gpiolib: add gpiochip_get_desc() driver function

Gnurou · linusw · commit bb1e88ccb771 · 2014-02-12T17:11:35.000+01:00
Some drivers dealing with a gpio_chip might need to act on its
descriptors directly; one example is pinctrl drivers that need to lock a
GPIO for being used as IRQ using gpiod_lock_as_irq().

This patch exports a gpiochip_get_desc() function that returns the
GPIO descriptor at the requested index. It also sweeps the
gpio_to_chip() function out of the consumer interface since any holder
of a gpio_chip reference can manipulate its GPIOs way beyond what a
consumer should be allowed to do.

As a result, gpio_chip is not visible anymore to simple GPIO consumers.

Signed-off-by: Alexandre Courbot &lt;acourbot@nvidia.com&gt;
Reviewed-by: Mika Westerberg &lt;mika.westerberg@linux.intel.com&gt;
Reviewed-by: Jean-Jacques Hiblot &lt;jjhiblot@traphandler.com&gt;
Signed-off-by: Linus Walleij &lt;linus.walleij@linaro.org&gt;
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
@@ -164,16 +164,17 @@ struct gpio_desc *gpio_to_desc(unsigned gpio)
 EXPORT_SYMBOL_GPL(gpio_to_desc);
 
 /**
- * Convert an offset on a certain chip to a corresponding descriptor
+ * Get the GPIO descriptor corresponding to the given hw number for this chip.
  */
-static struct gpio_desc *gpiochip_offset_to_desc(struct gpio_chip *chip,
-						 unsigned int offset)
+struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
+				    u16 hwnum)
 {
-	if (offset >= chip->ngpio)
+	if (hwnum >= chip->ngpio)
 		return ERR_PTR(-EINVAL);
 
-	return &chip->desc[offset];
+	return &chip->desc[hwnum];
 }
+EXPORT_SYMBOL_GPL(gpiochip_get_desc);
 
 /**
  * Convert a GPIO descriptor to the integer namespace.
@@ -2190,7 +2191,7 @@ EXPORT_SYMBOL_GPL(gpiod_lock_as_irq);
 
 int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
 {
-	return gpiod_lock_as_irq(gpiochip_offset_to_desc(chip, offset));
+	return gpiod_lock_as_irq(gpiochip_get_desc(chip, offset));
 }
 EXPORT_SYMBOL_GPL(gpio_lock_as_irq);
 
@@ -2212,7 +2213,7 @@ EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq);
 
 void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)
 {
-	return gpiod_unlock_as_irq(gpiochip_offset_to_desc(chip, offset));
+	return gpiod_unlock_as_irq(gpiochip_get_desc(chip, offset));
 }
 EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);
 
@@ -2433,7 +2434,7 @@ static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
 			return ERR_PTR(-EINVAL);
 		}
 
-		desc = gpiochip_offset_to_desc(chip, p->chip_hwnum);
+		desc = gpiochip_get_desc(chip, p->chip_hwnum);
 		*flags = p->flags;
 
 		return desc;
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
@@ -7,7 +7,6 @@
 #ifdef CONFIG_GPIOLIB
 
 struct device;
-struct gpio_chip;
 
 /**
  * Opaque descriptor for a GPIO. These are obtained using gpiod_get() and are
@@ -60,7 +59,6 @@ int gpiod_to_irq(const struct gpio_desc *desc);
 /* Convert between the old gpio_ and new gpiod_ interfaces */
 struct gpio_desc *gpio_to_desc(unsigned gpio);
 int desc_to_gpio(const struct gpio_desc *desc);
-struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
 
 #else /* CONFIG_GPIOLIB */
 
@@ -214,12 +212,6 @@ static inline int desc_to_gpio(const struct gpio_desc *desc)
 	WARN_ON(1);
 	return -EINVAL;
 }
-static inline struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
-{
-	/* GPIO can never have been requested */
-	WARN_ON(1);
-	return ERR_PTR(-ENODEV);
-}
 
 
 #endif /* CONFIG_GPIOLIB */
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
@@ -10,6 +10,8 @@ struct of_phandle_args;
 struct device_node;
 struct seq_file;
 
