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 #include <linux/module.h>
  26 #include <linux/of.h>
  27
  28 #define BH1780_REG_CONTROL      0x80
  29 #define BH1780_REG_PARTID       0x8A
  30 #define BH1780_REG_MANFID       0x8B
  31 #define BH1780_REG_DLOW 0x8C
  32 #define BH1780_REG_DHIGH        0x8D
  33
  34 #define BH1780_REVMASK          (0xf)
  35 #define BH1780_POWMASK          (0x3)
  36 #define BH1780_POFF             (0x0)
  37 #define BH1780_PON              (0x3)
  38
  39 /* power on settling time in ms */
  40 #define BH1780_PON_DELAY        2
  41
  42 struct bh1780_data {
  43         struct i2c_client *client;
  44         int power_state;
  45         /* lock for sysfs operations */
  46         struct mutex lock;
  47 };
  48
  49 static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
  50 {
  51         int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
  52         if (ret < 0)
  53                 dev_err(&ddata->client->dev,
  54                         "i2c_smbus_write_byte_data failed error %d Register (%s)\n",
  55                         ret, msg);
  56         return ret;
  57 }
  58
  59 static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
  60 {
  61         int ret = i2c_smbus_read_byte_data(ddata->client, reg);
  62         if (ret < 0)
  63                 dev_err(&ddata->client->dev,
  64                         "i2c_smbus_read_byte_data failed error %d Register (%s)\n",
  65                         ret, msg);
  66         return ret;
  67 }
  68
  69 static ssize_t bh1780_show_lux(struct device *dev,
  70                                 struct device_attribute *attr, char *buf)
  71 {
  72         struct platform_device *pdev = to_platform_device(dev);
  73         struct bh1780_data *ddata = platform_get_drvdata(pdev);
  74         int lsb, msb;
  75
  76         lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
  77         if (lsb < 0)
  78                 return lsb;
  79
  80         msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
  81         if (msb < 0)
  82                 return msb;
  83
  84         return sprintf(buf, "%d\n", (msb << 8) | lsb);
  85 }
  86
  87 static ssize_t bh1780_show_power_state(struct device *dev,
  88                                         struct device_attribute *attr,
  89                                         char *buf)
  90 {
  91         struct platform_device *pdev = to_platform_device(dev);
  92         struct bh1780_data *ddata = platform_get_drvdata(pdev);
  93         int state;
  94
  95         state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
  96         if (state < 0)
  97                 return state;
  98
  99         return sprintf(buf, "%d\n", state & BH1780_POWMASK);
 100 }
 101
 102 static ssize_t bh1780_store_power_state(struct device *dev,
 103                                         struct device_attribute *attr,
 104                                         const char *buf, size_t count)
 105 {
 106         struct platform_device *pdev = to_platform_device(dev);
 107         struct bh1780_data *ddata = platform_get_drvdata(pdev);
 108         unsigned long val;
 109         int error;
 110
 111         error = kstrtoul(buf, 0, &val);
 112         if (error)
 113                 return error;
 114
 115         if (val < BH1780_POFF || val > BH1780_PON)
 116                 return -EINVAL;
 117
 118         mutex_lock(&ddata->lock);
 119
 120         error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
 121         if (error < 0) {
 122                 mutex_unlock(&ddata->lock);
 123                 return error;
 124         }
 125
 126         msleep(BH1780_PON_DELAY);
 127         ddata->power_state = val;
 128         mutex_unlock(&ddata->lock);
 129
 130         return count;
 131 }
 132
 133 static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
 134
 135 static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
 136                 bh1780_show_power_state, bh1780_store_power_state);
 137
 138 static struct attribute *bh1780_attributes[] = {
 139         &dev_attr_power_state.attr,
 140         &dev_attr_lux.attr,
 141         NULL
 142 };
 143
 144 static const struct attribute_group bh1780_attr_group = {
 145         .attrs = bh1780_attributes,
 146 };
 147
 148 static int bh1780_probe(struct i2c_client *client,
 149                                                 const struct i2c_device_id *id)
 150 {
 151         int ret;
 152         struct bh1780_data *ddata;
 153         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 154
 155         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
 156                 return -EIO;
 157
 158         ddata = devm_kzalloc(&client->dev, sizeof(struct bh1780_data),
 159                              GFP_KERNEL);
 160         if (ddata == NULL)
 161                 return -ENOMEM;
 162
 163         ddata->client = client;
 164         i2c_set_clientdata(client, ddata);
 165
 166         ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
 167         if (ret < 0)
 168                 return ret;
 169
 170         dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
 171                         (ret & BH1780_REVMASK));
 172
 173         mutex_init(&ddata->lock);
 174
 175         return sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
 176 }
 177
 178 static int bh1780_remove(struct i2c_client *client)
 179 {
 180         sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
 181
 182         return 0;
 183 }
 184
 185 #ifdef CONFIG_PM_SLEEP
 186 static int bh1780_suspend(struct device *dev)
 187 {
 188         struct bh1780_data *ddata;
 189         int state, ret;
 190         struct i2c_client *client = to_i2c_client(dev);
 191
 192         ddata = i2c_get_clientdata(client);
 193         state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
 194         if (state < 0)
 195                 return state;
 196
 197         ddata->power_state = state & BH1780_POWMASK;
 198
 199         ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
 200                                 "CONTROL");
 201
 202         if (ret < 0)
 203                 return ret;
 204
 205         return 0;
 206 }
 207
 208 static int bh1780_resume(struct device *dev)
 209 {
 210         struct bh1780_data *ddata;
 211         int state, ret;
 212         struct i2c_client *client = to_i2c_client(dev);
 213
 214         ddata = i2c_get_clientdata(client);
 215         state = ddata->power_state;
 216         ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
 217                                 "CONTROL");
 218
 219         if (ret < 0)
 220                 return ret;
 221
 222         return 0;
 223 }
 224 #endif /* CONFIG_PM_SLEEP */
 225
 226 static SIMPLE_DEV_PM_OPS(bh1780_pm, bh1780_suspend, bh1780_resume);
 227
 228 static const struct i2c_device_id bh1780_id[] = {
 229         { "bh1780", 0 },
 230         { },
 231 };
 232
 233 #ifdef CONFIG_OF
 234 static const struct of_device_id of_bh1780_match[] = {
 235         { .compatible = "rohm,bh1780gli", },
 236         {},
 237 };
 238
 239 MODULE_DEVICE_TABLE(of, of_bh1780_match);
 240 #endif
 241
 242 static struct i2c_driver bh1780_driver = {
 243         .probe          = bh1780_probe,
 244         .remove         = bh1780_remove,
 245         .id_table       = bh1780_id,
 246         .driver = {
 247                 .name = "bh1780",
 248                 .pm     = &bh1780_pm,
 249                 .of_match_table = of_match_ptr(of_bh1780_match),
 250         },
 251 };
 252
 253 module_i2c_driver(bh1780_driver);
 254
 255 MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
 256 MODULE_LICENSE("GPL");
 257 MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");