drivers/video/backlight/tps65217_bl.c

   1 /*
   2  * tps65217_bl.c
   3  *
   4  * TPS65217 backlight driver
   5  *
   6  * Copyright (C) 2012 Matthias Kaehlcke
   7  * Author: Matthias Kaehlcke <matthias@kaehlcke.net>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation version 2.
  12  *
  13  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  14  * kind, whether express or implied; without even the implied warranty
  15  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/backlight.h>
  21 #include <linux/err.h>
  22 #include <linux/fb.h>
  23 #include <linux/mfd/tps65217.h>
  24 #include <linux/module.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/slab.h>
  27
  28 struct tps65217_bl {
  29         struct tps65217 *tps;
  30         struct device *dev;
  31         struct backlight_device *bl;
  32         bool is_enabled;
  33 };
  34
  35 static int tps65217_bl_enable(struct tps65217_bl *tps65217_bl)
  36 {
  37         int rc;
  38
  39         rc = tps65217_set_bits(tps65217_bl->tps, TPS65217_REG_WLEDCTRL1,
  40                         TPS65217_WLEDCTRL1_ISINK_ENABLE,
  41                         TPS65217_WLEDCTRL1_ISINK_ENABLE, TPS65217_PROTECT_NONE);
  42         if (rc) {
  43                 dev_err(tps65217_bl->dev,
  44                         "failed to enable backlight: %d\n", rc);
  45                 return rc;
  46         }
  47
  48         tps65217_bl->is_enabled = true;
  49
  50         dev_dbg(tps65217_bl->dev, "backlight enabled\n");
  51
  52         return 0;
  53 }
  54
  55 static int tps65217_bl_disable(struct tps65217_bl *tps65217_bl)
  56 {
  57         int rc;
  58
  59         rc = tps65217_clear_bits(tps65217_bl->tps,
  60                                 TPS65217_REG_WLEDCTRL1,
  61                                 TPS65217_WLEDCTRL1_ISINK_ENABLE,
  62                                 TPS65217_PROTECT_NONE);
  63         if (rc) {
  64                 dev_err(tps65217_bl->dev,
  65                         "failed to disable backlight: %d\n", rc);
  66                 return rc;
  67         }
  68
  69         tps65217_bl->is_enabled = false;
  70
  71         dev_dbg(tps65217_bl->dev, "backlight disabled\n");
  72
  73         return 0;
  74 }
  75
  76 static int tps65217_bl_update_status(struct backlight_device *bl)
  77 {
  78         struct tps65217_bl *tps65217_bl = bl_get_data(bl);
  79         int rc;
  80         int brightness = backlight_get_brightness(bl);
  81
  82         if (brightness > 0) {
  83                 rc = tps65217_reg_write(tps65217_bl->tps,
  84                                         TPS65217_REG_WLEDCTRL2,
  85                                         brightness - 1,
  86                                         TPS65217_PROTECT_NONE);
  87                 if (rc) {
  88                         dev_err(tps65217_bl->dev,
  89                                 "failed to set brightness level: %d\n", rc);
  90                         return rc;
  91                 }
  92
  93                 dev_dbg(tps65217_bl->dev, "brightness set to %d\n", brightness);
  94
  95                 if (!tps65217_bl->is_enabled)
  96                         rc = tps65217_bl_enable(tps65217_bl);
  97         } else {
  98                 rc = tps65217_bl_disable(tps65217_bl);
  99         }
 100
 101         return rc;
 102 }
 103
 104 static const struct backlight_ops tps65217_bl_ops = {
 105         .options        = BL_CORE_SUSPENDRESUME,
 106         .update_status  = tps65217_bl_update_status,
 107 };
 108
 109 static int tps65217_bl_hw_init(struct tps65217_bl *tps65217_bl,
 110                         struct tps65217_bl_pdata *pdata)
 111 {
 112         int rc;
 113
 114         rc = tps65217_bl_disable(tps65217_bl);
 115         if (rc)
 116                 return rc;
 117
 118         switch (pdata->isel) {
