spi: spi_bfin handles spi_transfer.cs_change

Respect per-transfer cs_change field (protocol tweaking support) by
adding and using cs_active/cs_deactive functions.

Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 54 insertions, 22 deletions

diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index 803c5b25db50..c2d51cf3c639 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -115,6 +115,7 @@ struct driver_data {
         size_t rx_map_len;
         size_t tx_map_len;
         u8 n_bytes;
+        int cs_change;
         void (*write) (struct driver_data *);
         void (*read) (struct driver_data *);
         void (*duplex) (struct driver_data *);
@@ -179,6 +180,26 @@ static int flush(struct driver_data *drv_data)
         return limit;
 }
 
+/* Chip select operation functions for cs_change flag */
+static void cs_active(struct chip_data *chip)
+{
+        u16 flag = read_FLAG();
+
+        flag |= chip->flag;
+        flag &= ~(chip->flag << 8);
+
+        write_FLAG(flag);
+}
+
+static void cs_deactive(struct chip_data *chip)
+{
+        u16 flag = read_FLAG();
+
+        flag |= (chip->flag << 8);
+
+        write_FLAG(flag);
+}
+
 #define MAX_SPI0_SSEL   7
 
 /* stop controller and re-config current chip*/
@@ -198,7 +219,7 @@ static int restore_state(struct driver_data *drv_data)
         /* Load the registers */
         write_CTRL(chip->ctl_reg);
         write_BAUD(chip->baud);
-        write_FLAG(chip->flag);
+        cs_active(chip);
 
         if (!chip->chip_select_requested) {
                 int i = chip->chip_select_num;
@@ -273,20 +294,20 @@ static void u8_cs_chg_writer(struct driver_data *drv_data)
         struct chip_data *chip = drv_data->cur_chip;
 
         while (drv_data->tx < drv_data->tx_end) {
-                write_FLAG(chip->flag);
+                cs_active(chip);
 
                 write_TDBR(*(u8 *) (drv_data->tx));
                 while (read_STAT() & BIT_STAT_TXS)
                         continue;
                 while (!(read_STAT() & BIT_STAT_SPIF))
                         continue;
-                write_FLAG(0xFF00 | chip->flag);
+                cs_deactive(chip);
 
                 if (chip->cs_chg_udelay)
                         udelay(chip->cs_chg_udelay);
                 ++drv_data->tx;
         }
-        write_FLAG(0xFF00);
+        cs_deactive(chip);
 
 }
 
@@ -318,7 +339,7 @@ static void u8_cs_chg_reader(struct driver_data *drv_data)
         struct chip_data *chip = drv_data->cur_chip;
 
         while (drv_data->rx < drv_data->rx_end) {
-                write_FLAG(chip->flag);
+                cs_active(chip);
 
                 read_RDBR();    /* kick off */
                 while (!(read_STAT() & BIT_STAT_RXS))
@@ -326,13 +347,13 @@ static void u8_cs_chg_reader(struct driver_data *drv_data)
                 while (!(read_STAT() & BIT_STAT_SPIF))
                         continue;
                 *(u8 *) (drv_data->rx) = read_SHAW();
-                write_FLAG(0xFF00 | chip->flag);
+                cs_deactive(chip);
 
                 if (chip->cs_chg_udelay)
                         udelay(chip->cs_chg_udelay);
                 ++drv_data->rx;
         }
-        write_FLAG(0xFF00);
+        cs_deactive(chip);
 
 }
 
@@ -356,7 +377,7 @@ static void u8_cs_chg_duplex(struct driver_data *drv_data)
         struct chip_data *chip = drv_data->cur_chip;
 
         while (drv_data->rx < drv_data->rx_end) {
-                write_FLAG(chip->flag);
+                cs_active(chip);
 
 
                 write_TDBR(*(u8 *) (drv_data->tx));
@@ -365,15 +386,14 @@ static void u8_cs_chg_duplex(struct driver_data *drv_data)
                 while (!(read_STAT() & BIT_STAT_RXS))
                         continue;
                 *(u8 *) (drv_data->rx) = read_RDBR();
-                write_FLAG(0xFF00 | chip->flag);
+                cs_deactive(chip);
 
                 if (chip->cs_chg_udelay)
                         udelay(chip->cs_chg_udelay);
                 ++drv_data->rx;
                 ++drv_data->tx;
         }
-        write_FLAG(0xFF00);
-
+        cs_deactive(chip);
 }
 
 static void u16_writer(struct driver_data *drv_data)
@@ -398,20 +418,20 @@ static void u16_cs_chg_writer(struct driver_data *drv_data)
         struct chip_data *chip = drv_data->cur_chip;
 
         while (drv_data->tx < drv_data->tx_end) {
-                write_FLAG(chip->flag);
+                cs_active(chip);
 
                 write_TDBR(*(u16 *) (drv_data->tx));
                 while ((read_STAT() & BIT_STAT_TXS))
                         continue;
                 while (!(read_STAT() & BIT_STAT_SPIF))
                         continue;
-                write_FLAG(0xFF00 | chip->flag);
+                cs_deactive(chip);
 
