drivers/video/backlight/pm8941-wled.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2015, Sony Mobile Communications, AB.
   3  */
   4
   5 #include <linux/kernel.h>
   6 #include <linux/backlight.h>
   7 #include <linux/module.h>
   8 #include <linux/of.h>
   9 #include <linux/of_device.h>
  10 #include <linux/regmap.h>
  11
  12 /* From DT binding */
  13 #define PM8941_WLED_DEFAULT_BRIGHTNESS          2048
  14
  15 #define PM8941_WLED_REG_VAL_BASE                0x40
  16 #define  PM8941_WLED_REG_VAL_MAX                0xFFF
  17
  18 #define PM8941_WLED_REG_MOD_EN                  0x46
  19 #define  PM8941_WLED_REG_MOD_EN_BIT             BIT(7)
  20 #define  PM8941_WLED_REG_MOD_EN_MASK            BIT(7)
  21
  22 #define PM8941_WLED_REG_SYNC                    0x47
  23 #define  PM8941_WLED_REG_SYNC_MASK              0x07
  24 #define  PM8941_WLED_REG_SYNC_LED1              BIT(0)
  25 #define  PM8941_WLED_REG_SYNC_LED2              BIT(1)
  26 #define  PM8941_WLED_REG_SYNC_LED3              BIT(2)
  27 #define  PM8941_WLED_REG_SYNC_ALL               0x07
  28 #define  PM8941_WLED_REG_SYNC_CLEAR             0x00
  29
  30 #define PM8941_WLED_REG_FREQ                    0x4c
  31 #define  PM8941_WLED_REG_FREQ_MASK              0x0f
  32
  33 #define PM8941_WLED_REG_OVP                     0x4d
  34 #define  PM8941_WLED_REG_OVP_MASK               0x03
  35
  36 #define PM8941_WLED_REG_BOOST                   0x4e
  37 #define  PM8941_WLED_REG_BOOST_MASK             0x07
  38
  39 #define PM8941_WLED_REG_SINK                    0x4f
  40 #define  PM8941_WLED_REG_SINK_MASK              0xe0
  41 #define  PM8941_WLED_REG_SINK_SHFT              0x05
  42
  43 /* Per-'string' registers below */
  44 #define PM8941_WLED_REG_STR_OFFSET              0x10
  45
  46 #define PM8941_WLED_REG_STR_MOD_EN_BASE         0x60
  47 #define  PM8941_WLED_REG_STR_MOD_MASK           BIT(7)
  48 #define  PM8941_WLED_REG_STR_MOD_EN             BIT(7)
  49
  50 #define PM8941_WLED_REG_STR_SCALE_BASE          0x62
  51 #define  PM8941_WLED_REG_STR_SCALE_MASK         0x1f
  52
  53 #define PM8941_WLED_REG_STR_MOD_SRC_BASE        0x63
  54 #define  PM8941_WLED_REG_STR_MOD_SRC_MASK       0x01
  55 #define  PM8941_WLED_REG_STR_MOD_SRC_INT        0x00
  56 #define  PM8941_WLED_REG_STR_MOD_SRC_EXT        0x01
  57
  58 #define PM8941_WLED_REG_STR_CABC_BASE           0x66
  59 #define  PM8941_WLED_REG_STR_CABC_MASK          BIT(7)
  60 #define  PM8941_WLED_REG_STR_CABC_EN            BIT(7)
  61
  62 struct pm8941_wled_config {
  63         u32 i_boost_limit;
  64         u32 ovp;
  65         u32 switch_freq;
  66         u32 num_strings;
  67         u32 i_limit;
  68         bool cs_out_en;
  69         bool ext_gen;
  70         bool cabc_en;
  71 };
  72
  73 struct pm8941_wled {
  74         const char *name;
  75         struct regmap *regmap;
  76         u16 addr;
  77
  78         struct pm8941_wled_config cfg;
  79 };
  80
  81 static int pm8941_wled_update_status(struct backlight_device *bl)
  82 {
  83         struct pm8941_wled *wled = bl_get_data(bl);
  84         u16 val = bl->props.brightness;
  85         u8 ctrl = 0;
  86         int rc;
  87         int i;
  88
  89         if (bl->props.power != FB_BLANK_UNBLANK ||
  90             bl->props.fb_blank != FB_BLANK_UNBLANK ||
  91             bl->props.state & BL_CORE_FBBLANK)
  92                 val = 0;
  93
  94         if (val != 0)
  95                 ctrl = PM8941_WLED_REG_MOD_EN_BIT;
  96
  97         rc = regmap_update_bits(wled->regmap,
  98                         wled->addr + PM8941_WLED_REG_MOD_EN,
  99                         PM8941_WLED_REG_MOD_EN_MASK, ctrl);
