1// SPDX-License-Identifier: GPL-2.0-or-later
2//
3// max20086-regulator.c - MAX20086-MAX20089 camera power protector driver
4//
5// Copyright (C) 2022 Laurent Pinchart <laurent.pinchart@idesonboard.com>
6// Copyright (C) 2018 Avnet, Inc.
7
8#include <linux/err.h>
9#include <linux/gpio/consumer.h>
10#include <linux/i2c.h>
11#include <linux/module.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#include <linux/slab.h>
17
18/* Register Offset */
19#define MAX20086_REG_MASK		0x00
20#define MAX20086_REG_CONFIG		0x01
21#define	MAX20086_REG_ID			0x02
22#define	MAX20086_REG_STAT1		0x03
23#define	MAX20086_REG_STAT2_L		0x04
24#define	MAX20086_REG_STAT2_H		0x05
25#define	MAX20086_REG_ADC1		0x06
26#define	MAX20086_REG_ADC2		0x07
27#define	MAX20086_REG_ADC3		0x08
28#define	MAX20086_REG_ADC4		0x09
29
30/* DEVICE IDs */
31#define MAX20086_DEVICE_ID_MAX20086	0x40
32#define MAX20086_DEVICE_ID_MAX20087	0x20
33#define MAX20086_DEVICE_ID_MAX20088	0x10
34#define MAX20086_DEVICE_ID_MAX20089	0x00
35#define DEVICE_ID_MASK			0xf0
36
37/* Register bits */
38#define MAX20086_EN_MASK		0x0f
39#define MAX20086_EN_OUT1		0x01
40#define MAX20086_EN_OUT2		0x02
41#define MAX20086_EN_OUT3		0x04
42#define MAX20086_EN_OUT4		0x08
43#define MAX20086_INT_DISABLE_ALL	0x3f
44
45#define MAX20086_MAX_REGULATORS		4
46
47struct max20086_chip_info {
48	u8 id;
49	unsigned int num_outputs;
50};
51
52struct max20086_regulator {
53	struct device_node *of_node;
54	struct regulator_init_data *init_data;
55	const struct regulator_desc *desc;
56	struct regulator_dev *rdev;
57};
58
59struct max20086 {
60	struct device *dev;
61	struct regmap *regmap;
62	struct gpio_desc *ena_gpiod;
63
64	const struct max20086_chip_info *info;
65
66	struct max20086_regulator regulators[MAX20086_MAX_REGULATORS];
67};
68
69static const struct regulator_ops max20086_buck_ops = {
70	.enable = regulator_enable_regmap,
71	.disable = regulator_disable_regmap,
72	.is_enabled = regulator_is_enabled_regmap,
73};
74
75#define MAX20086_REGULATOR_DESC(n)		\
76{						\
77	.name = "OUT"#n,			\
78	.supply_name = "in",			\
79	.id = (n) - 1,				\
80	.ops = &max20086_buck_ops,		\
81	.type = REGULATOR_VOLTAGE,		\
82	.owner = THIS_MODULE,			\
83	.enable_reg = MAX20086_REG_CONFIG,	\
84	.enable_mask = 1 << ((n) - 1),		\
85	.enable_val = 1 << ((n) - 1),		\
86	.disable_val = 0,			\
87}
88
89static const char * const max20086_output_names[] = {
90	"OUT1",
91	"OUT2",
92	"OUT3",
93	"OUT4",
94};
95
96static const struct regulator_desc max20086_regulators[] = {
97	MAX20086_REGULATOR_DESC(1),
98	MAX20086_REGULATOR_DESC(2),
99	MAX20086_REGULATOR_DESC(3),
100	MAX20086_REGULATOR_DESC(4),
101};
102
103static int max20086_regulators_register(struct max20086 *chip)
104{
105	unsigned int i;
106
107	for (i = 0; i < chip->info->num_outputs; i++) {
108		struct max20086_regulator *reg = &chip->regulators[i];
109		struct regulator_config config = { };
110		struct regulator_dev *rdev;
111
112		config.dev = chip->dev;
113		config.init_data = reg->init_data;
114		config.driver_data = chip;
115		config.of_node = reg->of_node;
116		config.regmap = chip->regmap;
117		config.ena_gpiod = chip->ena_gpiod;
118
119		rdev = devm_regulator_register(chip->dev, reg->desc, &config);
120		if (IS_ERR(rdev)) {
121			dev_err(chip->dev,
122				"Failed to register regulator output %s\n",
123				reg->desc->name);
124			return PTR_ERR(rdev);
125		}
126
127		reg->rdev = rdev;
128	}
129
130	return 0;
131}
132
