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authorBarry Song <barry.song@analog.com>2009-11-17 09:45:59 +0000
committerMike Frysinger <vapier@gentoo.org>2010-10-18 02:49:36 -0400
commitd3cc71f71ae13596cb988e16bfa2b15f09fb7347 (patch)
tree6fcd5e9401931dbce719bcdfd1e5b4075f392598 /drivers/spi
parent0d2c6de2255cb299fdd77d4543738adee45f4f3f (diff)
spi/bfin_spi: redo GPIO CS handling
The common SPI layers take care of detecting CS conflicts and preventing two devices from claiming the same CS. This causes problems for the GPIO CS support we currently have as we are using CS0 to mean "GPIO CS". But if we have multiple devices using a GPIO CS, the common SPI layers see multiple devices using the virtual "CS0" and reject any such attempts. To make both work, we introduce an offset define. This represents the max number of hardware CS values that the SPI peripheral supports. If the CS is below this limit, we know we can use the hardware CS. If it's above, we treat it as a GPIO CS. This keeps the CS unique as seen by the common code and prevents conflicts. Signed-off-by: Barry Song <barry.song@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi_bfin5xx.c40
1 files changed, 21 insertions, 19 deletions
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index 07044d7db9a..278fe0a612c 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -183,7 +183,7 @@ static int bfin_spi_flush(struct master_data *drv_data)
/* Chip select operation functions for cs_change flag */
static void bfin_spi_cs_active(struct master_data *drv_data, struct slave_data *chip)
{
- if (likely(chip->chip_select_num)) {
+ if (likely(chip->chip_select_num < MAX_CTRL_CS)) {
u16 flag = read_FLAG(drv_data);
flag &= ~chip->flag;
@@ -196,7 +196,7 @@ static void bfin_spi_cs_active(struct master_data *drv_data, struct slave_data *
static void bfin_spi_cs_deactive(struct master_data *drv_data, struct slave_data *chip)
{
- if (likely(chip->chip_select_num)) {
+ if (likely(chip->chip_select_num < MAX_CTRL_CS)) {
u16 flag = read_FLAG(drv_data);
flag |= chip->flag;
@@ -214,20 +214,24 @@ static void bfin_spi_cs_deactive(struct master_data *drv_data, struct slave_data
/* enable or disable the pin muxed by GPIO and SPI CS to work as SPI CS */
static inline void bfin_spi_cs_enable(struct master_data *drv_data, struct slave_data *chip)
{
- u16 flag = read_FLAG(drv_data);
+ if (chip->chip_select_num < MAX_CTRL_CS) {
+ u16 flag = read_FLAG(drv_data);
- flag |= (chip->flag >> 8);
+ flag |= (chip->flag >> 8);
- write_FLAG(drv_data, flag);
+ write_FLAG(drv_data, flag);
+ }
}
static inline void bfin_spi_cs_disable(struct master_data *drv_data, struct slave_data *chip)
{
- u16 flag = read_FLAG(drv_data);
+ if (chip->chip_select_num < MAX_CTRL_CS) {
+ u16 flag = read_FLAG(drv_data);
- flag &= ~(chip->flag >> 8);
+ flag &= ~(chip->flag >> 8);
- write_FLAG(drv_data, flag);
+ write_FLAG(drv_data, flag);
+ }
}
/* stop controller and re-config current chip*/
@@ -1016,7 +1020,6 @@ static int bfin_spi_setup(struct spi_device *spi)
chip->ctl_reg = chip_info->ctl_reg;
chip->bits_per_word = chip_info->bits_per_word;
chip->cs_chg_udelay = chip_info->cs_chg_udelay;
- chip->cs_gpio = chip_info->cs_gpio;
chip->idle_tx_val = chip_info->idle_tx_val;
chip->pio_interrupt = chip_info->pio_interrupt;
}
@@ -1036,8 +1039,11 @@ static int bfin_spi_setup(struct spi_device *spi)
* SPI_BAUD, not the real baudrate
*/
chip->baud = hz_to_spi_baud(spi->max_speed_hz);
- chip->flag = (1 << (spi->chip_select)) << 8;
chip->chip_select_num = spi->chip_select;
+ if (chip->chip_select_num < MAX_CTRL_CS)
+ chip->flag = (1 << spi->chip_select) << 8;
+ else
+ chip->cs_gpio = chip->chip_select_num - MAX_CTRL_CS;
switch (chip->bits_per_word) {
case 8:
@@ -1098,7 +1104,7 @@ static int bfin_spi_setup(struct spi_device *spi)
disable_irq(drv_data->spi_irq);
}
- if (chip->chip_select_num == 0) {
+ if (chip->chip_select_num >= MAX_CTRL_CS) {
ret = gpio_request(chip->cs_gpio, spi->modalias);
if (ret) {
dev_err(&spi->dev, "gpio_request() error\n");
@@ -1115,8 +1121,7 @@ static int bfin_spi_setup(struct spi_device *spi)
spi_set_ctldata(spi, chip);
dev_dbg(&spi->dev, "chip select number is %d\n", chip->chip_select_num);
- if (chip->chip_select_num > 0 &&
- chip->chip_select_num <= spi->master->num_chipselect) {
+ if (chip->chip_select_num < MAX_CTRL_CS) {
ret = peripheral_request(ssel[spi->master->bus_num]
[chip->chip_select_num-1], spi->modalias);
if (ret) {
@@ -1131,7 +1136,7 @@ static int bfin_spi_setup(struct spi_device *spi)
return 0;
pin_error:
- if (chip->chip_select_num == 0)
+ if (chip->chip_select_num >= MAX_CTRL_CS)
gpio_free(chip->cs_gpio);
else
peripheral_free(ssel[spi->master->bus_num]
@@ -1162,14 +1167,11 @@ static void bfin_spi_cleanup(struct spi_device *spi)
if (!chip)
return;
- if ((chip->chip_select_num > 0)
- && (chip->chip_select_num <= spi->master->num_chipselect)) {
+ if (chip->chip_select_num < MAX_CTRL_CS) {
peripheral_free(ssel[spi->master->bus_num]
[chip->chip_select_num-1]);
bfin_spi_cs_disable(drv_data, chip);
- }
-
- if (chip->chip_select_num == 0)
+ } else
gpio_free(chip->cs_gpio);
kfree(chip);