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 = bl->props.brightness;
  81
  82         if (bl->props.state & BL_CORE_SUSPENDED)
  83                 brightness = 0;
  84
  85         if ((bl->props.power != FB_BLANK_UNBLANK) ||
  86                 (bl->props.fb_blank != FB_BLANK_UNBLANK))
  87                 /* framebuffer in low power mode or blanking active */
  88                 brightness = 0;
  89
  90         if (brightness > 0) {
  91                 rc = tps65217_reg_write(tps65217_bl->tps,
  92                                         TPS65217_REG_WLEDCTRL2,
  93                                         brightness - 1,
  94                                         TPS65217_PROTECT_NONE);
  95                 if (rc) {
  96                         dev_err(tps65217_bl->dev,
  97                                 "failed to set brightness level: %d\n", rc);
  98                         return rc;
  99                 }
 100
 101                 dev_dbg(tps65217_bl->dev, "brightness set to %d\n", brightness);
 102
 103                 if (!tps65217_bl->is_enabled)
 104                         rc = tps65217_bl_enable(tps65217_bl);
 105         } else {
 106                 rc = tps65217_bl_disable(tps65217_bl);
 107         }
 108
 109         return rc;
 110 }
 111
 112 static int tps65217_bl_get_brightness(struct backlight_device *bl)
 113 {
 114         return bl->props.brightness;
 115 }
 116
 117 static const struct backlight_ops tps65217_bl_ops = {
 118         .options        = BL_CORE_SUSPENDRESUME,
 119         .update_status  = tps65217_bl_update_status,
 120         .get_brightness = tps65217_bl_get_brightness
 121 };
 122
 123 static int tps65217_bl_hw_init(struct tps65217_bl *tps65217_bl,
 124                         struct tps65217_bl_pdata *pdata)
 125 {
 126         int rc;
 127
 128         rc = tps65217_bl_disable(tps65217_bl);
 129         if (rc)
 130                 return rc;
 131
 132         switch (pdata->isel) {
 133         case TPS65217_BL_ISET1:
 134                 /* select ISET_1 current level */
 135                 rc = tps65217_clear_bits(tps65217_bl->tps,
 136                                         TPS65217_REG_WLEDCTRL1,
 137                                         TPS65217_WLEDCTRL1_ISEL,
 138                                         TPS65217_PROTECT_NONE);
 139                 if (rc) {
 140                         dev_err(tps65217_bl->dev,
 141                                 "failed to select ISET1 current level: %d)\n",
 142                                 rc);
 143                         return rc;
 144                 }
 145
 146                 dev_dbg(tps65217_bl->dev, "selected ISET1 current level\n");
 147
 148                 break;
 149
 150         case TPS65217_BL_ISET2:
 151                 /* select ISET2 current level */
 152                 rc = tps65217_set_bits(tps65217_bl->tps, TPS65217_REG_WLEDCTRL1,
 153                                 TPS65217_WLEDCTRL1_ISEL,
 154                                 TPS65217_WLEDCTRL1_ISEL, TPS65217_PROTECT_NONE);
 155                 if (rc) {
 156                         dev_err(tps65217_bl->dev,
 157                                 "failed to select ISET2 current level: %d\n",
 158                                 rc);
 159                         return rc;
 160                 }
 161
 162                 dev_dbg(tps65217_bl->dev, "selected ISET2 current level\n");
 163
 164                 break;
 165
 166         default:
 167                 dev_err(tps65217_bl->dev,
 168                         "invalid value for current level: %d\n", pdata->isel);
 169                 return -EINVAL;
 170         }
 171
 172         /* set PWM frequency */
 173         rc = tps65217_set_bits(tps65217_bl->tps,
 174                         TPS65217_REG_WLEDCTRL1,
 175                         TPS65217_WLEDCTRL1_FDIM_MASK,
 176                         pdata->fdim,
 177                         TPS65217_PROTECT_NONE);
 178         if (rc) {
 179                 dev_err(tps65217_bl->dev,
 180                         "failed to select PWM dimming frequency: %d\n",
 181                         rc);
 182                 return rc;
 183         }
 184
 185         return 0;
 186 }
 187
 188 #ifdef CONFIG_OF
 189 static struct tps65217_bl_pdata *
 190 tps65217_bl_parse_dt(struct platform_device *pdev)
 191 {
 192         struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
 193         struct device_node *node = of_node_get(tps->dev->of_node);
 194         struct tps65217_bl_pdata *pdata, *err;
 195         u32 val;
 196
 197         node = of_find_node_by_name(node, "backlight");
 198         if (!node)
 199                 return ERR_PTR(-ENODEV);
 200
 201         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 202         if (!pdata) {
 203                 dev_err(&pdev->dev, "failed to allocate platform data\n");
