Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 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> |
Kim, Milo | f7f9505 | 2012-07-30 14:40:53 -0700 | [diff] [blame] | 17 | #include <linux/platform_data/lp855x.h> |
Kim, Milo | 8cc9764 | 2012-12-17 16:00:43 -0800 | [diff] [blame^] | 18 | #include <linux/pwm.h> |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 19 | |
| 20 | /* Registers */ |
Kim, Milo | a1fcb2e | 2012-07-30 14:40:50 -0700 | [diff] [blame] | 21 | #define BRIGHTNESS_CTRL 0x00 |
| 22 | #define DEVICE_CTRL 0x01 |
| 23 | #define EEPROM_START 0xA0 |
| 24 | #define EEPROM_END 0xA7 |
| 25 | #define EPROM_START 0xA0 |
| 26 | #define EPROM_END 0xAF |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 27 | |
| 28 | #define BUF_SIZE 20 |
| 29 | #define DEFAULT_BL_NAME "lcd-backlight" |
| 30 | #define MAX_BRIGHTNESS 255 |
| 31 | |
| 32 | struct lp855x { |
| 33 | const char *chipname; |
| 34 | enum lp855x_chip_id chip_id; |
| 35 | struct i2c_client *client; |
| 36 | struct backlight_device *bl; |
| 37 | struct device *dev; |
| 38 | struct mutex xfer_lock; |
| 39 | struct lp855x_platform_data *pdata; |
Kim, Milo | 8cc9764 | 2012-12-17 16:00:43 -0800 | [diff] [blame^] | 40 | struct pwm_device *pwm; |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 41 | }; |
| 42 | |
| 43 | static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data) |
| 44 | { |
| 45 | int ret; |
| 46 | |
| 47 | mutex_lock(&lp->xfer_lock); |
| 48 | ret = i2c_smbus_read_byte_data(lp->client, reg); |
| 49 | if (ret < 0) { |
| 50 | mutex_unlock(&lp->xfer_lock); |
| 51 | dev_err(lp->dev, "failed to read 0x%.2x\n", reg); |
| 52 | return ret; |
| 53 | } |
| 54 | mutex_unlock(&lp->xfer_lock); |
| 55 | |
| 56 | *data = (u8)ret; |
| 57 | return 0; |
| 58 | } |
| 59 | |
| 60 | static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) |
| 61 | { |
| 62 | int ret; |
| 63 | |
| 64 | mutex_lock(&lp->xfer_lock); |
| 65 | ret = i2c_smbus_write_byte_data(lp->client, reg, data); |
| 66 | mutex_unlock(&lp->xfer_lock); |
| 67 | |
| 68 | return ret; |
| 69 | } |
| 70 | |
| 71 | static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) |
| 72 | { |
| 73 | u8 start, end; |
| 74 | |
| 75 | switch (lp->chip_id) { |
| 76 | case LP8550: |
| 77 | case LP8551: |
| 78 | case LP8552: |
| 79 | case LP8553: |
| 80 | start = EEPROM_START; |
| 81 | end = EEPROM_END; |
| 82 | break; |
| 83 | case LP8556: |
| 84 | start = EPROM_START; |
| 85 | end = EPROM_END; |
| 86 | break; |
| 87 | default: |
| 88 | return false; |
| 89 | } |
| 90 | |
| 91 | return (addr >= start && addr <= end); |
| 92 | } |
| 93 | |
| 94 | static int lp855x_init_registers(struct lp855x *lp) |
| 95 | { |
| 96 | u8 val, addr; |
| 97 | int i, ret; |
| 98 | struct lp855x_platform_data *pd = lp->pdata; |
| 99 | |
| 100 | val = pd->initial_brightness; |
| 101 | ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); |
| 102 | if (ret) |
| 103 | return ret; |
| 104 | |
| 105 | val = pd->device_control; |
| 106 | ret = lp855x_write_byte(lp, DEVICE_CTRL, val); |
| 107 | if (ret) |
| 108 | return ret; |
| 109 | |
| 110 | if (pd->load_new_rom_data && pd->size_program) { |
| 111 | for (i = 0; i < pd->size_program; i++) { |
| 112 | addr = pd->rom_data[i].addr; |
| 113 | val = pd->rom_data[i].val; |
| 114 | if (!lp855x_is_valid_rom_area(lp, addr)) |
| 115 | continue; |
| 116 | |
| 117 | ret = lp855x_write_byte(lp, addr, val); |
| 118 | if (ret) |
| 119 | return ret; |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | return ret; |
| 124 | } |
| 125 | |
Kim, Milo | 8cc9764 | 2012-12-17 16:00:43 -0800 | [diff] [blame^] | 126 | static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) |
| 127 | { |
| 128 | unsigned int period = lp->pdata->period_ns; |
