1 /* 2 * Backlight driver for ArcticSand ARC_X_C_0N_0N Devices 3 * 4 * Copyright 2016 ArcticSand, Inc. 5 * Author : Brian Dodge <bdodge@arcticsand.com> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 9 * as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be useful, but 12 * WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License along 17 * with this program; if not, see <http://www.gnu.org/licenses/>. 18 */ 19 20 #include <linux/backlight.h> 21 #include <linux/err.h> 22 #include <linux/i2c.h> 23 #include <linux/module.h> 24 #include <linux/of.h> 25 #include <linux/slab.h> 26 27 enum arcxcnn_chip_id { 28 ARC2C0608 29 }; 30 31 /** 32 * struct arcxcnn_platform_data 33 * @name : Backlight driver name (NULL will use default) 34 * @initial_brightness : initial value of backlight brightness 35 * @leden : initial LED string enables, upper bit is global on/off 36 * @led_config_0 : fading speed (period between intensity steps) 37 * @led_config_1 : misc settings, see datasheet 38 * @dim_freq : pwm dimming frequency if in pwm mode 39 * @comp_config : misc config, see datasheet 40 * @filter_config : RC/PWM filter config, see datasheet 41 * @trim_config : full scale current trim, see datasheet 42 */ 43 struct arcxcnn_platform_data { 44 const char *name; 45 u16 initial_brightness; 46 u8 leden; 47 u8 led_config_0; 48 u8 led_config_1; 49 u8 dim_freq; 50 u8 comp_config; 51 u8 filter_config; 52 u8 trim_config; 53 }; 54 55 #define ARCXCNN_CMD 0x00 /* Command Register */ 56 #define ARCXCNN_CMD_STDBY 0x80 /* I2C Standby */ 57 #define ARCXCNN_CMD_RESET 0x40 /* Reset */ 58 #define ARCXCNN_CMD_BOOST 0x10 /* Boost */ 59 #define ARCXCNN_CMD_OVP_MASK 0x0C /* --- Over Voltage Threshold */ 60 #define ARCXCNN_CMD_OVP_XXV 0x0C /* <rsvrd> Over Voltage Threshold */ 61 #define ARCXCNN_CMD_OVP_20V 0x08 /* 20v Over Voltage Threshold */ 62 #define ARCXCNN_CMD_OVP_24V 0x04 /* 24v Over Voltage Threshold */ 63 #define ARCXCNN_CMD_OVP_31V 0x00 /* 31.4v Over Voltage Threshold */ 64 #define ARCXCNN_CMD_EXT_COMP 0x01 /* part (0) or full (1) ext. comp */ 65 66 #define ARCXCNN_CONFIG 0x01 /* Configuration */ 67 #define ARCXCNN_STATUS1 0x02 /* Status 1 */ 68 #define ARCXCNN_STATUS2 0x03 /* Status 2 */ 69 #define ARCXCNN_FADECTRL 0x04 /* Fading Control */ 70 #define ARCXCNN_ILED_CONFIG 0x05 /* ILED Configuration */ 71 #define ARCXCNN_ILED_DIM_PWM 0x00 /* config dim mode pwm */ 72 #define ARCXCNN_ILED_DIM_INT 0x04 /* config dim mode internal */ 73 #define ARCXCNN_LEDEN 0x06 /* LED Enable Register */ 74 #define ARCXCNN_LEDEN_ISETEXT 0x80 /* Full-scale current set extern */ 75 #define ARCXCNN_LEDEN_MASK 0x3F /* LED string enables mask */ 76 #define ARCXCNN_LEDEN_BITS 0x06 /* Bits of LED string enables */ 77 #define ARCXCNN_LEDEN_LED1 0x01 78 #define ARCXCNN_LEDEN_LED2 0x02 79 #define ARCXCNN_LEDEN_LED3 0x04 80 #define ARCXCNN_LEDEN_LED4 0x08 81 #define ARCXCNN_LEDEN_LED5 0x10 82 #define ARCXCNN_LEDEN_LED6 0x20 83 84 #define ARCXCNN_WLED_ISET_LSB 0x07 /* LED ISET LSB (in upper nibble) */ 85 #define ARCXCNN_WLED_ISET_LSB_SHIFT 0x04 /* ISET LSB Left Shift */ 86 #define