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kernel_arpi/include/linux/gpio/consumer.h
Linus Walleij f926dfc112 gpio: Make it possible for consumers to enforce open drain 
Some busses, like I2C, strictly need to have the line handled
as open drain, i.e. not actively driven high. For this reason
the i2c-gpio.c bit-banged I2C driver is reimplementing open
drain handling outside of gpiolib.

This is not very optimal. Instead make it possible for a
consumer to explcitly express that the line must be handled
as open drain instead of allowing local hacks papering over
this issue.

The descriptor tables, whether DT, ACPI or board files, should
of course have flagged these lines as open drain. E.g.:
enum gpio_lookup_flags GPIO_OPEN_DRAIN for a board file, or
gpios = <&foo 42 GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN>; in a
device tree using <dt-bindings/gpio/gpio.h>

But more often than not, these descriptors are wrong. So
we need to make it possible for consumers to enforce this
open drain behaviour.

We now have two new enumerated GPIO descriptor config flags:
GPIOD_OUT_LOW_OPEN_DRAIN and GPIOD_OUT_HIGH_OPEN_DRAIN
that will set up the lined enforced as open drain as output
low or high, using open drain (if the driver supports it)
or using open drain emulation (setting the line as input
to drive it high) from the gpiolib core.

Cc: linux-gpio@vger.kernel.org
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-10-30 08:42:31 +01:00

