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2.6.26: add gpiommc driver

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SVN-Revision: 12566
This commit is contained in:
Gabor Juhos 2008-09-10 19:46:56 +00:00
parent 55f3b8ade2
commit 74321caaf8
5 changed files with 1249 additions and 297 deletions
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242
target/linux/generic-2.6/files-2.6.26/drivers/spi/spi_gpio.c
View file

@ -1,242 +0,0 @@
/*
* Bitbanging SPI bus driver using GPIO API
*
* Copyright (c) 2008 Piotr Skamruk
* Copyright (c) 2008 Michael Buesch
*
* based on spi_s3c2410_gpio.c
* Copyright (c) 2006 Ben Dooks
* Copyright (c) 2006 Simtec Electronics
* and on i2c-gpio.c
* Copyright (C) 2007 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include "linux/spi/spi_gpio.h" //XXX
#include <asm/gpio.h>
struct spi_gpio {
struct spi_bitbang bitbang;
struct spi_gpio_platform_data *info;
struct platform_device *pdev;
struct spi_board_info bi;
};
static inline struct spi_gpio *spidev_to_sg(struct spi_device *dev)
{
return dev->controller_data;
}
static inline void setsck(struct spi_device *dev, int val)
{
struct spi_gpio *sp = spidev_to_sg(dev);
gpio_set_value(sp->info->pin_clk, val ? 1 : 0);
}
static inline void setmosi(struct spi_device *dev, int val )
{
struct spi_gpio *sp = spidev_to_sg(dev);
gpio_set_value(sp->info->pin_mosi, val ? 1 : 0);
}
static inline u32 getmiso(struct spi_device *dev)
{
struct spi_gpio *sp = spidev_to_sg(dev);
return gpio_get_value(sp->info->pin_miso) ? 1 : 0;
}
static inline void do_spidelay(struct spi_device *dev, unsigned nsecs)
{
struct spi_gpio *sp = spidev_to_sg(dev);
if (!sp->info->no_spi_delay)
ndelay(nsecs);
}
#define spidelay(nsecs) do { \
/* Steal the spi_device pointer from our caller. \
* The bitbang-API should probably get fixed here... */ \
do_spidelay(spi, nsecs); \
} while (0)
#define EXPAND_BITBANG_TXRX
#include <linux/spi/spi_bitbang.h>
static u32 spi_gpio_txrx_mode0(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
}
static u32 spi_gpio_txrx_mode1(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
}
static u32 spi_gpio_txrx_mode2(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
}
static u32 spi_gpio_txrx_mode3(struct spi_device *spi,
unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
}
static void spi_gpio_chipselect(struct spi_device *dev, int on)
{
struct spi_gpio *sp = spidev_to_sg(dev);
if (sp->info->cs_activelow)
on = !on;
gpio_set_value(sp->info->pin_cs, on ? 1 : 0);
}
static int spi_gpio_probe(struct platform_device *pdev)
{
struct spi_master *master;
struct spi_gpio_platform_data *pdata;
struct spi_gpio *sp;
struct spi_device *spidev;
int err;
pdata = pdev->dev.platform_data;
if (!pdata)
return -ENXIO;
err = -ENOMEM;
master = spi_alloc_master(&pdev->dev, sizeof(struct spi_gpio));
if (!master)
goto err_alloc_master;
sp = spi_master_get_devdata(master);
platform_set_drvdata(pdev, sp);
sp->info = pdata;
err = gpio_request(pdata->pin_clk, "spi_clock");
if (err)
goto err_request_clk;
err = gpio_request(pdata->pin_mosi, "spi_mosi");
if (err)
goto err_request_mosi;
err = gpio_request(pdata->pin_miso, "spi_miso");
if (err)
goto err_request_miso;
err = gpio_request(pdata->pin_cs, "spi_cs");
if (err)
goto err_request_cs;
sp->bitbang.master = spi_master_get(master);
sp->bitbang.master->bus_num = -1;
sp->bitbang.master->num_chipselect = 1;
sp->bitbang.chipselect = spi_gpio_chipselect;
sp->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_mode0;
sp->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_mode1;
sp->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_mode2;
sp->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_mode3;
gpio_direction_output(pdata->pin_clk, 0);
gpio_direction_output(pdata->pin_mosi, 0);
gpio_direction_output(pdata->pin_cs,
pdata->cs_activelow ? 1 : 0);
gpio_direction_input(pdata->pin_miso);
err = spi_bitbang_start(&sp->bitbang);
if (err)
goto err_no_bitbang;
err = pdata->boardinfo_setup(&sp->bi, master,
pdata->boardinfo_setup_data);
if (err)
goto err_bi_setup;
sp->bi.controller_data = sp;
spidev = spi_new_device(master, &sp->bi);
if (!spidev)
goto err_new_dev;
return 0;
err_new_dev:
err_bi_setup:
spi_bitbang_stop(&sp->bitbang);
err_no_bitbang:
spi_master_put(sp->bitbang.master);
gpio_free(pdata->pin_cs);
err_request_cs:
gpio_free(pdata->pin_miso);
err_request_miso:
gpio_free(pdata->pin_mosi);
err_request_mosi:
gpio_free(pdata->pin_clk);
err_request_clk:
kfree(master);
err_alloc_master:
return err;
}
static int __devexit spi_gpio_remove(struct platform_device *pdev)
{
struct spi_gpio *sp;
struct spi_gpio_platform_data *pdata;
pdata = pdev->dev.platform_data;
sp = platform_get_drvdata(pdev);
gpio_free(pdata->pin_clk);
gpio_free(pdata->pin_mosi);
gpio_free(pdata->pin_miso);
gpio_free(pdata->pin_cs);
spi_bitbang_stop(&sp->bitbang);
spi_master_put(sp->bitbang.master);
return 0;
}
static struct platform_driver spi_gpio_driver = {
.driver = {
.name = "spi-gpio",
.owner = THIS_MODULE,
},
.probe = spi_gpio_probe,
.remove = __devexit_p(spi_gpio_remove),
};
static int __init spi_gpio_init(void)
{
int err;
err = platform_driver_register(&spi_gpio_driver);
if (err)
printk(KERN_ERR "spi-gpio: register failed: %d\n", err);
return err;
}
module_init(spi_gpio_init);
static void __exit spi_gpio_exit(void)
{
platform_driver_unregister(&spi_gpio_driver);
}
module_exit(spi_gpio_exit);
MODULE_AUTHOR("Piot Skamruk <piotr.skamruk at gmail.com>");
MODULE_AUTHOR("Michael Buesch");
MODULE_DESCRIPTION("Platform independent GPIO bitbangling SPI driver");
MODULE_LICENSE("GPL v2");

53
target/linux/generic-2.6/files-2.6.26/include/linux/spi/spi_gpio.h
View file

@ -1,53 +0,0 @@
/*
* spi_gpio interface to platform code
*
* Copyright (c) 2008 Piotr Skamruk
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _LINUX_SPI_SPI_GPIO
#define _LINUX_SPI_SPI_GPIO
#include <linux/types.h>
#include <linux/spi/spi.h>
/** struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
* This structure holds information about a GPIO-based SPI device.
