drivers/leds/leds-pm8941-wled.c

   1 /* Copyright (c) 2015, Sony Mobile Communications, AB.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License version 2 and
   5  * only version 2 as published by the Free Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/leds.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/regmap.h>
  19
  20 #define PM8941_WLED_REG_VAL_BASE                0x40
  21 #define  PM8941_WLED_REG_VAL_MAX                0xFFF
  22
  23 #define PM8941_WLED_REG_MOD_EN                  0x46
  24 #define  PM8941_WLED_REG_MOD_EN_BIT             BIT(7)
  25 #define  PM8941_WLED_REG_MOD_EN_MASK            BIT(7)
  26
  27 #define PM8941_WLED_REG_SYNC                    0x47
  28 #define  PM8941_WLED_REG_SYNC_MASK              0x07
  29 #define  PM8941_WLED_REG_SYNC_LED1              BIT(0)
  30 #define  PM8941_WLED_REG_SYNC_LED2              BIT(1)
  31 #define  PM8941_WLED_REG_SYNC_LED3              BIT(2)
  32 #define  PM8941_WLED_REG_SYNC_ALL               0x07
  33 #define  PM8941_WLED_REG_SYNC_CLEAR             0x00
  34
  35 #define PM8941_WLED_REG_FREQ                    0x4c
  36 #define  PM8941_WLED_REG_FREQ_MASK              0x0f
  37
  38 #define PM8941_WLED_REG_OVP                     0x4d
  39 #define  PM8941_WLED_REG_OVP_MASK               0x03
  40
  41 #define PM8941_WLED_REG_BOOST                   0x4e
  42 #define  PM8941_WLED_REG_BOOST_MASK             0x07
  43
  44 #define PM8941_WLED_REG_SINK                    0x4f
  45 #define  PM8941_WLED_REG_SINK_MASK              0xe0
  46 #define  PM8941_WLED_REG_SINK_SHFT              0x05
  47
  48 /* Per-'string' registers below */
  49 #define PM8941_WLED_REG_STR_OFFSET              0x10
  50
  51 #define PM8941_WLED_REG_STR_MOD_EN_BASE         0x60
  52 #define  PM8941_WLED_REG_STR_MOD_MASK           BIT(7)
  53 #define  PM8941_WLED_REG_STR_MOD_EN             BIT(7)
  54
  55 #define PM8941_WLED_REG_STR_SCALE_BASE          0x62
  56 #define  PM8941_WLED_REG_STR_SCALE_MASK         0x1f
  57
  58 #define PM8941_WLED_REG_STR_MOD_SRC_BASE        0x63
  59 #define  PM8941_WLED_REG_STR_MOD_SRC_MASK       0x01
  60 #define  PM8941_WLED_REG_STR_MOD_SRC_INT        0x00
  61 #define  PM8941_WLED_REG_STR_MOD_SRC_EXT        0x01
  62
  63 #define PM8941_WLED_REG_STR_CABC_BASE           0x66
  64 #define  PM8941_WLED_REG_STR_CABC_MASK          BIT(7)
  65 #define  PM8941_WLED_REG_STR_CABC_EN            BIT(7)
  66
  67 struct pm8941_wled_config {
  68         u32 i_boost_limit;
  69         u32 ovp;
  70         u32 switch_freq;
  71         u32 num_strings;
  72         u32 i_limit;
  73         bool cs_out_en;
  74         bool ext_gen;
  75         bool cabc_en;
  76 };
  77
  78 struct pm8941_wled {
  79         struct regmap *regmap;
  80         u16 addr;
  81
  82         struct led_classdev cdev;
  83
  84         struct pm8941_wled_config cfg;
  85 };
  86
  87 static int pm8941_wled_set(struct led_classdev *cdev,
  88                            enum led_brightness value)
  89 {
  90         struct pm8941_wled *wled;
  91         u8 ctrl = 0;
  92         u16 val;
  93         int rc;
  94         int i;
  95
  96         wled = container_of(cdev, struct pm8941_wled, cdev);
  97
  98         if (value != 0)
  99                 ctrl = PM8941_WLED_REG_MOD_EN_BIT;
 100
 101         val = value * PM8941_WLED_REG_VAL_MAX / LED_FULL;
 102
 103         rc = regmap_update_bits(wled->regmap,
 104                         wled->addr + PM8941_WLED_REG_MOD_EN,
 105                         PM8941_WLED_REG_MOD_EN_MASK, ctrl);
 106         if (rc)
 107                 return rc;
 108
 109         for (i = 0; i < wled->cfg.num_strings; ++i) {
 110                 u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
 111
 112                 rc = regmap_bulk_write(wled->regmap,
 113                                 wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
 114                                 v, 2);
 115                 if (rc)
 116                         return rc;
 117         }
 118
 119         rc = regmap_update_bits(wled->regmap,
 120                         wled->addr + PM8941_WLED_REG_SYNC,
 121                         PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
 122         if (rc)
 123                 return rc;
 124
 125         rc = regmap_update_bits(wled->regmap,
 126                         wled->addr + PM8941_WLED_REG_SYNC,
 127                         PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
 128         return rc;
 129 }
 130
 131 static void pm8941_wled_set_brightness(struct led_classdev *cdev,
 132                                        enum led_brightness value)
 133 {
 134         if (pm8941_wled_set(cdev, value)) {
 135                 dev_err(cdev->dev, "Unable to set brightness\n");
 136                 return;
 137         }
 138         cdev->brightness = value;
 139 }
 140
 141 static int pm8941_wled_setup(struct pm8941_wled *wled)
 142 {
 143         int rc;
 144         int i;
 145
 146         rc = regmap_update_bits(wled->regmap,
 147                         wled->addr + PM8941_WLED_REG_OVP,
 148                         PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