 100         if (rc)
 101                 return rc;
 102
 103         for (i = 0; i < wled->cfg.num_strings; ++i) {
 104                 u8 v[2] = { val & 0xff, (val >> 8) & 0xf };
 105
 106                 rc = regmap_bulk_write(wled->regmap,
 107                                 wled->addr + PM8941_WLED_REG_VAL_BASE + 2 * i,
 108                                 v, 2);
 109                 if (rc)
 110                         return rc;
 111         }
 112
 113         rc = regmap_update_bits(wled->regmap,
 114                         wled->addr + PM8941_WLED_REG_SYNC,
 115                         PM8941_WLED_REG_SYNC_MASK, PM8941_WLED_REG_SYNC_ALL);
 116         if (rc)
 117                 return rc;
 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_CLEAR);
 122         return rc;
 123 }
 124
 125 static int pm8941_wled_setup(struct pm8941_wled *wled)
 126 {
 127         int rc;
 128         int i;
 129
 130         rc = regmap_update_bits(wled->regmap,
 131                         wled->addr + PM8941_WLED_REG_OVP,
 132                         PM8941_WLED_REG_OVP_MASK, wled->cfg.ovp);
 133         if (rc)
 134                 return rc;
 135
 136         rc = regmap_update_bits(wled->regmap,
 137                         wled->addr + PM8941_WLED_REG_BOOST,
 138                         PM8941_WLED_REG_BOOST_MASK, wled->cfg.i_boost_limit);
 139         if (rc)
 140                 return rc;
 141
 142         rc = regmap_update_bits(wled->regmap,
 143                         wled->addr + PM8941_WLED_REG_FREQ,
 144                         PM8941_WLED_REG_FREQ_MASK, wled->cfg.switch_freq);
 145         if (rc)
 146                 return rc;
 147
 148         if (wled->cfg.cs_out_en) {
 149                 u8 all = (BIT(wled->cfg.num_strings) - 1)
 150                                 << PM8941_WLED_REG_SINK_SHFT;
 151
 152                 rc = regmap_update_bits(wled->regmap,
 153                                 wled->addr + PM8941_WLED_REG_SINK,
 154                                 PM8941_WLED_REG_SINK_MASK, all);
 155                 if (rc)
 156                         return rc;
 157         }
 158
 159         for (i = 0; i < wled->cfg.num_strings; ++i) {
 160                 u16 addr = wled->addr + PM8941_WLED_REG_STR_OFFSET * i;
 161
 162                 rc = regmap_update_bits(wled->regmap,
 163                                 addr + PM8941_WLED_REG_STR_MOD_EN_BASE,
 164                                 PM8941_WLED_REG_STR_MOD_MASK,
 165                                 PM8941_WLED_REG_STR_MOD_EN);
 166                 if (rc)
 167                         return rc;
 168
 169                 if (wled->cfg.ext_gen) {
 170                         rc = regmap_update_bits(wled->regmap,
 171                                         addr + PM8941_WLED_REG_STR_MOD_SRC_BASE,
 172                                         PM8941_WLED_REG_STR_MOD_SRC_MASK,
 173                                         PM8941_WLED_REG_STR_MOD_SRC_EXT);
 174                         if (rc)
 175                                 return rc;
 176                 }
 177
 178                 rc = regmap_update_bits(wled->regmap,
 179                                 addr + PM8941_WLED_REG_STR_SCALE_BASE,
 180                                 PM8941_WLED_REG_STR_SCALE_MASK,
 181                                 wled->cfg.i_limit);
 182                 if (rc)
 183                         return rc;
 184
 185                 rc = regmap_update_bits(wled->regmap,
 186                                 addr + PM8941_WLED_REG_STR_CABC_BASE,
 187                                 PM8941_WLED_REG_STR_CABC_MASK,
 188                                 wled->cfg.cabc_en ?