133static int max20086_parse_regulators_dt(struct max20086 *chip, bool *boot_on)
134{
135	struct of_regulator_match matches[MAX20086_MAX_REGULATORS] = { };
136	struct device_node *node;
137	unsigned int i;
138	int ret;
139
140	node = of_get_child_by_name(chip->dev->of_node, "regulators");
141	if (!node) {
142		dev_err(chip->dev, "regulators node not found\n");
143		return -ENODEV;
144	}
145
146	for (i = 0; i < chip->info->num_outputs; ++i)
147		matches[i].name = max20086_output_names[i];
148
149	ret = of_regulator_match(chip->dev, node, matches,
150				 chip->info->num_outputs);
151	of_node_put(node);
152	if (ret < 0) {
153		dev_err(chip->dev, "Failed to match regulators\n");
154		return -EINVAL;
155	}
156
157	*boot_on = false;
158
159	for (i = 0; i < chip->info->num_outputs; i++) {
160		struct max20086_regulator *reg = &chip->regulators[i];
161
162		reg->init_data = matches[i].init_data;
163		reg->of_node = matches[i].of_node;
164		reg->desc = &max20086_regulators[i];
165
166		if (reg->init_data) {
167			if (reg->init_data->constraints.always_on ||
168			    reg->init_data->constraints.boot_on)
169				*boot_on = true;
170		}
171	}
172
173	return 0;
174}
175
176static int max20086_detect(struct max20086 *chip)
177{
178	unsigned int data;
179	int ret;
180
181	ret = regmap_read(chip->regmap, MAX20086_REG_ID, &data);
182	if (ret < 0) {
183		dev_err(chip->dev, "Failed to read DEVICE_ID reg: %d\n", ret);
184		return ret;
185	}
186
187	if ((data & DEVICE_ID_MASK) != chip->info->id) {
188		dev_err(chip->dev, "Invalid device ID 0x%02x\n", data);
189		return -ENXIO;
190	}
191
192	return 0;
193}
194
195static bool max20086_gen_is_writeable_reg(struct device *dev, unsigned int reg)
196{
197	switch (reg) {
198	case MAX20086_REG_MASK:
199	case MAX20086_REG_CONFIG:
200		return true;
201	default:
202		return false;
203	}
204}
205
206static const struct regmap_config max20086_regmap_config = {
207	.reg_bits = 8,
208	.val_bits = 8,
209	.writeable_reg = max20086_gen_is_writeable_reg,
210	.max_register = 0x9,
211	.cache_type = REGCACHE_NONE,
212};
213
214static int max20086_i2c_probe(struct i2c_client *i2c)
215{
216	struct max20086 *chip;
217	enum gpiod_flags flags;
218	bool boot_on;
219	int ret;
220
221	chip = devm_kzalloc(&i2c->dev, sizeof(*chip), GFP_KERNEL);
222	if (!chip)
223		return -ENOMEM;
224
225	chip->dev = &i2c->dev;
226	chip->info = i2c_get_match_data(i2c);
227
228	i2c_set_clientdata(i2c, chip);
229
230	chip->regmap = devm_regmap_init_i2c(i2c, &max20086_regmap_config);
231	if (IS_ERR(chip->regmap)) {
232		ret = PTR_ERR(chip->regmap);
233		dev_err(chip->dev, "Failed to allocate register map: %d\n", ret);
234		return ret;
235	}
236
237	ret = max20086_parse_regulators_dt(chip, &boot_on);
238	if (ret < 0)
239		return ret;
240
241	ret = max20086_detect(chip);
242	if (ret < 0)
243		return ret;
244
245	/* Until IRQ support is added, just disable all interrupts. */
246	ret = regmap_update_bits(chip->regmap, MAX20086_REG_MASK,
247				 MAX20086_INT_DISABLE_ALL,
248				 MAX20086_INT_DISABLE_ALL);
249	if (ret < 0) {
250		dev_err(chip->dev, "Failed to disable interrupts: %d\n", ret);
251		return ret;
252	}
253
254	/*
255	 * Get the enable GPIO. If any of the outputs is marked as being
256	 * enabled at boot, request the GPIO with an initial high state to
257	 * avoid disabling outputs that may have been turned on by the boot
258	 * loader. Otherwise, request it with a low state to enter lower-power
259	 * shutdown.