 119         case TPS65217_BL_ISET1:
 120                 /* select ISET_1 current level */
 121                 rc = tps65217_clear_bits(tps65217_bl->tps,
 122                                         TPS65217_REG_WLEDCTRL1,
 123                                         TPS65217_WLEDCTRL1_ISEL,
 124                                         TPS65217_PROTECT_NONE);
 125                 if (rc) {
 126                         dev_err(tps65217_bl->dev,
 127                                 "failed to select ISET1 current level: %d)\n",
 128                                 rc);
 129                         return rc;
 130                 }
 131
 132                 dev_dbg(tps65217_bl->dev, "selected ISET1 current level\n");
 133
 134                 break;
 135
 136         case TPS65217_BL_ISET2:
 137                 /* select ISET2 current level */
 138                 rc = tps65217_set_bits(tps65217_bl->tps, TPS65217_REG_WLEDCTRL1,
 139                                 TPS65217_WLEDCTRL1_ISEL,
 140                                 TPS65217_WLEDCTRL1_ISEL, TPS65217_PROTECT_NONE);
 141                 if (rc) {
 142                         dev_err(tps65217_bl->dev,
 143                                 "failed to select ISET2 current level: %d\n",
 144                                 rc);
 145                         return rc;
 146                 }
 147
 148                 dev_dbg(tps65217_bl->dev, "selected ISET2 current level\n");
 149
 150                 break;
 151
 152         default:
 153                 dev_err(tps65217_bl->dev,
 154                         "invalid value for current level: %d\n", pdata->isel);
 155                 return -EINVAL;
 156         }
 157
 158         /* set PWM frequency */
 159         rc = tps65217_set_bits(tps65217_bl->tps,
 160                         TPS65217_REG_WLEDCTRL1,
 161                         TPS65217_WLEDCTRL1_FDIM_MASK,
 162                         pdata->fdim,
 163                         TPS65217_PROTECT_NONE);
 164         if (rc) {
 165                 dev_err(tps65217_bl->dev,
 166                         "failed to select PWM dimming frequency: %d\n",
 167                         rc);
 168                 return rc;
 169         }
 170
 171         return 0;
 172 }
 173
 174 #ifdef CONFIG_OF
 175 static struct tps65217_bl_pdata *
 176 tps65217_bl_parse_dt(struct platform_device *pdev)
 177 {
 178         struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
 179         struct device_node *node;
 180         struct tps65217_bl_pdata *pdata, *err;
 181         u32 val;
 182
 183         node = of_get_child_by_name(tps->dev->of_node, "backlight");
 184         if (!node)
 185                 return ERR_PTR(-ENODEV);
 186
 187         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 188         if (!pdata) {
 189                 err = ERR_PTR(-ENOMEM);
 190                 goto err;
 191         }
 192
 193         pdata->isel = TPS65217_BL_ISET1;
 194         if (!of_property_read_u32(node, "isel", &val)) {
 195                 if (val < TPS65217_BL_ISET1 ||
 196                         val > TPS65217_BL_ISET2) {
 197                         dev_err(&pdev->dev,
 198                                 "invalid 'isel' value in the device tree\n");
 199                         err = ERR_PTR(-EINVAL);
 200                         goto err;
 201                 }
 202
 203                 pdata->isel = val;
 204         }
 205
 206         pdata->fdim = TPS65217_BL_FDIM_200HZ;
 207         if (!of_property_read_u32(node, "fdim", &val)) {
 208                 switch (val) {
 209                 case 100:
 210                         pdata->fdim = TPS65217_BL_FDIM_100HZ;
 211                         break;
 212
 213                 case 200:
 214                         pdata->fdim = TPS65217_BL_FDIM_200HZ;
 215                         break;
 216
