diff options
Diffstat (limited to 'drivers/spi/spi-bitbang.c')
-rw-r--r-- | drivers/spi/spi-bitbang.c | 260 |
1 files changed, 113 insertions, 147 deletions
diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c index a63d7da3bfe2..e3946e44e076 100644 --- a/drivers/spi/spi-bitbang.c +++ b/drivers/spi/spi-bitbang.c @@ -255,150 +255,140 @@ static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t) * Drivers can provide word-at-a-time i/o primitives, or provide * transfer-at-a-time ones to leverage dma or fifo hardware. */ -static void bitbang_work(struct work_struct *work) + +static int spi_bitbang_prepare_hardware(struct spi_master *spi) { - struct spi_bitbang *bitbang = - container_of(work, struct spi_bitbang, work); + struct spi_bitbang *bitbang; unsigned long flags; - struct spi_message *m, *_m; + + bitbang = spi_master_get_devdata(spi); spin_lock_irqsave(&bitbang->lock, flags); bitbang->busy = 1; - list_for_each_entry_safe(m, _m, &bitbang->queue, queue) { - struct spi_device *spi; - unsigned nsecs; - struct spi_transfer *t = NULL; - unsigned tmp; - unsigned cs_change; - int status; - int do_setup = -1; - - list_del(&m->queue); - spin_unlock_irqrestore(&bitbang->lock, flags); - - /* FIXME this is made-up ... the correct value is known to - * word-at-a-time bitbang code, and presumably chipselect() - * should enforce these requirements too? - */ - nsecs = 100; + spin_unlock_irqrestore(&bitbang->lock, flags); - spi = m->spi; - tmp = 0; - cs_change = 1; - status = 0; + return 0; +} - list_for_each_entry (t, &m->transfers, transfer_list) { - - /* override speed or wordsize? */ - if (t->speed_hz || t->bits_per_word) - do_setup = 1; - - /* init (-1) or override (1) transfer params */ - if (do_setup != 0) { - status = bitbang->setup_transfer(spi, t); - if (status < 0) - break; - if (do_setup == -1) - do_setup = 0; - } - - /* set up default clock polarity, and activate chip; - * this implicitly updates clock and spi modes as - * previously recorded for this device via setup(). - * (and also deselects any other chip that might be - * selected ...) - */ - if (cs_change) { - bitbang->chipselect(spi, BITBANG_CS_ACTIVE); - ndelay(nsecs); - } - cs_change = t->cs_change; - if (!t->tx_buf && !t->rx_buf && t->len) { - status = -EINVAL; - break; - } +static int spi_bitbang_transfer_one(struct spi_master *master, + struct spi_message *m) +{ + struct spi_bitbang *bitbang; + unsigned nsecs; + struct spi_transfer *t = NULL; + unsigned cs_change; + int status; + int do_setup = -1; + struct spi_device *spi = m->spi; + + bitbang = spi_master_get_devdata(master); + + /* FIXME this is made-up ... the correct value is known to + * word-at-a-time bitbang code, and presumably chipselect() + * should enforce these requirements too? + */ + nsecs = 100; - /* transfer data. the lower level code handles any - * new dma mappings it needs. our caller always gave - * us dma-safe buffers. - */ - if (t->len) { - /* REVISIT dma API still needs a designated - * DMA_ADDR_INVALID; ~0 might be better. - */ - if (!m->is_dma_mapped) - t->rx_dma = t->tx_dma = 0; - status = bitbang->txrx_bufs(spi, t); - } - if (status > 0) - m->actual_length += status; - if (status != t->len) { - /* always report some kind of error */ - if (status >= 0) - status = -EREMOTEIO; + cs_change = 1; + status = 0; + + list_for_each_entry (t, &m->transfers, transfer_list) { + + /* override speed or wordsize? */ + if (t->speed_hz || t->bits_per_word) + do_setup = 1; + + /* init (-1) or override (1) transfer params */ + if (do_setup != 0) { + status = bitbang->setup_transfer(spi, t); + if (status < 0) break; - } - status = 0; - - /* protocol tweaks before next transfer */ - if (t->delay_usecs) - udelay(t->delay_usecs); - - if (cs_change && !list_is_last(&t->transfer_list, &m->transfers)) { - /* sometimes a short mid-message deselect of the chip - * may be needed to terminate a mode or command - */ - ndelay(nsecs); - bitbang->chipselect(spi, BITBANG_CS_INACTIVE); - ndelay(nsecs); - } + if (do_setup == -1) + do_setup = 0; } - m->status = status; - m->complete(m->context); + /* set up default clock polarity, and activate chip; + * this implicitly updates clock and spi modes as + * previously recorded for this device via setup(). + * (and also deselects any other chip that might be + * selected ...) + */ + if (cs_change) { + bitbang->chipselect(spi, BITBANG_CS_ACTIVE); + ndelay(nsecs); + } + cs_change = t->cs_change; + if (!t->tx_buf && !t->rx_buf && t->len) { + status = -EINVAL; + break; + } - /* normally deactivate chipselect ... unless no error and - * cs_change has hinted that the next message will probably - * be for this chip too. + /* transfer data. the lower level code handles any + * new dma mappings it needs. our caller always gave + * us dma-safe buffers. */ - if (!