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of/gpio: Implement of_get_gpio_flags()
This adds a new function, of_get_gpio_flags, which is like of_get_gpio(), but accepts a new "flags" argument. This new function will be used by the drivers that need to retrieve additional GPIO information, such as active-low flag. Also, this changes the 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 <avorontsov@ru.mvista.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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@ -19,14 +19,17 @@
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#include <asm/prom.h>
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/**
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* of_get_gpio - Get a GPIO number from the device tree to use with GPIO API
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* of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API
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* @np: device node to get GPIO from
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* @index: index of the GPIO
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* @flags: a flags pointer to fill in
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*
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* Returns GPIO number to use with Linux generic GPIO API, or one of the errno
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* value on the error condition.
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* value on the error condition. If @flags is not NULL the function also fills
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* in flags for the GPIO.
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*/
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int of_get_gpio(struct device_node *np, int index)
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int of_get_gpio_flags(struct device_node *np, int index,
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enum of_gpio_flags *flags)
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{
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int ret;
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struct device_node *gc;
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@ -59,7 +62,11 @@ int of_get_gpio(struct device_node *np, int index)
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goto err1;
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}
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ret = of_gc->xlate(of_gc, np, gpio_spec);
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/* .xlate might decide to not fill in the flags, so clear it. */
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if (flags)
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*flags = 0;
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ret = of_gc->xlate(of_gc, np, gpio_spec, flags);
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if (ret < 0)
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goto err1;
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@ -70,26 +77,41 @@ err0:
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pr_debug("%s exited with status %d\n", __func__, ret);
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return ret;
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}
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EXPORT_SYMBOL(of_get_gpio);
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EXPORT_SYMBOL(of_get_gpio_flags);
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/**
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* of_gpio_simple_xlate - translate gpio_spec to the GPIO number
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* of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
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* @of_gc: pointer to the of_gpio_chip structure
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* @np: device node of the GPIO chip
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* @gpio_spec: gpio specifier as found in the device tree
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* @flags: a flags pointer to fill in
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*
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* This is simple translation function, suitable for the most 1:1 mapped
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* gpio chips. This function performs only one sanity check: whether gpio
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* is less than ngpios (that is specified in the gpio_chip).
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*/
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int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np,
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const void *gpio_spec)
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const void *gpio_spec, enum of_gpio_flags *flags)
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{
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const u32 *gpio = gpio_spec;
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/*
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* We're discouraging gpio_cells < 2, since that way you'll have to
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* write your own xlate function (that will have to retrive the GPIO
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* number and the flags from a single gpio cell -- this is possible,
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* but not recommended).
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*/
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if (of_gc->gpio_cells < 2) {
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WARN_ON(1);
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return -EINVAL;
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}
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if (*gpio > of_gc->gc.ngpio)
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return -EINVAL;
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if (flags)
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*flags = gpio[1];
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return *gpio;
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}
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EXPORT_SYMBOL(of_gpio_simple_xlate);
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@ -14,9 +14,22 @@
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#ifndef __LINUX_OF_GPIO_H
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#define __LINUX_OF_GPIO_H
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#include <linux/compiler.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/gpio.h>
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struct device_node;
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/*
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* This is Linux-specific flags. By default controllers' and Linux' mapping
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* match, but GPIO controllers are free to translate their own flags to
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* Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
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*/
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enum of_gpio_flags {
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OF_GPIO_ACTIVE_LOW = 0x1,
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};
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#ifdef CONFIG_OF_GPIO
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/*
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@ -26,7 +39,7 @@ struct of_gpio_chip {
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struct gpio_chip gc;
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int gpio_cells;
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int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
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const void *gpio_spec);
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const void *gpio_spec, enum of_gpio_flags *flags);
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};
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static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
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@ -50,20 +63,37 @@ static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
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return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
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}
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extern int of_get_gpio(struct device_node *np, int index);
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extern int of_get_gpio_flags(struct device_node *np, int index,
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enum of_gpio_flags *flags);
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extern int of_mm_gpiochip_add(struct device_node *np,
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struct of_mm_gpio_chip *mm_gc);
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extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
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struct device_node *np,
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const void *gpio_spec);
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const void *gpio_spec,
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enum of_gpio_flags *flags);
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#else
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/* Drivers may not strictly depend on the GPIO support, so let them link. */
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static inline int of_get_gpio(struct device_node *np, int index)
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static inline int of_get_gpio_flags(struct device_node *np, int index,
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enum of_gpio_flags *flags)
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{
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return -ENOSYS;
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}
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#endif /* CONFIG_OF_GPIO */
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/**
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* of_get_gpio - Get a GPIO number to use with GPIO API
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* @np: device node to get GPIO from
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* @index: index of the GPIO
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*
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* Returns GPIO number to use with Linux generic GPIO API, or one of the errno
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* value on the error condition.
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*/
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static inline int of_get_gpio(struct device_node *np, int index)
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{
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return of_get_gpio_flags(np, index, NULL);
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}
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#endif /* __LINUX_OF_GPIO_H */
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