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