diff options
| author | merge <null@invalid> | 2009-01-22 13:55:32 +0000 |
|---|---|---|
| committer | Andy Green <agreen@octopus.localdomain> | 2009-01-22 13:55:32 +0000 |
| commit | aa6f5ffbdba45aa8e19e5048648fc6c7b25376d3 (patch) | |
| tree | fbb786d0ac6f8a774fd834e9ce951197e60fbffa /include/linux/spi/spi_gpio.h | |
| parent | f2d78193eae5dccd3d588d2c8ea0866efc368332 (diff) | |
MERGE-via-pending-tracking-hist-MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141
pending-tracking-hist top was MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141 / fdf777a63bcb59e0dfd78bfe2c6242e01f6d4eb9 ... parent commitmessage:
From: merge <null@invalid>
MERGE-via-stable-tracking-hist-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040
stable-tracking-hist top was MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 / 90463bfd2d5a3c8b52f6e6d71024a00e052b0ced ... parent commitmessage:
From: merge <null@invalid>
MERGE-via-mokopatches-tracking-hist-fix-stray-endmenu-patch
mokopatches-tracking-hist top was fix-stray-endmenu-patch / 3630e0be570de8057e7f8d2fe501ed353cdf34e6 ... parent commitmessage:
From: Andy Green <andy@openmoko.com>
fix-stray-endmenu.patch
Signed-off-by: Andy Green <andy@openmoko.com>
Diffstat (limited to 'include/linux/spi/spi_gpio.h')
| -rw-r--r-- | include/linux/spi/spi_gpio.h | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/include/linux/spi/spi_gpio.h b/include/linux/spi/spi_gpio.h new file mode 100644 index 00000000000..0f01a0f1f40 --- /dev/null +++ b/include/linux/spi/spi_gpio.h @@ -0,0 +1,60 @@ +#ifndef __LINUX_SPI_GPIO_H +#define __LINUX_SPI_GPIO_H + +/* + * For each bitbanged SPI bus, set up a platform_device node with: + * - name "spi_gpio" + * - id the same as the SPI bus number it implements + * - dev.platform data pointing to a struct spi_gpio_platform_data + * + * Or, see the driver code for information about speedups that are + * possible on platforms that support inlined access for GPIOs (no + * spi_gpio_platform_data is used). + * + * Use spi_board_info with these busses in the usual way, being sure + * that the controller_data being the GPIO used for each device's + * chipselect: + * + * static struct spi_board_info ... [] = { + * ... + * // this slave uses GPIO 42 for its chipselect + * .controller_data = (void *) 42, + * ... + * // this one uses GPIO 86 for its chipselect + * .controller_data = (void *) 86, + * ... + * }; + * + * If the bitbanged bus is later switched to a "native" controller, + * that platform_device and controller_data should be removed. + */ + +/** + * struct spi_gpio_platform_data - parameter for bitbanged SPI master + * @sck: number of the GPIO used for clock output + * @mosi: number of the GPIO used for Master Output, Slave In (MOSI) data + * @miso: number of the GPIO used for Master Input, Slave Output (MISO) data + * @num_chipselect: how many slaves to allow + * + * All GPIO signals used with the SPI bus managed through this driver + * (chipselects, MOSI, MISO, SCK) must be configured as GPIOs, instead + * of some alternate function. + * + * It can be convenient to use this driver with pins that have alternate + * functions associated with a "native" SPI controller if a driver for that + * controller is not available, or is missing important functionality. + * + * On platforms which can do so, configure MISO with a weak pullup unless + * there's an external pullup on that signal. That saves power by avoiding + * floating signals. (A weak pulldown would save power too, but many + * drivers expect to see all-ones data as the no slave "response".) + */ +struct spi_gpio_platform_data { + unsigned sck; + unsigned mosi; + unsigned miso; + + u16 num_chipselect; +}; + +#endif /* __LINUX_SPI_GPIO_H */ |