(status == 0 && cs_change)) { + if (t->len) { + /* REVISIT dma API still needs a designated + * DMA_ADDR_INVALID; ~0 might be better. + */ + if (!m->is_dma_mapped) + t->rx_dma = t->tx_dma = 0; + status = bitbang->txrx_bufs(spi, t); + } + if (status > 0) + m->actual_length += status; + if (status != t->len) { + /* always report some kind of error */ + if (status >= 0) + status = -EREMOTEIO; + break; + } + status = 0; + + /* protocol tweaks before next transfer */ + if (t->delay_usecs) + udelay(t->delay_usecs); + + if (cs_change && !list_is_last(&t->transfer_list, &m->transfers)) { + /* sometimes a short mid-message deselect of the chip + * may be needed to terminate a mode or command + */ ndelay(nsecs); bitbang->chipselect(spi, BITBANG_CS_INACTIVE); ndelay(nsecs); } + } + + m->status = status; - spin_lock_irqsave(&bitbang->lock, flags); + /* normally deactivate chipselect ... unless no error and + * cs_change has hinted that the next message will probably + * be for this chip too. + */ + if (!(status == 0 && cs_change)) { + ndelay(nsecs); + bitbang->chipselect(spi, BITBANG_CS_INACTIVE); + ndelay(nsecs); } - bitbang->busy = 0; - spin_unlock_irqrestore(&bitbang->lock, flags); + + spi_finalize_current_message(master); + + return status; } -/** - * spi_bitbang_transfer - default submit to transfer queue - */ -int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m) +static int spi_bitbang_unprepare_hardware(struct spi_master *spi) { - struct spi_bitbang *bitbang; + struct spi_bitbang *bitbang; unsigned long flags; - int status = 0; - m->actual_length = 0; - m->status = -EINPROGRESS; - - bitbang = spi_master_get_devdata(spi->master); + bitbang = spi_master_get_devdata(spi); spin_lock_irqsave(&bitbang->lock, flags); - if (!spi->max_speed_hz) - status = -ENETDOWN; - else { - list_add_tail(&m->queue, &bitbang->queue); - queue_work(bitbang->workqueue, &bitbang->work); - } + bitbang->busy = 0; spin_unlock_irqrestore(&bitbang->lock, flags); - return status; + return 0; } -EXPORT_SYMBOL_GPL(spi_bitbang_transfer); /*----------------------------------------------------------------------*/ @@ -428,20 +418,22 @@ EXPORT_SYMBOL_GPL(spi_bitbang_transfer); int spi_bitbang_start(struct spi_bitbang *bitbang) { struct spi_master *master = bitbang->master; - int status; if (!master || !bitbang->chipselect) return -EINVAL; - INIT_WORK(&bitbang->work, bitbang_work); spin_lock_init(&bitbang->lock); - INIT_LIST_HEAD(&bitbang->queue); if (!master->mode_bits) master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags; - if (!master->transfer) - master->transfer = spi_bitbang_transfer; + if (master->transfer || master->transfer_one_message) + return -EINVAL; + + master->prepare_transfer_hardware = spi_bitbang_prepare_hardware; + master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware; + master->transfer_one_message = spi_bitbang_transfer_one; + if (!bitbang->txrx_bufs) { bitbang->use_dma = 0; bitbang->txrx_bufs = spi_bitbang_bufs; @@ -452,34 +444,12 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) master->setup = spi_bitbang_setup; master->cleanup = spi_bitbang_cleanup; } - } else if (!master->setup) - return -EINVAL; - if (master->transfer == spi_bitbang_transfer && - !bitbang->setup_transfer) - return -EINVAL; - - /* this task is the only thing to touch the SPI bits */ - bitbang->busy = 0; - bitbang->workqueue = create_singlethread_workqueue( - dev_name(master->dev.parent)); - if (bitbang->workqueue == NULL) { - status = -EBUSY; - goto err1; } /* driver may get busy before register() returns, especially * if someone registered boardinfo for devices */ - status = spi_register_master(master); - if (status < 0) - goto err2; - - return status; - -err2: - destroy_workqueue(bitbang->workqueue); -err1: - return status; + return spi_register_master(master); } EXPORT_SYMBOL_GPL(spi_bitbang_start); @@ -490,10 +460,6 @@ int spi_bitbang_stop(struct spi_bitbang *bitbang) { spi_unregister_master(bitbang->master); - WARN_ON(!list_empty(&bitbang->queue)); - - destroy_workqueue(bitbang->workqueue); - return 0; } EXPORT_SYMBOL_GPL(spi_bitbang_stop); |