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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 | // SPDX-License-Identifier: GPL-2.0-only /* 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 <linux/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); |