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#ifndef __LINUX_GPIO_CONSUMER_H
#define __LINUX_GPIO_CONSUMER_H
#include <linux/bug.h>
#include <linux/err.h>
#include <linux/kernel.h>
struct device;
/**
* Opaque descriptor for a GPIO. These are obtained using gpiod_get() and are
* preferable to the old integer-based handles.
*
* Contrary to integers, a pointer to a gpio_desc is guaranteed to be valid
* until the GPIO is released.
*/
struct gpio_desc;
/**
* Struct containing an array of descriptors that can be obtained using
* gpiod_get_array().
*/
struct gpio_descs {
unsigned int ndescs;
struct gpio_desc *desc[];
};
#define GPIOD_FLAGS_BIT_DIR_SET BIT(0)
#define GPIOD_FLAGS_BIT_DIR_OUT BIT(1)
#define GPIOD_FLAGS_BIT_DIR_VAL BIT(2)
#define GPIOD_FLAGS_BIT_OPEN_DRAIN BIT(3)
/**
* Optional flags that can be passed to one of gpiod_* to configure direction
* and output value. These values cannot be OR'd.
*/
enum gpiod_flags {
GPIOD_ASIS = 0,
GPIOD_IN = GPIOD_FLAGS_BIT_DIR_SET,
GPIOD_OUT_LOW = GPIOD_FLAGS_BIT_DIR_SET | GPIOD_FLAGS_BIT_DIR_OUT,
GPIOD_OUT_HIGH = GPIOD_FLAGS_BIT_DIR_SET | GPIOD_FLAGS_BIT_DIR_OUT |
GPIOD_FLAGS_BIT_DIR_VAL,
GPIOD_OUT_LOW_OPEN_DRAIN = GPIOD_FLAGS_BIT_DIR_SET |
GPIOD_FLAGS_BIT_DIR_OUT | GPIOD_FLAGS_BIT_OPEN_DRAIN,
GPIOD_OUT_HIGH_OPEN_DRAIN = GPIOD_FLAGS_BIT_DIR_SET |
GPIOD_FLAGS_BIT_DIR_OUT | GPIOD_FLAGS_BIT_DIR_VAL |
GPIOD_FLAGS_BIT_OPEN_DRAIN,
};
#ifdef CONFIG_GPIOLIB
/* Return the number of GPIOs associated with a device / function */
int gpiod_count(struct device *dev, const char *con_id);
/* Acquire and dispose GPIOs */
struct gpio_desc *__must_check gpiod_get(struct device *dev,
const char *con_id,
enum gpiod_flags flags);
struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
const char *con_id,
unsigned int idx,
enum gpiod_flags flags);
struct gpio_desc *__must_check gpiod_get_optional(struct device *dev,
const char *con_id,
enum gpiod_flags flags);
struct gpio_desc *__must_check gpiod_get_index_optional(struct device *dev,
const char *con_id,
unsigned int index,
enum gpiod_flags flags);
struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
const char *con_id,
enum gpiod_flags flags);
struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
const char *con_id,
enum gpiod_flags flags);
void gpiod_put(struct gpio_desc *desc);
void gpiod_put_array(struct gpio_descs *descs);
struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
const char *con_id,
enum gpiod_flags flags);
struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
const char *con_id,
unsigned int idx,
enum gpiod_flags flags);
struct gpio_desc *__must_check devm_gpiod_get_optional(struct device *dev,
const char *con_id,
enum gpiod_flags flags);
struct gpio_desc *__must_check
devm_gpiod_get_index_optional(struct device *dev, const char *con_id,
unsigned int index, enum gpiod_flags flags);
struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev,
const char *con_id,
enum gpiod_flags flags);
struct gpio_descs *__must_check
devm_gpiod_get_array_optional(struct device *dev, const char *con_id,
enum gpiod_flags flags);
void devm_gpiod_put(struct device *dev, struct gpio_desc *desc);
void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs);
int gpiod_get_direction(struct gpio_desc *desc);
int gpiod_direction_input(struct gpio_desc *desc);
int gpiod_direction_output(struct gpio_desc *desc, int value);
int gpiod_direction_output_raw(struct gpio_desc *desc, int value);
/* Value get/set from non-sleeping context */
int gpiod_get_value(const struct gpio_desc *desc);
void gpiod_set_value(struct gpio_desc *desc, int value);
void gpiod_set_array_value(unsigned int array_size,
struct gpio_desc **desc_array, int *value_array);
int gpiod_get_raw_value(const struct gpio_desc *desc);
void gpiod_set_raw_value(struct gpio_desc *desc, int value);
void gpiod_set_raw_array_value(unsigned int array_size,
struct gpio_desc **desc_array,
int *value_array);
/* Value get/set from sleeping context */
int gpiod_get_value_cansleep(const struct gpio_desc *desc);
void gpiod_set_value_cansleep(struct gpio_desc *desc, int value);
void gpiod_set_array_value_cansleep(unsigned int array_size,
struct gpio_desc **desc_array,
int *value_array);
int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc);
void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value);
void gpiod_set_raw_array_value_cansleep(unsigned int array_size,
struct gpio_desc **desc_array,
int *value_array);
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce);
int gpiod_is_active_low(const struct gpio_desc *desc);
int gpiod_cansleep(const struct gpio_desc *desc);
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);
/* Child properties interface */
struct fwnode_handle;
struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
const char *propname, int index,
enum gpiod_flags dflags,
const char *label);
struct gpio_desc *devm_fwnode_get_index_gpiod_from_child(struct device *dev,
const char *con_id, int index,
struct fwnode_handle *child,
enum gpiod_flags flags,
const char *label);
#else /* CONFIG_GPIOLIB */
static inline int gpiod_count(struct device *dev, const char *con_id)
{
return 0;
}
static inline struct gpio_desc *__must_check gpiod_get(struct device *dev,
const char *con_id,
enum gpiod_flags flags)
{
return ERR_PTR(-ENOSYS);
}
static inline struct gpio_desc *__must_check
gpiod_get_index(struct device *dev,
const char *con_id,
unsigned int idx,
enum gpiod_flags flags)
{
return ERR_PTR(-ENOSYS);
}
static inline struct gpio_desc *__must_check