*
* @pin_clk: The GPIO pin number of the CLOCK pin.
*
* @pin_miso: The GPIO pin number of the MISO pin.
*
* @pin_mosi: The GPIO pin number of the MOSI pin.
*
* @pin_cs: The GPIO pin number of the CHIPSELECT pin.
*
* @cs_activelow: If true, the chip is selected when the CS line is low.
*
* @no_spi_delay: If true, no delay is done in the lowlevel bitbanging.
* Note that doing no delay is not standards compliant,
* but it might be needed to speed up transfers on some
* slow embedded machines.
*
* @boardinfo_setup: This callback is called after the
* SPI master device was registered, but before the
* device is registered.
* @boardinfo_setup_data: Data argument passed to boardinfo_setup().
*/
struct spi_gpio_platform_data {
unsigned int pin_clk;
unsigned int pin_miso;
unsigned int pin_mosi;
unsigned int pin_cs;
bool cs_activelow;
bool no_spi_delay;
int (*boardinfo_setup)(struct spi_board_info *bi,
struct spi_master *master,
void *data);
void *boardinfo_setup_data;
};
#endif /* _LINUX_SPI_SPI_GPIO */

356
target/linux/generic-2.6/patches-2.6.26/921-gpio_spi_driver.patch
View file

@ -1,13 +1,351 @@
--- /dev/null
+++ b/include/linux/spi/spi_gpio.h
@@ -0,0 +1,73 @@
+/*
+ * spi_gpio interface to platform code
+ *
+ * Copyright (c) 2008 Piotr Skamruk
+ * Copyright (c) 2008 Michael Buesch
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#ifndef _LINUX_SPI_SPI_GPIO
+#define _LINUX_SPI_SPI_GPIO
+
+#include <linux/types.h>
+#include <linux/spi/spi.h>
+
+
+/**
+ * struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
+ *
+ * This structure holds information about a GPIO-based SPI device.
+ *
+ * @pin_clk: The GPIO pin number of the CLOCK pin.
+ *
+ * @pin_miso: The GPIO pin number of the MISO pin.
+ *
+ * @pin_mosi: The GPIO pin number of the MOSI pin.
+ *
+ * @pin_cs: The GPIO pin number of the CHIPSELECT pin.
+ *
+ * @cs_activelow: If true, the chip is selected when the CS line is low.
+ *
+ * @no_spi_delay: If true, no delay is done in the lowlevel bitbanging.
+ * Note that doing no delay is not standards compliant,
+ * but it might be needed to speed up transfers on some
+ * slow embedded machines.
+ *
+ * @boardinfo_setup: This callback is called after the
+ * SPI master device was registered, but before the
+ * device is registered.
+ * @boardinfo_setup_data: Data argument passed to boardinfo_setup().
+ */
+struct spi_gpio_platform_data {
+ unsigned int pin_clk;
+ unsigned int pin_miso;
+ unsigned int pin_mosi;
+ unsigned int pin_cs;
+ bool cs_activelow;
+ bool no_spi_delay;
+ int (*boardinfo_setup)(struct spi_board_info *bi,
+ struct spi_master *master,
+ void *data);
+ void *boardinfo_setup_data;
+};
+
+/**
+ * SPI_GPIO_PLATDEV_NAME - The platform device name string.
+ *
+ * The name string that has to be used for platform_device_alloc
+ * when allocating a spi-gpio device.
+ */
+#define SPI_GPIO_PLATDEV_NAME "spi-gpio"
+
+/**
+ * spi_gpio_next_id - Get another platform device ID number.
+ *
+ * This returns the next platform device ID number that has to be used
+ * for platform_device_alloc. The ID is opaque and should not be used for
+ * anything else.