                 if (chip->cs_chg_udelay)
                         udelay(chip->cs_chg_udelay);
                 drv_data->tx += 2;
         }
-        write_FLAG(0xFF00);
+        cs_deactive(chip);
 }
 
 static void u16_reader(struct driver_data *drv_data)
@@ -438,7 +458,7 @@ static void u16_cs_chg_reader(struct driver_data *drv_data)
         struct chip_data *chip = drv_data->cur_chip;
 
         while (drv_data->rx < drv_data->rx_end) {
-                write_FLAG(chip->flag);
+                cs_active(chip);
 
                 read_RDBR();    /* kick off */
                 while (!(read_STAT() & BIT_STAT_RXS))
@@ -446,13 +466,13 @@ static void u16_cs_chg_reader(struct driver_data *drv_data)
                 while (!(read_STAT() & BIT_STAT_SPIF))
                         continue;
                 *(u16 *) (drv_data->rx) = read_SHAW();
-                write_FLAG(0xFF00 | chip->flag);
+                cs_deactive(chip);
 
                 if (chip->cs_chg_udelay)
                         udelay(chip->cs_chg_udelay);
                 drv_data->rx += 2;
         }
-        write_FLAG(0xFF00);
+        cs_deactive(chip);
 }
 
 static void u16_duplex(struct driver_data *drv_data)
@@ -475,7 +495,7 @@ static void u16_cs_chg_duplex(struct driver_data *drv_data)
         struct chip_data *chip = drv_data->cur_chip;
 
         while (drv_data->tx < drv_data->tx_end) {
-                write_FLAG(chip->flag);
+                cs_active(chip);
 
                 write_TDBR(*(u16 *) (drv_data->tx));
                 while (!(read_STAT() & BIT_STAT_SPIF))
@@ -483,14 +503,14 @@ static void u16_cs_chg_duplex(struct driver_data *drv_data)
                 while (!(read_STAT() & BIT_STAT_RXS))
                         continue;
                 *(u16 *) (drv_data->rx) = read_RDBR();
-                write_FLAG(0xFF00 | chip->flag);
+                cs_deactive(chip);
 
                 if (chip->cs_chg_udelay)
                         udelay(chip->cs_chg_udelay);
                 drv_data->rx += 2;
                 drv_data->tx += 2;
         }
-        write_FLAG(0xFF00);
+        cs_deactive(chip);
 }
 
 /* test if ther is more transfer to be done */
@@ -515,6 +535,7 @@ static void *next_transfer(struct driver_data *drv_data)
  */
 static void giveback(struct driver_data *drv_data)
 {
+        struct chip_data *chip = drv_data->cur_chip;
         struct spi_transfer *last_transfer;
         unsigned long flags;
         struct spi_message *msg;
@@ -534,10 +555,13 @@ static void giveback(struct driver_data *drv_data)
 
         /* disable chip select signal. And not stop spi in autobuffer mode */
         if (drv_data->tx_dma != 0xFFFF) {
-                write_FLAG(0xFF00);
+                cs_deactive(chip);
                 bfin_spi_disable(drv_data);
         }
 
+        if (!drv_data->cs_change)
+                cs_deactive(chip);
+
         if (msg->complete)
                 msg->complete(msg->context);
 }
@@ -546,6 +570,7 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
 {
         struct driver_data *drv_data = (struct driver_data *)dev_id;
         struct spi_message *msg = drv_data->cur_msg;
+        struct chip_data *chip = drv_data->cur_chip;
 
         dev_dbg(&drv_data->pdev->dev, "in dma_irq_handler\n");
         clear_dma_irqstat(CH_SPI);
@@ -573,6 +598,9 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
 
         msg->actual_length += drv_data->len_in_bytes;
 
+        if (drv_data->cs_change)
+                cs_deactive(chip);
+
         /* Move to next transfer */
         msg->state = next_transfer(drv_data);
 
@@ -659,6 +687,7 @@ static void pump_transfers(unsigned long data)
         drv_data->rx_dma = transfer->rx_dma;
         drv_data->tx_dma = transfer->tx_dma;
         drv_data->len_in_bytes = transfer->len;
+        drv_data->cs_change = transfer->cs_change;
 
         width = chip->width;
         if (width == CFG_SPI_WORDSIZE16) {
@@ -683,7 +712,7 @@ static void pump_transfers(unsigned long data)
         } else {
                 write_BAUD(chip->baud);
         }
-        write_FLAG(chip->flag);
+        cs_active(chip);
 
         dev_dbg(&drv_data->pdev->dev,
                 "now pumping a transfer: width is %d, len is %d\n",
@@ -834,6 +863,9 @@ static void pump_transfers(unsigned long data)
                         /* Update total byte transfered */
                         message->actual_length += drv_data->len;
 
+                        if (drv_data->cs_change)
+                                cs_deactive(chip);
+
                         /* Move to next transfer of this msg */
                         message->state = next_transfer(drv_data);
                 }