drivers/video/backlight/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/backlight.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/regmap.h>
  19
  20 /* From DT binding */
  21 #define PM8941_WLED_DEFAULT_BRIGHTNESS          2048
  22
  23 #define PM8941_WLED_REG_VAL_BASE                0x40
  24 #define  PM8941_WLED_REG_VAL_MAX                0xFFF
  25
  26 #define PM8941_WLED_REG_MOD_EN                  0x46
  27 #define  PM8941_WLED_REG_MOD_EN_BIT             BIT(7)
  28 #define  PM8941_WLED_REG_MOD_EN_MASK            BIT(7)
  29
  30 #define PM8941_WLED_REG_SYNC                    0x47
  31 #define  PM8941_WLED_REG_SYNC_MASK              0x07
  32 #define  PM8941_WLED_REG_SYNC_LED1              BIT(0)
  33 #define  PM8941_WLED_REG_SYNC_LED2              BIT(1)
  34 #define  PM8941_WLED_REG_SYNC_LED3              BIT(2)
  35 #define  PM8941_WLED_REG_SYNC_ALL               0x07
  36 #define  PM8941_WLED_REG_SYNC_CLEAR             0x00
  37
  38 #define PM8941_WLED_REG_FREQ                    0x4c
  39 #define  PM8941_WLED_REG_FREQ_MASK              0x0f
  40
  41 #define PM8941_WLED_REG_OVP                     0x4d
  42 #define  PM8941_WLED_REG_OVP_MASK               0x03
  43
  44 #define PM8941_WLED_REG_BOOST                   0x4e
  45 #define  PM8941_WLED_REG_BOOST_MASK             0x07
  46
  47 #define PM8941_WLED_REG_SINK                    0x4f
  48 #define  PM8941_WLED_REG_SINK_MASK              0xe0
  49 #define  PM8941_WLED_REG_SINK_SHFT              0x05
  50
  51 /* Per-'string' registers below */
  52 #define PM8941_WLED_REG_STR_OFFSET              0x10
  53
  54 #define PM8941_WLED_REG_STR_MOD_EN_BASE         0x60
  55 #define  PM8941_WLED_REG_STR_MOD_MASK           BIT(7)
  56 #define  PM8941_WLED_REG_STR_MOD_EN             BIT(7)
  57
  58 #define PM8941_WLED_REG_STR_SCALE_BASE          0x62
  59 #define  PM8941_WLED_REG_STR_SCALE_MASK         0x1f
  60
  61 #define PM8941_WLED_REG_STR_MOD_SRC_BASE        0x63
  62 #define  PM8941_WLED_REG_STR_MOD_SRC_MASK       0x01
  63 #define  PM8941_WLED_REG_STR_MOD_SRC_INT        0x00
  64 #define  PM8941_WLED_REG_STR_MOD_SRC_EXT        0x01
  65
  66 #define PM8941_WLED_REG_STR_CABC_BASE           0x66
  67 #define  PM8941_WLED_REG_STR_CABC_MASK          BIT(7)
  68 #define  PM8941_WLED_REG_STR_CABC_EN            BIT(7)
  69
  70 struct pm8941_wled_config {
  71         u32 i_boost_limit;
  72         u32 ovp;
  73         u32 switch_freq;
  74         u32 num_strings;
  75         u32 i_limit;
  76         bool cs_out_en;
  77         bool ext_gen;
  78         bool cabc_en;
  79 };
  80
  81 struct pm8941_wled {
  82         const char *name;
  83         struct regmap *regmap;
  84         u16 addr;
  85
  86         struct pm8941_wled_config cfg;
  87 };
  88
  89 static int pm8941_wled_update_status(struct backlight_device *bl)
  90 {
  91         struct pm8941_wled *wled = bl_get_data(bl);
  92         u16 val = bl->props.brightness;
  93         u8 ctrl = 0;
  94         int rc;
  95         int i;
  96
  97         if (bl->props.power != FB_BLANK_UNBLANK ||
  98             bl->props.fb_blank != FB_BLANK_UNBLANK ||
  99             bl->props.state & BL_CORE_FBBLANK)
 100                 val = 0;
 101
 102         if (val != 0)
 103                 ctrl = PM8941_WLED_REG_MOD_EN_BIT;
 104
 105         rc = regmap_update_bits(wled->regmap,
 106                         wled->addr + PM8941_WLED_REG_MOD_EN,
 107                         PM8941_WLED_REG_MOD_EN_MASK, ctrl);
 108         if (rc)
 109                 return rc;
 110
 111         for (i = 0; i < wled->cfg.num_strings; ++i) {
 112                 u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
 113
 114                 rc = regmap_bulk_write(wled->regmap,
 115                                 wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
 116                                 v, 2);
 117                 if (rc)
 118                         return rc;
 119         }
 120
 121         rc = regmap_update_bits(wled->regmap,
 122                         wled->addr + PM8941_WLED_REG_SYNC,
 123                         PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
 124         if (rc)
 125                 return rc;
 126
 127         rc = regmap_update_bits(wled->regmap,
 128                         wled->addr + PM8941_WLED_REG_SYNC,
 129                         PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_CLEAR);
 130         return rc;
 131 }
 132
 133 static int pm8941_wled_setup(struct pm8941_wled *wled)
 134 {
 135         int rc;
 136         int i;
 137
 138         rc = regmap_update_bits(wled->regmap,
 139                         wled->addr + PM8941_WLED_REG_OVP,
 140                         PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
 141         if (rc)
 142                 return rc;
 143
 144         rc = regmap_update_bits(wled->regmap,
 145                         wled->addr + PM8941_WLED_REG_BOOST,
 146                         PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
 147         if (rc)
 148                 return rc;
 149
 150         rc = regmap_update_bits(wled->regmap,