+ */
+int spi_gpio_next_id(void);
+
+#endif /* _LINUX_SPI_SPI_GPIO */
--- /dev/null
+++ b/drivers/spi/spi_gpio.c
@@ -0,0 +1,251 @@
+/*
+ * Bitbanging SPI bus driver using GPIO API
+ *
+ * Copyright (c) 2008 Piotr Skamruk
+ * Copyright (c) 2008 Michael Buesch
+ *
+ * based on spi_s3c2410_gpio.c
+ * Copyright (c) 2006 Ben Dooks
+ * Copyright (c) 2006 Simtec Electronics
+ * and on i2c-gpio.c
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi_bitbang.h>
+#include <linux/spi/spi_gpio.h>
+#include <linux/gpio.h>
+#include <asm/atomic.h>
+
+
+struct spi_gpio {
+ struct spi_bitbang bitbang;
+ struct spi_gpio_platform_data *info;
+ struct platform_device *pdev;
+ struct spi_board_info bi;
+};
+
+
+static inline struct spi_gpio *spidev_to_sg(struct spi_device *dev)
+{
+ return dev->controller_data;
+}
+
+static inline void setsck(struct spi_device *dev, int val)
+{
+ struct spi_gpio *sp = spidev_to_sg(dev);
+ gpio_set_value(sp->info->pin_clk, val ? 1 : 0);
+}
+
+static inline void setmosi(struct spi_device *dev, int val)
+{
+ struct spi_gpio *sp = spidev_to_sg(dev);
+ gpio_set_value(sp->info->pin_mosi, val ? 1 : 0);
+}
+
+static inline u32 getmiso(struct spi_device *dev)
+{
+ struct spi_gpio *sp = spidev_to_sg(dev);
+ return gpio_get_value(sp->info->pin_miso) ? 1 : 0;
+}
+
+static inline void do_spidelay(struct spi_device *dev, unsigned nsecs)
+{
+ struct spi_gpio *sp = spidev_to_sg(dev);
+
+ if (!sp->info->no_spi_delay)
+ ndelay(nsecs);
+}
+
+#define spidelay(nsecs) do { \
+ /* Steal the spi_device pointer from our caller. \
+ * The bitbang-API should probably get fixed here... */ \
+ do_spidelay(spi, nsecs); \
+ } while (0)
+
+#define EXPAND_BITBANG_TXRX
+#include <linux/spi/spi_bitbang.h>
+
+static u32 spi_gpio_txrx_mode0(struct spi_device *spi,
+ unsigned nsecs, u32 word, u8 bits)
+{
+ return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
+}
+
+static u32 spi_gpio_txrx_mode1(struct spi_device *spi,
+ unsigned nsecs, u32 word, u8 bits)
+{
+ return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
+}
+
+static u32 spi_gpio_txrx_mode2(struct spi_device *spi,
+ unsigned nsecs, u32 word, u8 bits)
+{
+ return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
+}
+
+static u32 spi_gpio_txrx_mode3(struct spi_device *spi,
+ unsigned nsecs, u32 word, u8 bits)
+{
+ return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
+}
+
+static void spi_gpio_chipselect(struct spi_device *dev, int on)
+{
+ struct spi_gpio *sp = spidev_to_sg(dev);
+
+ if (sp->info->cs_activelow)
+ on = !on;
+ gpio_set_value(sp->info->pin_cs, on ? 1 : 0);
+}
+
+static int spi_gpio_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct spi_gpio_platform_data *pdata;
+ struct spi_gpio *sp;
+ struct spi_device *spidev;
+ int err;
+
+ pdata = pdev->dev.platform_data;
+ if (!pdata)
+ return -ENXIO;
+
+ err = -ENOMEM;
+ master = spi_alloc_master(&pdev->dev, sizeof(struct spi_gpio));
+ if (!master)
+ goto err_alloc_master;
+
+ sp = spi_master_get_devdata(master);
+ platform_set_drvdata(pdev, sp);
+ sp->info = pdata;
+
+ err = gpio_request(pdata->pin_clk, "spi_clock");
+ if (err)
+ goto err_request_clk;
+ err = gpio_request(pdata->pin_mosi, "spi_mosi");
+ if (err)
+ goto err_request_mosi;
+ err = gpio_request(pdata->pin_miso, "spi_miso");
+ if (err)
+ goto err_request_miso;
+ err = gpio_request(pdata->pin_cs, "spi_cs");
+ if (err)
+ goto err_request_cs;
+
+ sp->bitbang.master = spi_master_get(master);
+ sp->bitbang.master->bus_num = -1;
+ sp->bitbang.master->num_chipselect = 1;
+ sp->bitbang.chipselect = spi_gpio_chipselect;
+ sp->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_mode0;
+ sp->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_mode1;
+ sp->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_mode2;
+ sp->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_txrx_mode3;
+
+ gpio_direction_output(pdata->pin_clk, 0);
+ gpio_direction_output(pdata->pin_mosi, 0);
+ gpio_direction_output(pdata->pin_cs,
+ pdata->cs_activelow ? 1 : 0);
+ gpio_direction_input(pdata->pin_miso);
+
+ err = spi_bitbang_start(&sp->bitbang);
+ if (err)
+ goto err_no_bitbang;
+ err = pdata->boardinfo_setup(&sp->bi, master,
+ pdata->boardinfo_setup_data);
+ if (err)
+ goto err_bi_setup;
+ sp->bi.controller_data = sp;
+ spidev = spi_new_device(master, &sp->bi);
+ if (!spidev)
+ goto err_new_dev;
+
+ return 0;
+
+err_new_dev:
+err_bi_setup:
+ spi_bitbang_stop(&sp->bitbang);
+err_no_bitbang:
+ spi_master_put(sp->bitbang.master);
+ gpio_free(pdata->pin_cs);
+err_request_cs:
+ gpio_free(pdata->pin_miso);
+err_request_miso:
+ gpio_free(pdata->pin_mosi);
+err_request_mosi:
+ gpio_free(pdata->pin_clk);
+err_request_clk:
+ kfree(master);
+
+err_alloc_master:
+ return err;
+}
+
+static int __devexit spi_gpio_remove(struct platform_device *pdev)
+{
+ struct spi_gpio *sp;
+ struct spi_gpio_platform_data *pdata;
+
+ pdata = pdev->dev.platform_data;
+ sp = platform_get_drvdata(pdev);
+
+ gpio_free(pdata->pin_clk);
+ gpio_free(pdata->pin_mosi);
+ gpio_free(pdata->pin_miso);
+ gpio_free(pdata->pin_cs);
+ spi_bitbang_stop(&sp->bitbang);
+ spi_master_put(sp->bitbang.master);
+
+ return 0;
+}
+
+static struct platform_driver spi_gpio_driver = {
+ .driver = {
+ .name = SPI_GPIO_PLATDEV_NAME,
+ .owner = THIS_MODULE,
+ },
+ .probe = spi_gpio_probe,
+ .remove = __devexit_p(spi_gpio_remove),
+};
+
+int spi_gpio_next_id(void)
+{
+ static atomic_t counter = ATOMIC_INIT(-1);
+
+ return atomic_inc_return(&counter);
+}
+EXPORT_SYMBOL(spi_gpio_next_id);
+
+static int __init spi_gpio_init(void)
+{
+ int err;
+
+ err = platform_driver_register(&spi_gpio_driver);
+ if (err)
+ printk(KERN_ERR "spi-gpio: register failed: %d\n", err);
+
+ return err;
+}
+module_init(spi_gpio_init);
+
+static void __exit spi_gpio_exit(void)
+{
+ platform_driver_unregister(&spi_gpio_driver);
+}
+module_exit(spi_gpio_exit);
+
+MODULE_AUTHOR("Piot Skamruk <piotr.skamruk at gmail.com>");
+MODULE_AUTHOR("Michael Buesch");
+MODULE_DESCRIPTION("Platform independent GPIO bitbanging SPI driver");
+MODULE_LICENSE("GPL v2");
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -100,6 +100,11 @@
@@ -100,6 +100,19 @@
inexpensive battery powered microcontroller evaluation board.
