1 // SPDX-License-Identifier: GPL-2.0-only
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>
12 #define RT4831_REG_BLCFG 0x02
13 #define RT4831_REG_BLDIML 0x04
14 #define RT4831_REG_ENABLE 0x08
16 #define RT4831_BLMAX_BRIGHTNESS 2048
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
29 struct regmap *regmap;
30 struct backlight_device *bl;
33 static int rt4831_bl_update_status(struct backlight_device *bl_dev)
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;
42 v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
43 v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
45 ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
50 return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
54 static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
56 struct rt4831_priv *priv = bl_get_data(bl_dev);
61 ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
65 if (!(val & RT4831_BLEN_MASK))
68 ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
72 ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
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,
83 static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
84 struct backlight_properties *bl_props)
86 struct device *dev = priv->dev;
92 /* common properties */
93 ret = device_property_read_u32(dev, "max-brightness", &brightness);
95 brightness = RT4831_BLMAX_BRIGHTNESS;
97 bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
99 ret = device_property_read_u32(dev, "default-brightness", &brightness);
101 brightness = bl_props->max_brightness;
103 bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
105 /* vendor properties */
106 if (device_property_read_bool(dev, "richtek,pwm-enable"))
107 val = RT4831_BLPWMEN_MASK;
109 ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
113 ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
115 propval = RT4831_BLOVPLVL_21V;
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);
123 ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
125 dev_err(dev, "richtek,channel-use DT property missing\n");
129 if (!(propval & RT4831_BLCH_MASK)) {
130 dev_err(dev, "No channel specified\n");
134 return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
137 static int rt4831_bl_probe(struct platform_device *pdev)
139 struct rt4831_priv *priv;
140 struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
141 .scale = BACKLIGHT_SCALE_LINEAR };
144 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
148 priv->dev = &pdev->dev;
150 priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
152 dev_err(&pdev->dev, "Failed to init regmap\n");
156 ret = rt4831_parse_backlight_properties(priv, &bl_props);
158 dev_err(&pdev->dev, "Failed to parse backlight properties\n");
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);
169 backlight_update_status(priv->bl);
170 platform_set_drvdata(pdev, priv);
175 static int rt4831_bl_remove(struct platform_device *pdev)
177 struct rt4831_priv *priv = platform_get_drvdata(pdev);
178 struct backlight_device *bl_dev = priv->bl;
180 bl_dev->props.brightness = 0;
181 backlight_update_status(priv->bl);
186 static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
187 { .compatible = "richtek,rt4831-backlight", },
190 MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
192 static struct platform_driver rt4831_bl_driver = {
194 .name = "rt4831-backlight",
195 .of_match_table = rt4831_bl_of_match,
197 .probe = rt4831_bl_probe,
198 .remove = rt4831_bl_remove,
200 module_platform_driver(rt4831_bl_driver);
202 MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
203 MODULE_LICENSE("GPL v2");