 204                 err = ERR_PTR(-ENOMEM);
 205                 goto err;
 206         }
 207
 208         pdata->isel = TPS65217_BL_ISET1;
 209         if (!of_property_read_u32(node, "isel", &val)) {
 210                 if (val < TPS65217_BL_ISET1 ||
 211                         val > TPS65217_BL_ISET2) {
 212                         dev_err(&pdev->dev,
 213                                 "invalid 'isel' value in the device tree\n");
 214                         err = ERR_PTR(-EINVAL);
 215                         goto err;
 216                 }
 217
 218                 pdata->isel = val;
 219         }
 220
 221         pdata->fdim = TPS65217_BL_FDIM_200HZ;
 222         if (!of_property_read_u32(node, "fdim", &val)) {
 223                 switch (val) {
 224                 case 100:
 225                         pdata->fdim = TPS65217_BL_FDIM_100HZ;
 226                         break;
 227
 228                 case 200:
 229                         pdata->fdim = TPS65217_BL_FDIM_200HZ;
 230                         break;
 231
 232                 case 500:
 233                         pdata->fdim = TPS65217_BL_FDIM_500HZ;
 234                         break;
 235
 236                 case 1000:
 237                         pdata->fdim = TPS65217_BL_FDIM_1000HZ;
 238                         break;
 239
 240                 default:
 241                         dev_err(&pdev->dev,
 242                                 "invalid 'fdim' value in the device tree\n");
 243                         err = ERR_PTR(-EINVAL);
 244                         goto err;
 245                 }
 246         }
 247
 248         of_node_put(node);
 249
 250         return pdata;
 251
 252 err:
 253         of_node_put(node);
 254
 255         return err;
 256 }
 257 #else
 258 static struct tps65217_bl_pdata *
 259 tps65217_bl_parse_dt(struct platform_device *pdev)
 260 {
 261         return NULL;
 262 }
 263 #endif
 264
 265 static int tps65217_bl_probe(struct platform_device *pdev)
 266 {
 267         int rc;
 268         struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
 269         struct tps65217_bl *tps65217_bl;
 270         struct tps65217_bl_pdata *pdata;
 271         struct backlight_properties bl_props;
 272
 273         if (tps->dev->of_node) {
 274                 pdata = tps65217_bl_parse_dt(pdev);
 275                 if (IS_ERR(pdata))
 276                         return PTR_ERR(pdata);
 277         } else {
 278                 if (!pdev->dev.platform_data) {
 279                         dev_err(&pdev->dev, "no platform data provided\n");
 280                         return -EINVAL;
 281                 }
 282
 283                 pdata = pdev->dev.platform_data;
 284         }
 285
 286         tps65217_bl = devm_kzalloc(&pdev->dev, sizeof(*tps65217_bl),
 287                                 GFP_KERNEL);
 288         if (tps65217_bl == NULL) {
 289                 dev_err(&pdev->dev, "allocation of struct tps65217_bl failed\n");
 290                 return -ENOMEM;
 291         }
 292
 293         tps65217_bl->tps = tps;
 294         tps65217_bl->dev = &pdev->dev;
 295         tps65217_bl->is_enabled = false;
 296
 297         rc = tps65217_bl_hw_init(tps65217_bl, pdata);
 298         if (rc)
 299                 return rc;
 300
 301         memset(&bl_props, 0, sizeof(struct backlight_properties));
 302         bl_props.type = BACKLIGHT_RAW;
 303         bl_props.max_brightness = 100;
 304
 305         tps65217_bl->bl = backlight_device_register(pdev->name,
 306                                                 tps65217_bl->dev, tps65217_bl,
 307                                                 &tps65217_bl_ops, &bl_props);
 308         if (IS_ERR(tps65217_bl->bl)) {
 309                 dev_err(tps65217_bl->dev,
 310                         "registration of backlight device failed: %d\n", rc);
 311                 return PTR_ERR(tps65217_bl->bl);
 312         }
 313
 314         tps65217_bl->bl->props.brightness = 0;
 315         platform_set_drvdata(pdev, tps65217_bl);
 316
 317         return 0;
 318 }
 319
 320 static int tps65217_bl_remove(struct platform_device *pdev)
 321 {
 322         struct tps65217_bl *tps65217_bl = platform_get_drvdata(pdev);
 323
 324         backlight_device_unregister(tps65217_bl->bl);
 325
 326         return 0;
 327 }
 328
 329 static struct platform_driver tps65217_bl_driver = {
 330         .probe          = tps65217_bl_probe,
 331         .remove         = tps65217_bl_remove,
 332         .driver         = {
 333                 .owner  = THIS_MODULE,
 334                 .name   = "tps65217-bl",
 335         },
 336 };
 337
 338 module_platform_driver(tps65217_bl_driver);
 339
 340 MODULE_DESCRIPTION("TPS65217 Backlight driver");
 341 MODULE_LICENSE("GPL v2");
 342 MODULE_AUTHOR("Matthias Kaehlcke <matthias@kaehlcke.net>");