Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/mod_devicetable.h>
8#include <linux/module.h>
9#include <linux/platform_device.h>
10#include <linux/property.h>
11#include <linux/regmap.h>
12
13#define RT4831_REG_BLCFG 0x02
14#define RT4831_REG_BLDIML 0x04
15#define RT4831_REG_ENABLE 0x08
16#define RT4831_REG_BLOPT2 0x11
17
18#define RT4831_BLMAX_BRIGHTNESS 2048
19
20#define RT4831_BLOVP_MASK GENMASK(7, 5)
21#define RT4831_BLOVP_SHIFT 5
22#define RT4831_BLPWMEN_MASK BIT(0)
23#define RT4831_BLEN_MASK BIT(4)
24#define RT4831_BLCH_MASK GENMASK(3, 0)
25#define RT4831_BLDIML_MASK GENMASK(2, 0)
26#define RT4831_BLDIMH_MASK GENMASK(10, 3)
27#define RT4831_BLDIMH_SHIFT 3
28#define RT4831_BLOCP_MASK GENMASK(1, 0)
29
30#define RT4831_BLOCP_MINUA 900000
31#define RT4831_BLOCP_MAXUA 1800000
32#define RT4831_BLOCP_STEPUA 300000
33
34struct rt4831_priv {
35 struct device *dev;
36 struct regmap *regmap;
37 struct backlight_device *bl;
38};
39
40static int rt4831_bl_update_status(struct backlight_device *bl_dev)
41{
42 struct rt4831_priv *priv = bl_get_data(bl_dev);
43 int brightness = backlight_get_brightness(bl_dev);
44 unsigned int enable = brightness ? RT4831_BLEN_MASK : 0;
45 u8 v[2];
46 int ret;
47
48 if (brightness) {
49 v[0] = (brightness - 1) & RT4831_BLDIML_MASK;
50 v[1] = ((brightness - 1) & RT4831_BLDIMH_MASK) >> RT4831_BLDIMH_SHIFT;
51
52 ret = regmap_raw_write(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
53 if (ret)
54 return ret;
55 }
56
57 return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLEN_MASK, enable);
58
59}
60
61static int rt4831_bl_get_brightness(struct backlight_device *bl_dev)
62{
63 struct rt4831_priv *priv = bl_get_data(bl_dev);
64 unsigned int val;
65 u8 v[2];
66 int ret;
67
68 ret = regmap_read(priv->regmap, RT4831_REG_ENABLE, &val);
69 if (ret)
70 return ret;
71
72 if (!(val & RT4831_BLEN_MASK))
73 return 0;
74
75 ret = regmap_raw_read(priv->regmap, RT4831_REG_BLDIML, v, sizeof(v));
76 if (ret)
77 return ret;
78
79 ret = (v[1] << RT4831_BLDIMH_SHIFT) + (v[0] & RT4831_BLDIML_MASK) + 1;
80
81 return ret;
82}
83
84static const struct backlight_ops rt4831_bl_ops = {
85 .options = BL_CORE_SUSPENDRESUME,
86 .update_status = rt4831_bl_update_status,
87 .get_brightness = rt4831_bl_get_brightness,
88};
89
90static int rt4831_parse_backlight_properties(struct rt4831_priv *priv,
91 struct backlight_properties *bl_props)
92{
93 struct device *dev = priv->dev;
94 u8 propval;
95 u32 brightness, ocp_uA;
96 unsigned int val = 0;
97 int ret;
98
99 /* common properties */
100 ret = device_property_read_u32(dev, "max-brightness", &brightness);
101 if (ret)
102 brightness = RT4831_BLMAX_BRIGHTNESS;
103
104 bl_props->max_brightness = min_t(u32, brightness, RT4831_BLMAX_BRIGHTNESS);
105
106 ret = device_property_read_u32(dev, "default-brightness", &brightness);
107 if (ret)
108 brightness = bl_props->max_brightness;
109
110 bl_props->brightness = min_t(u32, brightness, bl_props->max_brightness);
111
112 /* vendor properties */
113 if (device_property_read_bool(dev, "richtek,pwm-enable"))
114 val = RT4831_BLPWMEN_MASK;
115
116 ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLPWMEN_MASK, val);
117 if (ret)
118 return ret;
119
120 ret = device_property_read_u8(dev, "richtek,bled-ovp-sel", &propval);
121 if (ret)
122 propval = RT4831_BLOVPLVL_21V;
123
124 propval = min_t(u8, propval, RT4831_BLOVPLVL_29V);
125 ret = regmap_update_bits(priv->regmap, RT4831_REG_BLCFG, RT4831_BLOVP_MASK,
126 propval << RT4831_BLOVP_SHIFT);
127 if (ret)
128 return ret;
129
130 /*
131 * This OCP level is used to protect and limit the inductor current.
