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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ec_sys.c4 *5 * Copyright (C) 2010 SUSE Products GmbH/Novell6 * Author:7 * Thomas Renninger <trenn@suse.de>8 */9 10#include <linux/kernel.h>11#include <linux/acpi.h>12#include <linux/debugfs.h>13#include <linux/module.h>14#include <linux/uaccess.h>15#include "internal.h"16 17MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");18MODULE_DESCRIPTION("ACPI EC sysfs access driver");19MODULE_LICENSE("GPL");20 21static bool write_support;22module_param_hw(write_support, bool, other, 0644);23MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "24 "be needed.");25 26#define EC_SPACE_SIZE 25627 28static struct dentry *acpi_ec_debugfs_dir;29 30static ssize_t acpi_ec_read_io(struct file *f, char __user *buf,31 size_t count, loff_t *off)32{33 /* Use this if support reading/writing multiple ECs exists in ec.c:34 * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;35 */36 unsigned int size = EC_SPACE_SIZE;37 loff_t init_off = *off;38 int err = 0;39 40 if (*off >= size)41 return 0;42 if (*off + count >= size) {43 size -= *off;44 count = size;45 } else46 size = count;47 48 while (size) {49 u8 byte_read;50 err = ec_read(*off, &byte_read);51 if (err)52 return err;53 if (put_user(byte_read, buf + *off - init_off)) {54 if (*off - init_off)55 return *off - init_off; /* partial read */56 return -EFAULT;57 }58 *off += 1;59 size--;60 }61 return count;62}63 64static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf,65 size_t count, loff_t *off)66{67 /* Use this if support reading/writing multiple ECs exists in ec.c:68 * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;69 */70 71 unsigned int size = count;72 loff_t init_off = *off;73 int err = 0;74 75 if (!write_support)76 return -EINVAL;77 78 if (*off >= EC_SPACE_SIZE)79 return 0;80 if (*off + count >= EC_SPACE_SIZE) {81 size = EC_SPACE_SIZE - *off;82 count = size;83 }84 85 while (size) {86 u8 byte_write;87 if (get_user(byte_write, buf + *off - init_off)) {88 if (*off - init_off)89 return *off - init_off; /* partial write */90 return -EFAULT;91 }92 err = ec_write(*off, byte_write);93 if (err)94 return err;95 96 *off += 1;97 size--;98 }99 return count;100}101 102static const struct file_operations acpi_ec_io_ops = {103 .owner = THIS_MODULE,104 .open = simple_open,105 .read = acpi_ec_read_io,106 .write = acpi_ec_write_io,107 .llseek = default_llseek,108};109 110static void acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)111{112 struct dentry *dev_dir;113 char name[64];114 umode_t mode = 0400;115 116 if (ec_device_count == 0)117 acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);118 119 sprintf(name, "ec%u", ec_device_count);120 dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);121 122 debugfs_create_x32("gpe", 0444, dev_dir, &first_ec->gpe);123 debugfs_create_bool("use_global_lock", 0444, dev_dir,124 &first_ec->global_lock);125 126 if (write_support)127 mode = 0600;128 debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops);129}130 131static int __init acpi_ec_sys_init(void)132{133 if (first_ec)134 acpi_ec_add_debugfs(first_ec, 0);135 return 0;136}137 138static void __exit acpi_ec_sys_exit(void)139{140 debugfs_remove_recursive(acpi_ec_debugfs_dir);141}142 143module_init(acpi_ec_sys_init);144module_exit(acpi_ec_sys_exit);145