This same cable can be used to flash new firmware.
+config SPI_GPIO
+ tristate "GPIO API based bitbanging SPI controller"
+ depends on SPI_MASTER && GENERIC_GPIO && EXPERIMENTAL
+ depends on SPI_MASTER && GENERIC_GPIO
+ select SPI_BITBANG
+ help
+ This is a platform driver that can be used for bitbanging
+ an SPI bus over GPIO pins.
+ Select this if you have any SPI device that is connected via
+ GPIO pins.
+ The module will be called spi_gpio.
+
+ If unsure, say N.
+
config SPI_IMX
tristate "Freescale iMX SPI controller"
@ -22,3 +360,17 @@
obj-$(CONFIG_SPI_IMX) += spi_imx.o
obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o
obj-$(CONFIG_SPI_PXA2XX) += pxa2xx_spi.o
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3795,6 +3795,11 @@
W: http://www.ibm.com/developerworks/power/cell/
S: Supported
+SPI GPIO MASTER DRIVER
+P: Michael Buesch
+M: mb@bu3sch.de
+S: Maintained
+
STABLE BRANCH:
P: Greg Kroah-Hartman
M: greg@kroah.com

837
target/linux/generic-2.6/patches-2.6.26/922-gpiommc.patch Normal file
View file

@ -0,0 +1,837 @@
--- /dev/null
+++ b/drivers/mmc/host/gpiommc.c
@@ -0,0 +1,608 @@
+/*
+ * Driver an MMC/SD card on a bitbanging GPIO SPI bus.
+ * This module hooks up the mmc_spi and spi_gpio modules and also
+ * provides a configfs interface.
+ *
+ * Copyright 2008 Michael Buesch <mb@bu3sch.de>
+ *
+ * Licensed under the GNU/GPL. See COPYING for details.
+ */
+
+#include <linux/mmc/gpiommc.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/spi/spi_gpio.h>
+#include <linux/configfs.h>
+#include <linux/gpio.h>
+#include <asm/atomic.h>
+
+
+#define PFX "gpio-mmc: "
+
+
+struct gpiommc_device {
+ struct platform_device *pdev;
+ struct platform_device *spi_pdev;
+ struct spi_board_info boardinfo;
+};
+
+
+MODULE_DESCRIPTION("GPIO based MMC driver");
+MODULE_AUTHOR("Michael Buesch");
+MODULE_LICENSE("GPL");
+
+
+static int gpiommc_boardinfo_setup(struct spi_board_info *bi,
+ struct spi_master *master,
+ void *data)
+{
+ struct gpiommc_device *d = data;
+ struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
+
+ /* Bind the SPI master to the MMC-SPI host driver. */
+ strlcpy(bi->modalias, "mmc_spi", sizeof(bi->modalias));
+
+ bi->max_speed_hz = pdata->max_bus_speed;
+ bi->bus_num = master->bus_num;
+ bi->mode = pdata->mode;
+
+ return 0;
+}
+
+static int gpiommc_probe(struct platform_device *pdev)
+{
+ struct gpiommc_platform_data *mmc_pdata = pdev->dev.platform_data;
+ struct spi_gpio_platform_data spi_pdata;
+ struct gpiommc_device *d;
+ int err;
+
+ err = -ENXIO;
+ if (!mmc_pdata)
+ goto error;
+
+#ifdef CONFIG_MMC_SPI_MODULE
+ err = request_module("mmc_spi");
+ if (err) {
+ printk(KERN_WARNING PFX
+ "Failed to request mmc_spi module.\n");
+ }
+#endif /* CONFIG_MMC_SPI_MODULE */
+
+ /* Allocate the GPIO-MMC device */
+ err = -ENOMEM;
+ d = kzalloc(sizeof(*d), GFP_KERNEL);
+ if (!d)
+ goto error;
+ d->pdev = pdev;
+
+ /* Create the SPI-GPIO device */
+ d->spi_pdev = platform_device_alloc(SPI_GPIO_PLATDEV_NAME,
+ spi_gpio_next_id());
+ if (!d->spi_pdev)
+ goto err_free_d;
+
+ memset(&spi_pdata, 0, sizeof(spi_pdata));
+ spi_pdata.pin_clk = mmc_pdata->pins.gpio_clk;
+ spi_pdata.pin_miso = mmc_pdata->pins.gpio_do;
+ spi_pdata.pin_mosi = mmc_pdata->pins.gpio_di;
+ spi_pdata.pin_cs = mmc_pdata->pins.gpio_cs;
+ spi_pdata.cs_activelow = mmc_pdata->pins.cs_activelow;
+ spi_pdata.no_spi_delay = mmc_pdata->no_spi_delay;
+ spi_pdata.boardinfo_setup = gpiommc_boardinfo_setup;
+ spi_pdata.boardinfo_setup_data = d;
+
+ err = platform_device_add_data(d->spi_pdev, &spi_pdata,
+ sizeof(spi_pdata));
+ if (err)
+ goto err_free_pdev;
+ err = platform_device_add(d->spi_pdev);
+ if (err)
+ goto err_free_pdata;
+ platform_set_drvdata(pdev, d);
+
+ printk(KERN_INFO PFX "MMC-Card \"%s\" "
+ "attached to GPIO pins di=%u, do=%u, clk=%u, cs=%u\n",
+ mmc_pdata->name, mmc_pdata->pins.gpio_di,
+ mmc_pdata->pins.gpio_do,
+ mmc_pdata->pins.gpio_clk,
+ mmc_pdata->pins.gpio_cs);
+
+ return 0;
+
+err_free_pdata:
+ kfree(d->spi_pdev->dev.platform_data);
+ d->spi_pdev->dev.platform_data = NULL;
+err_free_pdev:
+ platform_device_put(d->spi_pdev);
+err_free_d:
+ kfree(d);
+error:
+ return err;
+}
+
+static int gpiommc_remove(struct platform_device *pdev)
+{
+ struct gpiommc_device *d = platform_get_drvdata(pdev);
+ struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
+
+ platform_device_unregister(d->spi_pdev);
+ printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n",
+ pdata->name);
+ platform_device_put(d->spi_pdev);
+
+ return 0;
+}
+
