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_desc *enable_gpios[DSV_OUT_MAX];
33 	unsigned int enable_flag;
34 	unsigned int volt_sel[DSV_OUT_MAX];
35 };
36 
37 static int rt4801_of_parse_cb(struct device_node *np,
38 			      const struct regulator_desc *desc,
39 			      struct regulator_config *config)
40 {
41 	struct rt4801_priv *priv = config->driver_data;
42 	int id = desc->id;
43 
44 	if (priv->enable_gpios[id]) {
45 		dev_warn(priv->dev, "duplicated enable-gpios property\n");
46 		return 0;
47 	}
48 	priv->enable_gpios[id] = devm_fwnode_gpiod_get_index(priv->dev,
49 							     of_fwnode_handle(np),
50 							     "enable", 0,
51 							     GPIOD_OUT_HIGH,
52 							     "rt4801");
53 	if (IS_ERR(priv->enable_gpios[id]))
54 		priv->enable_gpios[id] = NULL;
55 
56 	return 0;
57 }
58 
59 static int rt4801_set_voltage_sel(struct regulator_dev *rdev, unsigned int selector)
60 {
61 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
62 	int id = rdev_get_id(rdev), ret;
63 
64 	if (priv->enable_flag & BIT(id)) {
65 		ret = regulator_set_voltage_sel_regmap(rdev, selector);
66 		if (ret)
67 			return ret;
68 	}
69 
70 	priv->volt_sel[id] = selector;
71 	return 0;
72 }
73 
74 static int rt4801_get_voltage_sel(struct regulator_dev *rdev)
75 {
76 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
77 	int id = rdev_get_id(rdev);
78 
79 	if (priv->enable_flag & BIT(id))
80 		return regulator_get_voltage_sel_regmap(rdev);
81 
82 	return priv->volt_sel[id];
83 }
84 
85 static int rt4801_enable(struct regulator_dev *rdev)
86 {
87 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
88 	int id = rdev_get_id(rdev), ret;
89 
90 	if (!priv->enable_gpios[id]) {
91 		dev_warn(&rdev->dev, "no dedicated gpio can control\n");
92 		goto bypass_gpio;
93 	}
94 
95 	gpiod_set_value(priv->enable_gpios[id], 1);
96 
97 bypass_gpio:
98 	ret = regmap_write(rdev->regmap, rdev->desc->vsel_reg, priv->volt_sel[id]);
99 	if (ret)
100 		return ret;
101 
102 	priv->enable_flag |= BIT(id);
103 	return 0;
104 }
105 
106 static int rt4801_disable(struct regulator_dev *rdev)
107 {
108 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
109 	int id = rdev_get_id(rdev);
110 
111 	if (!priv->enable_gpios[id]) {
112 		dev_warn(&rdev->dev, "no dedicated gpio can control\n");
113 		goto bypass_gpio;
114 	}
115 
116 	gpiod_set_value(priv->enable_gpios[id], 0);
117 
118 bypass_gpio:
119 	priv->enable_flag &= ~BIT(id);
120 	return 0;
121 }
122 
123 static int rt4801_is_enabled(struct regulator_dev *rdev)
124 {
125 	struct rt4801_priv *priv = rdev_get_drvdata(rdev);
126 	int id = rdev_get_id(rdev);
127 
128 	return !!(priv->enable_flag & BIT(id));
129 }
130 
131 static const struct regulator_ops rt4801_regulator_ops = {
132 	.list_voltage = regulator_list_voltage_linear,
133 	.set_voltage_sel = rt4801_set_voltage_sel,
134 	.get_voltage_sel = rt4801_get_voltage_sel,
135 	.enable = rt4801_enable,
136 	.disable = rt4801_disable,
137 	.is_enabled = rt4801_is_enabled,
138 };
139 
140 static const struct regulator_desc rt4801_regulator_descs[] = {
141 	{
142 		.name = "DSVP",
143 		.ops = &rt4801_regulator_ops,
