drivers/hwmon/ds620.c

   1 /*
   2  *  ds620.c - Support for temperature sensor and thermostat DS620
   3  *
   4  *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
   5  *
   6  *  based on ds1621.c by Christian W. Zuckschwerdt  <zany@triq.net>
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/init.h>
  25 #include <linux/slab.h>
  26 #include <linux/jiffies.h>
  27 #include <linux/i2c.h>
  28 #include <linux/hwmon.h>
  29 #include <linux/hwmon-sysfs.h>
  30 #include <linux/err.h>
  31 #include <linux/mutex.h>
  32 #include <linux/sysfs.h>
  33 #include <linux/i2c/ds620.h>
  34
  35 /*
  36  * Many DS620 constants specified below
  37  *  15   14   13   12   11   10   09    08
  38  * |Done|NVB |THF |TLF |R1  |R0  |AUTOC|1SHOT|
  39  *
  40  *  07   06   05   04   03   02   01    00
  41  * |PO2 |PO1 |A2  |A1  |A0  |    |     |     |
  42  */
  43 #define DS620_REG_CONFIG_DONE           0x8000
  44 #define DS620_REG_CONFIG_NVB            0x4000
  45 #define DS620_REG_CONFIG_THF            0x2000
  46 #define DS620_REG_CONFIG_TLF            0x1000
  47 #define DS620_REG_CONFIG_R1             0x0800
  48 #define DS620_REG_CONFIG_R0             0x0400
  49 #define DS620_REG_CONFIG_AUTOC          0x0200
  50 #define DS620_REG_CONFIG_1SHOT          0x0100
  51 #define DS620_REG_CONFIG_PO2            0x0080
  52 #define DS620_REG_CONFIG_PO1            0x0040
  53 #define DS620_REG_CONFIG_A2             0x0020
  54 #define DS620_REG_CONFIG_A1             0x0010
  55 #define DS620_REG_CONFIG_A0             0x0008
  56
  57 /* The DS620 registers */
  58 static const u8 DS620_REG_TEMP[3] = {
  59         0xAA,                   /* input, word, RO */
  60         0xA2,                   /* min, word, RW */
  61         0xA0,                   /* max, word, RW */
  62 };
  63
  64 #define DS620_REG_CONF          0xAC    /* word, RW */
  65 #define DS620_COM_START         0x51    /* no data */
  66 #define DS620_COM_STOP          0x22    /* no data */
  67
  68 /* Each client has this additional data */
  69 struct ds620_data {
  70         struct device *hwmon_dev;
  71         struct mutex update_lock;
  72         char valid;             /* !=0 if following fields are valid */
  73         unsigned long last_updated;     /* In jiffies */
  74
  75         s16 temp[3];            /* Register values, word */
  76 };
  77
  78 static void ds620_init_client(struct i2c_client *client)
  79 {
  80         struct ds620_platform_data *ds620_info = client->dev.platform_data;
  81         u16 conf, new_conf;
  82
  83         new_conf = conf =
  84             i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
  85
  86         /* switch to continuous conversion mode */
  87         new_conf &= ~DS620_REG_CONFIG_1SHOT;
  88         /* already high at power-on, but don't trust the BIOS! */
  89         new_conf |= DS620_REG_CONFIG_PO2;
  90         /* thermostat mode according to platform data */
  91         if (ds620_info && ds620_info->pomode == 1)
  92                 new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
  93         else if (ds620_info && ds620_info->pomode == 2)
  94                 new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
  95         else
  96                 new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
  97         /* with highest precision */
  98         new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;
  99
 100         if (conf != new_conf)
 101                 i2c_smbus_write_word_swapped(client, DS620_REG_CONF, new_conf);
 102
 103         /* start conversion */
 104         i2c_smbus_write_byte(client, DS620_COM_START);
 105 }
 106
 107 static struct ds620_data *ds620_update_client(struct device *dev)
 108 {
 109         struct i2c_client *client = to_i2c_client(dev);
 110         struct ds620_data *data = i2c_get_clientdata(client);
 111         struct ds620_data *ret = data;
 112
 113         mutex_lock(&data->update_lock);
 114
 115         if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
 116             || !data->valid) {
 117                 int i;
 118                 int res;
 119
 120                 dev_dbg(&client->dev, "Starting ds620 update\n");
 121
 122                 for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
 123                         res = i2c_smbus_read_word_swapped(client,
 124                                                           DS620_REG_TEMP[i]);
 125                         if (res < 0) {
 126                                 ret = ERR_PTR(res);
 127                                 goto abort;
 128                         }
 129
 130                         data->temp[i] = res;
 131                 }
 132
 133                 data->last_updated = jiffies;
 134                 data->valid = 1;
 135         }
 136 abort:
 137         mutex_unlock(&data->update_lock);
 138
 139         return ret;
 140 }
 141
 142 static ssize_t show_temp(struct device *dev, struct device_attribute *da,
 143                          char *buf)
 144 {
 145         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 146         struct ds620_data *data = ds620_update_client(dev);
 147
