diff options
Diffstat (limited to 'include/linux/spi/spi.h')
| -rw-r--r-- | include/linux/spi/spi.h | 45 |
1 files changed, 28 insertions, 17 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index b05f1463a267..e928c0dcc297 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -31,18 +31,23 @@ extern struct bus_type spi_bus_type; * @master: SPI controller used with the device. * @max_speed_hz: Maximum clock rate to be used with this chip * (on this board); may be changed by the device's driver. + * The spi_transfer.speed_hz can override this for each transfer. * @chip-select: Chipselect, distinguishing chips handled by "master". * @mode: The spi mode defines how data is clocked out and in. * This may be changed by the device's driver. + * The "active low" default for chipselect mode can be overridden, + * as can the "MSB first" default for each word in a transfer. * @bits_per_word: Data transfers involve one or more words; word sizes - * like eight or 12 bits are common. In-memory wordsizes are + * like eight or 12 bits are common. In-memory wordsizes are * powers of two bytes (e.g. 20 bit samples use 32 bits). - * This may be changed by the device's driver. + * This may be changed by the device's driver, or left at the + * default (0) indicating protocol words are eight bit bytes. + * The spi_transfer.bits_per_word can override this for each transfer. * @irq: Negative, or the number passed to request_irq() to receive - * interrupts from this device. + * interrupts from this device. * @controller_state: Controller's runtime state * @controller_data: Board-specific definitions for controller, such as - * FIFO initialization parameters; from board_info.controller_data + * 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. @@ -65,6 +70,7 @@ struct spi_device { #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_LSB_FIRST 0x08 /* per-word bits-on-wire */ u8 bits_per_word; int irq; void *controller_state; @@ -73,7 +79,6 @@ struct spi_device { // likely need more hooks for more protocol options affecting how // 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 @@ -143,13 +148,13 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * 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. + * given SPI controller. * @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. + * 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. * @setup: updates the device mode and clocking records used by a - * device's SPI controller; protocol code may call this. + * device's SPI controller; protocol code may call this. * @transfer: adds a message to the controller's transfer queue. * @cleanup: frees controller-specific state * @@ -167,13 +172,13 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) struct spi_master { struct class_device cdev; - /* other than zero (== assign one dynamically), bus_num is fully + /* other than negative (== assign one dynamically), bus_num is fully * board-specific. usually that simplifies to being SOC-specific. - * example: one SOC has three SPI controllers, numbered 1..3, + * example: one SOC has three SPI controllers, numbered 0..2, * and one board's schematics might show it using SPI-2. software * would normally use bus_num=2 for that controller. */ - u16 bus_num; + s16 bus_num; /* chipselects will be integral to many controllers; some others * might use board-specific GPIOs. @@ -268,10 +273,14 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum); * @tx_dma: DMA address of tx_buf, if spi_message.is_dma_mapped * @rx_dma: DMA address of rx_buf, if spi_message.is_dma_mapped * @len: size of rx and tx buffers (in bytes) + * @speed_hz: Select a speed other then the device default for this + * transfer. If 0 the default (from spi_device) is used. + * @bits_per_word: select a bits_per_word other then the device default + * for this transfer. If 0 the default (from spi_device) is used. * @cs_change: affects chipselect after this transfer completes * @delay_usecs: microseconds to delay after this transfer before - * (optionally) changing the chipselect status, then starting - * the next transfer or completing this spi_message. + * (optionally) changing the chipselect status, then starting + * the next transfer or completing this spi_message. * @transfer_list: transfers are sequenced through spi_message.transfers * * SPI transfers always write the same number of bytes as they read. @@ -322,7 +331,9 @@ struct spi_transfer { dma_addr_t rx_dma; unsigned cs_change:1; + u8 bits_per_word; u16 delay_usecs; + u32 speed_hz; struct list_head transfer_list; }; @@ -356,7 +367,7 @@ struct spi_transfer { * and its transfers, ignore them until its completion callback. */ struct spi_message { - struct list_head transfers; + struct list_head transfers; struct spi_device *spi; @@ -374,7 +385,7 @@ struct spi_message { */ /* completion is reported through a callback */ - void (*complete)(void *context); + void (*complete)(void *context); void *context; unsigned actual_length; int status; |