1 /* 2 * ec_sys.c 3 * 4 * Copyright (C) 2010 SUSE Products GmbH/Novell 5 * Author: 6 * Thomas Renninger <trenn@suse.de> 7 * 8 * This work is licensed under the terms of the GNU GPL, version 2. 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/acpi.h> 13 #include <linux/debugfs.h> 14 #include <linux/module.h> 15 #include <linux/uaccess.h> 16 #include "internal.h" 17 18 MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>"); 19 MODULE_DESCRIPTION("ACPI EC sysfs access driver"); 20 MODULE_LICENSE("GPL"); 21 22 static bool write_support; 23 module_param(write_support, bool, 0644); 24 MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may " 25 "be needed."); 26 27 #define EC_SPACE_SIZE 256 28 29 static struct dentry *acpi_ec_debugfs_dir; 30 31 static ssize_t acpi_ec_read_io(struct file *f, char __user *buf, 32 size_t count, loff_t *off) 33 { 34 /* Use this if support reading/writing multiple ECs exists in ec.c: 35 * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private; 36 */ 37 unsigned int size = EC_SPACE_SIZE; 38 loff_t init_off = *off; 39 int err = 0; 40 41 if (*off >= size) 42 return 0; 43 if (*off + count >= size) { 44 size -= *off; 45 count = size; 46 } else 47 size = count; 48 49 while (size) { 50 u8 byte_read; 51 err = ec_read(*off, &byte_read); 52 if (err) 53 return err; 54 if (put_user(byte_read, buf + *off - init_off)) { 55 if (*off - init_off) 56 return *off - init_off; /* partial read */ 57 return -EFAULT; 58 } 59 *off += 1; 60 size--; 61 } 62 return count; 63 } 64 65 static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf, 66 size_t count, loff_t *off) 67 { 68 /* Use this if support reading/writing multiple ECs exists in ec.c: 69 * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private; 70 */ 71 72 unsigned int size = count; 73 loff_t init_off = *off; 74 int err = 0; 75 76 if (!write_support) 77 return -EINVAL; 78 79 if (*off >= EC_SPACE_SIZE) 80 return 0; 81 if (*off + count >= EC_SPACE_SIZE) { 82 size = EC_SPACE_SIZE - *off; 83 count = size; 84 } 85 86 while (size) { 87 u8 byte_write; 88 if (get_user(byte_write, buf + *off - init_off)) { 89 if (*off - init_off) 90 return *off - init_off; /* partial write */ 91 return -EFAULT; 92 } 93 err = ec_write(*off, byte_write); 94 if (err) 95 return err; 96 97 *off += 1; 98 size--; 99 } 100 return count; 101 } 102 103 static const struct file_operations acpi_ec_io_ops = { 104 .owner = THIS_MODULE, 105 .open = simple_open, 106 .read = acpi_ec_read_io, 107 .write = acpi_ec_write_io, 108 .llseek = default_llseek, 109 }; 110 111 static int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count) 112 { 113 struct dentry *dev_dir; 114 char name[64]; 115 umode_t mode = 0400; 116 117 if (ec_device_count == 0) { 118 acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL); 119 if (!acpi_ec_debugfs_dir) 120 return -ENOMEM; 121 } 122 123 sprintf(name, "ec%u", ec_device_count); 124 dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir); 125 if (!dev_dir) { 126 if (ec_device_count != 0) 127 goto error; 128 return -ENOMEM; 129 } 130 131 if (!debugfs_create_x32("gpe", 0444, dev_dir, &first_ec->gpe)) 132 goto error; 133 if (!debugfs_create_bool("use_global_lock", 0444, dev_dir, 134 &first_ec->global_lock)) 135 goto error; 136 137 if (write_support) 138 mode = 0600; 139 if (!debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops)) 140 goto error; 141 142 return 0; 143 144 error: 145 debugfs_remove_recursive(acpi_ec_debugfs_dir); 146 return -ENOMEM; 147 } 148 149 static int __init acpi_ec_sys_init(void) 150 { 151 int err = 0; 152 if (first_ec) 153 err = acpi_ec_add_debugfs(first_ec, 0); 154 else 155 err = -ENODEV; 156 return err; 157 } 158 159 static void __exit acpi_ec_sys_exit(void) 160 { 161 debugfs_remove_recursive(acpi_ec_debugfs_dir); 162 } 163 164 module_init(acpi_ec_sys_init); 165 module_exit(acpi_ec_sys_exit); 166