gpiod_get_optional(struct device *dev, const char *con_id,
enum gpiod_flags flags)
{
return NULL;
}
static inline struct gpio_desc *__must_check
gpiod_get_index_optional(struct device *dev, const char *con_id,
unsigned int index, enum gpiod_flags flags)
{
return NULL;
}
static inline struct gpio_descs *__must_check
gpiod_get_array(struct device *dev, const char *con_id,
enum gpiod_flags flags)
{
return ERR_PTR(-ENOSYS);
}
static inline struct gpio_descs *__must_check
gpiod_get_array_optional(struct device *dev, const char *con_id,
enum gpiod_flags flags)
{
return NULL;
}
static inline void gpiod_put(struct gpio_desc *desc)
{
might_sleep();
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline void gpiod_put_array(struct gpio_descs *descs)
{
might_sleep();
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline struct gpio_desc *__must_check
devm_gpiod_get(struct device *dev,
const char *con_id,
enum gpiod_flags flags)
{
return ERR_PTR(-ENOSYS);
}
static inline
struct gpio_desc *__must_check
devm_gpiod_get_index(struct device *dev,
const char *con_id,
unsigned int idx,
enum gpiod_flags flags)
{
return ERR_PTR(-ENOSYS);
}
static inline struct gpio_desc *__must_check
devm_gpiod_get_optional(struct device *dev, const char *con_id,
enum gpiod_flags flags)
{
return NULL;
}
static inline struct gpio_desc *__must_check
devm_gpiod_get_index_optional(struct device *dev, const char *con_id,
unsigned int index, enum gpiod_flags flags)
{
return NULL;
}
static inline struct gpio_descs *__must_check
devm_gpiod_get_array(struct device *dev, const char *con_id,
enum gpiod_flags flags)
{
return ERR_PTR(-ENOSYS);
}
static inline struct gpio_descs *__must_check
devm_gpiod_get_array_optional(struct device *dev, const char *con_id,
enum gpiod_flags flags)
{
return NULL;
}
static inline void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
{
might_sleep();
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline void devm_gpiod_put_array(struct device *dev,
struct gpio_descs *descs)
{
might_sleep();
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_direction(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_direction_input(struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_direction_output(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_direction_output_raw(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_get_value(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_value(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline void gpiod_set_array_value(unsigned int array_size,
struct gpio_desc **desc_array,
int *value_array)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_raw_value(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_raw_value(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline void gpiod_set_raw_array_value(unsigned int array_size,
struct gpio_desc **desc_array,
int *value_array)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_value_cansleep(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline void gpiod_set_array_value_cansleep(unsigned int array_size,
struct gpio_desc **desc_array,
int *value_array)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline void gpiod_set_raw_value_cansleep(struct gpio_desc *desc,
int value)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline void gpiod_set_raw_array_value_cansleep(unsigned int array_size,
struct gpio_desc **desc_array,
int *value_array)
{
/* GPIO can never have been requested */
WARN_ON(1);
}
static inline int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -ENOSYS;
}
static inline int gpiod_is_active_low(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline int gpiod_cansleep(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return 0;
}
static inline int gpiod_to_irq(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -EINVAL;
}
static inline struct gpio_desc *gpio_to_desc(unsigned gpio)
{
return ERR_PTR(-EINVAL);
}
static inline int desc_to_gpio(const struct gpio_desc *desc)
{
/* GPIO can never have been requested */
WARN_ON(1);
return -EINVAL;
}
/* Child properties interface */
struct fwnode_handle;
static inline
struct gpio_desc *fwnode_get_named_gpiod(struct fwnode_handle *fwnode,
const char *propname, int index,
enum gpiod_flags dflags,
const char *label)
{
return ERR_PTR(-ENOSYS);
}
static inline
struct gpio_desc *devm_fwnode_get_index_gpiod_from_child(struct device *dev,
const char *con_id, int index,
struct fwnode_handle *child,
enum gpiod_flags flags,
const char *label)
{
return ERR_PTR(-ENOSYS);
}
#endif /* CONFIG_GPIOLIB */
static inline
struct gpio_desc *devm_fwnode_get_gpiod_from_child(struct device *dev,
const char *con_id,
struct fwnode_handle *child,
enum gpiod_flags flags,
const char *label)
{
return devm_fwnode_get_index_gpiod_from_child(dev, con_id, 0, child,
flags, label);
}
#if IS_ENABLED(CONFIG_GPIOLIB) && IS_ENABLED(CONFIG_GPIO_SYSFS)
int gpiod_export(struct gpio_desc *desc, bool direction_may_change);
int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc);
void gpiod_unexport(struct gpio_desc *desc);
#else /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
static inline int gpiod_export(struct gpio_desc *desc,
bool direction_may_change)
{
return -ENOSYS;
}
static inline int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc)
{
return -ENOSYS;
}
static inline void gpiod_unexport(struct gpio_desc *desc)
{
}
#endif /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
#endif
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