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[gpio] Add a framework for GPIO controllers

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Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2025-08-05 13:54:27 +01:00
parent 5f10b74555
commit 90fe3a2924
3 changed files with 365 additions and 0 deletions
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1
src/include/ipxe/errfile.h
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@@ -87,6 +87,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define ERRFILE_efi_open ( ERRFILE_CORE | 0x002f0000 )
#define ERRFILE_efi_table ( ERRFILE_CORE | 0x00300000 )
#define ERRFILE_efi_connect ( ERRFILE_CORE | 0x00310000 )
#define ERRFILE_gpio ( ERRFILE_CORE | 0x00320000 )
#define ERRFILE_eisa ( ERRFILE_DRIVER | 0x00000000 )
#define ERRFILE_isa ( ERRFILE_DRIVER | 0x00010000 )

199
src/include/ipxe/gpio.h Normal file
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@@ -0,0 +1,199 @@
#ifndef _IPXE_GPIO_H
#define _IPXE_GPIO_H
/** @file
*
* General purpose I/O
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <ipxe/list.h>
#include <ipxe/refcnt.h>
#include <ipxe/device.h>
/** A GPIO pin */
struct gpio {
/** GPIO controller */
struct gpios *gpios;
/** Pin index */
unsigned int index;
/** Configuration */
unsigned int config;
};
/** GPIO is active low
*
* This bit is chosen to match the devicetree standard usage.
*/
#define GPIO_CFG_ACTIVE_LOW 0x01
/** GPIO is an output */
#define GPIO_CFG_OUTPUT 0x0100
/** A GPIO controller */
struct gpios {
/** Reference count */
struct refcnt refcnt;
/** List of GPIO controllers */
struct list_head list;
/** Generic device */
struct device *dev;
/** Number of GPIOs */
unsigned int count;
/** Individual GPIOs */
struct gpio *gpio;
/** GPIO operations */
struct gpio_operations *op;
/** Driver-private data */
void *priv;
};
/** GPIO operations */
struct gpio_operations {
/**
* Get current GPIO input value
*
* @v gpios GPIO controller
* @v gpio GPIO pin
* @ret active Pin is in the active state
*/
int ( * in ) ( struct gpios *gpios, struct gpio *gpio );
/**
* Set current GPIO output value
*
* @v gpios GPIO controller
* @v gpio GPIO pin
* @v active Set pin to active state
*/
void ( * out ) ( struct gpios *gpios, struct gpio *gpio, int active );
/**
* Configure GPIO pin
*
* @v gpios GPIO controller
* @v gpio GPIO pin
* @v config Configuration
* @ret rc Return status code
*/
int ( * config ) ( struct gpios *gpios, struct gpio *gpio,
unsigned int config );
};
extern struct gpio_operations null_gpio_operations;
/**
* Get reference to GPIO controller
*
* @v gpios GPIO controller
* @ret gpios GPIO controller
*/
static inline __attribute__ (( always_inline )) struct gpios *
gpios_get ( struct gpios *gpios ) {
ref_get ( &gpios->refcnt );
return gpios;
}
/**
* Drop reference to GPIO controller
*
* @v gpios GPIO controller
*/
static inline __attribute__ (( always_inline )) void
gpios_put ( struct gpios *gpios ) {
ref_put ( &gpios->refcnt );
}
/**
* Get reference to GPIO pin
*
* @v gpio GPIO pin
* @ret gpio GPIO pin
*/
static inline __attribute__ (( always_inline )) struct gpio *
gpio_get ( struct gpio *gpio ) {
gpios_get ( gpio->gpios );
return gpio;
}
/**
* Drop reference to GPIO ping
*
* @v gpio GPIO pin
*/
static inline __attribute__ (( always_inline )) void
gpio_put ( struct gpio *gpio ) {
gpios_put ( gpio->gpios );
}
/**
* Initialise a GPIO controller
*
* @v gpios GPIO controller
* @v op GPIO operations
*/
static inline __attribute__ (( always_inline )) void
gpios_init ( struct gpios *gpios, struct gpio_operations *op ) {
gpios->op = op;
}
/**
* Stop using a GPIO controller
*
* @v gpios GPIO controller
*
* Drivers should call this method immediately before the final call
* to gpios_put().
*/
static inline __attribute__ (( always_inline )) void
gpios_nullify ( struct gpios *gpios ) {
gpios->op = &null_gpio_operations;
}
/**
* Get current GPIO input value
*
* @v gpio GPIO pin
* @ret active Pin is in the active state
*/
static inline int gpio_in ( struct gpio *gpio ) {
struct gpios *gpios = gpio->gpios;
return gpios->op->in ( gpios, gpio );
}
/**
* Set current GPIO output value
*
* @v gpio GPIO pin
* @v active Set pin to active state
*/
static inline void gpio_out ( struct gpio *gpio, int active ) {
struct gpios *gpios = gpio->gpios;
gpios->op->out ( gpios, gpio, active );
}
/**
* Configure GPIO pin
*
* @v gpio GPIO pin
* @v config Configuration
* @ret rc Return status code
*/
static inline int gpio_config ( struct gpio *gpio, unsigned int config ) {
struct gpios *gpios = gpio->gpios;
return gpios->op->config ( gpios, gpio, config );
}
extern struct gpios * alloc_gpios ( unsigned int count, size_t priv_len );
extern int gpios_register ( struct gpios *gpios );
extern void gpios_unregister ( struct gpios *gpios );
extern struct gpios * gpios_find ( unsigned int bus_type,
unsigned int location );
#endif /* _IPXE_GPIO_H */