 189                                         PM8941_WLED_REG_STR_CABC_EN : 0);
 190                 if (rc)
 191                         return rc;
 192         }
 193
 194         return 0;
 195 }
 196
 197 static const struct pm8941_wled_config pm8941_wled_config_defaults = {
 198         .i_boost_limit = 3,
 199         .i_limit = 20,
 200         .ovp = 2,
 201         .switch_freq = 5,
 202         .num_strings = 0,
 203         .cs_out_en = false,
 204         .ext_gen = false,
 205         .cabc_en = false,
 206 };
 207
 208 struct pm8941_wled_var_cfg {
 209         const u32 *values;
 210         u32 (*fn)(u32);
 211         int size;
 212 };
 213
 214 static const u32 pm8941_wled_i_boost_limit_values[] = {
 215         105, 385, 525, 805, 980, 1260, 1400, 1680,
 216 };
 217
 218 static const struct pm8941_wled_var_cfg pm8941_wled_i_boost_limit_cfg = {
 219         .values = pm8941_wled_i_boost_limit_values,
 220         .size = ARRAY_SIZE(pm8941_wled_i_boost_limit_values),
 221 };
 222
 223 static const u32 pm8941_wled_ovp_values[] = {
 224         35, 32, 29, 27,
 225 };
 226
 227 static const struct pm8941_wled_var_cfg pm8941_wled_ovp_cfg = {
 228         .values = pm8941_wled_ovp_values,
 229         .size = ARRAY_SIZE(pm8941_wled_ovp_values),
 230 };
 231
 232 static u32 pm8941_wled_num_strings_values_fn(u32 idx)
 233 {
 234         return idx + 1;
 235 }
 236
 237 static const struct pm8941_wled_var_cfg pm8941_wled_num_strings_cfg = {
 238         .fn = pm8941_wled_num_strings_values_fn,
 239         .size = 3,
 240 };
 241
 242 static u32 pm8941_wled_switch_freq_values_fn(u32 idx)
 243 {
 244         return 19200 / (2 * (1 + idx));
 245 }
 246
 247 static const struct pm8941_wled_var_cfg pm8941_wled_switch_freq_cfg = {
 248         .fn = pm8941_wled_switch_freq_values_fn,
 249         .size = 16,
 250 };
 251
 252 static const struct pm8941_wled_var_cfg pm8941_wled_i_limit_cfg = {
 253         .size = 26,
 254 };
 255
 256 static u32 pm8941_wled_values(const struct pm8941_wled_var_cfg *cfg, u32 idx)
 257 {
 258         if (idx >= cfg->size)
 259                 return UINT_MAX;
 260         if (cfg->fn)
 261                 return cfg->fn(idx);
 262         if (cfg->values)
 263                 return cfg->values[idx];
 264         return idx;
 265 }
 266
 267 static int pm8941_wled_configure(struct pm8941_wled *wled, struct device *dev)
 268 {
 269         struct pm8941_wled_config *cfg = &wled->cfg;
 270         u32 val;
 271         int rc;
 272         u32 c;
 273         int i;
 274         int j;
 275
 276         const struct {
 277                 const char *name;
 278                 u32 *val_ptr;
 279                 const struct pm8941_wled_var_cfg *cfg;
 280         } u32_opts[] = {
 281                 {
 282                         "qcom,current-boost-limit",
 283                         &cfg->i_boost_limit,
 284                         .cfg = &pm8941_wled_i_boost_limit_cfg,
 285                 },
 286                 {
 287                         "qcom,current-limit",
 288                         &cfg->i_limit,
 289                         .cfg = &pm8941_wled_i_limit_cfg,
 290                 },
 291                 {
 292                         "qcom,ovp",
 293                         &cfg->ovp,
 294                         .cfg = &pm8941_wled_ovp_cfg,
 295                 },
 296                 {
 297                         "qcom,switching-freq",
 298                         &cfg->switch_freq,
 299                         .cfg = &pm8941_wled_switch_freq_cfg,
 300                 },
 301                 {
 302                         "qcom,num-strings",
 303                         &cfg->num_strings,
 304                         .cfg = &pm8941_wled_num_strings_cfg,
 305                 },
 306         };
 307         const struct {
 308                 const char *name;
 309                 bool *val_ptr;
 310         } bool_opts[] = {
 311                 { "qcom,cs-out", &cfg->cs_out_en, },
 312                 { "qcom,ext-gen", &cfg->ext_gen, },
 313                 { "qcom,cabc", &cfg->cabc_en, },
