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