diff options
Diffstat (limited to 'target/linux/generic-2.6/patches-2.6.28/922-gpiommc.patch')
| -rw-r--r-- | target/linux/generic-2.6/patches-2.6.28/922-gpiommc.patch | 838 |
1 files changed, 838 insertions, 0 deletions
diff --git a/target/linux/generic-2.6/patches-2.6.28/922-gpiommc.patch b/target/linux/generic-2.6/patches-2.6.28/922-gpiommc.patch new file mode 100644 index 0000000..cc16a10 --- /dev/null +++ b/target/linux/generic-2.6/patches-2.6.28/922-gpiommc.patch @@ -0,0 +1,838 @@ +--- /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 +@@ -192,3 +192,28 @@ config MMC_TMIO + help + This provides support for the SD/MMC cell found in TC6393XB, + T7L66XB and also ipaq ASIC3 ++ ++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 +@@ -22,4 +22,5 @@ obj-$(CONFIG_MMC_SPI) += mmc_spi.o + obj-$(CONFIG_MMC_S3C) += s3cmci.o + obj-$(CONFIG_MMC_SDRICOH_CS) += sdricoh_cs.o + obj-$(CONFIG_MMC_TMIO) += tmio_mmc.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 +@@ -1910,6 +1910,11 @@ W: http://moinejf.free.fr + L: video4linux-list@redhat.com + S: Maintained + ++GPIOMMC DRIVER ++P: Michael Buesch ++M: mb@bu3sch.de ++S: Maintained ++ + HARDWARE MONITORING + L: lm-sensors@lm-sensors.org + W: http://www.lm-sensors.org/ |