 151                         wled->addr + PM8941_WLED_REG_FREQ,
 152                         PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
 153         if (rc)
 154                 return rc;
 155
 156         if (wled->cfg.cs_out_en) {
 157                 u8 all = (BIT(wled->cfg.num_strings) - 1)
 158                                 << PM8941_WLED_REG_SINK_SHFT;
 159
 160                 rc = regmap_update_bits(wled->regmap,
 161                                 wled->addr + PM8941_WLED_REG_SINK,
 162                                 PM8941_WLED_REG_SINK_MASK, all);
 163                 if (rc)
 164                         return rc;
 165         }
 166
 167         for (i = 0; i < wled->cfg.num_strings; ++i) {
 168                 u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
 169
 170                 rc = regmap_update_bits(wled->regmap,
 171                                 addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
 172                                 PM8941_WLED_REG_STR_MOD_MASK,
 173                                 PM8941_WLED_REG_STR_MOD_EN);
 174                 if (rc)
 175                         return rc;
 176
 177                 if (wled->cfg.ext_gen) {
 178                         rc = regmap_update_bits(wled->regmap,
 179                                         addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
 180                                         PM8941_WLED_REG_STR_MOD_SRC_MASK,
 181                                         PM8941_WLED_REG_STR_MOD_SRC_EXT);
 182                         if (rc)
 183                                 return rc;
 184                 }
 185
 186                 rc = regmap_update_bits(wled->regmap,
 187                                 addr + PM8941_WLED_REG_STR_SCALE_BASE,
 188                                 PM8941_WLED_REG_STR_SCALE_MASK,
 189                                 wled->cfg.i_limit);
 190                 if (rc)
 191                         return rc;
 192
 193                 rc = regmap_update_bits(wled->regmap,
 194                                 addr + PM8941_WLED_REG_STR_CABC_BASE,
 195                                 PM8941_WLED_REG_STR_CABC_MASK,
 196                                 wled->cfg.cabc_en ?
 197                                         PM8941_WLED_REG_STR_CABC_EN : 0);
 198                 if (rc)
 199                         return rc;
 200         }
 201
 202         return 0;
 203 }
 204
 205 static const struct pm8941_wled_config pm8941_wled_config_defaults = {
 206         .i_boost_limit = 3,
 207         .i_limit = 20,
 208         .ovp = 2,
 209         .switch_freq = 5,
 210         .num_strings = 0,
 211         .cs_out_en = false,
 212         .ext_gen = false,
 213         .cabc_en = false,
 214 };
 215
 216 struct pm8941_wled_var_cfg {
 217         const u32 *values;
 218         u32 (*fn)(u32);
 219         int size;
 220 };
 221
 222 static const u32 pm8941_wled_i_boost_limit_values[] = {
 223         105, 385, 525, 805, 980, 1260, 1400, 1680,
 224 };
 225
 226 static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
 227         .values = pm8941_wled_i_boost_limit_values,
 228         .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
 229 };
 230
 231 static const u32 pm8941_wled_ovp_values[] = {
 232         35, 32, 29, 27,
 233 };
 234
 235 static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
 236         .values = pm8941_wled_ovp_values,
 237         .size = ARRAY_SIZE(pm8941_wled_ovp_values),
 238 };
 239
 240 static u32 pm8941_wled_num_strings_values_fn(u32 idx)
 241 {
 242         return idx + 1;
 243 }
 244
 245 static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
 246         .fn = pm8941_wled_num_strings_values_fn,
 247         .size = 3,
 248 };
 249
 250 static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
 251 {
 252         return 19200 / (2 * (1 + idx));
 253 }
 254
 255 static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
 256         .fn = pm8941_wled_switch_freq_values_fn,
 257         .size = 16,
 258 };
 259
 260 static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
 261         .size = 26,
 262 };
 263
 264 static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
 265 {
 266         if (idx >= cfg->size)
 267                 return UINT_MAX;
 268         if (cfg->fn)
 269                 return cfg->fn(idx);
 270         if (cfg->values)
 271                 return cfg->values[idx];
 272         return idx;
 273 }
 274
 275 static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
 276 {
 277         struct pm8941_wled_config *cfg = &wled->cfg;
 278         u32 val;
 279         int rc;
 280         u32 c;
 281         int i;
 282         int j;
 283
 284         const struct {
 285                 const char *name;
 286                 u32 *val_ptr;
 287                 const struct pm8941_wled_var_cfg *cfg;
 288         } u32_opts[] = {
 289                 {
 290                         "qcom,current-boost-limit",
 291                         &cfg->i_boost_limit,
 292                         .cfg = &pm8941_wled_i_boost_limit_cfg,
 293                 },
 294                 {