260	 */
261	flags = boot_on ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
262	chip->ena_gpiod = devm_gpiod_get(chip->dev, "enable", flags);
263	if (IS_ERR(chip->ena_gpiod)) {
264		ret = PTR_ERR(chip->ena_gpiod);
265		dev_err(chip->dev, "Failed to get enable GPIO: %d\n", ret);
266		return ret;
267	}
268
269	ret = max20086_regulators_register(chip);
270	if (ret < 0) {
271		dev_err(chip->dev, "Failed to register regulators: %d\n", ret);
272		return ret;
273	}
274
275	return 0;
276}
277
278static const struct max20086_chip_info max20086_chip_info = {
279	.id = MAX20086_DEVICE_ID_MAX20086,
280	.num_outputs = 4,
281};
282
283static const struct max20086_chip_info max20087_chip_info = {
284	.id = MAX20086_DEVICE_ID_MAX20087,
285	.num_outputs = 4,
286};
287
288static const struct max20086_chip_info max20088_chip_info = {
289	.id = MAX20086_DEVICE_ID_MAX20088,
290	.num_outputs = 2,
291};
292
293static const struct max20086_chip_info max20089_chip_info = {
294	.id = MAX20086_DEVICE_ID_MAX20089,
295	.num_outputs = 2,
296};
297
298static const struct i2c_device_id max20086_i2c_id[] = {
299	{ "max20086", (kernel_ulong_t)&max20086_chip_info },
300	{ "max20087", (kernel_ulong_t)&max20087_chip_info },
301	{ "max20088", (kernel_ulong_t)&max20088_chip_info },
302	{ "max20089", (kernel_ulong_t)&max20089_chip_info },
303	{ /* Sentinel */ }
304};
305MODULE_DEVICE_TABLE(i2c, max20086_i2c_id);
306
307static const struct of_device_id max20086_dt_ids[] __maybe_unused = {
308	{ .compatible = "maxim,max20086", .data = &max20086_chip_info },
309	{ .compatible = "maxim,max20087", .data = &max20087_chip_info },
310	{ .compatible = "maxim,max20088", .data = &max20088_chip_info },
311	{ .compatible = "maxim,max20089", .data = &max20089_chip_info },
312	{ /* Sentinel */ }
313};
314MODULE_DEVICE_TABLE(of, max20086_dt_ids);
315
316static struct i2c_driver max20086_regulator_driver = {
317	.driver = {
318		.name = "max20086",
319		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
320		.of_match_table = of_match_ptr(max20086_dt_ids),
321	},
322	.probe = max20086_i2c_probe,
323	.id_table = max20086_i2c_id,
324};
325
326module_i2c_driver(max20086_regulator_driver);
327
328MODULE_AUTHOR("Watson Chow <watson.chow@avnet.com>");
329MODULE_DESCRIPTION("MAX20086-MAX20089 Camera Power Protector Driver");
330MODULE_LICENSE("GPL");
331