132 * If inductor peak current reach the level, low-side MOSFET will be
133 * turned off. Meanwhile, the output channel current may be limited.
134 * To match the configured channel current, the inductor chosen must
135 * be higher than the OCP level.
136 *
137 * Not like the OVP level, the default 21V can be used in the most
138 * application. But if the chosen OCP level is smaller than needed,
139 * it will also affect the backlight channel output current to be
140 * smaller than the register setting.
141 */
142 ret = device_property_read_u32(dev, "richtek,bled-ocp-microamp",
143 &ocp_uA);
144 if (!ret) {
145 ocp_uA = clamp_val(ocp_uA, RT4831_BLOCP_MINUA,
146 RT4831_BLOCP_MAXUA);
147 val = DIV_ROUND_UP(ocp_uA - RT4831_BLOCP_MINUA,
148 RT4831_BLOCP_STEPUA);
149 ret = regmap_update_bits(priv->regmap, RT4831_REG_BLOPT2,
150 RT4831_BLOCP_MASK, val);
151 if (ret)
152 return ret;
153 }
154
155 ret = device_property_read_u8(dev, "richtek,channel-use", &propval);
156 if (ret) {
157 dev_err(dev, "richtek,channel-use DT property missing\n");
158 return ret;
159 }
160
161 if (!(propval & RT4831_BLCH_MASK)) {
162 dev_err(dev, "No channel specified\n");
163 return -EINVAL;
164 }
165
166 return regmap_update_bits(priv->regmap, RT4831_REG_ENABLE, RT4831_BLCH_MASK, propval);
167}
168
169static int rt4831_bl_probe(struct platform_device *pdev)
170{
171 struct rt4831_priv *priv;
172 struct backlight_properties bl_props = { .type = BACKLIGHT_RAW,
173 .scale = BACKLIGHT_SCALE_LINEAR };
174 int ret;
175
176 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
177 if (!priv)
178 return -ENOMEM;
179
180 priv->dev = &pdev->dev;
181
182 priv->regmap = dev_get_regmap(pdev->dev.parent, NULL);
183 if (!priv->regmap) {
184 dev_err(&pdev->dev, "Failed to init regmap\n");
185 return -ENODEV;
186 }
187
188 ret = rt4831_parse_backlight_properties(priv, &bl_props);
189 if (ret) {
190 dev_err(&pdev->dev, "Failed to parse backlight properties\n");
191 return ret;
192 }
193
194 priv->bl = devm_backlight_device_register(&pdev->dev, pdev->name, &pdev->dev, priv,
195 &rt4831_bl_ops, &bl_props);
196 if (IS_ERR(priv->bl)) {
197 dev_err(&pdev->dev, "Failed to register backlight\n");
198 return PTR_ERR(priv->bl);
199 }
200
201 backlight_update_status(priv->bl);
202 platform_set_drvdata(pdev, priv);
203
204 return 0;
205}
206
207static void rt4831_bl_remove(struct platform_device *pdev)
208{
209 struct rt4831_priv *priv = platform_get_drvdata(pdev);
210 struct backlight_device *bl_dev = priv->bl;
211
212 bl_dev->props.brightness = 0;
213 backlight_update_status(priv->bl);
214}
215
216static const struct of_device_id __maybe_unused rt4831_bl_of_match[] = {
217 { .compatible = "richtek,rt4831-backlight", },
218 {}
219};
220MODULE_DEVICE_TABLE(of, rt4831_bl_of_match);
221
222static struct platform_driver rt4831_bl_driver = {
223 .driver = {
224 .name = "rt4831-backlight",
225 .of_match_table = rt4831_bl_of_match,
226 },
227 .probe = rt4831_bl_probe,
228 .remove = rt4831_bl_remove,
229};
230module_platform_driver(rt4831_bl_driver);
231
232MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
233MODULE_DESCRIPTION("Richtek RT4831 Backlight Driver");
234MODULE_LICENSE("GPL v2");