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.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/i2c.h>
12 #include <linux/module.h>
13 #include <linux/regmap.h>
14 #include <linux/regulator/driver.h>
15 #include <linux/regulator/machine.h>
16 #include <linux/regulator/of_regulator.h>
17 #include <linux/slab.h>
18
19 /* Register Offset */
20 #define MAX20086_REG_MASK 0x00
21 #define MAX20086_REG_CONFIG 0x01
22 #define MAX20086_REG_ID 0x02
23 #define MAX20086_REG_STAT1 0x03
24 #define MAX20086_REG_STAT2_L 0x04
25 #define MAX20086_REG_STAT2_H 0x05
26 #define MAX20086_REG_ADC1 0x06
27 #define MAX20086_REG_ADC2 0x07
28 #define MAX20086_REG_ADC3 0x08
29 #define MAX20086_REG_ADC4 0x09
30
31 /* DEVICE IDs */
32 #define MAX20086_DEVICE_ID_MAX20086 0x40
33 #define MAX20086_DEVICE_ID_MAX20087 0x20
34 #define MAX20086_DEVICE_ID_MAX20088 0x10
35 #define MAX20086_DEVICE_ID_MAX20089 0x00
36 #define DEVICE_ID_MASK 0xf0
37
38 /* Register bits */
39 #define MAX20086_EN_MASK 0x0f
40 #define MAX20086_EN_OUT1 0x01
41 #define MAX20086_EN_OUT2 0x02
42 #define MAX20086_EN_OUT3 0x04
43 #define MAX20086_EN_OUT4 0x08
44 #define MAX20086_INT_DISABLE_ALL 0x3f
45
46 #define MAX20086_MAX_REGULATORS 4
47
48 struct max20086_chip_info {
49 u8 id;
50 unsigned int num_outputs;
51 };
52
53 struct max20086_regulator {
54 struct device_node *of_node;
55 struct regulator_init_data *init_data;
56 const struct regulator_desc *desc;
57 struct regulator_dev *rdev;
58 };
59
60 struct max20086 {
61 struct device *dev;
62 struct regmap *regmap;
63 struct gpio_desc *ena_gpiod;
64
65 const struct max20086_chip_info *info;
66
67 struct max20086_regulator regulators[MAX20086_MAX_REGULATORS];
68 };
69
70 static const struct regulator_ops max20086_buck_ops = {
71 .enable = regulator_enable_regmap,
72 .disable = regulator_disable_regmap,
73 .is_enabled = regulator_is_enabled_regmap,
74 };
75
76 #define MAX20086_REGULATOR_DESC(n) \
77 { \
78 .name = "OUT"#n, \
79 .supply_name = "in", \
80 .id = (n) - 1, \
81 .ops = &max20086_buck_ops, \
82 .type = REGULATOR_VOLTAGE, \
83 .owner = THIS_MODULE, \
84 .enable_reg = MAX20086_REG_CONFIG, \
85 .enable_mask = 1 << ((n) - 1), \
86 .enable_val = 1 << ((n) - 1), \
87 .disable_val = 0, \
88 }
89
90 static const char * const max20086_output_names[] = {
91 "OUT1",
92 "OUT2",
93 "OUT3",
94 "OUT4",
95 };
96
97 static const struct regulator_desc max20086_regulators[] = {
98 MAX20086_REGULATOR_DESC(1),
99 MAX20086_REGULATOR_DESC(2),
100 MAX20086_REGULATOR_DESC(3),
101 MAX20086_REGULATOR_DESC(4),
102 };
103
max20086_regulators_register(struct max20086 * chip)104 static int max20086_regulators_register(struct max20086 *chip)
105 {
106 unsigned int i;
107
108 for (i = 0; i < chip->info->num_outputs; i++) {
109 struct max20086_regulator *reg = &chip->regulators[i];
110 struct regulator_config config = { };
111 struct regulator_dev *rdev;
112
113 config.dev = chip->dev;
114 config.init_data = reg->init_data;
115 config.driver_data = chip;