+#ifdef CONFIG_GPIOMMC_CONFIGFS
+
+/* A device that was created through configfs */
+struct gpiommc_configfs_device {
+ struct config_item item;
+ /* The platform device, after registration. */
+ struct platform_device *pdev;
+ /* The configuration */
+ struct gpiommc_platform_data pdata;
+};
+
+#define GPIO_INVALID -1
+
+static inline bool gpiommc_is_registered(struct gpiommc_configfs_device *dev)
+{
+ return (dev->pdev != NULL);
+}
+
+static inline struct gpiommc_configfs_device *ci_to_gpiommc(struct config_item *item)
+{
+ return item ? container_of(item, struct gpiommc_configfs_device, item) : NULL;
+}
+
+static struct configfs_attribute gpiommc_attr_DI = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "gpio_data_in",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_DO = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "gpio_data_out",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_CLK = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "gpio_clock",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_CS = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "gpio_chipselect",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_CS_activelow = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "gpio_chipselect_activelow",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_spimode = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "spi_mode",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_spidelay = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "spi_delay",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_max_bus_speed = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "max_bus_speed",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute gpiommc_attr_register = {
+ .ca_owner = THIS_MODULE,
+ .ca_name = "register",
+ .ca_mode = S_IRUGO | S_IWUSR,
+};
+
+static struct configfs_attribute *gpiommc_config_attrs[] = {
+ &gpiommc_attr_DI,
+ &gpiommc_attr_DO,
+ &gpiommc_attr_CLK,
+ &gpiommc_attr_CS,
+ &gpiommc_attr_CS_activelow,
+ &gpiommc_attr_spimode,
+ &gpiommc_attr_spidelay,
+ &gpiommc_attr_max_bus_speed,
+ &gpiommc_attr_register,
+ NULL,
+};
+
+static ssize_t gpiommc_config_attr_show(struct config_item *item,
+ struct configfs_attribute *attr,
+ char *page)
+{
+ struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
+ ssize_t count = 0;
+ unsigned int gpio;
+ int err = 0;
+
+ if (attr == &gpiommc_attr_DI) {
+ gpio = dev->pdata.pins.gpio_di;
+ if (gpio == GPIO_INVALID)
+ count = snprintf(page, PAGE_SIZE, "not configured\n");
+ else
+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_DO) {
+ gpio = dev->pdata.pins.gpio_do;
+ if (gpio == GPIO_INVALID)
+ count = snprintf(page, PAGE_SIZE, "not configured\n");
+ else
+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_CLK) {
+ gpio = dev->pdata.pins.gpio_clk;
+ if (gpio == GPIO_INVALID)
+ count = snprintf(page, PAGE_SIZE, "not configured\n");
+ else
+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_CS) {
+ gpio = dev->pdata.pins.gpio_cs;
+ if (gpio == GPIO_INVALID)
+ count = snprintf(page, PAGE_SIZE, "not configured\n");
+ else
+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_CS_activelow) {
+ count = snprintf(page, PAGE_SIZE, "%u\n",
+ dev->pdata.pins.cs_activelow);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_spimode) {
+ count = snprintf(page, PAGE_SIZE, "%u\n",
+ dev->pdata.mode);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_spidelay) {
+ count = snprintf(page, PAGE_SIZE, "%u\n",
+ !dev->pdata.no_spi_delay);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_max_bus_speed) {
+ count = snprintf(page, PAGE_SIZE, "%u\n",
+ dev->pdata.max_bus_speed);
+ goto out;
+ }
+ if (attr == &gpiommc_attr_register) {
+ count = snprintf(page, PAGE_SIZE, "%u\n",
+ gpiommc_is_registered(dev));
+ goto out;
+ }
+ WARN_ON(1);
+ err = -ENOSYS;
+out:
+ return err ? err : count;
+}
+
+static int gpiommc_do_register(struct gpiommc_configfs_device *dev,
+ const char *name)
+{
+ int err;
+
+ if (gpiommc_is_registered(dev))
+ return 0;
+
+ if (!gpio_is_valid(dev->pdata.pins.gpio_di) ||
+ !gpio_is_valid(dev->pdata.pins.gpio_do) ||
+ !gpio_is_valid(dev->pdata.pins.gpio_clk) ||
+ !gpio_is_valid(dev->pdata.pins.gpio_cs)) {
+ printk(KERN_ERR PFX
+ "configfs: Invalid GPIO pin number(s)\n");
+ return -EINVAL;
+ }
+
+ strlcpy(dev->pdata.name, name,
+ sizeof(dev->pdata.name));
+
+ dev->pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME,
+ gpiommc_next_id());
+ if (!dev->pdev)
+ return -ENOMEM;
+ err = platform_device_add_data(dev->pdev, &dev->pdata,
