drivers/misc/bh1780gli.c

   1 /*
   2  * bh1780gli.c
   3  * ROHM Ambient Light Sensor Driver
   4  *
   5  * Copyright (C) 2010 Texas Instruments
   6  * Author: Hemanth V <hemanthv@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published by
  10  * the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20 #include <linux/i2c.h>
  21 #include <linux/slab.h>
  22 #include <linux/mutex.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/delay.h>
  25
  26 #define BH1780_REG_CONTROL      0x80
  27 #define BH1780_REG_PARTID       0x8A
  28 #define BH1780_REG_MANFID       0x8B
  29 #define BH1780_REG_DLOW 0x8C
  30 #define BH1780_REG_DHIGH        0x8D
  31
  32 #define BH1780_REVMASK          (0xf)
  33 #define BH1780_POWMASK          (0x3)
  34 #define BH1780_POFF             (0x0)
  35 #define BH1780_PON              (0x3)
  36
  37 /* power on settling time in ms */
  38 #define BH1780_PON_DELAY        2
  39
  40 struct bh1780_data {
  41         struct i2c_client *client;
  42         int power_state;
  43         /* lock for sysfs operations */
  44         struct mutex lock;
  45 };
  46
  47 static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
  48 {
  49         int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
  50         if (ret < 0)
  51                 dev_err(&ddata->client->dev,
  52                         "i2c_smbus_write_byte_data failed error %d\
  53                         Register (%s)\n", ret, msg);
  54         return ret;
  55 }
  56
  57 static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
  58 {
  59         int ret = i2c_smbus_read_byte_data(ddata->client, reg);
  60         if (ret < 0)
  61                 dev_err(&ddata->client->dev,
  62                         "i2c_smbus_read_byte_data failed error %d\
  63                          Register (%s)\n", ret, msg);
  64         return ret;
  65 }
  66
  67 static ssize_t bh1780_show_lux(struct device *dev,
  68                                 struct device_attribute *attr, char *buf)
  69 {
  70         struct platform_device *pdev = to_platform_device(dev);
  71         struct bh1780_data *ddata = platform_get_drvdata(pdev);
  72         int lsb, msb;
  73
  74         lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
  75         if (lsb < 0)
  76                 return lsb;
  77
  78         msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
  79         if (msb < 0)
  80                 return msb;
  81
  82         return sprintf(buf, "%d\n", (msb << 8) | lsb);
  83 }
  84
  85 static ssize_t bh1780_show_power_state(struct device *dev,
  86                                         struct device_attribute *attr,
  87                                         char *buf)
  88 {
  89         struct platform_device *pdev = to_platform_device(dev);
  90         struct bh1780_data *ddata = platform_get_drvdata(pdev);
  91         int state;
  92
  93         state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
  94         if (state < 0)
  95                 return state;
  96
  97         return sprintf(buf, "%d\n", state & BH1780_POWMASK);
  98 }
  99
 100 static ssize_t bh1780_store_power_state(struct device *dev,
 101                                         struct device_attribute *attr,
 102                                         const char *buf, size_t count)
 103 {
 104         struct platform_device *pdev = to_platform_device(dev);
 105         struct bh1780_data *ddata = platform_get_drvdata(pdev);
 106         unsigned long val;
 107         int error;
 108
 109         error = strict_strtoul(buf, 0, &val);
 110         if (error)
 111                 return error;
 112
 113         if (val < BH1780_POFF || val > BH1780_PON)
 114                 return -EINVAL;
 115
 116         mutex_lock(&ddata->lock);
 117
 118         error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
 119         if (error < 0) {
 120                 mutex_unlock(&ddata->lock);
 121                 return error;
 122         }
 123
 124         msleep(BH1780_PON_DELAY);
 125         ddata->power_state = val;
 126         mutex_unlock(&ddata->lock);
 127
 128         return count;
 129 }
 130
 131 static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
 132
 133 static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
 134                 bh1780_show_power_state, bh1780_store_power_state);
 135
 136 static struct attribute *bh1780_attributes[] = {
 137         &dev_attr_power_state.attr,
 138         &dev_attr_lux.attr,
 139         NULL
 140 };
 141
 142 static const struct attribute_group bh1780_attr_group = {
 143         .attrs = bh1780_attributes,
 144 };
 145
 146 static int __devinit bh1780_probe(struct i2c_client *client,
 147                                                 const struct i2c_device_id *id)
 148 {
 149         int ret;
 150         struct bh1780_data *ddata = NULL;
 151         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 152
 153         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) {
 154                 ret = -EIO;
 155                 goto err_op_failed;
 156         }
 157
 158         ddata = kzalloc(sizeof(struct bh1780_data), GFP_KERNEL);
 159         if (ddata == NULL) {
 160                 ret = -ENOMEM;
 161                 goto err_op_failed;
 162         }
 163
 164         ddata->client = client;
 165         i2c_set_clientdata(client, ddata);
 166
 167         ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
 168         if (ret < 0)
 169                 goto err_op_failed;
 170
 171         dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
 172                         (ret & BH1780_REVMASK));
 173
 174         mutex_init(&ddata->lock);
 175
 176         ret = sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
 177         if (ret)
 178                 goto err_op_failed;
 179
 180         return 0;
 181
 182 err_op_failed:
 183         kfree(ddata);
 184         return ret;
 185 }
 186
 187 static int __devexit bh1780_remove(struct i2c_client *client)
 188 {
 189         struct bh1780_data *ddata;
 190
 191         ddata = i2c_get_clientdata(client);
 192         sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
 193         kfree(ddata);
 194
 195         return 0;
 196 }
 197
 198 #ifdef CONFIG_PM
 199 static int bh1780_suspend(struct i2c_client *client, pm_message_t mesg)
 200 {
 201         struct bh1780_data *ddata;
 202         int state, ret;
 203
 204         ddata = i2c_get_clientdata(client);
 205         state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
 206         if (state < 0)
 207                 return state;
 208
 209         ddata->power_state = state & BH1780_POWMASK;
 210
 211         ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
 212                                 "CONTROL");
 213
 214         if (ret < 0)
 215                 return ret;
 216
 217         return 0;
 218 }
 219
 220 static int bh1780_resume(struct i2c_client *client)
 221 {
 222         struct bh1780_data *ddata;
 223         int state, ret;
 224
 225         ddata = i2c_get_clientdata(client);
 226         state = ddata->power_state;
 227
 228         ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
 229                                 "CONTROL");
 230
 231         if (ret < 0)
 232                 return ret;
 233
 234         return 0;
 235 }
 236 #else
 237 #define bh1780_suspend NULL
 238 #define bh1780_resume NULL
 239 #endif /* CONFIG_PM */
 240
 241 static const struct i2c_device_id bh1780_id[] = {
 242         { "bh1780", 0 },
 243         { },
 244 };
 245
 246 static struct i2c_driver bh1780_driver = {
 247         .probe          = bh1780_probe,
 248         .remove         = bh1780_remove,
 249         .id_table       = bh1780_id,
 250         .suspend        = bh1780_suspend,
 251         .resume         = bh1780_resume,
 252         .driver = {
 253                 .name = "bh1780"
 254         },
 255 };
 256
 257 static int __init bh1780_init(void)
 258 {
 259         return i2c_add_driver(&bh1780_driver);
 260 }
 261
 262 static void __exit bh1780_exit(void)
 263 {
 264         i2c_del_driver(&bh1780_driver);
 265 }
 266
 267 module_init(bh1780_init)
 268 module_exit(bh1780_exit)
 269
 270 MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
 271 MODULE_LICENSE("GPL");
 272 MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");