1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ec_sys.c 4 * 5 * Copyright (C) 2010 SUSE Products GmbH/Novell 6 * 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 17 MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>"); 18 MODULE_DESCRIPTION("ACPI EC sysfs access driver"); 19 MODULE_LICENSE("GPL"); 20 21 static bool write_support; 22 module_param_hw(write_support, bool, other, 0644); 23 MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may " 24 "be needed."); 25 26 #define EC_SPACE_SIZE 256 27 28 static struct dentry *acpi_ec_debugfs_dir; 29 30 static 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 } else 46 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 64 static 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 } 101 102 static 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 }; 109 110 static 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 } 130 131 static int __init acpi_ec_sys_init(void) 132 { 133 if (first_ec) 134 acpi_ec_add_debugfs(first_ec, 0); 135 return 0; 136 } 137 138 static void __exit acpi_ec_sys_exit(void) 139 { 140 debugfs_remove_recursive(acpi_ec_debugfs_dir); 141 } 142 143 module_init(acpi_ec_sys_init); 144 module_exit(acpi_ec_sys_exit); 145