 149         if (rc)
 150                 return rc;
 151
 152         rc = regmap_update_bits(wled->regmap,
 153                         wled->addr + PM8941_WLED_REG_BOOST,
 154                         PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
 155         if (rc)
 156                 return rc;
 157
 158         rc = regmap_update_bits(wled->regmap,
 159                         wled->addr + PM8941_WLED_REG_FREQ,
 160                         PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
 161         if (rc)
 162                 return rc;
 163
 164         if (wled->cfg.cs_out_en) {
 165                 u8 all = (BIT(wled->cfg.num_strings) - 1)
 166                                 << PM8941_WLED_REG_SINK_SHFT;
 167
 168                 rc = regmap_update_bits(wled->regmap,
 169                                 wled->addr + PM8941_WLED_REG_SINK,
 170                                 PM8941_WLED_REG_SINK_MASK, all);
 171                 if (rc)
 172                         return rc;
 173         }
 174
 175         for (i = 0; i < wled->cfg.num_strings; ++i) {
 176                 u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
 177
 178                 rc = regmap_update_bits(wled->regmap,
 179                                 addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
 180                                 PM8941_WLED_REG_STR_MOD_MASK,
 181                                 PM8941_WLED_REG_STR_MOD_EN);
 182                 if (rc)
 183                         return rc;
 184
 185                 if (wled->cfg.ext_gen) {
 186                         rc = regmap_update_bits(wled->regmap,
 187                                         addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
 188                                         PM8941_WLED_REG_STR_MOD_SRC_MASK,
 189                                         PM8941_WLED_REG_STR_MOD_SRC_EXT);
 190                         if (rc)
 191                                 return rc;
 192                 }
 193
 194                 rc = regmap_update_bits(wled->regmap,
 195                                 addr + PM8941_WLED_REG_STR_SCALE_BASE,
 196                                 PM8941_WLED_REG_STR_SCALE_MASK,
 197                                 wled->cfg.i_limit);
 198                 if (rc)
 199                         return rc;
 200
 201                 rc = regmap_update_bits(wled->regmap,
 202                                 addr + PM8941_WLED_REG_STR_CABC_BASE,
 203                                 PM8941_WLED_REG_STR_CABC_MASK,
 204                                 wled->cfg.cabc_en ?
 205                                         PM8941_WLED_REG_STR_CABC_EN : 0);
 206                 if (rc)
 207                         return rc;
 208         }
 209
 210         return 0;
 211 }
 212
 213 static const struct pm8941_wled_config pm8941_wled_config_defaults = {
 214         .i_boost_limit = 3,
 215         .i_limit = 20,
 216         .ovp = 2,
 217         .switch_freq = 5,
 218         .num_strings = 0,
 219         .cs_out_en = false,
 220         .ext_gen = false,
 221         .cabc_en = false,
 222 };
 223
 224 struct pm8941_wled_var_cfg {
 225         const u32 *values;
 226         u32 (*fn)(u32);
 227         int size;
 228 };
 229
 230 static const u32 pm8941_wled_i_boost_limit_values[] = {
 231         105, 385, 525, 805, 980, 1260, 1400, 1680,
 232 };
 233
 234 static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
 235         .values = pm8941_wled_i_boost_limit_values,
 236         .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
 237 };
 238
 239 static const u32 pm8941_wled_ovp_values[] = {
 240         35, 32, 29, 27,
 241 };
 242
 243 static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
 244         .values = pm8941_wled_ovp_values,
 245         .size = ARRAY_SIZE(pm8941_wled_ovp_values),
 246 };
 247
 248 static u32 pm8941_wled_num_strings_values_fn(u32 idx)
 249 {
 250         return idx + 1;
 251 }
 252
 253 static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
 254         .fn = pm8941_wled_num_strings_values_fn,
 255         .size = 3,
 256 };
 257
 258 static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
 259 {
 260         return 19200 / (2 * (1 + idx));
 261 }
 262
 263 static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
 264         .fn = pm8941_wled_switch_freq_values_fn,
 265         .size = 16,
 266 };
 267
 268 static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
 269         .size = 26,
 270 };
 271
 272 static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
 273 {
 274         if (idx >= cfg->size)
 275                 return UINT_MAX;
 276         if (cfg->fn)
 277                 return cfg->fn(idx);
 278         if (cfg->values)
 279                 return cfg->values[idx];
 280         return idx;
 281 }
 282
 283 static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
 284 {
 285         struct pm8941_wled_config *cfg = &wled->cfg;
 286         u32 val;
 287         int rc;
 288         u32 c;
 289         int i;
 290         int j;
 291
 292         const struct {
 293                 const char *name;
