1
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
27struct rt4831_priv {
28 struct device *dev;
29 struct regmap *regmap;
30 struct backlight_device *bl;
31};
32
33static 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
54static 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
77static 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
83static 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
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
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
137static 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
175static 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
186static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
187 { .compatible = "richtek,rt4831-backlight", },
188 {}
189};
190MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
191
192static 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};
200module_platform_driver(rt4831_bl_driver);
201
202MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
203MODULE_LICENSE("GPL v2");
204