ARCXCNN_WLED_ISET_MSB 0x08 /* LED ISET MSB (8 bits) */ 87 88 #define ARCXCNN_DIMFREQ 0x09 89 #define ARCXCNN_COMP_CONFIG 0x0A 90 #define ARCXCNN_FILT_CONFIG 0x0B 91 #define ARCXCNN_IMAXTUNE 0x0C 92 #define ARCXCNN_ID_MSB 0x1E 93 #define ARCXCNN_ID_LSB 0x1F 94 95 #define MAX_BRIGHTNESS 4095 96 #define INIT_BRIGHT 60 97 98 struct arcxcnn { 99 struct i2c_client *client; 100 struct backlight_device *bl; 101 struct device *dev; 102 struct arcxcnn_platform_data *pdata; 103 }; 104 105 static int arcxcnn_update_field(struct arcxcnn *lp, u8 reg, u8 mask, u8 data) 106 { 107 int ret; 108 u8 tmp; 109 110 ret = i2c_smbus_read_byte_data(lp->client, reg); 111 if (ret < 0) { 112 dev_err(lp->dev, "failed to read 0x%.2x\n", reg); 113 return ret; 114 } 115 116 tmp = (u8)ret; 117 tmp &= ~mask; 118 tmp |= data & mask; 119 120 return i2c_smbus_write_byte_data(lp->client, reg, tmp); 121 } 122 123 static int arcxcnn_set_brightness(struct arcxcnn *lp, u32 brightness) 124 { 125 int ret; 126 u8 val; 127 128 /* lower nibble of brightness goes in upper nibble of LSB register */ 129 val = (brightness & 0xF) << ARCXCNN_WLED_ISET_LSB_SHIFT; 130 ret = i2c_smbus_write_byte_data(lp->client, 131 ARCXCNN_WLED_ISET_LSB, val); 132 if (ret < 0) 133 return ret; 134 135 /* remaining 8 bits of brightness go in MSB register */ 136 val = (brightness >> 4); 137 return i2c_smbus_write_byte_data(lp->client, 138 ARCXCNN_WLED_ISET_MSB, val); 139 } 140 141 static int arcxcnn_bl_update_status(struct backlight_device *bl) 142 { 143 struct arcxcnn *lp = bl_get_data(bl); 144 u32 brightness = bl->props.brightness; 145 int ret; 146 147 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) 148 brightness = 0; 149 150 ret = arcxcnn_set_brightness(lp, brightness); 151 if (ret) 152 return ret; 153 154 /* set power-on/off/save modes */ 155 return arcxcnn_update_field(lp, ARCXCNN_CMD, ARCXCNN_CMD_STDBY, 156 (bl->props.power == 0) ? 0 : ARCXCNN_CMD_STDBY); 157 } 158 159 static const struct backlight_ops arcxcnn_bl_ops = { 160 .options = BL_CORE_SUSPENDRESUME, 161 .update_status = arcxcnn_bl_update_status, 162 }; 163 164 static int arcxcnn_backlight_register(struct arcxcnn *lp) 165 { 166 struct backlight_properties *props; 167 const char *name = lp->pdata->name ? : "arctic_bl"; 168 169 props = devm_kzalloc(lp->dev, sizeof(*props), GFP_KERNEL); 170 if (!props) 171 return -ENOMEM; 172 173 props->type = BACKLIGHT_PLATFORM; 174 props->max_brightness = MAX_BRIGHTNESS; 175 176 if (lp->pdata->initial_brightness > props->max_brightness) 177 lp->pdata->initial_brightness = props->max_brightness; 178 179 props->brightness = lp->pdata->initial_brightness; 180 181 lp->bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, 182 &arcxcnn_bl_ops, props); 183 return PTR_ERR_OR_ZERO(lp->bl); 184 } 185 186 static void arcxcnn_parse_dt(struct arcxcnn *lp) 187 { 188 struct device *dev = lp->dev; 189 struct device_node *node = dev->of_node; 190 u32 prog_val, num_entry, entry, sources[ARCXCNN_LEDEN_BITS]; 191 int ret; 192 193 /* device tree entry isn't required, defaults are OK */ 194 if (!node) 195 return; 