 294                 u32 *val_ptr;
 295                 const struct pm8941_wled_var_cfg *cfg;
 296         } u32_opts[] = {
 297                 {
 298                         "qcom,current-boost-limit",
 299                         &cfg->i_boost_limit,
 300                         .cfg = &pm8941_wled_i_boost_limit_cfg,
 301                 },
 302                 {
 303                         "qcom,current-limit",
 304                         &cfg->i_limit,
 305                         .cfg = &pm8941_wled_i_limit_cfg,
 306                 },
 307                 {
 308                         "qcom,ovp",
 309                         &cfg->ovp,
 310                         .cfg = &pm8941_wled_ovp_cfg,
 311                 },
 312                 {
 313                         "qcom,switching-freq",
 314                         &cfg->switch_freq,
 315                         .cfg = &pm8941_wled_switch_freq_cfg,
 316                 },
 317                 {
 318                         "qcom,num-strings",
 319                         &cfg->num_strings,
 320                         .cfg = &pm8941_wled_num_strings_cfg,
 321                 },
 322         };
 323         const struct {
 324                 const char *name;
 325                 bool *val_ptr;
 326         } bool_opts[] = {
 327                 { "qcom,cs-out", &cfg->cs_out_en, },
 328                 { "qcom,ext-gen", &cfg->ext_gen, },
 329                 { "qcom,cabc", &cfg->cabc_en, },
 330         };
 331
 332         rc = of_property_read_u32(dev->of_node, "reg", &val);
 333         if (rc || val > 0xffff) {
 334                 dev_err(dev, "invalid IO resources\n");
 335                 return rc ? rc : -EINVAL;
 336         }
 337         wled->addr = val;
 338
 339         rc = of_property_read_string(dev->of_node, "label", &wled->cdev.name);
 340         if (rc)
 341                 wled->cdev.name = dev->of_node->name;
 342
 343         wled->cdev.default_trigger = of_get_property(dev->of_node,
 344                         "linux,default-trigger", NULL);
 345
 346         *cfg = pm8941_wled_config_defaults;
 347         for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
 348                 rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
 349                 if (rc == -EINVAL) {
 350                         continue;
 351                 } else if (rc) {
 352                         dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
 353                         return rc;
 354                 }
 355
 356                 c = UINT_MAX;
 357                 for (j = 0; c != val; j++) {
 358                         c = pm8941_wled_values(u32_opts[i].cfg, j);
 359                         if (c == UINT_MAX) {
 360                                 dev_err(dev, "invalid value for '%s'\n",
 361                                         u32_opts[i].name);
 362                                 return -EINVAL;
 363                         }
 364                 }
 365
 366                 dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
 367                 *u32_opts[i].val_ptr = j;
 368         }
 369
 370         for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
 371                 if (of_property_read_bool(dev->of_node, bool_opts[i].name))
 372                         *bool_opts[i].val_ptr = true;
 373         }
 374
 375         cfg->num_strings = cfg->num_strings + 1;
 376
 377         return 0;
 378 }
 379
 380 static int pm8941_wled_probe(struct platform_device *pdev)
 381 {
 382         struct pm8941_wled *wled;
 383         struct regmap *regmap;
 384         int rc;
 385
 386         regmap = dev_get_regmap(pdev->dev.parent, NULL);
 387         if (!regmap) {
 388                 dev_err(&pdev->dev, "Unable to get regmap\n");
 389                 return -EINVAL;
 390         }
 391
 392         wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
 393         if (!wled)
 394                 return -ENOMEM;
 395
 396         wled->regmap = regmap;
 397
 398         rc = pm8941_wled_configure(wled, &pdev->dev);
 399         if (rc)
 400                 return rc;
 401
 402         rc = pm8941_wled_setup(wled);
 403         if (rc)
 404                 return rc;
 405
 406         wled->cdev.brightness_set = pm8941_wled_set_brightness;
 407
 408         rc = devm_led_classdev_register(&pdev->dev, &wled->cdev);
 409         if (rc)
 410                 return rc;
 411
 412         platform_set_drvdata(pdev, wled);
 413
 414         return 0;
 415 };
 416
 417 static const struct of_device_id pm8941_wled_match_table[] = {
 418         { .compatible = "qcom,pm8941-wled" },
 419         {}
 420 };
 421 MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
 422
 423 static struct platform_driver pm8941_wled_driver = {
 424         .probe = pm8941_wled_probe,
 425         .driver = {
 426                 .name = "pm8941-wled",
 427                 .of_match_table = pm8941_wled_match_table,
 428         },
 429 };
 430
 431 module_platform_driver(pm8941_wled_driver);
 432
 433 MODULE_DESCRIPTION("pm8941 wled driver");
 434 MODULE_LICENSE("GPL v2");
 435 MODULE_ALIAS("platform:pm8941-wled");