1 files changed, 48 insertions, 11 deletions

diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c
index 34c7c9875681..a7b9070e1b46 100644
--- a/drivers/spi/pxa2xx_spi.c
+++ b/drivers/spi/pxa2xx_spi.c
@@ -144,7 +144,6 @@ struct driver_data {
         size_t tx_map_len;
         u8 n_bytes;
         u32 dma_width;
-        int cs_change;
         int (*write)(struct driver_data *drv_data);
         int (*read)(struct driver_data *drv_data);
         irqreturn_t (*transfer_handler)(struct driver_data *drv_data);
@@ -406,8 +405,45 @@ static void giveback(struct driver_data *drv_data)
                                         struct spi_transfer,
                                         transfer_list);
 
+        /* Delay if requested before any change in chip select */
+        if (last_transfer->delay_usecs)
+                udelay(last_transfer->delay_usecs);
+
+        /* Drop chip select UNLESS cs_change is true or we are returning
+         * a message with an error, or next message is for another chip
+         */
         if (!last_transfer->cs_change)
                 drv_data->cs_control(PXA2XX_CS_DEASSERT);
+        else {
+                struct spi_message *next_msg;
+
+                /* Holding of cs was hinted, but we need to make sure
+                 * the next message is for the same chip.  Don't waste
+                 * time with the following tests unless this was hinted.
+                 *
+                 * We cannot postpone this until pump_messages, because
+                 * after calling msg->complete (below) the driver that
+                 * sent the current message could be unloaded, which
+                 * could invalidate the cs_control() callback...
+                 */
+
+                /* get a pointer to the next message, if any */
+                spin_lock_irqsave(&drv_data->lock, flags);
+                if (list_empty(&drv_data->queue))
+                        next_msg = NULL;
+                else
+                        next_msg = list_entry(drv_data->queue.next,
+                                        struct spi_message, queue);
+                spin_unlock_irqrestore(&drv_data->lock, flags);
+
+                /* see if the next and current messages point
+                 * to the same chip
+                 */
+                if (next_msg && next_msg->spi != msg->spi)
+                        next_msg = NULL;
+                if (!next_msg || msg->state == ERROR_STATE)
+                        drv_data->cs_control(PXA2XX_CS_DEASSERT);
+        }
 
         msg->state = NULL;
         if (msg->complete)
@@ -490,10 +526,9 @@ static void dma_transfer_complete(struct driver_data *drv_data)
         msg->actual_length += drv_data->len -
                                 (drv_data->rx_end - drv_data->rx);
 
-        /* Release chip select if requested, transfer delays are
-         * handled in pump_transfers */
-        if (drv_data->cs_change)
-                drv_data->cs_control(PXA2XX_CS_DEASSERT);
+        /* Transfer delays and chip select release are
+         * handled in pump_transfers or giveback
+         */
 
         /* Move to next transfer */
         msg->state = next_transfer(drv_data);
@@ -602,10 +637,9 @@ static void int_transfer_complete(struct driver_data *drv_data)
         drv_data->cur_msg->actual_length += drv_data->len -
                                 (drv_data->rx_end - drv_data->rx);
 
-        /* Release chip select if requested, transfer delays are
-         * handled in pump_transfers */
-        if (drv_data->cs_change)
-                drv_data->cs_control(PXA2XX_CS_DEASSERT);
+        /* Transfer delays and chip select release are
+         * handled in pump_transfers or giveback
+         */
 
         /* Move to next transfer */
         drv_data->cur_msg->state = next_transfer(drv_data);
@@ -840,13 +874,17 @@ static void pump_transfers(unsigned long data)
                 return;
         }
 
-        /* Delay if requested at end of transfer*/
+        /* Delay if requested at end of transfer before CS change */
         if (message->state == RUNNING_STATE) {
                 previous = list_entry(transfer->transfer_list.prev,
                                         struct spi_transfer,
                                         transfer_list);
                 if (previous->delay_usecs)
                         udelay(previous->delay_usecs);
+
+                /* Drop chip select only if cs_change is requested */
+                if (previous->cs_change)
+                        drv_data->cs_control(PXA2XX_CS_DEASSERT);
         }
 
         /* Check transfer length */
@@ -878,7 +916,6 @@ static void pump_transfers(unsigned long data)
         drv_data->len = transfer->len & DCMD_LENGTH;
         drv_data->write = drv_data->tx ? chip->write : null_writer;
         drv_data->read = drv_data->rx ? chip->read : null_reader;
-        drv_data->cs_change = transfer->cs_change;
 
         /* Change speed and bit per word on a per transfer */
         cr0 = chip->cr0;