1 /* 2 * TI LP855x Backlight Driver 3 * 4 * Copyright (C) 2011 Texas Instruments 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 */ 11 12 #include <linux/module.h> 13 #include <linux/slab.h> 14 #include <linux/i2c.h> 15 #include <linux/backlight.h> 16 #include <linux/err.h> 17 #include <linux/platform_data/lp855x.h> 18 19 /* Registers */ 20 #define BRIGHTNESS_CTRL 0x00 21 #define DEVICE_CTRL 0x01 22 #define EEPROM_START 0xA0 23 #define EEPROM_END 0xA7 24 #define EPROM_START 0xA0 25 #define EPROM_END 0xAF 26 27 #define BUF_SIZE 20 28 #define DEFAULT_BL_NAME "lcd-backlight" 29 #define MAX_BRIGHTNESS 255 30 31 struct lp855x { 32 const char *chipname; 33 enum lp855x_chip_id chip_id; 34 struct i2c_client *client; 35 struct backlight_device *bl; 36 struct device *dev; 37 struct mutex xfer_lock; 38 struct lp855x_platform_data *pdata; 39 }; 40 41 static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data) 42 { 43 int ret; 44 45 mutex_lock(&lp->xfer_lock); 46 ret = i2c_smbus_read_byte_data(lp->client, reg); 47 if (ret < 0) { 48 mutex_unlock(&lp->xfer_lock); 49 dev_err(lp->dev, "failed to read 0x%.2x\n", reg); 50 return ret; 51 } 52 mutex_unlock(&lp->xfer_lock); 53 54 *data = (u8)ret; 55 return 0; 56 } 57 58 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) 59 { 60 int ret; 61 62 mutex_lock(&lp->xfer_lock); 63 ret = i2c_smbus_write_byte_data(lp->client, reg, data); 64 mutex_unlock(&lp->xfer_lock); 65 66 return ret; 67 } 68 69 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) 70 { 71 u8 start, end; 72 73 switch (lp->chip_id) { 74 case LP8550: 75 case LP8551: 76 case LP8552: 77 case LP8553: 78 start = EEPROM_START; 79 end = EEPROM_END; 80 break; 81 case LP8556: 82 start = EPROM_START; 83 end = EPROM_END; 84 break; 85 default: 86 return false; 87 } 88 89 return (addr >= start && addr <= end); 90 } 91 92 static int lp855x_init_registers(struct lp855x *lp) 93 { 94 u8 val, addr; 95 int i, ret; 96 struct lp855x_platform_data *pd = lp->pdata; 97 98 val = pd->initial_brightness; 99 ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); 100 if (ret) 101 return ret; 102 103 val = pd->device_control; 104 ret = lp855x_write_byte(lp, DEVICE_CTRL, val); 105 if (ret) 106 return ret; 107 108 if (pd->load_new_rom_data && pd->size_program) { 109 for (i = 0; i < pd->size_program; i++) { 110 addr = pd->rom_data[i].addr; 111 val = pd->rom_data[i].val; 112 if (!lp855x_is_valid_rom_area(lp, addr)) 113 continue; 114 115 ret = lp855x_write_byte(lp, addr, val); 116 if (ret) 117 return ret; 118 } 119 } 120 121 return ret; 122 } 123 124 static int lp855x_bl_update_status(struct backlight_device *bl) 125 { 126 struct lp855x *lp = bl_get_data(bl); 127 enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; 128 129 if (bl->props.state & BL_CORE_SUSPENDED) 130 bl->props.brightness = 0; 131 132 if (mode == PWM_BASED) { 133 struct lp855x_pwm_data *pd = &lp->pdata->pwm_data; 134 int br = bl->props.brightness; 135 int max_br = bl->props.max_brightness; 136 137 if (pd->pwm_set_intensity) 138 pd->pwm_set_intensity(br, max_br); 139 140 } else if (mode == REGISTER_BASED) { 141 u8 val = bl->props.brightness; 142 lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); 143 } 144 145 return 0; 146 } 147 148 static int lp855x_bl_get_brightness(struct backlight_device *bl) 149 { 150 struct lp855x *lp = bl_get_data(bl); 151 enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; 152 153 if (mode == PWM_BASED) { 154 struct lp855x_pwm_data *pd = &lp->pdata->pwm_data; 155 int max_br = bl->props.max_brightness; 156 157 if (pd->pwm_get_intensity) 158 bl->props.brightness = pd->pwm_get_intensity(max_br); 159 160 } else if (mode == REGISTER_BASED) { 161 u8 val = 0; 162 163 lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val); 164 bl->props.brightness = val; 165 } 166 167 return bl->props.brightness; 168 } 169 170 static const struct backlight_ops lp855x_bl_ops = { 171 .options = BL_CORE_SUSPENDRESUME, 172 .update_status = lp855x_bl_update_status, 173 .get_brightness = lp855x_bl_get_brightness, 174 }; 175 176 static int lp855x_backlight_register(struct