 217                 case 500:
 218                         pdata->fdim = TPS65217_BL_FDIM_500HZ;
 219                         break;
 220
 221                 case 1000:
 222                         pdata->fdim = TPS65217_BL_FDIM_1000HZ;
 223                         break;
 224
 225                 default:
 226                         dev_err(&pdev->dev,
 227                                 "invalid 'fdim' value in the device tree\n");
 228                         err = ERR_PTR(-EINVAL);
 229                         goto err;
 230                 }
 231         }
 232
 233         if (!of_property_read_u32(node, "default-brightness", &val)) {
 234                 if (val > 100) {
 235                         dev_err(&pdev->dev,
 236                                 "invalid 'default-brightness' value in the device tree\n");
 237                         err = ERR_PTR(-EINVAL);
 238                         goto err;
 239                 }
 240
 241                 pdata->dft_brightness = val;
 242         }
 243
 244         of_node_put(node);
 245
 246         return pdata;
 247
 248 err:
 249         of_node_put(node);
 250
 251         return err;
 252 }
 253 #else
 254 static struct tps65217_bl_pdata *
 255 tps65217_bl_parse_dt(struct platform_device *pdev)
 256 {
 257         return NULL;
 258 }
 259 #endif
 260
 261 static int tps65217_bl_probe(struct platform_device *pdev)
 262 {
 263         int rc;
 264         struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
 265         struct tps65217_bl *tps65217_bl;
 266         struct tps65217_bl_pdata *pdata;
 267         struct backlight_properties bl_props;
 268
 269         pdata = tps65217_bl_parse_dt(pdev);
 270         if (IS_ERR(pdata))
 271                 return PTR_ERR(pdata);
 272
 273         tps65217_bl = devm_kzalloc(&pdev->dev, sizeof(*tps65217_bl),
 274                                 GFP_KERNEL);
 275         if (tps65217_bl == NULL)
 276                 return -ENOMEM;
 277
 278         tps65217_bl->tps = tps;
 279         tps65217_bl->dev = &pdev->dev;
 280         tps65217_bl->is_enabled = false;
 281
 282         rc = tps65217_bl_hw_init(tps65217_bl, pdata);
 283         if (rc)
 284                 return rc;
 285
 286         memset(&bl_props, 0, sizeof(struct backlight_properties));
 287         bl_props.type = BACKLIGHT_RAW;
 288         bl_props.max_brightness = 100;
 289
 290         tps65217_bl->bl = devm_backlight_device_register(&pdev->dev, pdev->name,
 291                                                 tps65217_bl->dev, tps65217_bl,
 292                                                 &tps65217_bl_ops, &bl_props);
 293         if (IS_ERR(tps65217_bl->bl)) {
 294                 dev_err(tps65217_bl->dev,
 295                         "registration of backlight device failed: %d\n", rc);
 296                 return PTR_ERR(tps65217_bl->bl);
 297         }
 298
 299         tps65217_bl->bl->props.brightness = pdata->dft_brightness;
 300         backlight_update_status(tps65217_bl->bl);
 301         platform_set_drvdata(pdev, tps65217_bl);
 302
 303         return 0;
 304 }
 305
 306 #ifdef CONFIG_OF
 307 static const struct of_device_id tps65217_bl_of_match[] = {
 308         { .compatible = "ti,tps65217-bl", },
 309         { /* sentinel */ },
 310 };
 311 MODULE_DEVICE_TABLE(of, tps65217_bl_of_match);
 312 #endif
 313
 314 static struct platform_driver tps65217_bl_driver = {
 315         .probe          = tps65217_bl_probe,
 316         .driver         = {
 317                 .name   = "tps65217-bl",
 318                 .of_match_table = of_match_ptr(tps65217_bl_of_match),
 319         },
 320 };
 321
 322 module_platform_driver(tps65217_bl_driver);
 323
 324 MODULE_DESCRIPTION("TPS65217 Backlight driver");
 325 MODULE_LICENSE("GPL v2");
 326 MODULE_AUTHOR("Matthias Kaehlcke <matthias@kaehlcke.net>");