844 lines
22 KiB
Diff
844 lines
22 KiB
Diff
--- /dev/null
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+++ b/drivers/mmc/host/gpiommc.c
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@@ -0,0 +1,608 @@
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+/*
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+ * Driver an MMC/SD card on a bitbanging GPIO SPI bus.
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+ * This module hooks up the mmc_spi and spi_gpio modules and also
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+ * provides a configfs interface.
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+ *
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+ * Copyright 2008 Michael Buesch <mb@bu3sch.de>
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+ *
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+ * Licensed under the GNU/GPL. See COPYING for details.
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+ */
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+
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+#include <linux/mmc/gpiommc.h>
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+#include <linux/platform_device.h>
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+#include <linux/list.h>
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+#include <linux/mutex.h>
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+#include <linux/spi/spi_gpio_old.h>
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+#include <linux/configfs.h>
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+#include <linux/gpio.h>
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+#include <asm/atomic.h>
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+
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+
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+#define PFX "gpio-mmc: "
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+
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+
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+struct gpiommc_device {
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+ struct platform_device *pdev;
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+ struct platform_device *spi_pdev;
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+ struct spi_board_info boardinfo;
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+};
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+
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+
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+MODULE_DESCRIPTION("GPIO based MMC driver");
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+MODULE_AUTHOR("Michael Buesch");
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+MODULE_LICENSE("GPL");
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+
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+
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+static int gpiommc_boardinfo_setup(struct spi_board_info *bi,
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+ struct spi_master *master,
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+ void *data)
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+{
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+ struct gpiommc_device *d = data;
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+ struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
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+
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+ /* Bind the SPI master to the MMC-SPI host driver. */
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+ strlcpy(bi->modalias, "mmc_spi", sizeof(bi->modalias));
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+
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+ bi->max_speed_hz = pdata->max_bus_speed;
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+ bi->bus_num = master->bus_num;
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+ bi->mode = pdata->mode;
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+
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+ return 0;
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+}
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+
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+static int gpiommc_probe(struct platform_device *pdev)
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+{
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+ struct gpiommc_platform_data *mmc_pdata = pdev->dev.platform_data;
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+ struct spi_gpio_platform_data spi_pdata;
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+ struct gpiommc_device *d;
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+ int err;
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+
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+ err = -ENXIO;
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+ if (!mmc_pdata)
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+ goto error;
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+
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+#ifdef CONFIG_MMC_SPI_MODULE
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+ err = request_module("mmc_spi");
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+ if (err) {
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+ printk(KERN_WARNING PFX
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+ "Failed to request mmc_spi module.\n");
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+ }
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+#endif /* CONFIG_MMC_SPI_MODULE */
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+
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+ /* Allocate the GPIO-MMC device */
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+ err = -ENOMEM;
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+ d = kzalloc(sizeof(*d), GFP_KERNEL);
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+ if (!d)
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+ goto error;
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+ d->pdev = pdev;
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+
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+ /* Create the SPI-GPIO device */
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+ d->spi_pdev = platform_device_alloc(SPI_GPIO_PLATDEV_NAME,
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+ spi_gpio_next_id());
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+ if (!d->spi_pdev)
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+ goto err_free_d;
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+
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+ memset(&spi_pdata, 0, sizeof(spi_pdata));
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+ spi_pdata.pin_clk = mmc_pdata->pins.gpio_clk;
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+ spi_pdata.pin_miso = mmc_pdata->pins.gpio_do;
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+ spi_pdata.pin_mosi = mmc_pdata->pins.gpio_di;
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+ spi_pdata.pin_cs = mmc_pdata->pins.gpio_cs;
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+ spi_pdata.cs_activelow = mmc_pdata->pins.cs_activelow;
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+ spi_pdata.no_spi_delay = mmc_pdata->no_spi_delay;
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+ spi_pdata.boardinfo_setup = gpiommc_boardinfo_setup;
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+ spi_pdata.boardinfo_setup_data = d;
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+
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+ err = platform_device_add_data(d->spi_pdev, &spi_pdata,
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+ sizeof(spi_pdata));
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+ if (err)
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+ goto err_free_pdev;
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+ err = platform_device_add(d->spi_pdev);
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+ if (err)
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+ goto err_free_pdata;
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+ platform_set_drvdata(pdev, d);
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+
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+ printk(KERN_INFO PFX "MMC-Card \"%s\" "
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+ "attached to GPIO pins di=%u, do=%u, clk=%u, cs=%u\n",
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+ mmc_pdata->name, mmc_pdata->pins.gpio_di,
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+ mmc_pdata->pins.gpio_do,
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+ mmc_pdata->pins.gpio_clk,
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+ mmc_pdata->pins.gpio_cs);
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+
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+ return 0;
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+
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+err_free_pdata:
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+ kfree(d->spi_pdev->dev.platform_data);
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+ d->spi_pdev->dev.platform_data = NULL;
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+err_free_pdev:
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+ platform_device_put(d->spi_pdev);
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+err_free_d:
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+ kfree(d);
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+error:
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+ return err;
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+}
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+
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+static int gpiommc_remove(struct platform_device *pdev)
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+{
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+ struct gpiommc_device *d = platform_get_drvdata(pdev);
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+ struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
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+
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+ platform_device_unregister(d->spi_pdev);
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+ printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n",
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+ pdata->name);
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+ platform_device_put(d->spi_pdev);
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+
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+ return 0;
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+}
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+
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+#ifdef CONFIG_GPIOMMC_CONFIGFS
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+
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+/* A device that was created through configfs */
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+struct gpiommc_configfs_device {
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+ struct config_item item;
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+ /* The platform device, after registration. */
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+ struct platform_device *pdev;
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+ /* The configuration */
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+ struct gpiommc_platform_data pdata;
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+};
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+
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+#define GPIO_INVALID -1
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+
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+static inline bool gpiommc_is_registered(struct gpiommc_configfs_device *dev)
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+{
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+ return (dev->pdev != NULL);
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+}
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+
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+static inline struct gpiommc_configfs_device *ci_to_gpiommc(struct config_item *item)
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+{
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+ return item ? container_of(item, struct gpiommc_configfs_device, item) : NULL;
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+}
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+
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+static struct configfs_attribute gpiommc_attr_DI = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "gpio_data_in",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_DO = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "gpio_data_out",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_CLK = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "gpio_clock",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_CS = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "gpio_chipselect",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_CS_activelow = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "gpio_chipselect_activelow",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_spimode = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "spi_mode",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_spidelay = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "spi_delay",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_max_bus_speed = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "max_bus_speed",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute gpiommc_attr_register = {
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+ .ca_owner = THIS_MODULE,
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+ .ca_name = "register",
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+ .ca_mode = S_IRUGO | S_IWUSR,
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+};
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+
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+static struct configfs_attribute *gpiommc_config_attrs[] = {
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+ &gpiommc_attr_DI,
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+ &gpiommc_attr_DO,
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+ &gpiommc_attr_CLK,
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+ &gpiommc_attr_CS,
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+ &gpiommc_attr_CS_activelow,
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+ &gpiommc_attr_spimode,
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+ &gpiommc_attr_spidelay,
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+ &gpiommc_attr_max_bus_speed,
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+ &gpiommc_attr_register,
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+ NULL,
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+};
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+
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+static ssize_t gpiommc_config_attr_show(struct config_item *item,
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+ struct configfs_attribute *attr,
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+ char *page)
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+{
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+ struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
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+ ssize_t count = 0;
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+ unsigned int gpio;
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+ int err = 0;
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+
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+ if (attr == &gpiommc_attr_DI) {
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+ gpio = dev->pdata.pins.gpio_di;
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+ if (gpio == GPIO_INVALID)
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+ count = snprintf(page, PAGE_SIZE, "not configured\n");
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+ else
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+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_DO) {
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+ gpio = dev->pdata.pins.gpio_do;
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+ if (gpio == GPIO_INVALID)
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+ count = snprintf(page, PAGE_SIZE, "not configured\n");
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+ else
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+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_CLK) {
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+ gpio = dev->pdata.pins.gpio_clk;
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+ if (gpio == GPIO_INVALID)
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+ count = snprintf(page, PAGE_SIZE, "not configured\n");
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+ else
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+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_CS) {
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+ gpio = dev->pdata.pins.gpio_cs;
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+ if (gpio == GPIO_INVALID)
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+ count = snprintf(page, PAGE_SIZE, "not configured\n");
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+ else
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+ count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_CS_activelow) {
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+ count = snprintf(page, PAGE_SIZE, "%u\n",
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+ dev->pdata.pins.cs_activelow);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_spimode) {
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+ count = snprintf(page, PAGE_SIZE, "%u\n",
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+ dev->pdata.mode);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_spidelay) {
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+ count = snprintf(page, PAGE_SIZE, "%u\n",
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+ !dev->pdata.no_spi_delay);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_max_bus_speed) {
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+ count = snprintf(page, PAGE_SIZE, "%u\n",
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+ dev->pdata.max_bus_speed);
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+ goto out;
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+ }
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+ if (attr == &gpiommc_attr_register) {
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+ count = snprintf(page, PAGE_SIZE, "%u\n",
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+ gpiommc_is_registered(dev));
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+ goto out;
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+ }