 314         };
 315
 316         rc = of_property_read_u32(dev->of_node, "reg", &val);
 317         if (rc || val > 0xffff) {
 318                 dev_err(dev, "invalid IO resources\n");
 319                 return rc ? rc : -EINVAL;
 320         }
 321         wled->addr = val;
 322
 323         rc = of_property_read_string(dev->of_node, "label", &wled->name);
 324         if (rc)
 325                 wled->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node);
 326
 327         *cfg = pm8941_wled_config_defaults;
 328         for (i = 0; i < ARRAY_SIZE(u32_opts); ++i) {
 329                 rc = of_property_read_u32(dev->of_node, u32_opts[i].name, &val);
 330                 if (rc == -EINVAL) {
 331                         continue;
 332                 } else if (rc) {
 333                         dev_err(dev, "error reading '%s'\n", u32_opts[i].name);
 334                         return rc;
 335                 }
 336
 337                 c = UINT_MAX;
 338                 for (j = 0; c != val; j++) {
 339                         c = pm8941_wled_values(u32_opts[i].cfg, j);
 340                         if (c == UINT_MAX) {
 341                                 dev_err(dev, "invalid value for '%s'\n",
 342                                         u32_opts[i].name);
 343                                 return -EINVAL;
 344                         }
 345                 }
 346
 347                 dev_dbg(dev, "'%s' = %u\n", u32_opts[i].name, c);
 348                 *u32_opts[i].val_ptr = j;
 349         }
 350
 351         for (i = 0; i < ARRAY_SIZE(bool_opts); ++i) {
 352                 if (of_property_read_bool(dev->of_node, bool_opts[i].name))
 353                         *bool_opts[i].val_ptr = true;
 354         }
 355
 356         cfg->num_strings = cfg->num_strings + 1;
 357
 358         return 0;
 359 }
 360
 361 static const struct backlight_ops pm8941_wled_ops = {
 362         .update_status = pm8941_wled_update_status,
 363 };
 364
 365 static int pm8941_wled_probe(struct platform_device *pdev)
 366 {
 367         struct backlight_properties props;
 368         struct backlight_device *bl;
 369         struct pm8941_wled *wled;
 370         struct regmap *regmap;
 371         u32 val;
 372         int rc;
 373
 374         regmap = dev_get_regmap(pdev->dev.parent, NULL);
 375         if (!regmap) {
 376                 dev_err(&pdev->dev, "Unable to get regmap\n");
 377                 return -EINVAL;
 378         }
 379
 380         wled = devm_kzalloc(&pdev->dev, sizeof(*wled), GFP_KERNEL);
 381         if (!wled)
 382                 return -ENOMEM;
 383
 384         wled->regmap = regmap;
 385
 386         rc = pm8941_wled_configure(wled, &pdev->dev);
 387         if (rc)
 388                 return rc;
 389
 390         rc = pm8941_wled_setup(wled);
 391         if (rc)
 392                 return rc;
 393
 394         val = PM8941_WLED_DEFAULT_BRIGHTNESS;
 395         of_property_read_u32(pdev->dev.of_node, "default-brightness", &val);
 396
 397         memset(&props, 0, sizeof(struct backlight_properties));
 398         props.type = BACKLIGHT_RAW;
 399         props.brightness = val;
 400         props.max_brightness = PM8941_WLED_REG_VAL_MAX;
 401         bl = devm_backlight_device_register(&pdev->dev, wled->name,
 402                                             &pdev->dev, wled,
 403                                             &pm8941_wled_ops, &props);
 404         return PTR_ERR_OR_ZERO(bl);
 405 };
 406
 407 static const struct of_device_id pm8941_wled_match_table[] = {
 408         { .compatible = "qcom,pm8941-wled" },
 409         {}
 410 };
 411 MODULE_DEVICE_TABLE(of, pm8941_wled_match_table);
 412
 413 static struct platform_driver pm8941_wled_driver = {
 414         .probe = pm8941_wled_probe,
 415         .driver = {
 416                 .name = "pm8941-wled",
 417                 .of_match_table = pm8941_wled_match_table,
 418         },
 419 };
 420
 421 module_platform_driver(pm8941_wled_driver);
 422
 423 MODULE_DESCRIPTION("pm8941 wled driver");
 424 MODULE_LICENSE("GPL v2");