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