196 197 ret = of_property_read_string(node, "label", &lp->pdata->name); 198 if (ret < 0) 199 lp->pdata->name = NULL; 200 201 ret = of_property_read_u32(node, "default-brightness", &prog_val); 202 if (ret == 0) 203 lp->pdata->initial_brightness = prog_val; 204 205 ret = of_property_read_u32(node, "arc,led-config-0", &prog_val); 206 if (ret == 0) 207 lp->pdata->led_config_0 = (u8)prog_val; 208 209 ret = of_property_read_u32(node, "arc,led-config-1", &prog_val); 210 if (ret == 0) 211 lp->pdata->led_config_1 = (u8)prog_val; 212 213 ret = of_property_read_u32(node, "arc,dim-freq", &prog_val); 214 if (ret == 0) 215 lp->pdata->dim_freq = (u8)prog_val; 216 217 ret = of_property_read_u32(node, "arc,comp-config", &prog_val); 218 if (ret == 0) 219 lp->pdata->comp_config = (u8)prog_val; 220 221 ret = of_property_read_u32(node, "arc,filter-config", &prog_val); 222 if (ret == 0) 223 lp->pdata->filter_config = (u8)prog_val; 224 225 ret = of_property_read_u32(node, "arc,trim-config", &prog_val); 226 if (ret == 0) 227 lp->pdata->trim_config = (u8)prog_val; 228 229 ret = of_property_count_u32_elems(node, "led-sources"); 230 if (ret < 0) { 231 lp->pdata->leden = ARCXCNN_LEDEN_MASK; /* all on is default */ 232 } else { 233 num_entry = ret; 234 if (num_entry > ARCXCNN_LEDEN_BITS) 235 num_entry = ARCXCNN_LEDEN_BITS; 236 237 ret = of_property_read_u32_array(node, "led-sources", sources, 238 num_entry); 239 if (ret < 0) { 240 dev_err(dev, "led-sources node is invalid.\n"); 241 return; 242 } 243 244 lp->pdata->leden = 0; 245 246 /* for each enable in source, set bit in led enable */ 247 for (entry = 0; entry < num_entry; entry++) { 248 u8 onbit = 1 << sources[entry]; 249 250 lp->pdata->leden |= onbit; 251 } 252 } 253 } 254 255 static int arcxcnn_probe(struct i2c_client *cl, const struct i2c_device_id *id) 256 { 257 struct arcxcnn *lp; 258 int ret; 259 260 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 261 return -EIO; 262 263 lp = devm_kzalloc(&cl->dev, sizeof(*lp), GFP_KERNEL); 264 if (!lp) 265 return -ENOMEM; 266 267 lp->client = cl; 268 lp->dev = &cl->dev; 269 lp->pdata = dev_get_platdata(&cl->dev); 270 271 /* reset the device */ 272 ret = i2c_smbus_write_byte_data(lp->client, 273 ARCXCNN_CMD, ARCXCNN_CMD_RESET); 274 if (ret) 275 goto probe_err; 276 277 if (!lp->pdata) { 278 lp->pdata = devm_kzalloc(lp->dev, 279 sizeof(*lp->pdata), GFP_KERNEL); 280 if (!lp->pdata) 281 return -ENOMEM; 282 283 /* Setup defaults based on power-on defaults */ 284 lp->pdata->name = NULL; 285 lp->pdata->initial_brightness = INIT_BRIGHT; 286 lp->pdata->leden = ARCXCNN_LEDEN_MASK; 287 288 lp->pdata->led_config_0 = i2c_smbus_read_byte_data( 289 lp->client, ARCXCNN_FADECTRL); 290 291 lp->pdata->led_config_1 = i2c_smbus_read_byte_data( 292 lp->client, ARCXCNN_ILED_CONFIG); 293 /* insure dim mode is not default pwm */ 294 lp->pdata->led_config_1 |= ARCXCNN_ILED_DIM_INT; 295 296 lp->pdata->dim_freq = i2c_smbus_read_byte_data( 297 lp->client, ARCXCNN_DIMFREQ); 298 299 lp->pdata->comp_config = i2c_smbus_read_byte_data( 300 lp->client, ARCXCNN_COMP_CONFIG); 301 302 