Edit File: spi_gpio.h
#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 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 MISO or MOSI pin is not available then it should be set to * SPI_GPIO_NO_MISO or SPI_GPIO_NO_MOSI. * * 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) #define SPI_GPIO_NO_MISO ((unsigned long)-1l) #define SPI_GPIO_NO_MOSI ((unsigned long)-1l) /** * 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 long mosi; unsigned long miso; u16 num_chipselect; }; #endif /* __LINUX_SPI_GPIO_H */