 148         if (IS_ERR(data))
 149                 return PTR_ERR(data);
 150
 151         return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
 152 }
 153
 154 static ssize_t set_temp(struct device *dev, struct device_attribute *da,
 155                         const char *buf, size_t count)
 156 {
 157         int res;
 158         long val;
 159
 160         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 161         struct i2c_client *client = to_i2c_client(dev);
 162         struct ds620_data *data = i2c_get_clientdata(client);
 163
 164         res = kstrtol(buf, 10, &val);
 165
 166         if (res)
 167                 return res;
 168
 169         val = (val * 10 / 625) * 8;
 170
 171         mutex_lock(&data->update_lock);
 172         data->temp[attr->index] = val;
 173         i2c_smbus_write_word_swapped(client, DS620_REG_TEMP[attr->index],
 174                                      data->temp[attr->index]);
 175         mutex_unlock(&data->update_lock);
 176         return count;
 177 }
 178
 179 static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
 180                           char *buf)
 181 {
 182         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 183         struct ds620_data *data = ds620_update_client(dev);
 184         struct i2c_client *client = to_i2c_client(dev);
 185         u16 conf, new_conf;
 186         int res;
 187
 188         if (IS_ERR(data))
 189                 return PTR_ERR(data);
 190
 191         /* reset alarms if necessary */
 192         res = i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
 193         if (res < 0)
 194                 return res;
 195
 196         new_conf = conf = res;
 197         new_conf &= ~attr->index;
 198         if (conf != new_conf) {
 199                 res = i2c_smbus_write_word_swapped(client, DS620_REG_CONF,
 200                                                    new_conf);
 201                 if (res < 0)
 202                         return res;
 203         }
 204
 205         return sprintf(buf, "%d\n", !!(conf & attr->index));
 206 }
 207
 208 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
 209 static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
 210 static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
 211 static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
 212                           DS620_REG_CONFIG_TLF);
 213 static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
 214                           DS620_REG_CONFIG_THF);
 215
 216 static struct attribute *ds620_attributes[] = {
 217         &sensor_dev_attr_temp1_input.dev_attr.attr,
 218         &sensor_dev_attr_temp1_min.dev_attr.attr,
 219         &sensor_dev_attr_temp1_max.dev_attr.attr,
 220         &sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
 221         &sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
 222         NULL
 223 };
 224
 225 static const struct attribute_group ds620_group = {
 226         .attrs = ds620_attributes,
 227 };
 228
 229 static int ds620_probe(struct i2c_client *client,
 230                        const struct i2c_device_id *id)
 231 {
 232         struct ds620_data *data;
 233         int err;
 234
 235         data = devm_kzalloc(&client->dev, sizeof(struct ds620_data),
 236                             GFP_KERNEL);
 237         if (!data)
 238                 return -ENOMEM;
 239
 240         i2c_set_clientdata(client, data);
 241         mutex_init(&data->update_lock);
 242
 243         /* Initialize the DS620 chip */
 244         ds620_init_client(client);
 245
 246         /* Register sysfs hooks */
 247         err = sysfs_create_group(&client->dev.kobj, &ds620_group);
 248         if (err)
 249                 return err;
 250
 251         data->hwmon_dev = hwmon_device_register(&client->dev);
 252         if (IS_ERR(data->hwmon_dev)) {
 253                 err = PTR_ERR(data->hwmon_dev);
 254                 goto exit_remove_files;
 255         }
 256
 257         dev_info(&client->dev, "temperature sensor found\n");
 258
 259         return 0;
 260
 261 exit_remove_files:
 262         sysfs_remove_group(&client->dev.kobj, &ds620_group);
 263         return err;
 264 }
 265
 266 static int ds620_remove(struct i2c_client *client)
 267 {
 268         struct ds620_data *data = i2c_get_clientdata(client);
 269
 270         hwmon_device_unregister(data->hwmon_dev);
 271         sysfs_remove_group(&client->dev.kobj, &ds620_group);
 272
 273         return 0;
 274 }
 275
 276 static const struct i2c_device_id ds620_id[] = {
 277         {"ds620", 0},
 278         {}
 279 };
 280
 281 MODULE_DEVICE_TABLE(i2c, ds620_id);
 282
 283 /* This is the driver that will be inserted */
 284 static struct i2c_driver ds620_driver = {
 285         .class = I2C_CLASS_HWMON,
 286         .driver = {
 287                    .name = "ds620",
 288         },
 289         .probe = ds620_probe,
 290         .remove = ds620_remove,
 291         .id_table = ds620_id,
 292 };
 293
 294 module_i2c_driver(ds620_driver);
 295
 296 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
 297 MODULE_DESCRIPTION("DS620 driver");
 298 MODULE_LICENSE("GPL");