1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (c) 2021, The Linux Foundation. All rights reserved.
  4 * Copyright (c) 2022, Linaro Ltd.
  5 */
  6
  7#include <linux/bitfield.h>
  8#include <linux/gpio/consumer.h>
  9#include <linux/i2c.h>
 10#include <linux/module.h>
 11#include <linux/of_platform.h>
 12#include <linux/regmap.h>
 13#include <linux/regulator/driver.h>
 14#include <linux/regulator/machine.h>
 15#include <linux/regulator/of_regulator.h>
 16
 17#define MAX20411_UV_STEP		6250
 18#define MAX20411_BASE_UV		243750
 19#define MAX20411_MIN_SEL		41 /* 0.5V */
 20#define MAX20411_MAX_SEL		165 /* 1.275V */
 21#define MAX20411_VID_OFFSET		0x7
 22#define MAX20411_VID_MASK		0xff
 23#define MAX20411_SLEW_OFFSET		0x6
 24#define MAX20411_SLEW_DVS_MASK		0xc
 25#define MAX20411_SLEW_SR_MASK		0x3
 26
 27struct max20411 {
 28	struct device *dev;
 29	struct device_node *of_node;
 30	struct regulator_desc desc;
 31	struct regulator_dev *rdev;
 32	struct regmap *regmap;
 33};
 34
 35static const unsigned int max20411_slew_rates[] = { 13100, 6600, 3300, 1600 };
 36
 37static int max20411_enable_time(struct regulator_dev *rdev)
 38{
 39	int voltage, rate, ret;
 40	unsigned int val;
 41
 42	/* get voltage */
 43	ret = regmap_read(rdev->regmap, rdev->desc->vsel_reg, &val);
 44	if (ret)
 45		return ret;
 46
 47	val &= rdev->desc->vsel_mask;
 48	voltage = regulator_list_voltage_linear(rdev, val);
 49
 50	/* get rate */
 51	ret = regmap_read(rdev->regmap, MAX20411_SLEW_OFFSET, &val);
 52	if (ret)
 53		return ret;
 54
 55	val = FIELD_GET(MAX20411_SLEW_SR_MASK, val);
 56	rate = max20411_slew_rates[val];
 57
 58	return DIV_ROUND_UP(voltage, rate);
 59}
 60
 61static const struct regmap_config max20411_regmap_config = {
 62	.reg_bits		= 8,
 63	.val_bits		= 8,
 64	.max_register		= 0xe,
 65};
 66
 67static const struct regulator_ops max20411_ops = {
 68	.get_voltage_sel	= regulator_get_voltage_sel_regmap,
 69	.set_voltage_sel	= regulator_set_voltage_sel_regmap,
 70	.list_voltage		= regulator_list_voltage_linear,
 71	.enable_time		= max20411_enable_time,
 72};
 73
 74static const struct regulator_desc max20411_desc = {
 75	.ops = &max20411_ops,
 76	.owner = THIS_MODULE,
 77	.type = REGULATOR_VOLTAGE,
 78	.supply_name = "vin",
 79	.name = "max20411",
 80
 81	/*
 82	 * voltage = 0.24375V + selector * 6.25mV
 83	 * with valid selector between 41 to 165 (0.5V to 1.275V)
 84	 */
 85	.min_uV = MAX20411_BASE_UV,
 86	.uV_step = MAX20411_UV_STEP,
 87	.linear_min_sel = MAX20411_MIN_SEL,
 88	.n_voltages = MAX20411_MAX_SEL + 1,
 89
 90	.vsel_reg = MAX20411_VID_OFFSET,
 91	.vsel_mask = MAX20411_VID_MASK,
 92
 93	.ramp_reg = MAX20411_SLEW_OFFSET,
 94	.ramp_mask = MAX20411_SLEW_DVS_MASK,
 95	.ramp_delay_table = max20411_slew_rates,
 96	.n_ramp_values = ARRAY_SIZE(max20411_slew_rates),
 97};
 98
 99static int max20411_probe(struct i2c_client *client)
100{
101	struct regulator_init_data *init_data;
102	struct device *dev = &client->dev;
103	struct regulator_config cfg = {};
104	struct max20411 *max20411;
105
106	max20411 = devm_kzalloc(dev, sizeof(*max20411), GFP_KERNEL);
107	if (!max20411)
108		return -ENOMEM;
109
110	max20411->regmap = devm_regmap_init_i2c(client, &max20411_regmap_config);
111	if (IS_ERR(max20411->regmap)) {
112		dev_err(dev, "Failed to allocate regmap!\n");
113		return PTR_ERR(max20411->regmap);
114	}
115
116	max20411->dev = dev;
117	max20411->of_node = dev->of_node;
118
119	max20411->desc = max20411_desc;
120	init_data = of_get_regulator_init_data(max20411->dev, max20411->of_node, &max20411->desc);
121	if (!init_data)
122		return -ENODATA;
123
124	cfg.dev = max20411->dev;
125	cfg.init_data = init_data;
126	cfg.of_node = max20411->of_node;
127	cfg.driver_data = max20411;
128
129	cfg.ena_gpiod = gpiod_get(max20411->dev, "enable", GPIOD_ASIS);
130	if (IS_ERR(cfg.ena_gpiod))
131		return dev_err_probe(dev, PTR_ERR(cfg.ena_gpiod),
132				     "unable to acquire enable gpio\n");
133
134	max20411->rdev = devm_regulator_register(max20411->dev, &max20411->desc, &cfg);
135	if (IS_ERR(max20411->rdev))
136		dev_err(max20411->dev, "Failed to register regulator\n");
137
138	return PTR_ERR_OR_ZERO(max20411->rdev);
139}
140
141static const struct of_device_id of_max20411_match_tbl[] = {
142	{ .compatible = "maxim,max20411", },
143	{ },
144};
145MODULE_DEVICE_TABLE(of, of_max20411_match_tbl);
146
147static const struct i2c_device_id max20411_id[] = {
148	{ "max20411" },
149	{ }
150};
151MODULE_DEVICE_TABLE(i2c, max20411_id);
152
153static struct i2c_driver max20411_i2c_driver = {
154	.driver	= {
155		.name = "max20411",
156		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
157		.of_match_table	= of_max20411_match_tbl,
158	},
159	.probe = max20411_probe,
160	.id_table = max20411_id,
161};
162module_i2c_driver(max20411_i2c_driver);
163
164MODULE_DESCRIPTION("Maxim MAX20411 High-Efficiency Single Step-Down Converter driver");
165MODULE_LICENSE("GPL");