spi/bitbang: Factor out message transfer from message pump loop

In order to make it easier to convert to transfer_one_message() lift the
code that does the actual message transfer out of the work function that
implements the message pump. This should have no functional impact, it's
just a simple code motion patch.

Signed-off-by: Mark Brown <broonie@linaro.org>

diff --git a/drivers/spi/spi-bitbang.c b/drivers/spi/spi-bitbang.c
index 495ce0a51d2f57b04920b44e78a504eaa7ff06cc..8b8487c9694ea3df199e69273b84a558eef3e3cd 100644 (file)
--- a/drivers/spi/spi-bitbang.c
+++ b/drivers/spi/spi-bitbang.c
@@ -255,117 +255,126 @@ 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_transfer_one(struct spi_device *spi,
+                                   struct spi_message *m)
 {
-       struct spi_bitbang      *bitbang =
-               container_of(work, struct spi_bitbang, work);
-       unsigned long           flags;
-       struct spi_message      *m, *_m;
+       struct spi_bitbang      *bitbang;
+       unsigned                nsecs;
+       struct spi_transfer     *t = NULL;
+       unsigned                tmp;
+       unsigned                cs_change;
+       int                     status;
+       int                     do_setup = -1;
 
-       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;
+       bitbang = spi_master_get_devdata(spi->master);
 
-               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;
 
-               /* 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;
+       tmp = 0;
+       cs_change = 1;
+       status = 0;
 
-               spi = m->spi;
-               tmp = 0;
-               cs_change = 1;
-               status = 0;
+       list_for_each_entry (t, &m->transfers, transfer_list) {
 
-               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;
-                       }
+               /* override speed or wordsize? */
+               if (t->speed_hz || t->bits_per_word)
+                       do_setup = 1;
 
-                       /* 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;
+               /* 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;
+       m->complete(m->context);
+
+       /* 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);
+       }
+
+       return status;
+}
+
+static void bitbang_work(struct work_struct *work)
+{
+       struct spi_bitbang      *bitbang =
+               container_of(work, struct spi_bitbang, work);
+       unsigned long           flags;
+       struct spi_message      *m, *_m;
+
+       spin_lock_irqsave(&bitbang->lock, flags);
+       bitbang->busy = 1;
+       list_for_each_entry_safe(m, _m, &bitbang->queue, queue) {
+               list_del(&m->queue);
+               spin_unlock_irqrestore(&bitbang->lock, flags);
+
+               spi_bitbang_transfer_one(m->spi, m);
 
                spin_lock_irqsave(&bitbang->lock, flags);
        }