diff options
Diffstat (limited to 'include/linux/spi')
| -rw-r--r-- | include/linux/spi/spi.h | 75 |
1 files changed, 69 insertions, 6 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index c851b3d13208..6a41e2650b2e 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -60,8 +60,8 @@ struct spi_device { u8 mode; #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) /* (original MicroWire) */ +#define SPI_MODE_0 (0|0) /* (original MicroWire) */ +#define SPI_MODE_1 (0|SPI_CPHA) #define SPI_MODE_2 (SPI_CPOL|0) #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) #define SPI_CS_HIGH 0x04 /* chipselect active high? */ @@ -209,6 +209,30 @@ struct spi_master { void (*cleanup)(const struct spi_device *spi); }; +static inline void *spi_master_get_devdata(struct spi_master *master) +{ + return class_get_devdata(&master->cdev); +} + +static inline void spi_master_set_devdata(struct spi_master *master, void *data) +{ + class_set_devdata(&master->cdev, data); +} + +static inline struct spi_master *spi_master_get(struct spi_master *master) +{ + if (!master || !class_device_get(&master->cdev)) + return NULL; + return master; +} + +static inline void spi_master_put(struct spi_master *master) +{ + if (master) + class_device_put(&master->cdev); +} + + /* the spi driver core manages memory for the spi_master classdev */ extern struct spi_master * spi_alloc_master(struct device *host, unsigned size); @@ -271,11 +295,17 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum); * stay selected until the next transfer. This is purely a performance * hint; the controller driver may need to select a different device * for the next message. + * + * The code that submits an spi_message (and its spi_transfers) + * to the lower layers is responsible for managing its memory. + * Zero-initialize every field you don't set up explicitly, to + * insulate against future API updates. */ struct spi_transfer { /* it's ok if tx_buf == rx_buf (right?) * for MicroWire, one buffer must be null - * buffers must work with dma_*map_single() calls + * buffers must work with dma_*map_single() calls, unless + * spi_message.is_dma_mapped reports a pre-existing mapping */ const void *tx_buf; void *rx_buf; @@ -302,6 +332,11 @@ struct spi_transfer { * @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 + * + * The code that submits an spi_message (and its spi_transfers) + * to the lower layers is responsible for managing its memory. + * Zero-initialize every field you don't set up explicitly, to + * insulate against future API updates. */ struct spi_message { struct spi_transfer *transfers; @@ -336,6 +371,29 @@ struct spi_message { void *state; }; +/* It's fine to embed message and transaction structures in other data + * structures so long as you don't free them while they're in use. + */ + +static inline struct spi_message *spi_message_alloc(unsigned ntrans, gfp_t flags) +{ + struct spi_message *m; + + m = kzalloc(sizeof(struct spi_message) + + ntrans * sizeof(struct spi_transfer), + flags); + if (m) { + m->transfers = (void *)(m + 1); + m->n_transfer = ntrans; + } + return m; +} + +static inline void spi_message_free(struct spi_message *m) +{ + kfree(m); +} + /** * spi_setup -- setup SPI mode and clock rate * @spi: the device whose settings are being modified @@ -363,7 +421,10 @@ spi_setup(struct spi_device *spi) * The completion callback is invoked in a context which can't sleep. * Before that invocation, the value of message->status is undefined. * When the callback is issued, message->status holds either zero (to - * indicate complete success) or a negative error code. + * indicate complete success) or a negative error code. After that + * callback returns, the driver which issued the transfer request may + * deallocate the associated memory; it's no longer in use by any SPI + * core or controller driver code. * * Note that although all messages to a spi_device are handled in * FIFO order, messages may go to different devices in other orders. @@ -445,6 +506,7 @@ spi_read(struct spi_device *spi, u8 *buf, size_t len) return spi_sync(spi, &m); } +/* this copies txbuf and rxbuf data; for small transfers only! */ extern int spi_write_then_read(struct spi_device *spi, const u8 *txbuf, unsigned n_tx, u8 *rxbuf, unsigned n_rx); @@ -555,8 +617,9 @@ 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 would then call - * spi_unregister_device() to start making that device vanish. + * use spi_new_device() to describe each device. You can also call + * spi_unregister_device() to start making that device vanish, but + * normally that would be handled by spi_unregister_master(). */ extern struct spi_device * spi_new_device(struct spi_master *, struct spi_board_info *); |