lp->pdata->filter_config = i2c_smbus_read_byte_data( 303 lp->client, ARCXCNN_FILT_CONFIG); 304 305 lp->pdata->trim_config = i2c_smbus_read_byte_data( 306 lp->client, ARCXCNN_IMAXTUNE); 307 308 if (IS_ENABLED(CONFIG_OF)) 309 arcxcnn_parse_dt(lp); 310 } 311 312 i2c_set_clientdata(cl, lp); 313 314 /* constrain settings to what is possible */ 315 if (lp->pdata->initial_brightness > MAX_BRIGHTNESS) 316 lp->pdata->initial_brightness = MAX_BRIGHTNESS; 317 318 /* set initial brightness */ 319 ret = arcxcnn_set_brightness(lp, lp->pdata->initial_brightness); 320 if (ret) 321 goto probe_err; 322 323 /* set other register values directly */ 324 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FADECTRL, 325 lp->pdata->led_config_0); 326 if (ret) 327 goto probe_err; 328 329 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_ILED_CONFIG, 330 lp->pdata->led_config_1); 331 if (ret) 332 goto probe_err; 333 334 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_DIMFREQ, 335 lp->pdata->dim_freq); 336 if (ret) 337 goto probe_err; 338 339 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_COMP_CONFIG, 340 lp->pdata->comp_config); 341 if (ret) 342 goto probe_err; 343 344 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_FILT_CONFIG, 345 lp->pdata->filter_config); 346 if (ret) 347 goto probe_err; 348 349 ret = i2c_smbus_write_byte_data(lp->client, ARCXCNN_IMAXTUNE, 350 lp->pdata->trim_config); 351 if (ret) 352 goto probe_err; 353 354 /* set initial LED Enables */ 355 arcxcnn_update_field(lp, ARCXCNN_LEDEN, 356 ARCXCNN_LEDEN_MASK, lp->pdata->leden); 357 358 ret = arcxcnn_backlight_register(lp); 359 if (ret) 360 goto probe_register_err; 361 362 backlight_update_status(lp->bl); 363 364 return 0; 365 366 probe_register_err: 367 dev_err(lp->dev, 368 "failed to register backlight.\n"); 369 370 probe_err: 371 dev_err(lp->dev, 372 "failure ret: %d\n", ret); 373 return ret; 374 } 375 376 static int arcxcnn_remove(struct i2c_client *cl) 377 { 378 struct arcxcnn *lp = i2c_get_clientdata(cl); 379 380 /* disable all strings (ignore errors) */ 381 i2c_smbus_write_byte_data(lp->client, 382 ARCXCNN_LEDEN, 0x00); 383 /* reset the device (ignore errors) */ 384 i2c_smbus_write_byte_data(lp->client, 385 ARCXCNN_CMD, ARCXCNN_CMD_RESET); 386 387 lp->bl->props.brightness = 0; 388 389 backlight_update_status(lp->bl); 390 391 return 0; 392 } 393 394 static const struct of_device_id arcxcnn_dt_ids[] = { 395 { .compatible = "arc,arc2c0608" }, 396 { } 397 }; 398 MODULE_DEVICE_TABLE(of, arcxcnn_dt_ids); 399 400 static const struct i2c_device_id arcxcnn_ids[] = { 401 {"arc2c0608", ARC2C0608}, 402 { } 403 }; 404 MODULE_DEVICE_TABLE(i2c, arcxcnn_ids); 405 406 static struct i2c_driver arcxcnn_driver = { 407 .driver = { 408 .name = "arcxcnn_bl", 409 .of_match_table = of_match_ptr(arcxcnn_dt_ids), 410 }, 411 .probe = arcxcnn_probe, 412 .remove = arcxcnn_remove, 413 .id_table = arcxcnn_ids, 414 }; 415 module_i2c_driver(arcxcnn_driver); 416 417 MODULE_LICENSE("GPL v2"); 418 MODULE_AUTHOR("Brian Dodge <bdodge@arcticsand.com>"); 419 MODULE_DESCRIPTION("ARCXCNN Backlight driver"); 420