diff options
| -rw-r--r-- | drivers/spi/spi_gpio.c | 21 | ||||
| -rw-r--r-- | include/linux/spi/spi_gpio.h | 6 |
2 files changed, 19 insertions, 8 deletions
diff --git a/drivers/spi/spi_gpio.c b/drivers/spi/spi_gpio.c index d2866c293de..26bd03e6185 100644 --- a/drivers/spi/spi_gpio.c +++ b/drivers/spi/spi_gpio.c @@ -178,8 +178,10 @@ static void spi_gpio_chipselect(struct spi_device *spi, int is_active) if (is_active) setsck(spi, spi->mode & SPI_CPOL); - /* SPI is normally active-low */ - gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); + if (cs != SPI_GPIO_NO_CHIPSELECT) { + /* SPI is normally active-low */ + gpio_set_value(cs, (spi->mode & SPI_CS_HIGH) ? is_active : !is_active); + } } static int spi_gpio_setup(struct spi_device *spi) @@ -191,15 +193,17 @@ static int spi_gpio_setup(struct spi_device *spi) return -EINVAL; if (!spi->controller_state) { - status = gpio_request(cs, dev_name(&spi->dev)); - if (status) - return status; - status = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH); + if (cs != SPI_GPIO_NO_CHIPSELECT) { + status = gpio_request(cs, dev_name(&spi->dev)); + if (status) + return status; + status = gpio_direction_output(cs, spi->mode & SPI_CS_HIGH); + } } if (!status) status = spi_bitbang_setup(spi); if (status) { - if (!spi->controller_state) + if (!spi->controller_state && cs != SPI_GPIO_NO_CHIPSELECT) gpio_free(cs); } return status; @@ -209,7 +213,8 @@ static void spi_gpio_cleanup(struct spi_device *spi) { unsigned long cs = (unsigned long) spi->controller_data; - gpio_free(cs); + if (cs != SPI_GPIO_NO_CHIPSELECT) + gpio_free(cs); spi_bitbang_cleanup(spi); } diff --git a/include/linux/spi/spi_gpio.h b/include/linux/spi/spi_gpio.h index 0f01a0f1f40..ca6782ee4b9 100644 --- a/include/linux/spi/spi_gpio.h +++ b/include/linux/spi/spi_gpio.h @@ -25,10 +25,16 @@ * ... * }; * + * If chipselect is not used (there's only one device on the bus), assign + * SPI_GPIO_NO_CHIPSELECT to the controller_data: + * .controller_data = (void *) SPI_GPIO_NO_CHIPSELECT; + * * If the bitbanged bus is later switched to a "native" controller, * that platform_device and controller_data should be removed. */ +#define SPI_GPIO_NO_CHIPSELECT ((unsigned long)-1l) + /** * struct spi_gpio_platform_data - parameter for bitbanged SPI master * @sck: number of the GPIO used for clock output |