This function is alike to the simple of_get_gpio(), but accepts new
argument: flags. This new function will be used by the drivers that
need to retrieve additional GPIO information, such as active-low flag.
Also, the patch changes default ("simple") .xlate routine to warn about
bogus (< 2) #gpio-cells usage: the second cell should always be present
for GPIO flags.
Signed-off-by: Anton Vorontsov <[EMAIL PROTECTED]>
---
v1 -> v2:
- Commit message mentions .xlate behaviour change;
- enum of_gpio_flags also defined for !CONFIG_OF_GPIO case.
drivers/of/gpio.c | 36 +++++++++++++++++++++++++++++-------
include/linux/of_gpio.h | 38 ++++++++++++++++++++++++++++++++++----
2 files changed, 63 insertions(+), 11 deletions(-)
diff --git a/drivers/of/gpio.c b/drivers/of/gpio.c
index 7cd7301..a4ba217 100644
--- a/drivers/of/gpio.c
+++ b/drivers/of/gpio.c
@@ -19,14 +19,17 @@
#include <asm/prom.h>
/**
- * of_get_gpio - Get a GPIO number from the device tree to use with GPIO API
+ * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API
* @np: device node to get GPIO from
* @index: index of the GPIO
+ * @flags: a flags pointer to fill in
*
* Returns GPIO number to use with Linux generic GPIO API, or one of the errno
- * value on the error condition.
+ * value on the error condition. If @flags is not NULL the function also fills
+ * in flags for the GPIO.
*/
-int of_get_gpio(struct device_node *np, int index)
+int of_get_gpio_flags(struct device_node *np, int index,
+ enum of_gpio_flags *flags)
{
int ret;
struct device_node *gc;
@@ -59,7 +62,11 @@ int of_get_gpio(struct device_node *np, int index)
goto err1;
}
- ret = of_gc->xlate(of_gc, np, gpio_spec);
+ /* .xlate might decide to not fill in the flags, so clear it. */
+ if (flags)
+ *flags = 0;
+
+ ret = of_gc->xlate(of_gc, np, gpio_spec, flags);
if (ret < 0)
goto err1;
@@ -70,26 +77,41 @@ err0:
pr_debug("%s exited with status %d\n", __func__, ret);
return ret;
}
-EXPORT_SYMBOL(of_get_gpio);
+EXPORT_SYMBOL(of_get_gpio_flags);
/**
- * of_gpio_simple_xlate - translate gpio_spec to the GPIO number
+ * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
* @of_gc: pointer to the of_gpio_chip structure
* @np: device node of the GPIO chip
* @gpio_spec: gpio specifier as found in the device tree
+ * @flags: a flags pointer to fill in
*
* This is simple translation function, suitable for the most 1:1 mapped
* gpio chips. This function performs only one sanity check: whether gpio
* is less than ngpios (that is specified in the gpio_chip).
*/
int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np,
- const void *gpio_spec)
+ const void *gpio_spec, enum of_gpio_flags *flags)
{
const u32 *gpio = gpio_spec;
+ /*
+ * We're discouraging gpio_cells < 2, since that way you'll have to
+ * write your own xlate function (that will have to retrive the GPIO
+ * number and the flags from a single gpio cell -- this is possible,
+ * but not recommended).
+ */
+ if (of_gc->gpio_cells < 2) {
+ WARN_ON(1);
+ return -EINVAL;
+ }
+
if (*gpio > of_gc->gc.ngpio)
return -EINVAL;
+ if (flags)
+ *flags = gpio[1];
+
return *gpio;
}
EXPORT_SYMBOL(of_gpio_simple_xlate);
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index 67db101..e25abf6 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -14,9 +14,22 @@
#ifndef __LINUX_OF_GPIO_H
#define __LINUX_OF_GPIO_H
+#include <linux/compiler.h>
+#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/gpio.h>
+struct device_node;
+
+/*
+ * This is Linux-specific flags. By default controllers' and Linux' mapping
+ * match, but GPIO controllers are free to translate their own flags to
+ * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
+ */
+enum of_gpio_flags {
+ OF_GPIO_ACTIVE_LOW = 0x1,
+};
+
#ifdef CONFIG_OF_GPIO
/*
@@ -26,7 +39,7 @@ struct of_gpio_chip {
struct gpio_chip gc;
int gpio_cells;
int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
- const void *gpio_spec);
+ const void *gpio_spec, enum of_gpio_flags *flags);
};
static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
@@ -50,20 +63,37 @@ static inline struct of_mm_gpio_chip
*to_of_mm_gpio_chip(struct gpio_chip *gc)
return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
}
-extern int of_get_gpio(struct device_node *np, int index);
+extern int of_get_gpio_flags(struct device_node *np, int index,
+ enum of_gpio_flags *flags);
+
extern int of_mm_gpiochip_add(struct device_node *np,
struct of_mm_gpio_chip *mm_gc);
extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
struct device_node *np,
- const void *gpio_spec);
+ const void *gpio_spec,
+ enum of_gpio_flags *flags);
#else
/* Drivers may not strictly depend on the GPIO support, so let them link. */
-static inline int of_get_gpio(struct device_node *np, int index)
+static inline int of_get_gpio_flags(struct device_node *np, int index,
+ enum of_gpio_flags *flags)
{
return -ENOSYS;
}
#endif /* CONFIG_OF_GPIO */
+/**
+ * of_get_gpio - Get a GPIO number to use with GPIO API
+ * @np: device node to get GPIO from
+ * @index: index of the GPIO
+ *
+ * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
+ * value on the error condition.
+ */
+static inline int of_get_gpio(struct device_node *np, int index)
+{
+ return of_get_gpio_flags(np, index, NULL);
+}
+
#endif /* __LINUX_OF_GPIO_H */
--
1.5.6.5
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