diff options
Diffstat (limited to 'drivers/char/scx200_gpio.c')
-rw-r--r-- | drivers/char/scx200_gpio.c | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/drivers/char/scx200_gpio.c b/drivers/char/scx200_gpio.c new file mode 100644 index 000000000..0bc135b9b --- /dev/null +++ b/drivers/char/scx200_gpio.c @@ -0,0 +1,132 @@ +/* linux/drivers/char/scx200_gpio.c + + National Semiconductor SCx200 GPIO driver. Allows a user space + process to play with the GPIO pins. + + Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */ + +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <asm/uaccess.h> +#include <asm/io.h> + +#include <linux/types.h> +#include <linux/cdev.h> + +#include <linux/scx200_gpio.h> +#include <linux/nsc_gpio.h> + +#define DRVNAME "scx200_gpio" + +static struct platform_device *pdev; + +MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>"); +MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver"); +MODULE_LICENSE("GPL"); + +static int major = 0; /* default to dynamic major */ +module_param(major, int, 0); +MODULE_PARM_DESC(major, "Major device number"); + +#define MAX_PINS 32 /* 64 later, when known ok */ + +struct nsc_gpio_ops scx200_gpio_ops = { + .owner = THIS_MODULE, + .gpio_config = scx200_gpio_configure, + .gpio_dump = nsc_gpio_dump, + .gpio_get = scx200_gpio_get, + .gpio_set = scx200_gpio_set, + .gpio_change = scx200_gpio_change, + .gpio_current = scx200_gpio_current +}; +EXPORT_SYMBOL_GPL(scx200_gpio_ops); + +static int scx200_gpio_open(struct inode *inode, struct file *file) +{ + unsigned m = iminor(inode); + file->private_data = &scx200_gpio_ops; + + if (m >= MAX_PINS) + return -EINVAL; + return nonseekable_open(inode, file); +} + +static int scx200_gpio_release(struct inode *inode, struct file *file) +{ + return 0; +} + +static const struct file_operations scx200_gpio_fileops = { + .owner = THIS_MODULE, + .write = nsc_gpio_write, + .read = nsc_gpio_read, + .open = scx200_gpio_open, + .release = scx200_gpio_release, + .llseek = no_llseek, +}; + +static struct cdev scx200_gpio_cdev; /* use 1 cdev for all pins */ + +static int __init scx200_gpio_init(void) +{ + int rc; + dev_t devid; + + if (!scx200_gpio_present()) { + printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n"); + return -ENODEV; + } + + /* support dev_dbg() with pdev->dev */ + pdev = platform_device_alloc(DRVNAME, 0); + if (!pdev) + return -ENOMEM; + + rc = platform_device_add(pdev); + if (rc) + goto undo_malloc; + + /* nsc_gpio uses dev_dbg(), so needs this */ + scx200_gpio_ops.dev = &pdev->dev; + + if (major) { + devid = MKDEV(major, 0); + rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio"); + } else { + rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio"); + major = MAJOR(devid); + } + if (rc < 0) { + dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc); + goto undo_platform_device_add; + } + + cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops); + cdev_add(&scx200_gpio_cdev, devid, MAX_PINS); + + return 0; /* succeed */ + +undo_platform_device_add: + platform_device_del(pdev); +undo_malloc: + platform_device_put(pdev); + + return rc; +} + +static void __exit scx200_gpio_cleanup(void) +{ + cdev_del(&scx200_gpio_cdev); + /* cdev_put(&scx200_gpio_cdev); */ + + unregister_chrdev_region(MKDEV(major, 0), MAX_PINS); + platform_device_unregister(pdev); +} + +module_init(scx200_gpio_init); +module_exit(scx200_gpio_cleanup); |