| 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>"); |