From 12b5a779b900708c9b787811c93763b9041282ad Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Michael=20B=C3=BCsch?= Date: Fri, 21 Mar 2008 16:52:27 +0000 Subject: linux-2.6: Add a driver to run an MMC or SD card over a GPIO based SPI interface. SVN-Revision: 10637 --- package/mmc_over_gpio/src/mmc_over_spigpio.c | 339 +++++++++++++++++++++++++++ 1 file changed, 339 insertions(+) create mode 100644 package/mmc_over_gpio/src/mmc_over_spigpio.c (limited to 'package/mmc_over_gpio/src/mmc_over_spigpio.c') diff --git a/package/mmc_over_gpio/src/mmc_over_spigpio.c b/package/mmc_over_gpio/src/mmc_over_spigpio.c new file mode 100644 index 0000000000..36dbd0f6a8 --- /dev/null +++ b/package/mmc_over_gpio/src/mmc_over_spigpio.c @@ -0,0 +1,339 @@ +/* + * Driver for driving an MMC card over a bitbanging GPIO SPI bus. + * + * Copyright 2008 Michael Buesch + * + * Licensed under the GNU/GPL. See COPYING for details. + */ + +#include +#include +#include +#include "linux/spi/spi_gpio.h" //XXX + + +/* This is the maximum speed in Hz */ +#define GPIOMMC_MAXSPEED 5000000 /* Hz */ + + +#define DRIVER_NAME "spi-gpio-mmc" +#define PFX DRIVER_NAME ": " + + +#define GPIOMMC_MAX_NAMELEN 15 +#define GPIOMMC_MAX_NAMELEN_STR __stringify(GPIOMMC_MAX_NAMELEN) + +struct gpiommc_pins { + unsigned int gpio_di; /* Card DI pin */ + unsigned int gpio_do; /* Card DO pin */ + unsigned int gpio_clk; /* Card CLK pin */ + unsigned int gpio_cs; /* Card CS pin */ +}; + +struct gpiommc_device { + char name[GPIOMMC_MAX_NAMELEN + 1]; + struct platform_device *pdev; + struct platform_device *spi_pdev; + struct gpiommc_pins pins; + u8 mode; /* SPI_MODE_X */ + struct spi_board_info boardinfo; + + struct list_head list; +}; + + +static LIST_HEAD(gpiommc_devices_list); +static DEFINE_MUTEX(gpiommc_mutex); + + +MODULE_DESCRIPTION("SPI-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; + + /* Bind the SPI master to the MMC-SPI host driver. */ + strlcpy(bi->modalias, "mmc_spi", sizeof(bi->modalias)); + + bi->max_speed_hz = GPIOMMC_MAXSPEED; + bi->bus_num = master->bus_num; + bi->mode = d->mode; + + return 0; +} + +static int gpiommc_probe(struct platform_device *pdev) +{ + static int instance; + struct gpiommc_device *d = platform_get_drvdata(pdev); + struct spi_gpio_platform_data pdata; + int err = -ENOMEM; + + d->spi_pdev = platform_device_alloc("spi-gpio", instance++); + if (!d->spi_pdev) + goto out; + + memset(&pdata, 0, sizeof(pdata)); + pdata.pin_clk = d->pins.gpio_clk; + pdata.pin_miso = d->pins.gpio_do; + pdata.pin_mosi = d->pins.gpio_di; + pdata.pin_cs = d->pins.gpio_cs; + pdata.cs_activelow = 1; + pdata.no_spi_delay = 1; + pdata.boardinfo_setup = gpiommc_boardinfo_setup; + pdata.boardinfo_setup_data = d; + + err = platform_device_add_data(d->spi_pdev, &pdata, sizeof(pdata)); + if (err) + goto err_free_pdev; + err = platform_device_register(d->spi_pdev); + if (err) + goto err_free_pdata; + + printk(KERN_INFO PFX "MMC-Card \"%s\" " + "attached to GPIO pins %u,%u,%u,%u\n", + d->name, d->pins.gpio_di, d->pins.gpio_do, + d->pins.gpio_clk, d->pins.gpio_cs); +out: + return err; + +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); + return err; +} + +static int gpiommc_remove(struct platform_device *pdev) +{ + struct gpiommc_device *d = platform_get_drvdata(pdev); + + platform_device_unregister(d->spi_pdev); + printk(KERN_INFO PFX "MMC-Card \"%s\" removed\n", d->name); + + return 0; +} + +static void gpiommc_free(struct gpiommc_device *d) +{ + kfree(d); +} + +static struct gpiommc_device * gpiommc_alloc(struct platform_device *pdev, + const char *name, + const struct gpiommc_pins *pins, + u8 mode) +{ + struct gpiommc_device *d; + + d = kmalloc(sizeof(*d), GFP_KERNEL); + if (!d) + return NULL; + + strcpy(d->name, name); + memcpy(&d->pins, pins, sizeof(d->pins)); + d->mode = mode; + INIT_LIST_HEAD(&d->list); + + return d; +} + +/* List must be locked. */ +static struct gpiommc_device * gpiommc_find_device(const char *name) +{ + struct gpiommc_device *d; + + list_for_each_entry(d, &gpiommc_devices_list, list) { + if (strcmp(d->name, name) == 0) + return d; + } + + return NULL; +} + +static void gpiommc_do_destroy_device(struct gpiommc_device *d) +{ + list_del(&d->list); + platform_device_unregister(d->pdev); + gpiommc_free(d); +} + +static int gpiommc_destroy_device(const char *name) +{ + struct gpiommc_device *d; + int err = -ENODEV; + + mutex_lock(&gpiommc_mutex); + d = gpiommc_find_device(name); + if (!d) + goto out_unlock; + gpiommc_do_destroy_device(d); + err = 0; +out_unlock: + mutex_unlock(&gpiommc_mutex); + + return err; +} + +static int gpiommc_create_device(const char *name, + const struct gpiommc_pins *pins, + u8 mode) +{ + static int instance; + struct platform_device *pdev; + struct gpiommc_device *d; + int err; + + mutex_lock(&gpiommc_mutex); + err = -EEXIST; + if (gpiommc_find_device(name)) + goto out_unlock; + err = -ENOMEM; + pdev = platform_device_alloc(DRIVER_NAME, instance++); + if (!pdev) + goto out_unlock; + d = gpiommc_alloc(pdev, name, pins, mode); + if (!d) + goto err_free_pdev; + platform_set_drvdata(pdev, d); + d->pdev = pdev; + err = platform_device_register(pdev); + if (err) + goto err_free_mdev; + list_add(&d->list, &gpiommc_devices_list); + + err = 0; +out_unlock: + mutex_unlock(&gpiommc_mutex); + + return err; + +err_free_mdev: + gpiommc_free(d); +err_free_pdev: + platform_device_put(pdev); + goto out_unlock; +} + +static ssize_t gpiommc_add_show(struct device_driver *drv, + char *buf) +{ + return snprintf(buf, PAGE_SIZE, "NAME DI_pin,DO_pin,CLK_pin,CS_pin [MODE]\n"); +} + +static ssize_t gpiommc_add_store(struct device_driver *drv, + const char *buf, size_t count) +{ + int res, err; + char name[GPIOMMC_MAX_NAMELEN + 1]; + struct gpiommc_pins pins; + unsigned int mode; + + res = sscanf(buf, "%" GPIOMMC_MAX_NAMELEN_STR "s %u,%u,%u,%u %u", + name, &pins.gpio_di, &pins.gpio_do, + &pins.gpio_clk, &pins.gpio_cs, &mode); + if (res == 5) + mode = 0; + else if (res != 6) + return -EINVAL; + switch (mode) { + case 0: + mode = SPI_MODE_0; + break; + case 1: + mode = SPI_MODE_1; + break; + case 2: + mode = SPI_MODE_2; + break; + case 3: + mode = SPI_MODE_3; + break; + default: + return -EINVAL; + } + err = gpiommc_create_device(name, &pins, mode); + + return err ? err : count; +} + +static ssize_t gpiommc_remove_show(struct device_driver *drv, + char *buf) +{ + return snprintf(buf, PAGE_SIZE, "write device-name to remove the device\n"); +} + +static ssize_t gpiommc_remove_store(struct device_driver *drv, + const char *buf, size_t count) +{ + int err; + + err = gpiommc_destroy_device(buf); + + return err ? err : count; +} + +static DRIVER_ATTR(add, 0600, + gpiommc_add_show, gpiommc_add_store); +static DRIVER_ATTR(remove, 0600, + gpiommc_remove_show, gpiommc_remove_store); + +static struct platform_driver gpiommc_plat_driver = { + .probe = gpiommc_probe, + .remove = gpiommc_remove, + .driver = { + .name = DRIVER_NAME, + .owner = THIS_MODULE, + }, +}; + +static int __init gpiommc_modinit(void) +{ + int err; + + err = platform_driver_register(&gpiommc_plat_driver); + if (err) + return err; + err = driver_create_file(&gpiommc_plat_driver.driver, + &driver_attr_add); + if (err) + goto err_drv_unreg; + err = driver_create_file(&gpiommc_plat_driver.driver, + &driver_attr_remove); + if (err) + goto err_remove_add; + + return 0; + +err_remove_add: + driver_remove_file(&gpiommc_plat_driver.driver, + &driver_attr_add); +err_drv_unreg: + platform_driver_unregister(&gpiommc_plat_driver); + return err; +} +module_init(gpiommc_modinit); + +static void __exit gpiommc_modexit(void) +{ + struct gpiommc_device *d, *tmp; + + driver_remove_file(&gpiommc_plat_driver.driver, + &driver_attr_remove); + driver_remove_file(&gpiommc_plat_driver.driver, + &driver_attr_add); + + mutex_lock(&gpiommc_mutex); + list_for_each_entry_safe(d, tmp, &gpiommc_devices_list, list) + gpiommc_do_destroy_device(d); + mutex_unlock(&gpiommc_mutex); + + platform_driver_unregister(&gpiommc_plat_driver); +} +module_exit(gpiommc_modexit); -- cgit v1.2.3