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spi: spi_bfin handles spi_transfer.cs_change
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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>
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Bryan Wu authored and Linus Torvalds committed Dec 5, 2007
1 parent 5fec5b5 commit fad91c8
Showing 1 changed file with 54 additions and 22 deletions.
76 changes: 54 additions & 22 deletions drivers/spi/spi_bfin5xx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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 *);
Expand Down Expand Up @@ -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*/
Expand All @@ -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;
Expand Down Expand Up @@ -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);

}

Expand Down Expand Up @@ -318,21 +339,21 @@ 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))
continue;
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);

}

Expand All @@ -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));
Expand All @@ -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)
Expand All @@ -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)
Expand All @@ -438,21 +458,21 @@ 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))
continue;
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)
Expand All @@ -475,22 +495,22 @@ 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))
continue;
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 */
Expand All @@ -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;
Expand All @@ -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);
}
Expand All @@ -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);
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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) {
Expand All @@ -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",
Expand Down Expand Up @@ -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);
}
Expand Down

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