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	0x30
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 
47 struct max20086_chip_info {
48 	u8 id;
49 	unsigned int num_outputs;
50 };
51 
52 struct 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 
59 struct 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 
69 static 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 
89 static const char * const max20086_output_names[] = {
90 	"OUT1",
91 	"OUT2",
92 	"OUT3",
93 	"OUT4",
94 };
95 
96 static 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 
103 static 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 
133 static int max20086_parse_regulators_dt(struct max20086 *chip, bool *boot_on)
134 {
135 	struct of_regulator_match *matches;
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 	matches = devm_kcalloc(chip->dev, chip->info->num_outputs,
147 			       sizeof(*matches), GFP_KERNEL);
148 	if (!matches)
149 		return -ENOMEM;
150 
151 	for (i = 0; i < chip->info->num_outputs; ++i)
152 		matches[i].name = max20086_output_names[i];
153 
154 	ret = of_regulator_match(chip->dev, node, matches,
155 				 chip->info->num_outputs);
156 	of_node_put(node);
157 	if (ret < 0) {
158 		dev_err(chip->dev, "Failed to match regulators\n");
159 		return -EINVAL;
160 	}
161 
162 	*boot_on = false;
163 
164 	for (i = 0; i < chip->info->num_outputs; i++) {
165 		struct max20086_regulator *reg = &chip->regulators[i];
166 
167 		reg->init_data = matches[i].init_data;
168 		reg->of_node = matches[i].of_node;
169 		reg->desc = &max20086_regulators[i];
170 
171 		if (reg->init_data) {
172 			if (reg->init_data->constraints.always_on ||
173 			    reg->init_data->constraints.boot_on)
174 				*boot_on = true;
175 		}
176 	}
177 
178 	return 0;
179 }
180 
181 static int max20086_detect(struct max20086 *chip)
182 {
183 	unsigned int data;
184 	int ret;
185 
186 	ret = regmap_read(chip->regmap, MAX20086_REG_ID, &data);
187 	if (ret < 0) {
188 		dev_err(chip->dev, "Failed to read DEVICE_ID reg: %d\n", ret);
189 		return ret;
190 	}
191 
192 	if ((data & DEVICE_ID_MASK) != chip->info->id) {
193 		dev_err(chip->dev, "Invalid device ID 0x%02x\n", data);
194 		return -ENXIO;
195 	}
196 
197 	return 0;
198 }
199 
200 static bool max20086_gen_is_writeable_reg(struct device *dev, unsigned int reg)
201 {
202 	switch (reg) {
203 	case MAX20086_REG_MASK:
204 	case MAX20086_REG_CONFIG:
205 		return true;
206 	default:
207 		return false;
208 	}
209 }
210 
211 static const struct regmap_config max20086_regmap_config = {
212 	.reg_bits = 8,
213 	.val_bits = 8,
214 	.writeable_reg = max20086_gen_is_writeable_reg,
215 	.max_register = 0x9,
216 	.cache_type = REGCACHE_NONE,
217 };
218 
219 static int max20086_i2c_probe(struct i2c_client *i2c)
220 {
221 	struct max20086 *chip;
222 	enum gpiod_flags flags;
223 	bool boot_on;
224 	int ret;
225 
226 	chip = devm_kzalloc(&i2c->dev, sizeof(*chip), GFP_KERNEL);
227 	if (!chip)
228 		return -ENOMEM;
229 
230 	chip->dev = &i2c->dev;
231 	chip->info = i2c_get_match_data(i2c);
232 
233 	i2c_set_clientdata(i2c, chip);
234 
235 	chip->regmap = devm_regmap_init_i2c(i2c, &max20086_regmap_config);
236 	if (IS_ERR(chip->regmap)) {
237 		ret = PTR_ERR(chip->regmap);
238 		dev_err(chip->dev, "Failed to allocate register map: %d\n", ret);
239 		return ret;
240 	}
241 
242 	ret = max20086_parse_regulators_dt(chip, &boot_on);
243 	if (ret < 0)
244 		return ret;
245 
246 	ret = max20086_detect(chip);
247 	if (ret < 0)
248 		return ret;
249 
250 	/* Until IRQ support is added, just disable all interrupts. */
251 	ret = regmap_update_bits(chip->regmap, MAX20086_REG_MASK,
252 				 MAX20086_INT_DISABLE_ALL,
253 				 MAX20086_INT_DISABLE_ALL);
254 	if (ret < 0) {
255 		dev_err(chip->dev, "Failed to disable interrupts: %d\n", ret);
256 		return ret;
257 	}
258 
259 	/*
260 	 * Get the enable GPIO. If any of the outputs is marked as being
261 	 * enabled at boot, request the GPIO with an initial high state to
262 	 * avoid disabling outputs that may have been turned on by the boot
263 	 * loader. Otherwise, request it with a low state to enter lower-power
264 	 * shutdown.
