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1// SPDX-License-Identifier: GPL-2.0-only2/* linux/drivers/char/scx200_gpio.c3 4 National Semiconductor SCx200 GPIO driver. Allows a user space5 process to play with the GPIO pins.6 7 Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> */8 9#include <linux/device.h>10#include <linux/fs.h>11#include <linux/module.h>12#include <linux/errno.h>13#include <linux/kernel.h>14#include <linux/init.h>15#include <linux/platform_device.h>16#include <linux/uaccess.h>17#include <asm/io.h>18 19#include <linux/types.h>20#include <linux/cdev.h>21 22#include <linux/scx200_gpio.h>23#include <linux/nsc_gpio.h>24 25#define DRVNAME "scx200_gpio"26 27static struct platform_device *pdev;28 29MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");30MODULE_DESCRIPTION("NatSemi/AMD SCx200 GPIO Pin Driver");31MODULE_LICENSE("GPL");32 33static int major = 0; /* default to dynamic major */34module_param(major, int, 0);35MODULE_PARM_DESC(major, "Major device number");36 37#define MAX_PINS 32 /* 64 later, when known ok */38 39struct nsc_gpio_ops scx200_gpio_ops = {40 .owner = THIS_MODULE,41 .gpio_config = scx200_gpio_configure,42 .gpio_dump = nsc_gpio_dump,43 .gpio_get = scx200_gpio_get,44 .gpio_set = scx200_gpio_set,45 .gpio_change = scx200_gpio_change,46 .gpio_current = scx200_gpio_current47};48EXPORT_SYMBOL_GPL(scx200_gpio_ops);49 50static int scx200_gpio_open(struct inode *inode, struct file *file)51{52 unsigned m = iminor(inode);53 file->private_data = &scx200_gpio_ops;54 55 if (m >= MAX_PINS)56 return -EINVAL;57 return nonseekable_open(inode, file);58}59 60static int scx200_gpio_release(struct inode *inode, struct file *file)61{62 return 0;63}64 65static const struct file_operations scx200_gpio_fileops = {66 .owner = THIS_MODULE,67 .write = nsc_gpio_write,68 .read = nsc_gpio_read,69 .open = scx200_gpio_open,70 .release = scx200_gpio_release,71};72 73static struct cdev scx200_gpio_cdev; /* use 1 cdev for all pins */74 75static int __init scx200_gpio_init(void)76{77 int rc;78 dev_t devid;79 80 if (!scx200_gpio_present()) {81 printk(KERN_ERR DRVNAME ": no SCx200 gpio present\n");82 return -ENODEV;83 }84 85 /* support dev_dbg() with pdev->dev */86 pdev = platform_device_alloc(DRVNAME, 0);87 if (!pdev)88 return -ENOMEM;89 90 rc = platform_device_add(pdev);91 if (rc)92 goto undo_malloc;93 94 /* nsc_gpio uses dev_dbg(), so needs this */95 scx200_gpio_ops.dev = &pdev->dev;96 97 if (major) {98 devid = MKDEV(major, 0);99 rc = register_chrdev_region(devid, MAX_PINS, "scx200_gpio");100 } else {101 rc = alloc_chrdev_region(&devid, 0, MAX_PINS, "scx200_gpio");102 major = MAJOR(devid);103 }104 if (rc < 0) {105 dev_err(&pdev->dev, "SCx200 chrdev_region err: %d\n", rc);106 goto undo_platform_device_add;107 }108 109 cdev_init(&scx200_gpio_cdev, &scx200_gpio_fileops);110 cdev_add(&scx200_gpio_cdev, devid, MAX_PINS);111 112 return 0; /* succeed */113 114undo_platform_device_add:115 platform_device_del(pdev);116undo_malloc:117 platform_device_put(pdev);118 119 return rc;120}121 122static void __exit scx200_gpio_cleanup(void)123{124 cdev_del(&scx200_gpio_cdev);125 /* cdev_put(&scx200_gpio_cdev); */126 127 unregister_chrdev_region(MKDEV(major, 0), MAX_PINS);128 platform_device_unregister(pdev);129}130 131module_init(scx200_gpio_init);132module_exit(scx200_gpio_cleanup);133