116 config.of_node = reg->of_node;
117 config.regmap = chip->regmap;
118 config.ena_gpiod = chip->ena_gpiod;
119
120 rdev = devm_regulator_register(chip->dev, reg->desc, &config);
121 if (IS_ERR(rdev)) {
122 dev_err(chip->dev,
123 "Failed to register regulator output %s\n",
124 reg->desc->name);
125 return PTR_ERR(rdev);
126 }
127
128 reg->rdev = rdev;
129 }
130
131 return 0;
132 }
133
max20086_parse_regulators_dt(struct max20086 * chip,bool * boot_on)134 static int max20086_parse_regulators_dt(struct max20086 *chip, bool *boot_on)
135 {
136 struct of_regulator_match matches[MAX20086_MAX_REGULATORS] = { };
137 struct device_node *node;
138 unsigned int i;
139 int ret;
140
141 node = of_get_child_by_name(chip->dev->of_node, "regulators");
142 if (!node) {
143 dev_err(chip->dev, "regulators node not found\n");
144 return -ENODEV;
145 }
146
147 for (i = 0; i < chip->info->num_outputs; ++i)
148 matches[i].name = max20086_output_names[i];
149
150 ret = of_regulator_match(chip->dev, node, matches,
151 chip->info->num_outputs);
152 of_node_put(node);
153 if (ret < 0) {
154 dev_err(chip->dev, "Failed to match regulators\n");
155 return -EINVAL;
156 }
157
158 *boot_on = false;
159
160 for (i = 0; i < chip->info->num_outputs; i++) {
161 struct max20086_regulator *reg = &chip->regulators[i];
162
163 reg->init_data = matches[i].init_data;
164 reg->of_node = matches[i].of_node;
165 reg->desc = &max20086_regulators[i];
166
167 if (reg->init_data) {
168 if (reg->init_data->constraints.always_on ||
169 reg->init_data->constraints.boot_on)
170 *boot_on = true;
171 }
172 }
173
174 return 0;
175 }
176
max20086_detect(struct max20086 * chip)177 static int max20086_detect(struct max20086 *chip)
178 {
179 unsigned int data;
180 int ret;
181
182 ret = regmap_read(chip->regmap, MAX20086_REG_ID, &data);
183 if (ret < 0) {
184 dev_err(chip->dev, "Failed to read DEVICE_ID reg: %d\n", ret);
185 return ret;
186 }
187
188 if ((data & DEVICE_ID_MASK) != chip->info->id) {
189 dev_err(chip->dev, "Invalid device ID 0x%02x\n", data);
190 return -ENXIO;
191 }
192
193 return 0;
194 }
195
max20086_gen_is_writeable_reg(struct device * dev,unsigned int reg)196 static bool max20086_gen_is_writeable_reg(struct device *dev, unsigned int reg)
197 {
198 switch (reg) {
199 case MAX20086_REG_MASK:
200 case MAX20086_REG_CONFIG:
201 return true;
202 default:
203 return false;
204 }
205 }
206
207 static const struct regmap_config max20086_regmap_config = {
208 .reg_bits = 8,
209 .val_bits = 8,
210 .writeable_reg = max20086_gen_is_writeable_reg,
211 .max_register = 0x9,
212 .cache_type = REGCACHE_NONE,
213 };
214
max20086_i2c_probe(struct i2c_client * i2c)215 static int max20086_i2c_probe(struct i2c_client *i2c)
216 {
217 struct max20086 *chip;
218 enum gpiod_flags flags;
219 bool boot_on;
220 int ret;
221
222 chip = devm_kzalloc(&i2c->dev, sizeof(*chip), GFP_KERNEL);
223 if (!chip)
224 return -ENOMEM;
225
226 chip->dev = &i2c->dev;
227 chip->info = device_get_match_data(chip->dev);
228