+ sizeof(dev->pdata));
+ if (err) {
+ platform_device_put(dev->pdev);
+ return err;
+ }
+ err = platform_device_add(dev->pdev);
+ if (err) {
+ platform_device_put(dev->pdev);
+ return err;
+ }
+
+ return 0;
+}
+
+static void gpiommc_do_unregister(struct gpiommc_configfs_device *dev)
+{
+ if (!gpiommc_is_registered(dev))
+ return;
+
+ platform_device_unregister(dev->pdev);
+ dev->pdev = NULL;
+}
+
+static ssize_t gpiommc_config_attr_store(struct config_item *item,
+ struct configfs_attribute *attr,
+ const char *page, size_t count)
+{
+ struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
+ int err = -EINVAL;
+ unsigned long data;
+
+ if (attr == &gpiommc_attr_register) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (data == 1)
+ err = gpiommc_do_register(dev, item->ci_name);
+ if (data == 0) {
+ gpiommc_do_unregister(dev);
+ err = 0;
+ }
+ goto out;
+ }
+
+ if (gpiommc_is_registered(dev)) {
+ /* The rest of the config parameters can only be set
+ * as long as the device is not registered, yet. */
+ err = -EBUSY;
+ goto out;
+ }
+
+ if (attr == &gpiommc_attr_DI) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (!gpio_is_valid(data))
+ goto out;
+ dev->pdata.pins.gpio_di = data;
+ err = 0;
+ goto out;
+ }
+ if (attr == &gpiommc_attr_DO) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (!gpio_is_valid(data))
+ goto out;
+ dev->pdata.pins.gpio_do = data;
+ err = 0;
+ goto out;
+ }
+ if (attr == &gpiommc_attr_CLK) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (!gpio_is_valid(data))
+ goto out;
+ dev->pdata.pins.gpio_clk = data;
+ err = 0;
+ goto out;
+ }
+ if (attr == &gpiommc_attr_CS) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (!gpio_is_valid(data))
+ goto out;
+ dev->pdata.pins.gpio_cs = data;
+ err = 0;
+ goto out;
+ }
+ if (attr == &gpiommc_attr_CS_activelow) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (data != 0 && data != 1)
+ goto out;
+ dev->pdata.pins.cs_activelow = data;
+ err = 0;
+ goto out;
+ }
+ if (attr == &gpiommc_attr_spimode) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ switch (data) {
+ case 0:
+ dev->pdata.mode = SPI_MODE_0;
+ break;
+ case 1:
+ dev->pdata.mode = SPI_MODE_1;
+ break;
+ case 2:
+ dev->pdata.mode = SPI_MODE_2;
+ break;
+ case 3:
+ dev->pdata.mode = SPI_MODE_3;
+ break;
+ default:
+ goto out;
+ }
+ err = 0;
+ goto out;
+ }
+ if (attr == &gpiommc_attr_spidelay) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (data != 0 && data != 1)
+ goto out;
+ dev->pdata.no_spi_delay = !data;
+ err = 0;
+ goto out;
+ }
+ if (attr == &gpiommc_attr_max_bus_speed) {
+ err = strict_strtoul(page, 10, &data);
+ if (err)
+ goto out;
+ err = -EINVAL;
+ if (data > UINT_MAX)
+ goto out;
+ dev->pdata.max_bus_speed = data;
+ err = 0;
+ goto out;
+ }
+ WARN_ON(1);
+ err = -ENOSYS;
+out:
+ return err ? err : count;
+}
+
+static void gpiommc_config_item_release(struct config_item *item)
+{
+ struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
+
+ kfree(dev);
+}
+
+static struct configfs_item_operations gpiommc_config_item_ops = {
+ .release = gpiommc_config_item_release,
+ .show_attribute = gpiommc_config_attr_show,
+ .store_attribute = gpiommc_config_attr_store,
+};
+
+static struct config_item_type gpiommc_dev_ci_type = {
+ .ct_item_ops = &gpiommc_config_item_ops,
+ .ct_attrs = gpiommc_config_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct config_item *gpiommc_make_item(struct config_group *group,
+ const char *name)
+{
+ struct gpiommc_configfs_device *dev;
+
+ if (strlen(name) > GPIOMMC_MAX_NAMELEN) {
+ printk(KERN_ERR PFX "configfs: device name too long\n");
+ return NULL;
+ }
+
+ dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+ if (!dev)
+ return NULL;
+
+ config_item_init_type_name(&dev->item, name,
+ &gpiommc_dev_ci_type);
+
+ /* Assign default configuration */
+ dev->pdata.pins.gpio_di = GPIO_INVALID;
+ dev->pdata.pins.gpio_do = GPIO_INVALID;
+ dev->pdata.pins.gpio_clk = GPIO_INVALID;
+ dev->pdata.pins.gpio_cs = GPIO_INVALID;
+ dev->pdata.pins.cs_activelow = 1;
+ dev->pdata.mode = SPI_MODE_0;
+ dev->pdata.no_spi_delay = 0;
+ dev->pdata.max_bus_speed = 5000000; /* 5 MHz */
+
+ return &(dev->item);
+}
+
+static void gpiommc_drop_item(struct config_group *group,
+ struct config_item *item)
+{
+ struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
+
+ gpiommc_do_unregister(dev);
+ kfree(dev);
+}
+
+static struct configfs_group_operations gpiommc_ct_group_ops = {
+ .make_item = gpiommc_make_item,
+ .drop_item = gpiommc_drop_item,
+};
+
+static struct config_item_type gpiommc_ci_type = {
