1 // SPDX-License-Identifier: GPL-2.0+
2 
3 #include <linux/gpio/consumer.h>
4 #include <linux/i2c.h>
5 #include <linux/kernel.h>
6 #include <linux/module.h>
7 #include <linux/of.h>
8 #include <linux/regmap.h>
9 #include <linux/regulator/driver.h>
10 
11 #define RT4801_REG_VOP	0x00
12 #define RT4801_REG_VON	0x01
13 #define RT4801_REG_APPS	0x03
14 
15 #define VOUT_MASK	0x1F
16 
17 #define MIN_UV		4000000
18 #define STEP_UV		100000
19 #define MAX_UV		6000000
20 #define N_VOLTAGES	((MAX_UV - MIN_UV) / STEP_UV + 1)
21 
22 #define DSV_OUT_POS	0
23 #define DSV_OUT_NEG	1
24 #define DSV_OUT_MAX	2
25 
26 #define DSVP_ENABLE	BIT(0)
27 #define DSVN_ENABLE	BIT(1)
28 #define DSVALL_ENABLE	(DSVP_ENABLE | DSVN_ENABLE)
29 
30 struct rt4801_priv {
31 	struct device *dev;
32 	struct gpio_descs *enable_gpios;
33 	unsigned int enable_flag;
34 	unsigned int volt_sel[DSV_OUT_MAX];
35 };
36 
37 static int rt4801_set_voltage_sel(struct regulator_dev *rdev, unsigned int selector)
38 {
39 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
40 	int id = rdev_get_id(rdev), ret;
41 
42 	if (priv->enable_flag & BIT(id)) {
43 		ret = regulator_set_voltage_sel_regmap(rdev, selector);
44 		if (ret)
45 			return ret;
46 	}
47 
48 	priv->volt_sel[id] = selector;
49 	return 0;
50 }
51 
52 static int rt4801_get_voltage_sel(struct regulator_dev *rdev)
53 {
54 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
55 	int id = rdev_get_id(rdev);
56 
57 	if (priv->enable_flag & BIT(id))
58 		return regulator_get_voltage_sel_regmap(rdev);
59 
60 	return priv->volt_sel[id];
61 }
62 
63 static int rt4801_enable(struct regulator_dev *rdev)
64 {
65 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
66 	struct gpio_descs *gpios = priv->enable_gpios;
67 	int id = rdev_get_id(rdev), ret;
68 
69 	if (!gpios || gpios->ndescs <= id) {
70 		dev_warn(&rdev->dev, "no dedicated gpio can control\n");
71 		goto bypass_gpio;
72 	}
73 
74 	gpiod_set_value(gpios->desc[id], 1);
75 
76 bypass_gpio:
77 	ret = regmap_write(rdev->regmap, rdev->desc->vsel_reg, priv->volt_sel[id]);
78 	if (ret)
79 		return ret;
80 
81 	priv->enable_flag |= BIT(id);
82 	return 0;
83 }
84 
85 static int rt4801_disable(struct regulator_dev *rdev)
86 {
87 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
88 	struct gpio_descs *gpios = priv->enable_gpios;
89 	int id = rdev_get_id(rdev);
90 
91 	if (!gpios || gpios->ndescs <= id) {
92 		dev_warn(&rdev->dev, "no dedicated gpio can control\n");
93 		goto bypass_gpio;
94 	}
95 
96 	gpiod_set_value(gpios->desc[id], 0);
97 
98 bypass_gpio:
99 	priv->enable_flag &= ~BIT(id);
100 	return 0;
101 }
102 
103 static int rt4801_is_enabled(struct regulator_dev *rdev)
104 {
105 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
106 	int id = rdev_get_id(rdev);
107 
108 	return !!(priv->enable_flag & BIT(id));
109 }
110 
111 static const struct regulator_ops rt4801_regulator_ops = {
112 	.list_voltage = regulator_list_voltage_linear,
113 	.set_voltage_sel = rt4801_set_voltage_sel,
114 	.get_voltage_sel = rt4801_get_voltage_sel,
115 	.enable = rt4801_enable,
116 	.disable = rt4801_disable,
