--- zzzz-none-000/linux-3.10.107/drivers/spi/spi-bitbang.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/drivers/spi/spi-bitbang.c 2021-02-04 17:41:59.000000000 +0000 @@ -10,13 +10,8 @@ * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ -#include #include #include #include @@ -29,6 +24,8 @@ #include #include +#define SPI_BITBANG_CS_DELAY 100 + /*----------------------------------------------------------------------*/ @@ -40,7 +37,7 @@ * to glue code. These bitbang setup() and cleanup() routines are always * used, though maybe they're called from controller-aware code. * - * chipselect() and friends may use use spi_device->controller_data and + * chipselect() and friends may use spi_device->controller_data and * controller registers as appropriate. * * @@ -185,13 +182,11 @@ { struct spi_bitbang_cs *cs = spi->controller_state; struct spi_bitbang *bitbang; - int retval; - unsigned long flags; bitbang = spi_master_get_devdata(spi->master); if (!cs) { - cs = kzalloc(sizeof *cs, GFP_KERNEL); + cs = kzalloc(sizeof(*cs), GFP_KERNEL); if (!cs) return -ENOMEM; spi->controller_state = cs; @@ -202,9 +197,11 @@ if (!cs->txrx_word) return -EINVAL; - retval = bitbang->setup_transfer(spi, NULL); - if (retval < 0) - return retval; + if (bitbang->setup_transfer) { + int retval = bitbang->setup_transfer(spi, NULL); + if (retval < 0) + return retval; + } dev_dbg(&spi->dev, "%s, %u nsec/bit\n", __func__, 2 * cs->nsecs); @@ -214,12 +211,12 @@ */ /* deselect chip (low or high) */ - spin_lock_irqsave(&bitbang->lock, flags); + mutex_lock(&bitbang->lock); if (!bitbang->busy) { bitbang->chipselect(spi, BITBANG_CS_INACTIVE); ndelay(cs->nsecs); } - spin_unlock_irqrestore(&bitbang->lock, flags); + mutex_unlock(&bitbang->lock); return 0; } @@ -234,13 +231,14 @@ } EXPORT_SYMBOL_GPL(spi_bitbang_cleanup); -static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t) +int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t) { struct spi_bitbang_cs *cs = spi->controller_state; unsigned nsecs = cs->nsecs; return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t); } +EXPORT_SYMBOL_GPL(spi_bitbang_bufs); /*----------------------------------------------------------------------*/ @@ -255,150 +253,75 @@ * 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); - unsigned long flags; - struct spi_message *m, *_m; + struct spi_bitbang *bitbang; + + bitbang = spi_master_get_devdata(spi); - spin_lock_irqsave(&bitbang->lock, flags); + mutex_lock(&bitbang->lock); 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; - - spi = m->spi; - tmp = 0; - cs_change = 1; - status = 0; + mutex_unlock(&bitbang->lock); + + return 0; +} - list_for_each_entry (t, &m->transfers, transfer_list) { +static int spi_bitbang_transfer_one(struct spi_master *master, + struct spi_device *spi, + struct spi_transfer *transfer) +{ + struct spi_bitbang *bitbang = spi_master_get_devdata(master); + int status = 0; - /* 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; - } - - /* 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; - 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 (bitbang->setup_transfer) { + status = bitbang->setup_transfer(spi, transfer); + if (status < 0) + goto out; + } - m->status = status; - m->complete(m->context); + if (transfer->len) + status = bitbang->txrx_bufs(spi, transfer); - /* 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); - } + if (status == transfer->len) + status = 0; + else if (status >= 0) + status = -EREMOTEIO; - spin_lock_irqsave(&bitbang->lock, flags); - } - bitbang->busy = 0; - spin_unlock_irqrestore(&bitbang->lock, flags); +out: + spi_finalize_current_transfer(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; - unsigned long flags; - int status = 0; - m->actual_length = 0; - m->status = -EINPROGRESS; + bitbang = spi_master_get_devdata(spi); - bitbang = spi_master_get_devdata(spi->master); + mutex_lock(&bitbang->lock); + bitbang->busy = 0; + mutex_unlock(&bitbang->lock); - 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); - } - spin_unlock_irqrestore(&bitbang->lock, flags); + return 0; +} - return status; +static void spi_bitbang_set_cs(struct spi_device *spi, bool enable) +{ + struct spi_bitbang *bitbang = spi_master_get_devdata(spi->master); + + /* SPI core provides CS high / low, but bitbang driver + * expects CS active + * spi device driver takes care of handling SPI_CS_HIGH + */ + enable = (!!(spi->mode & SPI_CS_HIGH) == enable); + + ndelay(SPI_BITBANG_CS_DELAY); + bitbang->chipselect(spi, enable ? BITBANG_CS_ACTIVE : + BITBANG_CS_INACTIVE); + ndelay(SPI_BITBANG_CS_DELAY); } -EXPORT_SYMBOL_GPL(spi_bitbang_transfer); /*----------------------------------------------------------------------*/ @@ -424,24 +347,33 @@ * This routine registers the spi_master, which will process requests in a * dedicated task, keeping IRQs unblocked most of the time. To stop * processing those requests, call spi_bitbang_stop(). + * + * On success, this routine will take a reference to master. The caller is + * responsible for calling spi_bitbang_stop() to decrement the reference and + * spi_master_put() as counterpart of spi_alloc_master() to prevent a memory + * leak. */ int spi_bitbang_start(struct spi_bitbang *bitbang) { struct spi_master *master = bitbang->master; - int status; + int ret; if (!master || !bitbang->chipselect) return -EINVAL; - INIT_WORK(&bitbang->work, bitbang_work); - spin_lock_init(&bitbang->lock); - INIT_LIST_HEAD(&bitbang->queue); + mutex_init(&bitbang->lock); 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 = spi_bitbang_transfer_one; + master->set_cs = spi_bitbang_set_cs; + if (!bitbang->txrx_bufs) { bitbang->use_dma = 0; bitbang->txrx_bufs = spi_bitbang_bufs; @@ -452,49 +384,25 @@ 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; + ret = spi_register_master(spi_master_get(master)); + if (ret) + spi_master_put(master); - return status; - -err2: - destroy_workqueue(bitbang->workqueue); -err1: - return status; + return 0; } EXPORT_SYMBOL_GPL(spi_bitbang_start); /** * spi_bitbang_stop - stops the task providing spi communication */ -int spi_bitbang_stop(struct spi_bitbang *bitbang) +void 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);