229 i2c_set_clientdata(i2c, chip);
230
231 chip->regmap = devm_regmap_init_i2c(i2c, &max20086_regmap_config);
232 if (IS_ERR(chip->regmap)) {
233 ret = PTR_ERR(chip->regmap);
234 dev_err(chip->dev, "Failed to allocate register map: %d\n", ret);
235 return ret;
236 }
237
238 ret = max20086_parse_regulators_dt(chip, &boot_on);
239 if (ret < 0)
240 return ret;
241
242 ret = max20086_detect(chip);
243 if (ret < 0)
244 return ret;
245
246 /* Until IRQ support is added, just disable all interrupts. */
247 ret = regmap_update_bits(chip->regmap, MAX20086_REG_MASK,
248 MAX20086_INT_DISABLE_ALL,
249 MAX20086_INT_DISABLE_ALL);
250 if (ret < 0) {
251 dev_err(chip->dev, "Failed to disable interrupts: %d\n", ret);
252 return ret;
253 }
254
255 /*
256 * Get the enable GPIO. If any of the outputs is marked as being
257 * enabled at boot, request the GPIO with an initial high state to
258 * avoid disabling outputs that may have been turned on by the boot
259 * loader. Otherwise, request it with a low state to enter lower-power
260 * shutdown.
261 */
262 flags = boot_on ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
263 chip->ena_gpiod = devm_gpiod_get(chip->dev, "enable", flags);
264 if (IS_ERR(chip->ena_gpiod)) {
265 ret = PTR_ERR(chip->ena_gpiod);
266 dev_err(chip->dev, "Failed to get enable GPIO: %d\n", ret);
267 return ret;
268 }
269
270 ret = max20086_regulators_register(chip);
271 if (ret < 0) {
272 dev_err(chip->dev, "Failed to register regulators: %d\n", ret);
273 return ret;
274 }
275
276 return 0;
277 }
278
279 static const struct i2c_device_id max20086_i2c_id[] = {
280 { "max20086" },
281 { "max20087" },
282 { "max20088" },
283 { "max20089" },
284 { /* Sentinel */ },
285 };
286
287 MODULE_DEVICE_TABLE(i2c, max20086_i2c_id);
288
289 static const struct of_device_id max20086_dt_ids[] = {
290 {
291 .compatible = "maxim,max20086",
292 .data = &(const struct max20086_chip_info) {
293 .id = MAX20086_DEVICE_ID_MAX20086,
294 .num_outputs = 4,
295 }
296 }, {
297 .compatible = "maxim,max20087",
298 .data = &(const struct max20086_chip_info) {
299 .id = MAX20086_DEVICE_ID_MAX20087,
300 .num_outputs = 4,
301 }
302 }, {
303 .compatible = "maxim,max20088",
304 .data = &(const struct max20086_chip_info) {
305 .id = MAX20086_DEVICE_ID_MAX20088,
306 .num_outputs = 2,
307 }
308 }, {
309 .compatible = "maxim,max20089",
310 .data = &(const struct max20086_chip_info) {
311 .id = MAX20086_DEVICE_ID_MAX20089,
312 .num_outputs = 2,
313 }
314 },
315 { /* Sentinel */ },
316 };
317
318 MODULE_DEVICE_TABLE(of, max20086_dt_ids);
319
320 static struct i2c_driver max20086_regulator_driver = {
321 .driver = {
322 .name = "max20086",
323 .of_match_table = of_match_ptr(max20086_dt_ids),
324 },
325 .probe_new = max20086_i2c_probe,
326 .id_table = max20086_i2c_id,
327 };
328
329 module_i2c_driver(max20086_regulator_driver);
330
331 MODULE_AUTHOR("Watson Chow <watson.chow@avnet.com>");
332 MODULE_DESCRIPTION("MAX20086-MAX20089 Camera Power Protector Driver");
333 MODULE_LICENSE("GPL");
334
