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[kernel] 2.6.26: add gpiommc driver

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git-svn-id: svn://svn.openwrt.org/openwrt/trunk@12566 3c298f89-4303-0410-b956-a3cf2f4a3e73
This commit is contained in:
juhosg 2008-09-10 19:46:56 +00:00
parent 942bc3ecb3
commit c47bb90874
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 --- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig
@@ -100,6 +100,11 @@ @@ -100,6 +100,19 @@
inexpensive battery powered microcontroller evaluation board. inexpensive battery powered microcontroller evaluation board.
This same cable can be used to flash new firmware. This same cable can be used to flash new firmware.
+config SPI_GPIO +config SPI_GPIO
+ tristate "GPIO API based bitbanging SPI controller" + tristate "GPIO API based bitbanging SPI controller"
+ depends on SPI_MASTER && GENERIC_GPIO && EXPERIMENTAL + depends on SPI_MASTER && GENERIC_GPIO
+ select SPI_BITBANG + 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 config SPI_IMX
tristate "Freescale iMX SPI controller" tristate "Freescale iMX SPI controller"
@ -22,3 +360,17 @@
obj-$(CONFIG_SPI_IMX) += spi_imx.o obj-$(CONFIG_SPI_IMX) += spi_imx.o
obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o obj-$(CONFIG_SPI_LM70_LLP) += spi_lm70llp.o
obj-$(CONFIG_SPI_PXA2XX) += pxa2xx_spi.o obj-$(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);