144 		.of_match = of_match_ptr("DSVP"),
145 		.of_parse_cb = rt4801_of_parse_cb,
146 		.type = REGULATOR_VOLTAGE,
147 		.id = DSV_OUT_POS,
148 		.min_uV = MIN_UV,
149 		.uV_step = STEP_UV,
150 		.n_voltages = N_VOLTAGES,
151 		.owner = THIS_MODULE,
152 		.vsel_reg = RT4801_REG_VOP,
153 		.vsel_mask = VOUT_MASK,
154 	},
155 	{
156 		.name = "DSVN",
157 		.ops = &rt4801_regulator_ops,
158 		.of_match = of_match_ptr("DSVN"),
159 		.of_parse_cb = rt4801_of_parse_cb,
160 		.type = REGULATOR_VOLTAGE,
161 		.id = DSV_OUT_NEG,
162 		.min_uV = MIN_UV,
163 		.uV_step = STEP_UV,
164 		.n_voltages = N_VOLTAGES,
165 		.owner = THIS_MODULE,
166 		.vsel_reg = RT4801_REG_VON,
167 		.vsel_mask = VOUT_MASK,
168 	},
169 };
170 
171 static const struct regmap_config rt4801_regmap_config = {
172 	.reg_bits = 8,
173 	.val_bits = 8,
174 	.max_register = RT4801_REG_APPS,
175 };
176 
177 static int rt4801_probe(struct i2c_client *i2c)
178 {
179 	struct rt4801_priv *priv;
180 	struct regmap *regmap;
181 	int i;
182 
183 	priv = devm_kzalloc(&i2c->dev, sizeof(*priv), GFP_KERNEL);
184 	if (!priv)
185 		return -ENOMEM;
186 
187 	priv->dev = &i2c->dev;
188 	/* bootloader will on, driver only reconfigure enable to all output high */
189 	priv->enable_flag = DSVALL_ENABLE;
190 
191 	regmap = devm_regmap_init_i2c(i2c, &rt4801_regmap_config);
192 	if (IS_ERR(regmap)) {
193 		dev_err(&i2c->dev, "Failed to init regmap\n");
194 		return PTR_ERR(regmap);
195 	}
196 
197 	for (i = 0; i < DSV_OUT_MAX; i++) {
198 		priv->enable_gpios[i] = devm_gpiod_get_index_optional(&i2c->dev,
199 								      "enable",
200 								      i,
201 								      GPIOD_OUT_HIGH);
202 		if (IS_ERR(priv->enable_gpios[i])) {
203 			dev_err(&i2c->dev, "Failed to get gpios\n");
204 			return PTR_ERR(priv->enable_gpios[i]);
205 		}
206 	}
207 
208 	for (i = 0; i < DSV_OUT_MAX; i++) {
209 		const struct regulator_desc *desc = rt4801_regulator_descs + i;
210 		struct regulator_config config = { .dev = &i2c->dev, .driver_data = priv,
211 						   .regmap = regmap, };
212 		struct regulator_dev *rdev;
213 		unsigned int val;
214 		int ret;
215 
216 		/* initialize volt_sel variable */
217 		ret = regmap_read(regmap, desc->vsel_reg, &val);
218 		if (ret)
219 			return ret;
220 
221 		priv->volt_sel[i] = val & desc->vsel_mask;
222 
223 		rdev = devm_regulator_register(&i2c->dev, desc, &config);
224 		if (IS_ERR(rdev)) {
225 			dev_err(&i2c->dev, "Failed to register [%d] regulator\n", i);
226 			return PTR_ERR(rdev);
227 		}
228 	}
229 
230 	return 0;
231 }
232 
233 static const struct of_device_id __maybe_unused rt4801_of_id[] = {
234 	{ .compatible = "richtek,rt4801", },
235 	{ },
236 };
237 MODULE_DEVICE_TABLE(of, rt4801_of_id);
238 
239 static struct i2c_driver rt4801_driver = {
240 	.driver = {
241 		.name = "rt4801",
242 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
243 		.of_match_table = of_match_ptr(rt4801_of_id),
244 	},
245 	.probe = rt4801_probe,
246 };
247 module_i2c_driver(rt4801_driver);
248 
249 MODULE_AUTHOR("ChiYuan Hwang <cy_huang@richtek.com>");
250 MODULE_DESCRIPTION("Richtek RT4801 Display Bias Driver");
251 MODULE_LICENSE("GPL v2");
252