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+ WARN_ON(1);
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+ err = -ENOSYS;
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+out:
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+ return err ? err : count;
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+}
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+
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+static int gpiommc_do_register(struct gpiommc_configfs_device *dev,
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+ const char *name)
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+{
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+ int err;
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+
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+ if (gpiommc_is_registered(dev))
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+ return 0;
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+
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+ if (!gpio_is_valid(dev->pdata.pins.gpio_di) ||
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+ !gpio_is_valid(dev->pdata.pins.gpio_do) ||
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+ !gpio_is_valid(dev->pdata.pins.gpio_clk) ||
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+ !gpio_is_valid(dev->pdata.pins.gpio_cs)) {
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+ printk(KERN_ERR PFX
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+ "configfs: Invalid GPIO pin number(s)\n");
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+ return -EINVAL;
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+ }
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+
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+ strlcpy(dev->pdata.name, name,
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+ sizeof(dev->pdata.name));
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+
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+ dev->pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME,
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+ gpiommc_next_id());
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+ if (!dev->pdev)
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+ return -ENOMEM;
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+ err = platform_device_add_data(dev->pdev, &dev->pdata,
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+ sizeof(dev->pdata));
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+ if (err) {
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+ platform_device_put(dev->pdev);
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+ return err;
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+ }
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+ err = platform_device_add(dev->pdev);
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+ if (err) {
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+ platform_device_put(dev->pdev);
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+ return err;
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+ }
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+
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+ return 0;
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+}
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+
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+static void gpiommc_do_unregister(struct gpiommc_configfs_device *dev)
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+{
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+ if (!gpiommc_is_registered(dev))
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+ return;
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+
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+ platform_device_unregister(dev->pdev);
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+ dev->pdev = NULL;
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+}
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+
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+static ssize_t gpiommc_config_attr_store(struct config_item *item,
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+ struct configfs_attribute *attr,
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+ const char *page, size_t count)
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+{
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+ struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
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+ int err = -EINVAL;
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+ unsigned long data;
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+
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+ if (attr == &gpiommc_attr_register) {
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+ err = strict_strtoul(page, 10, &data);
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+ if (err)
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+ goto out;
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+ err = -EINVAL;
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+ if (data == 1)
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+ err = gpiommc_do_register(dev, item->ci_name);
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+ if (data == 0) {
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+ gpiommc_do_unregister(dev);
|
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+ err = 0;
|
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+ }
|
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+ goto out;
|
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+ }
|
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+
|
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+ if (gpiommc_is_registered(dev)) {
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+ /* The rest of the config parameters can only be set
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+ * as long as the device is not registered, yet. */
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+ err = -EBUSY;
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+ goto out;
|
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+ }
|
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+
|
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+ if (attr == &gpiommc_attr_DI) {
|
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+ err = strict_strtoul(page, 10, &data);
|
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+ if (err)
|
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+ goto out;
|
|
+ err = -EINVAL;
|
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+ if (!gpio_is_valid(data))
|
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+ goto out;
|
|
+ dev->pdata.pins.gpio_di = data;
|
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+ err = 0;
|
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+ goto out;
|
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+ }
|
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+ if (attr == &gpiommc_attr_DO) {
|
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+ err = strict_strtoul(page, 10, &data);
|
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+ if (err)
|
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+ goto out;
|
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+ err = -EINVAL;
|
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+ if (!gpio_is_valid(data))
|
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+ goto out;
|
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+ dev->pdata.pins.gpio_do = data;
|
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+ err = 0;
|
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+ goto out;
|
|
+ }
|
|
+ if (attr == &gpiommc_attr_CLK) {
|
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+ err = strict_strtoul(page, 10, &data);
|
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+ if (err)
|
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+ goto out;
|
|
+ err = -EINVAL;
|
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+ if (!gpio_is_valid(data))
|
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+ goto out;
|
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+ dev->pdata.pins.gpio_clk = data;
|
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+ err = 0;
|
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+ goto out;
|
|
+ }
|
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+ if (attr == &gpiommc_attr_CS) {
|
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+ err = strict_strtoul(page, 10, &data);
|
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+ 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:
|
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+ dev->pdata.mode = SPI_MODE_1;
|
|
+ break;
|
|
+ case 2:
|
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+ 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
|
|
@@ -334,6 +334,31 @@ config MMC_TMIO
|
|
This provides support for the SD/MMC cell found in TC6393XB,
|
|
T7L66XB and also HTC ASIC3
|
|
|
|
+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
|
|
@@ -34,6 +34,7 @@ obj-$(CONFIG_MMC_SDRICOH_CS) += sdricoh_
|
|
obj-$(CONFIG_MMC_TMIO) += tmio_mmc.o
|
|
obj-$(CONFIG_MMC_CB710) += cb710-mmc.o
|
|
obj-$(CONFIG_MMC_VIA_SDMMC) += via-sdmmc.o
|
|
+obj-$(CONFIG_GPIOMMC) += gpiommc.o
|
|
|
|
ifeq ($(CONFIG_CB710_DEBUG),y)
|
|
CFLAGS-cb710-mmc += -DDEBUG
|
|
--- /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
|
|
@@ -2383,6 +2383,11 @@ T: git git://git.kernel.org/pub/scm/linu
|
|
S: Maintained
|
|
F: drivers/media/video/gspca/
|
|
|
|
+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/
|