 295                         "qcom,current-limit",
 296                         &cfg->i_limit,
 297                         .cfg = &pm8941_wled_i_limit_cfg,
 298                 },
 299                 {
 300                         "qcom,ovp",
 301                         &cfg->ovp,
 302                         .cfg = &pm8941_wled_ovp_cfg,
 303                 },
 304                 {
 305                         "qcom,switching-freq",
 306                         &cfg->switch_freq,
 307                         .cfg = &pm8941_wled_switch_freq_cfg,
 308                 },
 309                 {
 310                         "qcom,num-strings",
 311                         &cfg->num_strings,
 312                         .cfg = &pm8941_wled_num_strings_cfg,
 313                 },
 314         };
 315         const struct {
 316                 const char *name;
 317                 bool *val_ptr;
 318         } bool_opts[] = {
 319                 { "qcom,cs-out", &cfg->cs_out_en, },
 320                 { "qcom,ext-gen", &cfg->ext_gen, },
 321                 { "qcom,cabc", &cfg->cabc_en, },
 322         };
 323
 324         rc = of_property_read_u32(dev->of_node, "reg", &val);
 325         if (rc || val > 0xffff) {
 326                 dev_err(dev, "invalid IO resources\n");
 327                 return rc ? rc : -EINVAL;
 328         }
 329         wled->addr = val;
 330
 331         rc = of_property_read_string(dev->of_node, "label", &wled->name);
 332         if (rc)
 333                 wled->name = dev->of_node->name;
 334
 335         *cfg = pm8941_wled_config_defaults;
 336         for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
 337                 rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
 338                 if (rc == -EINVAL) {
 339                         continue;
 340                 } else if (rc) {
 341                         dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
 342                         return rc;
 343                 }
 344
 345                 c = UINT_MAX;
 346                 for (j = 0; c != val; j++) {
 347                         c = pm8941_wled_values(u32_opts[i].cfg, j);
 348                         if (c == UINT_MAX) {
 349                                 dev_err(dev, "invalid value for '%s'\n",
 350                                         u32_opts[i].name);
 351                                 return -EINVAL;
 352                         }
 353                 }
 354
 355                 dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
 356                 *u32_opts[i].val_ptr = j;
 357         }
 358
 359         for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
 360                 if (of_property_read_bool(dev->of_node, bool_opts[i].name))
 361                         *bool_opts[i].val_ptr = true;
 362         }
 363
 364         cfg->num_strings = cfg->num_strings + 1;
 365
 366         return 0;
 367 }
 368
 369 static const struct backlight_ops pm8941_wled_ops = {
 370         .update_status = pm8941_wled_update_status,
 371 };
 372
 373 static int pm8941_wled_probe(struct platform_device *pdev)
 374 {
 375         struct backlight_properties props;
 376         struct backlight_device *bl;
 377         struct pm8941_wled *wled;
 378         struct regmap *regmap;
 379         u32 val;
 380         int rc;
 381
 382         regmap = dev_get_regmap(pdev->dev.parent, NULL);
 383         if (!regmap) {
 384                 dev_err(&pdev->dev, "Unable to get regmap\n");
 385                 return -EINVAL;
 386         }
 387
 388         wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
 389         if (!wled)
 390                 return -ENOMEM;
 391
 392         wled->regmap = regmap;
 393
 394         rc = pm8941_wled_configure(wled, &pdev->dev);
 395         if (rc)
 396                 return rc;
 397
 398         rc = pm8941_wled_setup(wled);
 399         if (rc)
 400                 return rc;
 401
 402         val = PM8941_WLED_DEFAULT_BRIGHTNESS;
 403         of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
 404
 405         memset(&props, 0, sizeof(struct backlight_properties));
 406         props.type = BACKLIGHT_RAW;
 407         props.brightness = val;
 408         props.max_brightness = PM8941_WLED_REG_VAL_MAX;
 409         bl = devm_backlight_device_register(&pdev->dev, wled->name,
 410                                             &pdev->dev, wled,
 411                                             &pm8941_wled_ops, &props);
 412         return PTR_ERR_OR_ZERO(bl);
 413 };
 414
 415 static const struct of_device_id pm8941_wled_match_table[] = {
 416         { .compatible = "qcom,pm8941-wled" },
 417         {}
 418 };
 419 MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
 420
 421 static struct platform_driver pm8941_wled_driver = {
 422         .probe = pm8941_wled_probe,
 423         .driver = {
 424                 .name = "pm8941-wled",
 425                 .of_match_table = pm8941_wled_match_table,
 426         },
 427 };
 428
 429 module_platform_driver(pm8941_wled_driver);
 430
 431 MODULE_DESCRIPTION("pm8941 wled driver");
 432 MODULE_LICENSE("GPL v2");