int gpiod_export_link(struct device *dev, const char *name,
 
 	mutex_unlock(&sysfs_lock);
 
-done:
 	if (status)
 		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
 			 status);
@@ -896,8 +907,10 @@ static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
 	struct device		*dev = NULL;
 	int			status = -EINVAL;
 
-	if (!desc)
-		goto done;
+	if (!desc) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
 
 	mutex_lock(&sysfs_lock);
 
@@ -914,7 +927,6 @@ static int gpiod_sysfs_set_active_low(struct gpio_desc *desc, int value)
 unlock:
 	mutex_unlock(&sysfs_lock);
 
-done:
 	if (status)
 		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
 			 status);
@@ -940,8 +952,8 @@ static void gpiod_unexport(struct gpio_desc *desc)
 	struct device		*dev = NULL;
 
 	if (!desc) {
-		status = -EINVAL;
-		goto done;
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return;
 	}
 
 	mutex_lock(&sysfs_lock);
@@ -962,7 +974,7 @@ static void gpiod_unexport(struct gpio_desc *desc)
 		device_unregister(dev);
 		put_device(dev);
 	}
-done:
+
 	if (status)
 		pr_debug("%s: gpio%d status %d\n", __func__, desc_to_gpio(desc),
 			 status);
@@ -1384,12 +1396,13 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
 	int			status = -EPROBE_DEFER;
 	unsigned long		flags;
 
-	spin_lock_irqsave(&gpio_lock, flags);
-
 	if (!desc) {
-		status = -EINVAL;
-		goto done;
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
 	}
+
+	spin_lock_irqsave(&gpio_lock, flags);
+
 	chip = desc->chip;
 	if (chip == NULL)
 		goto done;
@@ -1432,8 +1445,7 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
 done:
 	if (status)
 		pr_debug("_gpio_request: gpio-%d (%s) status %d\n",
-			 desc ? desc_to_gpio(desc) : -1,
-			 label ? : "?", status);
+			 desc_to_gpio(desc), label ? : "?", status);
 	spin_unlock_irqrestore(&gpio_lock, flags);
 	return status;
 }
@@ -1616,10 +1628,13 @@ static int gpiod_direction_input(struct gpio_desc *desc)
 	int			status = -EINVAL;
 	int			offset;
 
+	if (!desc) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!desc)
-		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->get || !chip->direction_input)
 		goto fail;
@@ -1655,13 +1670,9 @@ lose:
 	return status;
 fail:
 	spin_unlock_irqrestore(&gpio_lock, flags);
-	if (status) {
-		int gpio = -1;
-		if (desc)
-			gpio = desc_to_gpio(desc);
-		pr_debug("%s: gpio-%d status %d\n",
-			__func__, gpio, status);
-	}
+	if (status)
+		pr_debug("%s: gpio-%d status %d\n", __func__,
+			 desc_to_gpio(desc), status);
 	return status;
 }
 
@@ -1678,6 +1689,11 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value)
 	int			status = -EINVAL;
 	int offset;
 
+	if (!desc) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+
 	/* Open drain pin should not be driven to 1 */
 	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))
 		return gpiod_direction_input(desc);
@@ -1688,8 +1704,6 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value)
 
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!desc)
-		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->set || !chip->direction_output)
 		goto fail;
@@ -1725,13 +1739,9 @@ lose:
 	return status;
 fail:
 	spin_unlock_irqrestore(&gpio_lock, flags);
-	if (status) {
-		int gpio = -1;
-		if (desc)
-			gpio = desc_to_gpio(desc);
-		pr_debug("%s: gpio-%d status %d\n",
-			__func__, gpio, status);
-	}
+	if (status)
+		pr_debug("%s: gpio-%d status %d\n", __func__,
+			 desc_to_gpio(desc), status);
 	return status;
 }
 
@@ -1753,10 +1763,13 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
 	int			status = -EINVAL;
 	int			offset;
 
+	if (!desc) {
+		pr_warn("%s: invalid GPIO\n", __func__);
+		return -EINVAL;
+	}
+
 	spin_lock_irqsave(&gpio_lock, flags);
 
-	if (!desc)
-		goto fail;
 	chip = desc->chip;
 	if (!chip || !chip->set || !chip->set_debounce)
 		goto fail;
@@ -1776,13 +1789,9 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
 
 fail:
 	spin_unlock_irqrestore(&gpio_lock, flags);
-	if (status) {
-		int gpio = -1;
-		if (desc)
-			gpio = desc_to_gpio(desc);
-		pr_debug("%s: gpio-%d status %d\n",
-			__func__, gpio, status);
-	}
+	if (status)
+		pr_debug("%s: gpio-%d status %d\n", __func__,
+			 desc_to_gpio(desc), status);
 
 	return status;
 }
@@ -1824,12 +1833,14 @@ EXPORT_SYMBOL_GPL(gpio_set_debounce);
  * It returns the zero or nonzero value provided by the associated
  * gpio_chip.get() method; or zero if no such method is provided.
  */
-static int gpiod_get_value(struct gpio_desc *desc)
+static int gpiod_get_value(const struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
 	int value;
 	int offset;
 
+	if (!desc)
+		return 0;
 	chip = desc->chip;
 	offset = gpio_chip_hwgpio(desc);
 	/* Should be using gpio_get_value_cansleep() */
@@ -1912,6 +1923,8 @@ static void gpiod_set_value(struct gpio_desc *desc, int value)
 {
 	struct gpio_chip	*chip;
 
+	if (!desc)
+		return;
 	chip = desc->chip;
 	/* Should be using gpio_set_value_cansleep() */
 	WARN_ON(chip->can_sleep);
@@ -1938,8 +1951,10 @@ EXPORT_SYMBOL_GPL(__gpio_set_value);
  * This is used directly or indirectly to implement gpio_cansleep().  It
  * returns nonzero if access reading or writing the GPIO value can sleep.
  */
-static int gpiod_cansleep(struct gpio_desc *desc)
+static int gpiod_cansleep(const struct gpio_desc *desc)
 {
+	if (!desc)
+		return 0;
 	/* only call this on GPIOs that are valid! */
 	return desc->chip->can_sleep;
 }
@@ -1959,11 +1974,13 @@ EXPORT_SYMBOL_GPL(__gpio_cansleep);
  * It returns the number of the IRQ signaled by this (input) GPIO,
  * or a negative errno.
  */
-static int gpiod_to_irq(struct gpio_desc *desc)
+static int gpiod_to_irq(const struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
 	int			offset;
 
+	if (!desc)
+		return -EINVAL;
 	chip = desc->chip;
 	offset = gpio_chip_hwgpio(desc);
 	return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;
@@ -1980,13 +1997,15 @@ EXPORT_SYMBOL_GPL(__gpio_to_irq);
  * Common examples include ones connected to I2C or SPI chips.
  */
 
-static int gpiod_get_value_cansleep(struct gpio_desc *desc)
+static int gpiod_get_value_cansleep(const struct gpio_desc *desc)
 {
 	struct gpio_chip	*chip;
 	int value;
 	int offset;
 
 	might_sleep_if(extra_checks);
+	if (!desc)
+		return 0;
 	chip = desc->chip;
 	offset = gpio_chip_hwgpio(desc);
 	value = chip->get ? chip->get(chip, offset) : 0;
@@ -2005,6 +2024,8 @@ static void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
 	struct gpio_chip	*chip;
 
 	might_sleep_if(extra_checks);
+	if (!desc)
+		return;
 	chip = desc->chip;
 	trace_gpio_value(desc_to_gpio(desc), 0, value);
 	if (test_bit(FLAG_OPEN_DRAIN,  &desc->flags))