@ -112,6 +112,18 @@ struct gpio_desc {
} ;
/**
* dm_gpio_is_valid ( ) - Check if a GPIO is gpio_is_valie
*
* @ desc : GPIO description containing device , offset and flags ,
* previously returned by gpio_request_by_name ( )
* @ return true if valid , false if not
*/
static inline bool dm_gpio_is_valid ( struct gpio_desc * desc )
{
return desc - > dev ! = NULL ;
}
/**
* gpio_get_status ( ) - get the current GPIO status as a string
*
* Obtain the current GPIO status as a string which can be presented to the
@ -313,4 +325,191 @@ int gpio_lookup_name(const char *name, struct udevice **devp,
*/
unsigned gpio_get_values_as_int ( const int * gpio_list ) ;
/**
* gpio_request_by_name ( ) - Locate and request a GPIO by name
*
* This operates by looking up the given list name in the device ( device
* tree property ) and requesting the GPIO for use . The property must exist
* in @ dev ' s node .
*
* Use @ flags to specify whether the GPIO should be an input or output . In
* principle this can also come from the device tree binding but most
* bindings don ' t provide this information . Specifically , when the GPIO uclass
* calls the xlate ( ) method , it can return default flags , which are then
* ORed with this @ flags .
*
* If we find that requesting the GPIO is not always needed we could add a
* new function or a new GPIOD_NO_REQUEST flag .
*
* At present driver model has no reference counting so if one device
* requests a GPIO which subsequently is unbound , the @ desc - > dev pointer
* will be invalid . However this will only happen if the GPIO device is
* unbound , not if it is removed , so this seems like a reasonable limitation
* for now . There is no real use case for unbinding drivers in normal
* operation .
*
* The device tree binding is doc / device - tree - bindings / gpio / gpio . txt in
* generate terms and each specific device may add additional details in
* a binding file in the same directory .
*
* @ dev : Device requesting the GPIO
* @ list_name : Name of GPIO list ( e . g . " board-id-gpios " )
* @ index : Index number of the GPIO in that list use request ( 0 = first )
* @ desc : Returns GPIO description information . If there is no such
* GPIO , dev - > dev will be NULL .
* @ flags : Indicates the GPIO input / output settings ( GPIOD_ . . . )
* @ return 0 if OK , - ENOENT if the GPIO does not exist , - EINVAL if there is
* something wrong with the list , or other - ve for another error ( e . g .
* - EBUSY if a GPIO was already requested )
*/
int gpio_request_by_name ( struct udevice * dev , const char * list_name ,
int index , struct gpio_desc * desc , int flags ) ;
/**
* gpio_request_list_by_name ( ) - Request a list of GPIOs
*
* Reads all the GPIOs from a list and requetss them . See
* gpio_request_by_name ( ) for additional details . Lists should not be
* misused to hold unrelated or optional GPIOs . They should only be used
* for things like parallel data lines . A zero phandle terminates the list
* the list .
*
* This function will either succeed , and request all GPIOs in the list , or
* fail and request none ( it will free already - requested GPIOs in case of
* an error part - way through ) .
*
* @ dev : Device requesting the GPIO
* @ list_name : Name of GPIO list ( e . g . " board-id-gpios " )
* @ desc_list : Returns a list of GPIO description information
* @ max_count : Maximum number of GPIOs to return ( @ desc_list must be at least
* this big )
* @ flags : Indicates the GPIO input / output settings ( GPIOD_ . . . )
* @ return number of GPIOs requested , or - ve on error
*/
int gpio_request_list_by_name ( struct udevice * dev , const char * list_name ,
struct gpio_desc * desc_list , int max_count ,
int flags ) ;
/**
* gpio_get_list_count ( ) - Returns the number of GPIOs in a list
*
* Counts the GPIOs in a list . See gpio_request_by_name ( ) for additional
* details .
