drivers/video/backlight/rt4831-backlight.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 #include <dt-bindings/leds/rt4831-backlight.h>
   4 #include <linux/backlight.h>
   5 #include <linux/bitops.h>
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/platform_device.h>
   9 #include <linux/property.h>
  10 #include <linux/regmap.h>
  11
  12 #define RT4831_REG_BLCFG        0x02
  13 #define RT4831_REG_BLDIML       0x04
  14 #define RT4831_REG_ENABLE       0x08
  15
  16 #define RT4831_BLMAX_BRIGHTNESS 2048
  17
  18 #define RT4831_BLOVP_MASK       GENMASK(7, 5)
  19 #define RT4831_BLOVP_SHIFT      5
  20 #define RT4831_BLPWMEN_MASK     BIT(0)
  21 #define RT4831_BLEN_MASK        BIT(4)
  22 #define RT4831_BLCH_MASK        GENMASK(3, 0)
  23 #define RT4831_BLDIML_MASK      GENMASK(2, 0)
  24 #define RT4831_BLDIMH_MASK      GENMASK(10, 3)
  25 #define RT4831_BLDIMH_SHIFT     3
  26
  27 struct rt4831_priv {
  28         struct device *dev;
  29         struct regmap *regmap;
  30         struct backlight_device *bl;
  31 };
  32
  33 static int rt4831_bl_update_status(struct backlight_device *bl_dev)
  34 {
  35         struct rt4831_priv *priv = bl_get_data(bl_dev);
  36         int brightness = backlight_get_brightness(bl_dev);
  37         unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
  38         u8 v[2];
  39         int ret;
  40
  41         if (brightness) {
  42                 v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
  43                 v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
  44
  45                 ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
  46                 if (ret)
  47                         return ret;
  48         }
  49
  50         return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
  51
  52 }
  53
  54 static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
  55 {
  56         struct rt4831_priv *priv = bl_get_data(bl_dev);
  57         unsigned int val;
  58         u8 v[2];
  59         int ret;
  60
  61         ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
  62         if (ret)
  63                 return ret;
  64
  65         if (!(val & RT4831_BLEN_MASK))
  66                 return 0;
  67
  68         ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
  69         if (ret)
  70                 return ret;
  71
  72         ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
  73
  74         return ret;
  75 }
  76
  77 static const struct backlight_ops rt4831_bl_ops = {
  78         .options = BL_CORE_SUSPENDRESUME,
  79         .update_status = rt4831_bl_update_status,
  80         .get_brightness = rt4831_bl_get_brightness,
  81 };
  82
  83 static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
  84                                              struct backlight_properties *bl_props)
  85 {
  86         struct device *dev = priv->dev;
  87         u8 propval;
  88         u32 brightness;
  89         unsigned int val = 0;
  90         int ret;
  91
  92         /* common properties */
  93         ret = device_property_read_u32(dev, "max-brightness", &brightness);
  94         if (ret)
  95                 brightness = RT4831_BLMAX_BRIGHTNESS;
  96
  97         bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
  98
  99         ret = device_property_read_u32(dev, "default-brightness", &brightness);
 100         if (ret)
 101                 brightness = bl_props->max_brightness;
 102
 103         bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
 104
 105         /* vendor properties */
 106         if (device_property_read_bool(dev, "richtek,pwm-enable"))
 107                 val = RT4831_BLPWMEN_MASK;
 108
 109         ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
 110         if (ret)
 111                 return ret;
 112
 113         ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
 114         if (ret)
 115                 propval = RT4831_BLOVPLVL_21V;
 116
 117         propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
 118         ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
 119                                  propval << RT4831_BLOVP_SHIFT);
 120         if (ret)
 121                 return ret;
 122
 123         ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
 124         if (ret) {
 125                 dev_err(dev, "richtek,channel-use DT property missing\n");
 126                 return ret;
 127         }
 128
 129         if (!(propval & RT4831_BLCH_MASK)) {
 130                 dev_err(dev, "No channel specified\n");
 131                 return -EINVAL;
 132         }
 133
 134         return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
 135 }
 136
 137 static int rt4831_bl_probe(struct platform_device *pdev)
 138 {
 139         struct rt4831_priv *priv;
 140         struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
 141                                                  .scale = BACKLIGHT_SCALE_LINEAR };
 142         int ret;
 143
 144         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 145         if (!priv)
 146                 return -ENOMEM;
 147
 148         priv->dev = &pdev->dev;
 149
 150         priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 151         if (!priv->regmap) {
 152                 dev_err(&pdev->dev, "Failed to init regmap\n");
 153                 return -ENODEV;
 154         }
 155
 156         ret = rt4831_parse_backlight_properties(priv, &bl_props);
 157         if (ret) {
 158                 dev_err(&pdev->dev, "Failed to parse backlight properties\n");
 159                 return ret;
 160         }
 161
 162         priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
 163                                                   &rt4831_bl_ops, &bl_props);
 164         if (IS_ERR(priv->bl)) {
 165                 dev_err(&pdev->dev, "Failed to register backlight\n");
 166                 return PTR_ERR(priv->bl);
 167         }
 168
 169         backlight_update_status(priv->bl);
 170         platform_set_drvdata(pdev, priv);
 171
 172         return 0;
 173 }
 174
 175 static int rt4831_bl_remove(struct platform_device *pdev)
 176 {
 177         struct rt4831_priv *priv = platform_get_drvdata(pdev);
 178         struct backlight_device *bl_dev = priv->bl;
 179
 180         bl_dev->props.brightness = 0;
 181         backlight_update_status(priv->bl);
 182
 183         return 0;
 184 }
 185
 186 static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
 187         { .compatible = "richtek,rt4831-backlight", },
 188         {}
 189 };
 190 MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
 191
 192 static struct platform_driver rt4831_bl_driver = {
 193         .driver = {
 194                 .name = "rt4831-backlight",
 195                 .of_match_table = rt4831_bl_of_match,
 196         },
 197         .probe = rt4831_bl_probe,
 198         .remove = rt4831_bl_remove,
 199 };
 200 module_platform_driver(rt4831_bl_driver);
 201
 202 MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
 203 MODULE_LICENSE("GPL v2");