1 /* 2 * Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net> 3 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with 4 * the help of Jean Delvare <jdelvare@suse.de> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 19 */ 20 21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 22 23 #include <linux/module.h> 24 #include <linux/init.h> 25 #include <linux/slab.h> 26 #include <linux/i2c.h> 27 #include <linux/mutex.h> 28 #include <linux/err.h> 29 #include <linux/hwmon.h> 30 31 /* Insmod parameters */ 32 33 static int input_mode; 34 module_param(input_mode, int, 0); 35 MODULE_PARM_DESC(input_mode, 36 "Analog input mode:\n" 37 " 0 = four single ended inputs\n" 38 " 1 = three differential inputs\n" 39 " 2 = single ended and differential mixed\n" 40 " 3 = two differential inputs\n"); 41 42 /* 43 * The PCF8591 control byte 44 * 7 6 5 4 3 2 1 0 45 * | 0 |AOEF| AIP | 0 |AINC| AICH | 46 */ 47 48 /* Analog Output Enable Flag (analog output active if 1) */ 49 #define PCF8591_CONTROL_AOEF 0x40 50 51 /* 52 * Analog Input Programming 53 * 0x00 = four single ended inputs 54 * 0x10 = three differential inputs 55 * 0x20 = single ended and differential mixed 56 * 0x30 = two differential inputs 57 */ 58 #define PCF8591_CONTROL_AIP_MASK 0x30 59 60 /* Autoincrement Flag (switch on if 1) */ 61 #define PCF8591_CONTROL_AINC 0x04 62 63 /* 64 * Channel selection 65 * 0x00 = channel 0 66 * 0x01 = channel 1 67 * 0x02 = channel 2 68 * 0x03 = channel 3 69 */ 70 #define PCF8591_CONTROL_AICH_MASK 0x03 71 72 /* Initial values */ 73 #define PCF8591_INIT_CONTROL ((input_mode << 4) | PCF8591_CONTROL_AOEF) 74 #define PCF8591_INIT_AOUT 0 /* DAC out = 0 */ 75 76 /* Conversions */ 77 #define REG_TO_SIGNED(reg) (((reg) & 0x80) ? ((reg) - 256) : (reg)) 78 79 struct pcf8591_data { 80 struct device *hwmon_dev; 81 struct mutex update_lock; 82 83 u8 control; 84 u8 aout; 85 }; 86 87 static void pcf8591_init_client(struct i2c_client *client); 88 static int pcf8591_read_channel(struct device *dev, int channel); 89 90 /* following are the sysfs callback functions */ 91 #define show_in_channel(channel) \ 92 static ssize_t show_in##channel##_input(struct device *dev, \ 93 struct device_attribute *attr, \ 94 char *buf) \ 95 { \ 96 return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\ 97 } \ 98 static DEVICE_ATTR(in##channel##_input, S_IRUGO, \ 99 show_in##channel##_input, NULL); 100 101 show_in_channel(0); 102 show_in_channel(1); 103 show_in_channel(2); 104 show_in_channel(3); 105 106 static ssize_t out0_output_show(struct device *dev, 107 struct device_attribute *attr, char *buf) 108 { 109 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev)); 110 return sprintf(buf, "%d\n", data->aout * 10); 111 } 112 113 static ssize_t out0_output_store(struct device *dev, 114 struct device_attribute *attr, 115 const char *buf, size_t count) 116 { 117 unsigned long val; 118 struct i2c_client *client = to_i2c_client(dev); 119 struct pcf8591_data *data = i2c_get_clientdata(client); 120 int err; 121 122 err = kstrtoul(buf, 10, &val); 123 if (err) 124 return err; 125 126 val /= 10; 127 if (val > 255) 128 return -EINVAL; 129 130 data->aout = val; 131 i2c_smbus_write_byte_data(client, data->control, data->aout); 132 return count; 133 } 134 135 static DEVICE_ATTR_RW(out0_output); 136 137 static ssize_t out0_enable_show(struct device *dev, 138 struct device_attribute *attr, char *buf) 139 { 140 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev)); 141 return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF))); 142 } 143 144 static ssize_t out0_enable_store(struct device *dev, 145 struct device_attribute *attr, 146 const char *buf, size_t count) 147 { 148 struct i2c_client *client = to_i2c_client(dev); 149 struct pcf8591_data *data = i2c_get_clientdata(client); 150 unsigned long val; 151 int err; 152 153 err = kstrtoul(buf, 10, &val); 154 if (err) 155 return err; 156 157 mutex_lock(&data->update_lock); 158 if (val) 159 data->control |= PCF8591_CONTROL_AOEF; 160 else 161 data->control &= ~PCF8591_CONTROL_AOEF; 162 i2c_smbus_write_byte(client, data->control); 163 mutex_unlock(&data->update_lock); 164 return count; 165 } 166 167 static DEVICE_ATTR_RW(out0_enable); 168 169 static struct attribute *pcf8591_attributes[] = { 170 &dev_attr_out0_enable.attr, 171 &dev_attr_out0_output.attr, 172 &dev_attr_in0_input.attr, 173 &dev_attr_in1_input.attr, 174 NULL 175 }; 176 177 static const struct attribute_group pcf8591_attr_group = { 178 .attrs = pcf8591_attributes, 179 }; 180 181 static struct attribute *pcf8591_attributes_opt[] = { 182 &dev_attr_in2_input.attr, 183 &dev_attr_in3_input.attr, 184 NULL 185 }; 186 187 static const struct attribute_group pcf8591_attr_group_opt = { 188 .attrs = pcf8591_attributes_opt, 189 }; 190 191 /* 192 * Real code 193 */ 194 195 static int pcf8591_probe(struct i2c_client *client, 196 const struct i2c_device_id *id) 197 { 198 struct pcf8591_data *data; 199 int err; 200 201 data = devm_kzalloc(&client->dev, sizeof(struct pcf8591_data), 202 GFP_KERNEL); 203 if (!data) 204 return -ENOMEM; 205 206 i2c_set_clientdata(client, data); 207 mutex_init(&data->update_lock); 208 209 /* Initialize the PCF8591 chip */ 210 pcf8591_init_client(client); 211 212 /* Register sysfs hooks */ 213 err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group); 214 if (err) 215 return err; 216 217 /* Register input2 if not in "two differential inputs" mode */ 218 if (input_mode != 3) { 219 err = device_create_file(&client->dev, &dev_attr_in2_input); 220 if (err) 221 goto exit_sysfs_remove; 222 } 223 224 /* Register input3 only in "four single ended inputs" mode */ 225 if (input_mode == 0) { 226 err = device_create_file(&client->dev, &dev_attr_in3_input); 227 if (err) 228 goto exit_sysfs_remove; 229 } 230 231 data->hwmon_dev = hwmon_device_register(&client->dev); 232 if (IS_ERR(data->hwmon_dev)) { 233 err = PTR_ERR(data->hwmon_dev); 234 goto exit_sysfs_remove; 235 } 236 237 return 0; 238 239 exit_sysfs_remove: 240 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt); 241 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group); 242 return err; 243 } 244 245 static int pcf8591_remove(struct i2c_client *client) 246 { 247 struct pcf8591_data *data = i2c_get_clientdata(client); 248 249 hwmon_device_unregister(data->hwmon_dev); 250 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt); 251 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group); 252 return 0; 253 } 254 255 /* Called when we have found a new PCF8591. */ 256 static void pcf8591_init_client(struct i2c_client *client) 257 { 258 struct pcf8591_data *data = i2c_get_clientdata(client); 259 data->control = PCF8591_INIT_CONTROL; 260 data->aout = PCF8591_INIT_AOUT; 261 262 i2c_smbus_write_byte_data(client, data->control, data->aout); 263 264 /* 265 * The first byte transmitted contains the conversion code of the 266 * previous read cycle. FLUSH IT! 267 */ 268 i2c_smbus_read_byte(client); 269 } 270 271 static int pcf8591_read_channel(struct device *dev, int channel) 272 { 273 u8 value; 274 struct i2c_client *client = to_i2c_client(dev); 275 struct pcf8591_data *data = i2c_get_clientdata(client); 276 277 mutex_lock(&data->update_lock); 278 279 if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) { 280 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK) 281 | channel; 282 i2c_smbus_write_byte(client, data->control); 283 284 /* 285 * The first byte transmitted contains the conversion code of 286 * the previous read cycle. FLUSH IT! 287 */ 288 i2c_smbus_read_byte(client); 289 } 290 value = i2c_smbus_read_byte(client); 291 292 mutex_unlock(&data->update_lock); 293 294 if ((channel == 2 && input_mode == 2) || 295 (channel != 3 && (input_mode == 1 || input_mode == 3))) 296 return 10 * REG_TO_SIGNED(value); 297 else 298 return 10 * value; 299 } 300 301 static const struct i2c_device_id pcf8591_id[] = { 302 { "pcf8591", 0 }, 303 { } 304 }; 305 MODULE_DEVICE_TABLE(i2c, pcf8591_id); 306 307 static struct i2c_driver pcf8591_driver = { 308 .driver = { 309 .name = "pcf8591", 310 }, 311 .probe = pcf8591_probe, 312 .remove = pcf8591_remove, 313 .id_table = pcf8591_id, 314 }; 315 316 static int __init pcf8591_init(void) 317 { 318 if (input_mode < 0 || input_mode > 3) { 319 pr_warn("invalid input_mode (%d)\n", input_mode); 320 input_mode = 0; 321 } 322 return i2c_add_driver(&pcf8591_driver); 323 } 324 325 static void __exit pcf8591_exit(void) 326 { 327 i2c_del_driver(&pcf8591_driver); 328 } 329 330 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>"); 331 MODULE_DESCRIPTION("PCF8591 driver"); 332 MODULE_LICENSE("GPL"); 333 334 module_init(pcf8591_init); 335 module_exit(pcf8591_exit); 336