265 	 */
266 	flags = boot_on ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
267 	chip->ena_gpiod = devm_gpiod_get_optional(chip->dev, "enable", flags);
268 	if (IS_ERR(chip->ena_gpiod)) {
269 		ret = PTR_ERR(chip->ena_gpiod);
270 		dev_err(chip->dev, "Failed to get enable GPIO: %d\n", ret);
271 		return ret;
272 	}
273 
274 	ret = max20086_regulators_register(chip);
275 	if (ret < 0) {
276 		dev_err(chip->dev, "Failed to register regulators: %d\n", ret);
277 		return ret;
278 	}
279 
280 	return 0;
281 }
282 
283 static const struct max20086_chip_info max20086_chip_info = {
284 	.id = MAX20086_DEVICE_ID_MAX20086,
285 	.num_outputs = 4,
286 };
287 
288 static const struct max20086_chip_info max20087_chip_info = {
289 	.id = MAX20086_DEVICE_ID_MAX20087,
290 	.num_outputs = 4,
291 };
292 
293 static const struct max20086_chip_info max20088_chip_info = {
294 	.id = MAX20086_DEVICE_ID_MAX20088,
295 	.num_outputs = 2,
296 };
297 
298 static const struct max20086_chip_info max20089_chip_info = {
299 	.id = MAX20086_DEVICE_ID_MAX20089,
300 	.num_outputs = 2,
301 };
302 
303 static const struct i2c_device_id max20086_i2c_id[] = {
304 	{ "max20086", (kernel_ulong_t)&max20086_chip_info },
305 	{ "max20087", (kernel_ulong_t)&max20087_chip_info },
306 	{ "max20088", (kernel_ulong_t)&max20088_chip_info },
307 	{ "max20089", (kernel_ulong_t)&max20089_chip_info },
308 	{ /* Sentinel */ }
309 };
310 MODULE_DEVICE_TABLE(i2c, max20086_i2c_id);
311 
312 static const struct of_device_id max20086_dt_ids[] __maybe_unused = {
313 	{ .compatible = "maxim,max20086", .data = &max20086_chip_info },
314 	{ .compatible = "maxim,max20087", .data = &max20087_chip_info },
315 	{ .compatible = "maxim,max20088", .data = &max20088_chip_info },
316 	{ .compatible = "maxim,max20089", .data = &max20089_chip_info },
317 	{ /* Sentinel */ }
318 };
319 MODULE_DEVICE_TABLE(of, max20086_dt_ids);
320 
321 static struct i2c_driver max20086_regulator_driver = {
322 	.driver = {
323 		.name = "max20086",
324 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
325 		.of_match_table = of_match_ptr(max20086_dt_ids),
326 	},
327 	.probe = max20086_i2c_probe,
328 	.id_table = max20086_i2c_id,
329 };
330 
331 module_i2c_driver(max20086_regulator_driver);
332 
333 MODULE_AUTHOR("Watson Chow <watson.chow@avnet.com>");
334 MODULE_DESCRIPTION("MAX20086-MAX20089 Camera Power Protector Driver");
335 MODULE_LICENSE("GPL");
336