+ .ct_group_ops = &gpiommc_ct_group_ops,
+ .ct_owner = THIS_MODULE,
+};
+
+static struct configfs_subsystem gpiommc_subsys = {
+ .su_group = {
+ .cg_item = {
+ .ci_namebuf = GPIOMMC_PLATDEV_NAME,
+ .ci_type = &gpiommc_ci_type,
+ },
+ },
+ .su_mutex = __MUTEX_INITIALIZER(gpiommc_subsys.su_mutex),
+};
+
+#endif /* CONFIG_GPIOMMC_CONFIGFS */
+
+static struct platform_driver gpiommc_plat_driver = {
+ .probe = gpiommc_probe,
+ .remove = gpiommc_remove,
+ .driver = {
+ .name = GPIOMMC_PLATDEV_NAME,
+ .owner = THIS_MODULE,
+ },
+};
+
+int gpiommc_next_id(void)
+{
+ static atomic_t counter = ATOMIC_INIT(-1);
+
+ return atomic_inc_return(&counter);
+}
+EXPORT_SYMBOL(gpiommc_next_id);
+
+static int __init gpiommc_modinit(void)
+{
+ int err;
+
+ err = platform_driver_register(&gpiommc_plat_driver);
+ if (err)
+ return err;
+
+#ifdef CONFIG_GPIOMMC_CONFIGFS
+ config_group_init(&gpiommc_subsys.su_group);
+ err = configfs_register_subsystem(&gpiommc_subsys);
+ if (err) {
+ platform_driver_unregister(&gpiommc_plat_driver);
+ return err;
+ }
+#endif /* CONFIG_GPIOMMC_CONFIGFS */
+
+ return 0;
+}
+module_init(gpiommc_modinit);
+
+static void __exit gpiommc_modexit(void)
+{
+#ifdef CONFIG_GPIOMMC_CONFIGFS
+ configfs_unregister_subsystem(&gpiommc_subsys);
+#endif
+ platform_driver_unregister(&gpiommc_plat_driver);
+}
+module_exit(gpiommc_modexit);
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -130,3 +130,27 @@
If unsure, or if your system has no SPI master driver, say N.
+config GPIOMMC
+ tristate "MMC/SD over GPIO-based SPI"
+ depends on MMC && MMC_SPI && SPI_GPIO
+ help
+ This driver hooks up the mmc_spi and spi_gpio modules so that
+ MMC/SD cards can be used on a GPIO based bus by bitbanging
+ the SPI protocol in software.
+
+ This driver provides a configfs interface to dynamically create
+ and destroy GPIO-based MMC/SD card devices. It also provides
+ a platform device interface API.
+ See Documentation/gpiommc.txt for details.
+
+ The module will be called gpiommc.
+
+ If unsure, say N.
+
+config GPIOMMC_CONFIGFS
+ bool
+ depends on GPIOMMC && CONFIGFS_FS
+ default y
+ help
+ This option automatically enables configfs support for gpiommc
+ if configfs is available.
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -17,4 +17,4 @@
obj-$(CONFIG_MMC_AT91) += at91_mci.o
obj-$(CONFIG_MMC_TIFM_SD) += tifm_sd.o
obj-$(CONFIG_MMC_SPI) += mmc_spi.o
-
+obj-$(CONFIG_GPIOMMC) += gpiommc.o
--- /dev/null
+++ b/include/linux/mmc/gpiommc.h
@@ -0,0 +1,71 @@
+/*
+ * Device driver for MMC/SD cards driven over a GPIO bus.
+ *
+ * Copyright (c) 2008 Michael Buesch
+ *
+ * Licensed under the GNU/GPL version 2.
+ */
+#ifndef LINUX_GPIOMMC_H_
+#define LINUX_GPIOMMC_H_
+
+#include <linux/types.h>
+
+
+#define GPIOMMC_MAX_NAMELEN 15
+#define GPIOMMC_MAX_NAMELEN_STR __stringify(GPIOMMC_MAX_NAMELEN)
+
+/**
+ * struct gpiommc_pins - Hardware pin assignments
+ *
+ * @gpio_di: The GPIO number of the DATA IN pin
+ * @gpio_do: The GPIO number of the DATA OUT pin
+ * @gpio_clk: The GPIO number of the CLOCK pin
+ * @gpio_cs: The GPIO number of the CHIPSELECT pin
+ * @cs_activelow: If true, the chip is considered selected if @gpio_cs is low.
+ */
+struct gpiommc_pins {
+ unsigned int gpio_di;
+ unsigned int gpio_do;
+ unsigned int gpio_clk;
+ unsigned int gpio_cs;
+ bool cs_activelow;
+};
+
+/**
+ * struct gpiommc_platform_data - Platform data for a MMC-over-SPI-GPIO device.
+ *
+ * @name: The unique name string of the device.
+ * @pins: The hardware pin assignments.
+ * @mode: The hardware mode. This is either SPI_MODE_0,
+ * SPI_MODE_1, SPI_MODE_2 or SPI_MODE_3. See the SPI documentation.
+ * @no_spi_delay: Do not use delays in the lowlevel SPI bitbanging code.
+ * This is not standards compliant, but may be required for some
+ * embedded machines to gain reasonable speed.
+ * @max_bus_speed: The maximum speed of the SPI bus, in Hertz.
+ */
+struct gpiommc_platform_data {
+ char name[GPIOMMC_MAX_NAMELEN + 1];
+ struct gpiommc_pins pins;
+ u8 mode;
+ bool no_spi_delay;
+ unsigned int max_bus_speed;
+};
+
+/**
+ * GPIOMMC_PLATDEV_NAME - The platform device name string.
+ *
+ * The name string that has to be used for platform_device_alloc
+ * when allocating a gpiommc device.
+ */
+#define GPIOMMC_PLATDEV_NAME "gpiommc"
+
+/**
+ * gpiommc_next_id - Get another platform device ID number.
+ *
+ * This returns the next platform device ID number that has to be used
+ * for platform_device_alloc. The ID is opaque and should not be used for
+ * anything else.
