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133 lines
3.1 KiB
133 lines
3.1 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* linux/drivers/char/scx200_gpio.c |
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National Semiconductor SCx200 GPIO driver. Allows a user space |
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process to play with the GPIO pins. |
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Copyright (c) 2001,2002 Christer Weinigel <[email protected]> */ |
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#include <linux/device.h> |
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#include <linux/fs.h> |
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#include <linux/module.h> |
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#include <linux/errno.h> |
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#include <linux/kernel.h> |
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#include <linux/init.h> |
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#include <linux/platform_device.h> |
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#include <linux/uaccess.h> |
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#include <asm/io.h> |
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#include <linux/types.h> |
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#include <linux/cdev.h> |
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#include <linux/scx200_gpio.h> |
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#include <linux/nsc_gpio.h> |
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#define DRVNAME "scx200_gpio" |
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static struct platform_device *pdev; |
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MODULE_AUTHOR("Christer Weinigel <[email protected]>"); |
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MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver"); |
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MODULE_LICENSE("GPL"); |
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static int major = 0; /* default to dynamic major */ |
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module_param(major, int, 0); |
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MODULE_PARM_DESC(major, "Major device number"); |
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#define MAX_PINS 32 /* 64 later, when known ok */ |
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struct nsc_gpio_ops scx200_gpio_ops = { |
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.owner = THIS_MODULE, |
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.gpio_config = scx200_gpio_configure, |
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.gpio_dump = nsc_gpio_dump, |
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.gpio_get = scx200_gpio_get, |
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.gpio_set = scx200_gpio_set, |
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.gpio_change = scx200_gpio_change, |
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.gpio_current = scx200_gpio_current |
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}; |
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EXPORT_SYMBOL_GPL(scx200_gpio_ops); |
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static int scx200_gpio_open(struct inode *inode, struct file *file) |
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{ |
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unsigned m = iminor(inode); |
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file->private_data = &scx200_gpio_ops; |
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if (m >= MAX_PINS) |
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return -EINVAL; |
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return nonseekable_open(inode, file); |
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} |
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static int scx200_gpio_release(struct inode *inode, struct file *file) |
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{ |
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return 0; |
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} |
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static const struct file_operations scx200_gpio_fileops = { |
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.owner = THIS_MODULE, |
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.write = nsc_gpio_write, |
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.read = nsc_gpio_read, |
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.open = scx200_gpio_open, |
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.release = scx200_gpio_release, |
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.llseek = no_llseek, |
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}; |
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static struct cdev scx200_gpio_cdev; /* use 1 cdev for all pins */ |
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static int __init scx200_gpio_init(void) |
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{ |
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int rc; |
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dev_t devid; |
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if (!scx200_gpio_present()) { |
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printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n"); |
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return -ENODEV; |
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} |
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/* support dev_dbg() with pdev->dev */ |
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pdev = platform_device_alloc(DRVNAME, 0); |
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if (!pdev) |
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return -ENOMEM; |
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rc = platform_device_add(pdev); |
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if (rc) |
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goto undo_malloc; |
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/* nsc_gpio uses dev_dbg(), so needs this */ |
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scx200_gpio_ops.dev = &pdev->dev; |
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if (major) { |
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devid = MKDEV(major, 0); |
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rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio"); |
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} else { |
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rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio"); |
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major = MAJOR(devid); |
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} |
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if (rc < 0) { |
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dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc); |
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goto undo_platform_device_add; |
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} |
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cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops); |
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cdev_add(&scx200_gpio_cdev, devid, MAX_PINS); |
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return 0; /* succeed */ |
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undo_platform_device_add: |
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platform_device_del(pdev); |
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undo_malloc: |
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platform_device_put(pdev); |
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return rc; |
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} |
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static void __exit scx200_gpio_cleanup(void) |
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{ |
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cdev_del(&scx200_gpio_cdev); |
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/* cdev_put(&scx200_gpio_cdev); */ |
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unregister_chrdev_region(MKDEV(major, 0), MAX_PINS); |
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platform_device_unregister(pdev); |
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} |
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module_init(scx200_gpio_init); |
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module_exit(scx200_gpio_cleanup);
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