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 40struct bh1780_data { 41 struct i2c_client *client; 42 int power_state; 43 /* lock for sysfs operations */ 44 struct mutex lock; 45}; 46 47static 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 57static 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 67static 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 85static 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 100static 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 131static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL); 132 133static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO, 134 bh1780_show_power_state, bh1780_store_power_state); 135 136static struct attribute *bh1780_attributes[] = { 137 &dev_attr_power_state.attr, 138 &dev_attr_lux.attr, 139 NULL 140}; 141 142static const struct attribute_group bh1780_attr_group = { 143 .attrs = bh1780_attributes, 144}; 145 146static 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 182err_op_failed: 183 kfree(ddata); 184 return ret; 185} 186 187static 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 199static 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 220static 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 241static const struct i2c_device_id bh1780_id[] = { 242 { "bh1780", 0 }, 243 { }, 244}; 245 246static 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 257static int __init bh1780_init(void) 258{ 259 return i2c_add_driver(&bh1780_driver); 260} 261 262static void __exit bh1780_exit(void) 263{ 264 i2c_del_driver(&bh1780_driver); 265} 266 267module_init(bh1780_init) 268module_exit(bh1780_exit) 269 270MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver"); 271MODULE_LICENSE("GPL"); 272MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>"); 273