diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/spi/spi.h | 75 |
1 files changed, 52 insertions, 23 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 51a6769114d..c851b3d1320 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -20,13 +20,8 @@ #define __LINUX_SPI_H /* - * INTERFACES between SPI master drivers and infrastructure + * INTERFACES between SPI master-side drivers and SPI infrastructure. * (There's no SPI slave support for Linux yet...) - * - * A "struct device_driver" for an spi_device uses "spi_bus_type" and - * needs no special API wrappers (much like platform_bus). These drivers - * are bound to devices based on their names (much like platform_bus), - * and are available in dev->driver. */ extern struct bus_type spi_bus_type; @@ -46,8 +41,8 @@ extern struct bus_type spi_bus_type; * @irq: Negative, or the number passed to request_irq() to receive * interrupts from this device. * @controller_state: Controller's runtime state - * @controller_data: Static board-specific definitions for controller, such - * as FIFO initialization parameters; from board_info.controller_data + * @controller_data: Board-specific definitions for controller, such as + * FIFO initialization parameters; from board_info.controller_data * * An spi_device is used to interchange data between an SPI slave * (usually a discrete chip) and CPU memory. @@ -63,31 +58,32 @@ struct spi_device { u32 max_speed_hz; u8 chip_select; u8 mode; -#define SPI_CPHA 0x01 /* clock phase */ -#define SPI_CPOL 0x02 /* clock polarity */ +#define SPI_CPHA 0x01 /* clock phase */ +#define SPI_CPOL 0x02 /* clock polarity */ #define SPI_MODE_0 (0|0) -#define SPI_MODE_1 (0|SPI_CPHA) +#define SPI_MODE_1 (0|SPI_CPHA) /* (original MicroWire) */ #define SPI_MODE_2 (SPI_CPOL|0) #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) -#define SPI_CS_HIGH 0x04 /* chipselect active high? */ +#define SPI_CS_HIGH 0x04 /* chipselect active high? */ u8 bits_per_word; int irq; void *controller_state; - const void *controller_data; + void *controller_data; const char *modalias; // likely need more hooks for more protocol options affecting how - // the controller talks to its chips, like: + // the controller talks to each chip, like: // - bit order (default is wordwise msb-first) // - memory packing (12 bit samples into low bits, others zeroed) // - priority + // - drop chipselect after each word // - chipselect delays // - ... }; static inline struct spi_device *to_spi_device(struct device *dev) { - return container_of(dev, struct spi_device, dev); + return dev ? container_of(dev, struct spi_device, dev) : NULL; } /* most drivers won't need to care about device refcounting */ @@ -117,12 +113,38 @@ static inline void spi_set_ctldata(struct spi_device *spi, void *state) struct spi_message; + +struct spi_driver { + int (*probe)(struct spi_device *spi); + int (*remove)(struct spi_device *spi); + void (*shutdown)(struct spi_device *spi); + int (*suspend)(struct spi_device *spi, pm_message_t mesg); + int (*resume)(struct spi_device *spi); + struct device_driver driver; +}; + +static inline struct spi_driver *to_spi_driver(struct device_driver *drv) +{ + return drv ? container_of(drv, struct spi_driver, driver) : NULL; +} + +extern int spi_register_driver(struct spi_driver *sdrv); + +static inline void spi_unregister_driver(struct spi_driver *sdrv) +{ + if (!sdrv) + return; + driver_unregister(&sdrv->driver); +} + + + /** * struct spi_master - interface to SPI master controller * @cdev: class interface to this driver * @bus_num: board-specific (and often SOC-specific) identifier for a * given SPI controller. - * @num_chipselects: chipselects are used to distinguish individual + * @num_chipselect: chipselects are used to distinguish individual * SPI slaves, and are numbered from zero to num_chipselects. * each slave has a chipselect signal, but it's common that not * every chipselect is connected to a slave. @@ -275,7 +297,8 @@ struct spi_transfer { * addresses for each transfer buffer * @complete: called to report transaction completions * @context: the argument to complete() when it's called - * @actual_length: how many bytes were transferd + * @actual_length: the total number of bytes that were transferred in all + * successful segments * @status: zero for success, else negative errno * @queue: for use by whichever driver currently owns the message * @state: for use by whichever driver currently owns the message @@ -295,7 +318,7 @@ struct spi_message { * * Some controller drivers (message-at-a-time queue processing) * could provide that as their default scheduling algorithm. But - * others (with multi-message pipelines) would need a flag to + * others (with multi-message pipelines) could need a flag to * tell them about such special cases. */ @@ -346,6 +369,13 @@ spi_setup(struct spi_device *spi) * FIFO order, messages may go to different devices in other orders. * Some device might be higher priority, or have various "hard" access * time requirements, for example. + * + * On detection of any fault during the transfer, processing of + * the entire message is aborted, and the device is deselected. + * Until returning from the associated message completion callback, + * no other spi_message queued to that device will be processed. + * (This rule applies equally to all the synchronous transfer calls, + * which are wrappers around this core asynchronous primitive.) */ static inline int spi_async(struct spi_device *spi, struct spi_message *message) @@ -484,12 +514,12 @@ struct spi_board_info { * "modalias" is normally the driver name. * * platform_data goes to spi_device.dev.platform_data, - * controller_data goes to spi_device.platform_data, + * controller_data goes to spi_device.controller_data, * irq is copied too */ char modalias[KOBJ_NAME_LEN]; const void *platform_data; - const void *controller_data; + void *controller_data; int irq; /* slower signaling on noisy or low voltage boards */ @@ -525,9 +555,8 @@ spi_register_board_info(struct spi_board_info const *info, unsigned n) /* If you're hotplugging an adapter with devices (parport, usb, etc) - * use spi_new_device() to describe each device. You can also call - * spi_unregister_device() to get start making that device vanish, - * but normally that would be handled by spi_unregister_master(). + * use spi_new_device() to describe each device. You would then call + * spi_unregister_device() to start making that device vanish. */ extern struct spi_device * spi_new_device(struct spi_master *, struct spi_board_info *); |