X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=drivers%2Fspi%2Fspi_bitbang.c;h=57289b61d0beadd3dd543b853c233918f22daccc;hb=refs%2Fheads%2Fvserver;hp=f037e5593269e8a79f700e7acf917919e0b13762;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c index f037e5593..57289b61d 100644 --- a/drivers/spi/spi_bitbang.c +++ b/drivers/spi/spi_bitbang.c @@ -16,7 +16,6 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ -#include #include #include #include @@ -138,6 +137,45 @@ static unsigned bitbang_txrx_32( return t->len - count; } +int spi_bitbang_setup_transfer(struct spi_device *spi, struct spi_transfer *t) +{ + struct spi_bitbang_cs *cs = spi->controller_state; + u8 bits_per_word; + u32 hz; + + if (t) { + bits_per_word = t->bits_per_word; + hz = t->speed_hz; + } else { + bits_per_word = 0; + hz = 0; + } + + /* spi_transfer level calls that work per-word */ + if (!bits_per_word) + bits_per_word = spi->bits_per_word; + if (bits_per_word <= 8) + cs->txrx_bufs = bitbang_txrx_8; + else if (bits_per_word <= 16) + cs->txrx_bufs = bitbang_txrx_16; + else if (bits_per_word <= 32) + cs->txrx_bufs = bitbang_txrx_32; + else + return -EINVAL; + + /* nsecs = (clock period)/2 */ + if (!hz) + hz = spi->max_speed_hz; + if (hz) { + cs->nsecs = (1000000000/2) / hz; + if (cs->nsecs > (MAX_UDELAY_MS * 1000 * 1000)) + return -EINVAL; + } + + return 0; +} +EXPORT_SYMBOL_GPL(spi_bitbang_setup_transfer); + /** * spi_bitbang_setup - default setup for per-word I/O loops */ @@ -145,42 +183,38 @@ int spi_bitbang_setup(struct spi_device *spi) { struct spi_bitbang_cs *cs = spi->controller_state; struct spi_bitbang *bitbang; + int retval; - if (!spi->max_speed_hz) + bitbang = spi_master_get_devdata(spi->master); + + /* REVISIT: some systems will want to support devices using lsb-first + * bit encodings on the wire. In pure software that would be trivial, + * just bitbang_txrx_le_cphaX() routines shifting the other way, and + * some hardware controllers also have this support. + */ + if ((spi->mode & SPI_LSB_FIRST) != 0) return -EINVAL; if (!cs) { - cs = kzalloc(sizeof *cs, SLAB_KERNEL); + cs = kzalloc(sizeof *cs, GFP_KERNEL); if (!cs) return -ENOMEM; spi->controller_state = cs; } - bitbang = spi_master_get_devdata(spi->master); if (!spi->bits_per_word) spi->bits_per_word = 8; - /* spi_transfer level calls that work per-word */ - if (spi->bits_per_word <= 8) - cs->txrx_bufs = bitbang_txrx_8; - else if (spi->bits_per_word <= 16) - cs->txrx_bufs = bitbang_txrx_16; - else if (spi->bits_per_word <= 32) - cs->txrx_bufs = bitbang_txrx_32; - else - return -EINVAL; - /* per-word shift register access, in hardware or bitbanging */ cs->txrx_word = bitbang->txrx_word[spi->mode & (SPI_CPOL|SPI_CPHA)]; if (!cs->txrx_word) return -EINVAL; - /* nsecs = (clock period)/2 */ - cs->nsecs = (1000000000/2) / (spi->max_speed_hz); - if (cs->nsecs > MAX_UDELAY_MS * 1000) - return -EINVAL; + retval = spi_bitbang_setup_transfer(spi, NULL); + if (retval < 0) + return retval; - dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec\n", + dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n", __FUNCTION__, spi->mode & (SPI_CPOL | SPI_CPHA), spi->bits_per_word, 2 * cs->nsecs); @@ -231,9 +265,10 @@ 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(void *_bitbang) +static void bitbang_work(struct work_struct *work) { - struct spi_bitbang *bitbang = _bitbang; + struct spi_bitbang *bitbang = + container_of(work, struct spi_bitbang, work); unsigned long flags; spin_lock_irqsave(&bitbang->lock, flags); @@ -246,6 +281,8 @@ static void bitbang_work(void *_bitbang) unsigned tmp; unsigned cs_change; int status; + int (*setup_transfer)(struct spi_device *, + struct spi_transfer *); m = container_of(bitbang->queue.next, struct spi_message, queue); @@ -262,6 +299,7 @@ static void bitbang_work(void *_bitbang) tmp = 0; cs_change = 1; status = 0; + setup_transfer = NULL; list_for_each_entry (t, &m->transfers, transfer_list) { if (bitbang->shutdown) { @@ -269,6 +307,20 @@ static void bitbang_work(void *_bitbang) break; } + /* override or restore speed and wordsize */ + if (t->speed_hz || t->bits_per_word) { + setup_transfer = bitbang->setup_transfer; + if (!setup_transfer) { + status = -ENOPROTOOPT; + break; + } + } + if (setup_transfer) { + status = setup_transfer(spi, t); + if (status < 0) + break; + } + /* set up default clock polarity, and activate chip; * this implicitly updates clock and spi modes as * previously recorded for this device via setup(). @@ -325,6 +377,10 @@ static void bitbang_work(void *_bitbang) m->status = status; m->complete(m->context); + /* restore speed and wordsize */ + if (setup_transfer) + setup_transfer(spi, NULL); + /* normally deactivate chipselect ... unless no error and * cs_change has hinted that the next message will probably * be for this chip too. @@ -348,6 +404,7 @@ int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m) { struct spi_bitbang *bitbang; unsigned long flags; + int status = 0; m->actual_length = 0; m->status = -EINPROGRESS; @@ -357,11 +414,15 @@ int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m) return -ESHUTDOWN; spin_lock_irqsave(&bitbang->lock, flags); - list_add_tail(&m->queue, &bitbang->queue); - queue_work(bitbang->workqueue, &bitbang->work); + if (!spi->max_speed_hz) + status = -ENETDOWN; + else { + list_add_tail(&m->queue, &bitbang->queue); + queue_work(bitbang->workqueue, &bitbang->work); + } spin_unlock_irqrestore(&bitbang->lock, flags); - return 0; + return status; } EXPORT_SYMBOL_GPL(spi_bitbang_transfer); @@ -396,7 +457,7 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) if (!bitbang->master || !bitbang->chipselect) return -EINVAL; - INIT_WORK(&bitbang->work, bitbang_work, bitbang); + INIT_WORK(&bitbang->work, bitbang_work); spin_lock_init(&bitbang->lock); INIT_LIST_HEAD(&bitbang->queue); @@ -406,6 +467,9 @@ int spi_bitbang_start(struct spi_bitbang *bitbang) bitbang->use_dma = 0; bitbang->txrx_bufs = spi_bitbang_bufs; if (!bitbang->master->setup) { + if (!bitbang->setup_transfer) + bitbang->setup_transfer = + spi_bitbang_setup_transfer; bitbang->master->setup = spi_bitbang_setup; bitbang->master->cleanup = spi_bitbang_cleanup; }