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
 30struct 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
 37static 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
 52static 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
 63static 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
 76bypass_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
 85static 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
 98bypass_gpio:
 99	priv->enable_flag &= ~BIT(id);
100	return 0;
101}
102
103static 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
111static 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
120static 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
149static const struct regmap_config rt4801_regmap_config = {
150	.reg_bits = 8,
151	.val_bits = 8,
152	.max_register = RT4801_REG_APPS,
153};
154
155static 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
206static const struct of_device_id __maybe_unused rt4801_of_id[] = {
207	{ .compatible = "richtek,rt4801", },
208	{ },
209};
210MODULE_DEVICE_TABLE(of, rt4801_of_id);
211
212static 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};
219module_i2c_driver(rt4801_driver);
220
221MODULE_AUTHOR("ChiYuan Hwang <cy_huang@richtek.com>");
222MODULE_DESCRIPTION("Richtek RT4801 Display Bias Driver");
223MODULE_LICENSE("GPL v2");