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Diffstat (limited to 'Documentation/spi/ep93xx_spi')
-rw-r--r-- | Documentation/spi/ep93xx_spi | 105 |
1 files changed, 0 insertions, 105 deletions
diff --git a/Documentation/spi/ep93xx_spi b/Documentation/spi/ep93xx_spi deleted file mode 100644 index 832ddce6e5fb..000000000000 --- a/Documentation/spi/ep93xx_spi +++ /dev/null @@ -1,105 +0,0 @@ -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 <linux/platform_data/spi-ep93xx.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)); -} - -The driver can use DMA for the transfers also. In this case ts72xx_spi_info -becomes: - -static struct ep93xx_spi_info ts72xx_spi_info = { - .num_chipselect = ARRAY_SIZE(ts72xx_spi_devices), - .use_dma = true; -}; - -Note that CONFIG_EP93XX_DMA should be enabled as well. - -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. |