*
* @ dev : Device requesting the GPIO
* @ list_name : Name of GPIO list ( e . g . " board-id-gpios " )
* @ return number of GPIOs ( 0 for an empty property ) or - ENOENT if the list
* does not exist
*/
int gpio_get_list_count ( struct udevice * dev , const char * list_name ) ;
/**
* gpio_request_by_name_nodev ( ) - request GPIOs without a device
*
* This is a version of gpio_request_list_by_name ( ) that does not use a
* device . Avoid it unless the caller is not yet using driver model
*/
int gpio_request_by_name_nodev ( const void * blob , int node ,
const char * list_name ,
int index , struct gpio_desc * desc , int flags ) ;
/**
* gpio_request_list_by_name_nodev ( ) - request GPIOs without a device
*
* This is a version of gpio_request_list_by_name ( ) that does not use a
* device . Avoid it unless the caller is not yet using driver model
*/
int gpio_request_list_by_name_nodev ( const void * blob , int node ,
const char * list_name ,
struct gpio_desc * desc_list , int max_count ,
int flags ) ;
/**
* dm_gpio_free ( ) - Free a single GPIO
*
* This frees a single GPIOs previously returned from gpio_request_by_name ( ) .
*
* @ dev : Device which requested the GPIO
* @ desc : GPIO to free
* @ return 0 if OK , - ve on error
*/
int dm_gpio_free ( struct udevice * dev , struct gpio_desc * desc ) ;
/**
* gpio_free_list ( ) - Free a list of GPIOs
*
* This frees a list of GPIOs previously returned from
* gpio_request_list_by_name ( ) .
*
* @ dev : Device which requested the GPIOs
* @ desc : List of GPIOs to free
* @ count : Number of GPIOs in the list
* @ return 0 if OK , - ve on error
*/
int gpio_free_list ( struct udevice * dev , struct gpio_desc * desc , int count ) ;
/**
* gpio_free_list_nodev ( ) - free GPIOs without a device
*
* This is a version of gpio_free_list ( ) that does not use a
* device . Avoid it unless the caller is not yet using driver model
*/
int gpio_free_list_nodev ( struct gpio_desc * desc , int count ) ;
/**
* dm_gpio_get_value ( ) - Get the value of a GPIO
*
* This is the driver model version of the existing gpio_get_value ( ) function
* and should be used instead of that .
*
* For now , these functions have a dm_ prefix since they conflict with
* existing names .
*
* @ desc : GPIO description containing device , offset and flags ,
* previously returned by gpio_request_by_name ( )
* @ return GPIO value ( 0 for inactive , 1 for active ) or - ve on error
*/
int dm_gpio_get_value ( struct gpio_desc * desc ) ;
int dm_gpio_set_value ( struct gpio_desc * desc , int value ) ;
/**
* dm_gpio_set_dir ( ) - Set the direction for a GPIO
*
* This sets up the direction according tot the provided flags . It will do
* nothing unless the direction is actually specified .
*
* @ desc : GPIO description containing device , offset and flags ,
* previously returned by gpio_request_by_name ( )
* @ return 0 if OK , - ve on error
*/
int dm_gpio_set_dir ( struct gpio_desc * desc ) ;
/**
* dm_gpio_set_dir_flags ( ) - Set direction using specific flags
*
* This is like dm_gpio_set_dir ( ) except that the flags value is provided
* instead of being used from desc - > flags . This is needed because in many
* cases the GPIO description does not include direction information .
* Note that desc - > flags is updated by this function .
*
* @ desc : GPIO description containing device , offset and flags ,
* previously returned by gpio_request_by_name ( )
* @ flags : New flags to use
* @ return 0 if OK , - ve on error , in which case desc - > flags is not updated
*/
int dm_gpio_set_dir_flags ( struct gpio_desc * desc , ulong flags ) ;
/**
* gpio_get_number ( ) - Get the global GPIO number of a GPIO
*
* This should only be used for debugging or interest . It returns the nummber
* that should be used for gpio_get_value ( ) etc . to access this GPIO .
*
* @ desc : GPIO description containing device , offset and flags ,
* previously returned by gpio_request_by_name ( )
* @ return GPIO number , or - ve if not found
*/
int gpio_get_number ( struct gpio_desc * desc ) ;
# endif /* _ASM_GENERIC_GPIO_H_ */
Simon Glass
10 years ago