+#ifdef CONFIG_GPIOLIB
+
 /**
  * struct gpio_chip - abstract a GPIO controller
  * @label: for diagnostics
@@ -129,6 +131,11 @@ extern struct gpio_chip *gpiochip_find(void *data,
 int gpiod_lock_as_irq(struct gpio_desc *desc);
 void gpiod_unlock_as_irq(struct gpio_desc *desc);
 
+struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc);
+
+struct gpio_desc *gpiochip_get_desc(struct gpio_chip *chip,
+				    u16 hwnum);
+
 enum gpio_lookup_flags {
 	GPIO_ACTIVE_HIGH = (0 << 0),
 	GPIO_ACTIVE_LOW = (1 << 0),
@@ -183,4 +190,15 @@ struct gpiod_lookup_table {
 
 void gpiod_add_lookup_table(struct gpiod_lookup_table *table);
 
+#else /* CONFIG_GPIOLIB */
+
+static inline struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
+{
+	/* GPIO can never have been requested */
+	WARN_ON(1);
+	return ERR_PTR(-ENODEV);
+}
+
+#endif /* CONFIG_GPIOLIB */
+
 #endif

Original file line number	Diff line number	Diff line change
`@@ -164,16 +164,17 @@ struct gpio_desc *gpio_to_desc(unsigned gpio)`
`164`	`164`	`EXPORT_SYMBOL_GPL(gpio_to_desc);`
`165`	`165`
`166`	`166`	`/**`
`167`		`- * Convert an offset on a certain chip to a corresponding descriptor`
	`167`	`+ * Get the GPIO descriptor corresponding to the given hw number for this chip.`
`168`	`168`	`*/`
`169`		`-static struct gpio_desc gpiochip_offset_to_desc(struct gpio_chip chip,`
`170`		`- unsigned int offset)`
	`169`	`+struct gpio_desc gpiochip_get_desc(struct gpio_chip chip,`
	`170`	`+ u16 hwnum)`
`171`	`171`	`{`
`172`		`- if (offset >= chip->ngpio)`
	`172`	`+ if (hwnum >= chip->ngpio)`
`173`	`173`	`return ERR_PTR(-EINVAL);`
`174`	`174`
`175`		`- return &chip->desc[offset];`
	`175`	`+ return &chip->desc[hwnum];`
`176`	`176`	`}`
	`177`	`+EXPORT_SYMBOL_GPL(gpiochip_get_desc);`
`177`	`178`
`178`	`179`	`/**`
`179`	`180`	`* Convert a GPIO descriptor to the integer namespace.`
`@@ -2190,7 +2191,7 @@ EXPORT_SYMBOL_GPL(gpiod_lock_as_irq);`
`2190`	`2191`
`2191`	`2192`	`int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset)`
`2192`	`2193`	`{`
`2193`		`- return gpiod_lock_as_irq(gpiochip_offset_to_desc(chip, offset));`
	`2194`	`+ return gpiod_lock_as_irq(gpiochip_get_desc(chip, offset));`
`2194`	`2195`	`}`
`2195`	`2196`	`EXPORT_SYMBOL_GPL(gpio_lock_as_irq);`
`2196`	`2197`
`@@ -2212,7 +2213,7 @@ EXPORT_SYMBOL_GPL(gpiod_unlock_as_irq);`
`2212`	`2213`
`2213`	`2214`	`void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset)`
`2214`	`2215`	`{`
`2215`		`- return gpiod_unlock_as_irq(gpiochip_offset_to_desc(chip, offset));`
	`2216`	`+ return gpiod_unlock_as_irq(gpiochip_get_desc(chip, offset));`
`2216`	`2217`	`}`
`2217`	`2218`	`EXPORT_SYMBOL_GPL(gpio_unlock_as_irq);`
`2218`	`2219`
`@@ -2433,7 +2434,7 @@ static struct gpio_desc gpiod_find(struct device dev, const char *con_id,`
`2433`	`2434`	`return ERR_PTR(-EINVAL);`
`2434`	`2435`	`}`
`2435`	`2436`
`2436`		`- desc = gpiochip_offset_to_desc(chip, p->chip_hwnum);`
	`2437`	`+ desc = gpiochip_get_desc(chip, p->chip_hwnum);`
`2437`	`2438`	`*flags = p->flags;`
`2438`	`2439`
`2439`	`2440`	`return desc;`