diff options
Diffstat (limited to 'package/mmc_over_gpio/src')
| -rw-r--r-- | package/mmc_over_gpio/src/Makefile | 2 | ||||
| -rw-r--r-- | package/mmc_over_gpio/src/linux/spi/spi_gpio.h | 53 | ||||
| -rw-r--r-- | package/mmc_over_gpio/src/mmc_over_spigpio.c | 339 | ||||
| -rw-r--r-- | package/mmc_over_gpio/src/spi_gpio.c | 242 |
4 files changed, 636 insertions, 0 deletions
diff --git a/package/mmc_over_gpio/src/Makefile b/package/mmc_over_gpio/src/Makefile new file mode 100644 index 0000000000..d2258bb95f --- /dev/null +++ b/package/mmc_over_gpio/src/Makefile @@ -0,0 +1,2 @@ +obj-m += spi_gpio.o +obj-m += mmc_over_spigpio.o diff --git a/package/mmc_over_gpio/src/linux/spi/spi_gpio.h b/package/mmc_over_gpio/src/linux/spi/spi_gpio.h new file mode 100644 index 0000000000..8e7d4b189d --- /dev/null +++ b/package/mmc_over_gpio/src/linux/spi/spi_gpio.h @@ -0,0 +1,53 @@ +/* + * 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 */ 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 <mb@bu3sch.de> + * + * Licensed under the GNU/GPL. See COPYING for details. + */ + +#include <linux/platform_device.h> +#include <linux/list.h> +#include <linux/mutex.h> +#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); diff --git a/package/mmc_over_gpio/src/spi_gpio.c b/package/mmc_over_gpio/src/spi_gpio.c new file mode 100644 index 0000000000..31048acc3f --- /dev/null +++ b/package/mmc_over_gpio/src/spi_gpio.c @@ -0,0 +1,242 @@ +/* + * 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"); |