| 129 | unsigned int duty = br * period / max_br; |
| 130 | struct pwm_device *pwm; |
| 131 | |
| 132 | /* request pwm device with the consumer name */ |
| 133 | if (!lp->pwm) { |
| 134 | pwm = devm_pwm_get(lp->dev, lp->chipname); |
| 135 | if (IS_ERR(pwm)) |
| 136 | return; |
| 137 | |
| 138 | lp->pwm = pwm; |
| 139 | } |
| 140 | |
| 141 | pwm_config(lp->pwm, duty, period); |
| 142 | if (duty) |
| 143 | pwm_enable(lp->pwm); |
| 144 | else |
| 145 | pwm_disable(lp->pwm); |
| 146 | } |
| 147 | |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 148 | static int lp855x_bl_update_status(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 (bl->props.state & BL_CORE_SUSPENDED) |
| 154 | bl->props.brightness = 0; |
| 155 | |
| 156 | if (mode == PWM_BASED) { |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 157 | int br = bl->props.brightness; |
| 158 | int max_br = bl->props.max_brightness; |
| 159 | |
Kim, Milo | 8cc9764 | 2012-12-17 16:00:43 -0800 | [diff] [blame^] | 160 | lp855x_pwm_ctrl(lp, br, max_br); |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 161 | |
| 162 | } else if (mode == REGISTER_BASED) { |
| 163 | u8 val = bl->props.brightness; |
| 164 | lp855x_write_byte(lp, BRIGHTNESS_CTRL, val); |
| 165 | } |
| 166 | |
| 167 | return 0; |
| 168 | } |
| 169 | |
| 170 | static int lp855x_bl_get_brightness(struct backlight_device *bl) |
| 171 | { |
| 172 | struct lp855x *lp = bl_get_data(bl); |
| 173 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; |
| 174 | |
Kim, Milo | 8cc9764 | 2012-12-17 16:00:43 -0800 | [diff] [blame^] | 175 | if (mode == REGISTER_BASED) { |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 176 | u8 val = 0; |
| 177 | |
| 178 | lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val); |
| 179 | bl->props.brightness = val; |
| 180 | } |
| 181 | |
| 182 | return bl->props.brightness; |
| 183 | } |
| 184 | |
| 185 | static const struct backlight_ops lp855x_bl_ops = { |
| 186 | .options = BL_CORE_SUSPENDRESUME, |
| 187 | .update_status = lp855x_bl_update_status, |
| 188 | .get_brightness = lp855x_bl_get_brightness, |
| 189 | }; |
| 190 | |
| 191 | static int lp855x_backlight_register(struct lp855x *lp) |
| 192 | { |
| 193 | struct backlight_device *bl; |
| 194 | struct backlight_properties props; |
| 195 | struct lp855x_platform_data *pdata = lp->pdata; |
| 196 | char *name = pdata->name ? : DEFAULT_BL_NAME; |
| 197 | |
| 198 | props.type = BACKLIGHT_PLATFORM; |
| 199 | props.max_brightness = MAX_BRIGHTNESS; |
| 200 | |
| 201 | if (pdata->initial_brightness > props.max_brightness) |
| 202 | pdata->initial_brightness = props.max_brightness; |
| 203 | |
| 204 | props.brightness = pdata->initial_brightness; |
| 205 | |
| 206 | bl = backlight_device_register(name, lp->dev, lp, |
| 207 | &lp855x_bl_ops, &props); |
| 208 | if (IS_ERR(bl)) |
| 209 | return PTR_ERR(bl); |
| 210 | |
| 211 | lp->bl = bl; |
| 212 | |
| 213 | return 0; |
| 214 | } |
| 215 | |
| 216 | static void lp855x_backlight_unregister(struct lp855x *lp) |
| 217 | { |
| 218 | if (lp->bl) |
| 219 | backlight_device_unregister(lp->bl); |
| 220 | } |
| 221 | |
| 222 | static ssize_t lp855x_get_chip_id(struct device *dev, |
| 223 | struct device_attribute *attr, char *buf) |
| 224 | { |
| 225 | struct lp855x *lp = dev_get_drvdata(dev); |
| 226 | return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname); |
| 227 | } |
| 228 | |
| 229 | static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, |
| 230 | struct device_attribute *attr, char *buf) |
| 231 | { |
| 232 | struct lp855x *lp = dev_get_drvdata(dev); |
| 233 | enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode; |
| 234 | char *strmode = NULL; |
| 235 | |
| 236 | if (mode == PWM_BASED) |
| 237 | strmode = "pwm based"; |
