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-rw-r--r--target/linux/generic/patches-3.18/863-gpiommc.patch844
1 files changed, 844 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.18/863-gpiommc.patch b/target/linux/generic/patches-3.18/863-gpiommc.patch
new file mode 100644
index 0000000000..380f33782d
--- /dev/null
+++ b/target/linux/generic/patches-3.18/863-gpiommc.patch
@@ -0,0 +1,844 @@
+--- /dev/null
++++ b/drivers/mmc/host/gpiommc.c
+@@ -0,0 +1,609 @@
++/*
++ * 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/module.h>
++#include <linux/mmc/gpiommc.h>
++#include <linux/platform_device.h>
++#include <linux/list.h>
++#include <linux/mutex.h>
++#include <linux/spi/spi_gpio_old.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 = kstrtoul(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 = kstrtoul(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 = kstrtoul(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 = kstrtoul(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 = kstrtoul(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 = kstrtoul(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 = kstrtoul(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 = kstrtoul(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 = kstrtoul(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
+@@ -534,6 +534,31 @@ config MMC_SDHI
+ This provides support for the SDHI SD/SDIO controller found in
+ SuperH and ARM SH-Mobile SoCs
+
++config GPIOMMC
++ tristate "MMC/SD over GPIO-based SPI"
++ depends on MMC && MMC_SPI && SPI_GPIO_OLD
++ 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.
++
+ config MMC_CB710
+ tristate "ENE CB710 MMC/SD Interface support"
+ depends on PCI
+--- a/drivers/mmc/host/Makefile
++++ b/drivers/mmc/host/Makefile
+@@ -40,6 +40,7 @@ tmio_mmc_core-$(subst m,y,$(CONFIG_MMC_S
+ obj-$(CONFIG_MMC_SDHI) += sh_mobile_sdhi.o
+ obj-$(CONFIG_MMC_CB710) += cb710-mmc.o
+ obj-$(CONFIG_MMC_VIA_SDMMC) += via-sdmmc.o
++obj-$(CONFIG_GPIOMMC) += gpiommc.o
+ obj-$(CONFIG_SDH_BFIN) += bfin_sdh.o
+ obj-$(CONFIG_MMC_DW) += dw_mmc.o
+ obj-$(CONFIG_MMC_DW_PLTFM) += dw_mmc-pltfm.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
+@@ -4263,6 +4263,11 @@ T: git git://linuxtv.org/anttip/media_tr
+ S: Maintained
+ F: drivers/media/usb/hackrf/
+
++GPIOMMC DRIVER
++P: Michael Buesch
++M: mb@bu3sch.de
++S: Maintained
++
+ HARDWARE MONITORING
+ M: Jean Delvare <jdelvare@suse.de>
+ M: Guenter Roeck <linux@roeck-us.net>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-18 23:23:56 +0000