lp855x *lp) 177 { 178 struct backlight_device *bl; 179 struct backlight_properties props; 180 struct lp855x_platform_data *pdata = lp->pdata; 181 char *name = pdata->name ? : DEFAULT_BL_NAME; 182 183 props.type = BACKLIGHT_PLATFORM; 184 props.max_brightness = MAX_BRIGHTNESS; 185 186 if (pdata->initial_brightness > props.max_brightness) 187 pdata->initial_brightness = props.max_brightness; 188 189 props.brightness = pdata->initial_brightness; 190 191 bl = backlight_device_register(name, lp->dev, lp, 192 &lp855x_bl_ops, &props); 193 if (IS_ERR(bl)) 194 return PTR_ERR(bl); 195 196 lp->bl = bl; 197 198 return 0; 199 } 200 201 static void lp855x_backlight_unregister(struct lp855x *lp) 202 { 203 if (lp->bl) 204 backlight_device_unregister(lp->bl); 205 } 206 207 static ssize_t lp855x_get_chip_id(struct device *dev, 208 struct device_attribute *attr, char *buf) 209 { 210 struct lp855x *lp = dev_get_drvdata(dev); 211 return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname); 212 } 213 214 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 215 struct device_attribute *attr, char *buf) 216 { 217 struct lp855x *lp = dev_get_drvdata(dev); 218 enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; 219 char *strmode = NULL; 220 221 if (mode == PWM_BASED) 222 strmode = "pwm based"; 223 else if (mode == REGISTER_BASED) 224 strmode = "register based"; 225 226 return scnprintf(buf, BUF_SIZE, "%s\n", strmode); 227 } 228 229 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 230 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 231 232 static struct attribute *lp855x_attributes[] = { 233 &dev_attr_chip_id.attr, 234 &dev_attr_bl_ctl_mode.attr, 235 NULL, 236 }; 237 238 static const struct attribute_group lp855x_attr_group = { 239 .attrs = lp855x_attributes, 240 }; 241 242 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) 243 { 244 struct lp855x *lp; 245 struct lp855x_platform_data *pdata = cl->dev.platform_data; 246 enum lp855x_brightness_ctrl_mode mode; 247 int ret; 248 249 if (!pdata) { 250 dev_err(&cl->dev, "no platform data supplied\n"); 251 return -EINVAL; 252 } 253 254 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 255 return -EIO; 256 257 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 258 if (!lp) 259 return -ENOMEM; 260 261 mode = pdata->mode; 262 lp->client = cl; 263 lp->dev = &cl->dev; 264 lp->pdata = pdata; 265 lp->chipname = id->name; 266 lp->chip_id = id->driver_data; 267 i2c_set_clientdata(cl, lp); 268 269 mutex_init(&lp->xfer_lock); 270 271 ret = lp855x_init_registers(lp); 272 if (ret) { 273 dev_err(lp->dev, "i2c communication err: %d", ret); 274 if (mode == REGISTER_BASED) 275 goto err_dev; 276 } 277 278 ret = lp855x_backlight_register(lp); 279 if (ret) { 280 dev_err(lp->dev, 281 "failed to register backlight. err: %d\n", ret); 282 goto err_dev; 283 } 284 285 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 286 if (ret) { 287 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 288 goto err_sysfs; 289 } 290 291 backlight_update_status(lp->bl); 292 return 0; 293 294 err_sysfs: 295 lp855x_backlight_unregister(lp); 296 err_dev: 297 return ret; 298 } 299 300 static int __devexit lp855x_remove(struct i2c_client *cl) 301 { 302 struct lp855x *lp = i2c_get_clientdata(cl); 303 304 lp->bl->props.brightness = 0; 305 backlight_update_status(lp->bl); 306 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 307 lp855x_backlight_unregister(lp); 308 309 return 0; 310 } 311 312 static const struct i2c_device_id lp855x_ids[] = { 313 {"lp8550", LP8550}, 314 {"lp8551", LP8551}, 315 {"lp8552", LP8552}, 316 {"lp8553", LP8553}, 317 {"lp8556", LP8556}, 318 { } 319 }; 320 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 321 322 static struct i2c_driver lp855x_driver = { 323 .driver = { 324 .name = "lp855x", 325 }, 326 .probe = lp855x_probe, 327 .remove = __devexit_p(lp855x_remove), 328 .id_table = lp855x_ids, 329 }; 330 331 module_i2c_driver(lp855x_driver); 332 333 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 334 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 335 MODULE_LICENSE("GPL"); 336