spi/ep93xx: implemented driver for Cirrus EP93xx SPI controller (011f23a3) · Commits · e / devices / android_kernel_teracube_emerald

Documentation/spi/ep93xx_spi

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		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.

arch/arm/mach-ep93xx/include/mach/ep93xx_spi.h

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		#ifndef __ASM_MACH_EP93XX_SPI_H
		#define __ASM_MACH_EP93XX_SPI_H

		struct spi_device;

		/**
		* struct ep93xx_spi_info - EP93xx specific SPI descriptor
		* @num_chipselect: number of chip selects on this board, must be
		* at least one
		*/
		struct ep93xx_spi_info {
		int num_chipselect;
		};

		/**
		* struct ep93xx_spi_chip_ops - operation callbacks for SPI slave device
		* @setup: setup the chip select mechanism
		* @cleanup: cleanup the chip select mechanism
		* @cs_control: control the device chip select
		*/
		struct ep93xx_spi_chip_ops {
		int (setup)(struct spi_device spi);
		void (cleanup)(struct spi_device spi);
		void (cs_control)(struct spi_device spi, int value);
		};

		#endif /* __ASM_MACH_EP93XX_SPI_H */

drivers/spi/Kconfig

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		@@ -117,6 +117,16 @@ config SPI_DAVINCI
		help
		SPI master controller for DaVinci and DA8xx SPI modules.

		config SPI_EP93XX
		tristate "Cirrus Logic EP93xx SPI controller"
		depends on ARCH_EP93XX
		help
		This enables using the Cirrus EP93xx SPI controller in master
		mode.

		To compile this driver as a module, choose M here. The module will be
		called ep93xx_spi.

		config SPI_GPIO
		tristate "GPIO-based bitbanging SPI Master"
		depends on GENERIC_GPIO

drivers/spi/Makefile

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		@@ -21,6 +21,7 @@ obj-$(CONFIG_SPI_DAVINCI) += davinci_spi.o
		obj-$(CONFIG_SPI_DESIGNWARE) += dw_spi.o
		obj-$(CONFIG_SPI_DW_PCI) += dw_spi_pci.o
		obj-$(CONFIG_SPI_DW_MMIO) += dw_spi_mmio.o
		obj-$(CONFIG_SPI_EP93XX) += ep93xx_spi.o
		obj-$(CONFIG_SPI_GPIO) += spi_gpio.o
		obj-$(CONFIG_SPI_IMX) += spi_imx.o
		obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o

drivers/spi/ep93xx_spi.c

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File added.

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