117 	.is_enabled = rt4801_is_enabled,
118 };
119 
120 static const struct regulator_desc rt4801_regulator_descs[] = {
121 	{
122 		.name = "DSVP",
123 		.ops = &rt4801_regulator_ops,
124 		.of_match = of_match_ptr("DSVP"),
125 		.type = REGULATOR_VOLTAGE,
126 		.id = DSV_OUT_POS,
127 		.min_uV = MIN_UV,
128 		.uV_step = STEP_UV,
129 		.n_voltages = N_VOLTAGES,
130 		.owner = THIS_MODULE,
131 		.vsel_reg = RT4801_REG_VOP,
132 		.vsel_mask = VOUT_MASK,
133 	},
134 	{
135 		.name = "DSVN",
136 		.ops = &rt4801_regulator_ops,
137 		.of_match = of_match_ptr("DSVN"),
138 		.type = REGULATOR_VOLTAGE,
139 		.id = DSV_OUT_NEG,
140 		.min_uV = MIN_UV,
141 		.uV_step = STEP_UV,
142 		.n_voltages = N_VOLTAGES,
143 		.owner = THIS_MODULE,
144 		.vsel_reg = RT4801_REG_VON,
145 		.vsel_mask = VOUT_MASK,
146 	},
147 };
148 
149 static const struct regmap_config rt4801_regmap_config = {
150 	.reg_bits = 8,
151 	.val_bits = 8,
152 	.max_register = RT4801_REG_APPS,
153 };
154 
155 static int rt4801_probe(struct i2c_client *i2c)
156 {
157 	struct rt4801_priv *priv;
158 	struct regmap *regmap;
159 	int i;
160 
161 	priv = devm_kzalloc(&i2c->dev, sizeof(*priv), GFP_KERNEL);
162 	if (!priv)
163 		return -ENOMEM;
164 
165 	priv->dev = &i2c->dev;
166 	/* bootloader will on, driver only reconfigure enable to all output high */
167 	priv->enable_flag = DSVALL_ENABLE;
168 
169 	regmap = devm_regmap_init_i2c(i2c, &rt4801_regmap_config);
170 	if (IS_ERR(regmap)) {
171 		dev_err(&i2c->dev, "Failed to init regmap\n");
172 		return PTR_ERR(regmap);
173 	}
174 
175 	priv->enable_gpios = devm_gpiod_get_array_optional(&i2c->dev, "enable", GPIOD_OUT_HIGH);
176 	if (IS_ERR(priv->enable_gpios)) {
177 		dev_err(&i2c->dev, "Failed to get gpios\n");
178 		return PTR_ERR(priv->enable_gpios);
179 	}
180 
181 	for (i = 0; i < DSV_OUT_MAX; i++) {
182 		const struct regulator_desc *desc = rt4801_regulator_descs + i;
183 		struct regulator_config config = { .dev = &i2c->dev, .driver_data = priv,
184 						   .regmap = regmap, };
185 		struct regulator_dev *rdev;
186 		unsigned int val;
187 		int ret;
188 
189 		/* initialize volt_sel variable */
190 		ret = regmap_read(regmap, desc->vsel_reg, &val);
191 		if (ret)
192 			return ret;
193 
194 		priv->volt_sel[i] = val & desc->vsel_mask;
195 
196 		rdev = devm_regulator_register(&i2c->dev, desc, &config);
197 		if (IS_ERR(rdev)) {
198 			dev_err(&i2c->dev, "Failed to register [%d] regulator\n", i);
199 			return PTR_ERR(rdev);
200 		}
201 	}
202 
203 	return 0;
204 }
205 
206 static const struct of_device_id __maybe_unused rt4801_of_id[] = {
207 	{ .compatible = "richtek,rt4801", },
208 	{ },
209 };
210 MODULE_DEVICE_TABLE(of, rt4801_of_id);
211 
212 static struct i2c_driver rt4801_driver = {
213 	.driver = {
214 		.name = "rt4801",
215 		.of_match_table = of_match_ptr(rt4801_of_id),
216 	},
217 	.probe_new = rt4801_probe,
218 };
219 module_i2c_driver(rt4801_driver);
220 
221 MODULE_AUTHOR("ChiYuan Hwang <cy_huang@richtek.com>");
222 MODULE_DESCRIPTION("Richtek RT4801 Display Bias Driver");
223 MODULE_LICENSE("GPL v2");
224