| 238 | else if (mode == REGISTER_BASED) |
| 239 | strmode = "register based"; |
| 240 | |
| 241 | return scnprintf(buf, BUF_SIZE, "%s\n", strmode); |
| 242 | } |
| 243 | |
| 244 | static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); |
| 245 | static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); |
| 246 | |
| 247 | static struct attribute *lp855x_attributes[] = { |
| 248 | &dev_attr_chip_id.attr, |
| 249 | &dev_attr_bl_ctl_mode.attr, |
| 250 | NULL, |
| 251 | }; |
| 252 | |
| 253 | static const struct attribute_group lp855x_attr_group = { |
| 254 | .attrs = lp855x_attributes, |
| 255 | }; |
| 256 | |
| 257 | static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) |
| 258 | { |
| 259 | struct lp855x *lp; |
| 260 | struct lp855x_platform_data *pdata = cl->dev.platform_data; |
| 261 | enum lp855x_brightness_ctrl_mode mode; |
| 262 | int ret; |
| 263 | |
| 264 | if (!pdata) { |
| 265 | dev_err(&cl->dev, "no platform data supplied\n"); |
| 266 | return -EINVAL; |
| 267 | } |
| 268 | |
| 269 | if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) |
| 270 | return -EIO; |
| 271 | |
| 272 | lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); |
| 273 | if (!lp) |
| 274 | return -ENOMEM; |
| 275 | |
| 276 | mode = pdata->mode; |
| 277 | lp->client = cl; |
| 278 | lp->dev = &cl->dev; |
| 279 | lp->pdata = pdata; |
| 280 | lp->chipname = id->name; |
| 281 | lp->chip_id = id->driver_data; |
| 282 | i2c_set_clientdata(cl, lp); |
| 283 | |
| 284 | mutex_init(&lp->xfer_lock); |
| 285 | |
| 286 | ret = lp855x_init_registers(lp); |
| 287 | if (ret) { |
| 288 | dev_err(lp->dev, "i2c communication err: %d", ret); |
| 289 | if (mode == REGISTER_BASED) |
| 290 | goto err_dev; |
| 291 | } |
| 292 | |
| 293 | ret = lp855x_backlight_register(lp); |
| 294 | if (ret) { |
| 295 | dev_err(lp->dev, |
| 296 | "failed to register backlight. err: %d\n", ret); |
| 297 | goto err_dev; |
| 298 | } |
| 299 | |
| 300 | ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); |
| 301 | if (ret) { |
| 302 | dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); |
| 303 | goto err_sysfs; |
| 304 | } |
| 305 | |
| 306 | backlight_update_status(lp->bl); |
| 307 | return 0; |
| 308 | |
| 309 | err_sysfs: |
| 310 | lp855x_backlight_unregister(lp); |
| 311 | err_dev: |
| 312 | return ret; |
| 313 | } |
| 314 | |
Bill Pemberton | 7e4b9d0 | 2012-11-19 13:26:34 -0500 | [diff] [blame] | 315 | static int lp855x_remove(struct i2c_client *cl) |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 316 | { |
| 317 | struct lp855x *lp = i2c_get_clientdata(cl); |
| 318 | |
| 319 | lp->bl->props.brightness = 0; |
| 320 | backlight_update_status(lp->bl); |
| 321 | sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); |
| 322 | lp855x_backlight_unregister(lp); |
| 323 | |
| 324 | return 0; |
| 325 | } |
| 326 | |
| 327 | static const struct i2c_device_id lp855x_ids[] = { |
| 328 | {"lp8550", LP8550}, |
| 329 | {"lp8551", LP8551}, |
| 330 | {"lp8552", LP8552}, |
| 331 | {"lp8553", LP8553}, |
| 332 | {"lp8556", LP8556}, |
| 333 | { } |
| 334 | }; |
| 335 | MODULE_DEVICE_TABLE(i2c, lp855x_ids); |
| 336 | |
| 337 | static struct i2c_driver lp855x_driver = { |
| 338 | .driver = { |
| 339 | .name = "lp855x", |
| 340 | }, |
| 341 | .probe = lp855x_probe, |
Bill Pemberton | d1723fa | 2012-11-19 13:21:09 -0500 | [diff] [blame] | 342 | .remove = lp855x_remove, |
Kim, Milo | 7be865a | 2012-03-23 15:02:01 -0700 | [diff] [blame] | 343 | .id_table = lp855x_ids, |
| 344 | }; |
| 345 | |
| 346 | module_i2c_driver(lp855x_driver); |
| 347 | |
| 348 | MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); |
| 349 | MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); |
| 350 | MODULE_LICENSE("GPL"); |