diff options
Diffstat (limited to 'Documentation/spi')
| -rw-r--r-- | Documentation/spi/ep93xx_spi | 95 | ||||
| -rw-r--r-- | Documentation/spi/spidev_fdx.c | 4 |
2 files changed, 97 insertions, 2 deletions
diff --git a/Documentation/spi/ep93xx_spi b/Documentation/spi/ep93xx_spi new file mode 100644 index 00000000000..6325f5b4863 --- /dev/null +++ b/Documentation/spi/ep93xx_spi @@ -0,0 +1,95 @@ +Cirrus EP93xx SPI controller driver HOWTO +========================================= + +ep93xx_spi driver brings SPI master support for EP93xx SPI controller. Chip +selects are implemented with GPIO lines. + +NOTE: If possible, don't use SFRMOUT (SFRM1) signal as a chip select. It will +not work correctly (it cannot be controlled by software). Use GPIO lines +instead. + +Sample configuration +==================== + +Typically driver configuration is done in platform board files (the files under +arch/arm/mach-ep93xx/*.c). In this example we configure MMC over SPI through +this driver on TS-7260 board. You can adapt the code to suit your needs. + +This example uses EGPIO9 as SD/MMC card chip select (this is wired in DIO1 +header on the board). + +You need to select CONFIG_MMC_SPI to use mmc_spi driver. + +arch/arm/mach-ep93xx/ts72xx.c: + +... +#include <linux/gpio.h> +#include <linux/spi/spi.h> + +#include <mach/ep93xx_spi.h> + +/* this is our GPIO line used for chip select */ +#define MMC_CHIP_SELECT_GPIO EP93XX_GPIO_LINE_EGPIO9 + +static int ts72xx_mmc_spi_setup(struct spi_device *spi) +{ + int err; + + err = gpio_request(MMC_CHIP_SELECT_GPIO, spi->modalias); + if (err) + return err; + + gpio_direction_output(MMC_CHIP_SELECT_GPIO, 1); + + return 0; +} + +static void ts72xx_mmc_spi_cleanup(struct spi_device *spi) +{ + gpio_set_value(MMC_CHIP_SELECT_GPIO, 1); + gpio_direction_input(MMC_CHIP_SELECT_GPIO); + gpio_free(MMC_CHIP_SELECT_GPIO); +} + +static void ts72xx_mmc_spi_cs_control(struct spi_device *spi, int value) +{ + gpio_set_value(MMC_CHIP_SELECT_GPIO, value); +} + +static struct ep93xx_spi_chip_ops ts72xx_mmc_spi_ops = { + .setup = ts72xx_mmc_spi_setup, + .cleanup = ts72xx_mmc_spi_cleanup, + .cs_control = ts72xx_mmc_spi_cs_control, +}; + +static struct spi_board_info ts72xx_spi_devices[] __initdata = { + { + .modalias = "mmc_spi", + .controller_data = &ts72xx_mmc_spi_ops, + /* + * We use 10 MHz even though the maximum is 7.4 MHz. The driver + * will limit it automatically to max. frequency. + */ + .max_speed_hz = 10 * 1000 * 1000, + .bus_num = 0, + .chip_select = 0, + .mode = SPI_MODE_0, + }, +}; + +static struct ep93xx_spi_info ts72xx_spi_info = { + .num_chipselect = ARRAY_SIZE(ts72xx_spi_devices), +}; + +static void __init ts72xx_init_machine(void) +{ + ... + ep93xx_register_spi(&ts72xx_spi_info, ts72xx_spi_devices, + ARRAY_SIZE(ts72xx_spi_devices)); +} + +Thanks to +========= +Martin Guy, H. Hartley Sweeten and others who helped me during development of +the driver. Simplemachines.it donated me a Sim.One board which I used testing +the driver on EP9307. diff --git a/Documentation/spi/spidev_fdx.c b/Documentation/spi/spidev_fdx.c index fc354f76038..36ec0774ca0 100644 --- a/Documentation/spi/spidev_fdx.c +++ b/Documentation/spi/spidev_fdx.c @@ -58,10 +58,10 @@ static void do_msg(int fd, int len) len = sizeof buf; buf[0] = 0xaa; - xfer[0].tx_buf = (__u64) buf; + xfer[0].tx_buf = (unsigned long)buf; xfer[0].len = 1; - xfer[1].rx_buf = (__u64) buf; + xfer[1].rx_buf = (unsigned long) buf; xfer[1].len = len; status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer); |