[PATCH] e1000: Fix PHY reset when blocked

[linux-2.6] / drivers / spi / spi_bitbang.c

diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c
index 44aff198eb960510faf4b5cfe64c5d437a3e2ada..f037e5593269e8a79f700e7acf917919e0b13762 100644 (file)
--- a/drivers/spi/spi_bitbang.c
+++ b/drivers/spi/spi_bitbang.c
@@ -146,6 +146,9 @@ int spi_bitbang_setup(struct spi_device *spi)
        struct spi_bitbang_cs   *cs = spi->controller_state;
        struct spi_bitbang      *bitbang;
 
+       if (!spi->max_speed_hz)
+               return -EINVAL;
+
        if (!cs) {
                cs = kzalloc(sizeof *cs, SLAB_KERNEL);
                if (!cs)
@@ -172,13 +175,8 @@ int spi_bitbang_setup(struct spi_device *spi)
        if (!cs->txrx_word)
                return -EINVAL;
 
-       if (!spi->max_speed_hz)
-               spi->max_speed_hz = 500 * 1000;
-
-       /* nsecs = max(50, (clock period)/2), be optimistic */
+       /* nsecs = (clock period)/2 */
        cs->nsecs = (1000000000/2) / (spi->max_speed_hz);
-       if (cs->nsecs < 50)
-               cs->nsecs = 50;
        if (cs->nsecs > MAX_UDELAY_MS * 1000)
                return -EINVAL;
 
@@ -194,7 +192,7 @@ int spi_bitbang_setup(struct spi_device *spi)
        /* deselect chip (low or high) */
        spin_lock(&bitbang->lock);
        if (!bitbang->busy) {
-               bitbang->chipselect(spi, 0);
+               bitbang->chipselect(spi, BITBANG_CS_INACTIVE);
                ndelay(cs->nsecs);
        }
        spin_unlock(&bitbang->lock);
@@ -244,9 +242,9 @@ static void bitbang_work(void *_bitbang)
                struct spi_message      *m;
                struct spi_device       *spi;
                unsigned                nsecs;
-               struct spi_transfer     *t;
+               struct spi_transfer     *t = NULL;
                unsigned                tmp;
-               unsigned                chipselect;
+               unsigned                cs_change;
                int                     status;
 
                m = container_of(bitbang->queue.next, struct spi_message,
@@ -254,37 +252,49 @@ static void bitbang_work(void *_bitbang)
                list_del_init(&m->queue);
                spin_unlock_irqrestore(&bitbang->lock, flags);
 
-// FIXME this is made-up
-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;
 
                spi = m->spi;
-               t = m->transfers;
                tmp = 0;
-               chipselect = 0;
+               cs_change = 1;
                status = 0;
 
-               for (;;t++) {
+               list_for_each_entry (t, &m->transfers, transfer_list) {
                        if (bitbang->shutdown) {
                                status = -ESHUTDOWN;
                                break;
                        }
 
-                       /* set up default clock polarity, and activate chip */
-                       if (!chipselect) {
-                               bitbang->chipselect(spi, 1);
+                       /* 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 */
+                       /* transfer data.  the lower level code handles any
+                        * new dma mappings it needs. our caller always gave
+                        * us dma-safe buffers.
+                        */
                        if (t->len) {
-                               /* FIXME if bitbang->use_dma, dma_map_single()
-                                * before the transfer, and dma_unmap_single()
-                                * afterwards, for either or both buffers...
+                               /* 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 != t->len) {
@@ -299,29 +309,31 @@ nsecs = 100;
                        if (t->delay_usecs)
                                udelay(t->delay_usecs);
 
-                       tmp++;
-                       if (tmp >= m->n_transfer)
-                               break;
-
-                       chipselect = !t->cs_change;
-                       if (chipselect);
+                       if (!cs_change)
                                continue;
+                       if (t->transfer_list.next == &m->transfers)
+                               break;
 
-                       bitbang->chipselect(spi, 0);
-
-                       /* REVISIT do we want the udelay here instead? */
-                       msleep(1);
+                       /* 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);
                }
 
-               tmp = m->n_transfer - 1;
-               tmp = m->transfers[tmp].cs_change;
-
                m->status = status;
                m->complete(m->context);
 
-               ndelay(2 * nsecs);
-               bitbang->chipselect(spi, status == 0 && tmp);
-               ndelay(nsecs);
+               /* 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);
+               }
 
                spin_lock_irqsave(&bitbang->lock, flags);
        }