+ */
+int gpiommc_next_id(void);
+
+#endif /* LINUX_GPIOMMC_H_ */
--- /dev/null
+++ b/Documentation/gpiommc.txt
@@ -0,0 +1,97 @@
+GPIOMMC - Driver for an MMC/SD card on a bitbanging GPIO SPI bus
+================================================================
+
+The gpiommc module hooks up the mmc_spi and spi_gpio modules for running an
+MMC or SD card on GPIO pins.
+
+Two interfaces for registering a new MMC/SD card device are provided:
+A static platform-device based mechanism and a dynamic configfs based interface.
+
+
+Registering devices via platform-device
+=======================================
+
+The platform-device interface is used for registering MMC/SD devices that are
+part of the hardware platform. This is most useful only for embedded machines
+with MMC/SD devices statically connected to the platform GPIO bus.
+
+The data structures are declared in <linux/mmc/gpiommc.h>.
+
+To register a new device, define an instance of struct gpiommc_platform_data.
+This structure holds any information about how the device is hooked up to the
+GPIO pins and what hardware modes the device supports. See the docbook-style
+documentation in the header file for more information on the struct fields.
+
+Then allocate a new instance of a platform device by doing:
+
+ pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME, gpiommc_next_id());
+
+This will allocate the platform device data structures and hook it up to the
+gpiommc driver.
+Then add the gpiommc_platform_data to the platform device.
+
+ err = platform_device_add_data(pdev, pdata, sizeof(struct gpiommc_platform_data));
+
+You may free the local instance of struct gpiommc_platform_data now. (So the
+struct may be allocated on the stack, too).
+Now simply register the platform device.
+
+ err = platform_device_add(pdev);
+
+Done. The gpiommc probe routine will be invoked now and you should see a kernel
+log message for the added device.
+
+
+Registering devices via configfs
+================================
+
+MMC/SD cards connected via GPIO often are a pretty dynamic thing, as for example
+selfmade hacks for soldering an MMC/SD card to standard GPIO pins on embedded
+hardware are a common situation.
+So we provide a dynamic interface to conveniently handle adding and removing
+devices from userspace, without the need to recompile the kernel.
+
+The "gpiommc" subdirectory at the configfs mountpoint is used for handling
+the dynamic configuration.
+
+To create a new device, it must first be allocated with mkdir.
+The following command will allocate a device named "my_mmc":
+ mkdir /config/gpiommc/my_mmc
+
+There are several configuration files available in the new
+/config/gpiommc/my_mmc/ directory:
+
+gpio_data_in = The SPI data-IN GPIO pin number.
+gpio_data_out = The SPI data-OUT GPIO pin number.
+gpio_clock = The SPI Clock GPIO pin number.
+gpio_chipselect = The SPI Chipselect GPIO pin number.
+gpio_chipselect_activelow = Boolean. If 0, Chipselect is active-HIGH.
+ If 1, Chipselect is active-LOW.
+spi_mode = The SPI data mode. Can be 0-3.
+spi_delay = Enable all delays in the lowlevel bitbanging.
+max_bus_speed = The maximum SPI bus speed. In Hertz.
+
+register = Not a configuration parameter.
+ Used to register the configured card
+ with the kernel.
+
+The device must first get configured and then registered by writing "1" to
+the "register" file.
+The configuration parameters "gpio_data_in", "gpio_data_out", "gpio_clock"
+and "gpio_chipselect" are essential and _must_ be configured before writing
+"1" to the "register" file. The registration will fail, otherwise.
+
+The default values for the other parameters are:
+gpio_chipselect_activelow = 1 (CS active-LOW)
+spi_mode = 0 (SPI_MODE_0)
+spi_delay = 1 (enabled)
+max_bus_speed = 5000000 (5 Mhz)
+
+Configuration values can not be changed after registration. To unregister
+the device, write a "0" to the "register" file. The configuration can be
+changed again after unregistering.
+
+To completely remove the device, simply rmdir the directory
+(/config/gpiommc/my_mmc in this example).
+There's no need to first unregister the device before removing it. That will
+be done automatically.
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1818,6 +1818,11 @@
W: http://gigaset307x.sourceforge.net/
S: Maintained
+GPIOMMC DRIVER
+P: Michael Buesch
+M: mb@bu3sch.de
+S: Maintained
+
HARDWARE MONITORING
P: Mark M. Hoffman
M: mhoffman@lightlink.com

58
target/linux/generic-2.6/patches-2.6.26/923-gpiommc-configfs-locking.patch Normal file
View file

@ -0,0 +1,58 @@
The gpiommc configfs context structure needs locking, as configfs
does not lock access between files.
--- a/drivers/mmc/host/gpiommc.c
+++ b/drivers/mmc/host/gpiommc.c
@@ -143,6 +143,8 @@
struct platform_device *pdev;
/* The configuration */
struct gpiommc_platform_data pdata;
+ /* Mutex to protect this structure */
+ struct mutex mutex;
};
#define GPIO_INVALID -1
@@ -233,6 +235,8 @@
unsigned int gpio;
int err = 0;
+ mutex_lock(&dev->mutex);
+
if (attr == &gpiommc_attr_DI) {
gpio = dev->pdata.pins.gpio_di;
if (gpio == GPIO_INVALID)
@@ -293,6 +297,8 @@
WARN_ON(1);
err = -ENOSYS;
out:
+ mutex_unlock(&dev->mutex);
+
return err ? err : count;
}
@@ -352,6 +358,8 @@
int err = -EINVAL;
unsigned long data;
+ mutex_lock(&dev->mutex);
+
if (attr == &gpiommc_attr_register) {
err = strict_strtoul(page, 10, &data);
if (err)
@@ -477,6 +485,8 @@
WARN_ON(1);
err = -ENOSYS;
out:
+ mutex_unlock(&dev->mutex);
+
return err ? err : count;
}
@@ -513,6 +523,7 @@
if (!dev)
return NULL;
+ mutex_init(&dev->mutex);
config_item_init_type_name(&dev->item, name,
&gpiommc_dev_ci_type);