max20086-regulator.c

  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/cleanup.h>
  9#include <linux/err.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	0x30
 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
 48struct max20086_chip_info {
 49	u8 id;
 50	unsigned int num_outputs;
 51};
 52
 53struct 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
 60struct 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
 70static 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
 90static const char * const max20086_output_names[] = {
 91	"OUT1",
 92	"OUT2",
 93	"OUT3",
 94	"OUT4",
 95};
 96
 97static 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
104static 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
134static int max20086_parse_regulators_dt(struct max20086 *chip, bool *boot_on)
135{
136	struct of_regulator_match *matches;
137	unsigned int i;
138	int ret;
139
140	struct device_node *node __free(device_node) =
141		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	matches = devm_kcalloc(chip->dev, chip->info->num_outputs,
148			       sizeof(*matches), GFP_KERNEL);
149	if (!matches)
150		return -ENOMEM;
151
152	for (i = 0; i < chip->info->num_outputs; ++i)
153		matches[i].name = max20086_output_names[i];
154
155	ret = of_regulator_match(chip->dev, node, matches,
156				 chip->info->num_outputs);
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
181static 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
200static 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
211static 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
219static 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
283static const struct max20086_chip_info max20086_chip_info = {
284	.id = MAX20086_DEVICE_ID_MAX20086,
285	.num_outputs = 4,
286};
287
288static const struct max20086_chip_info max20087_chip_info = {
289	.id = MAX20086_DEVICE_ID_MAX20087,
290	.num_outputs = 4,
291};
292
293static const struct max20086_chip_info max20088_chip_info = {
294	.id = MAX20086_DEVICE_ID_MAX20088,
295	.num_outputs = 2,
296};
297
298static const struct max20086_chip_info max20089_chip_info = {
299	.id = MAX20086_DEVICE_ID_MAX20089,
300	.num_outputs = 2,
301};
302
303static 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};
310MODULE_DEVICE_TABLE(i2c, max20086_i2c_id);
311
312static 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};
319MODULE_DEVICE_TABLE(of, max20086_dt_ids);
320
321static 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
331module_i2c_driver(max20086_regulator_driver);
332
333MODULE_AUTHOR("Watson Chow <watson.chow@avnet.com>");
334MODULE_DESCRIPTION("MAX20086-MAX20089 Camera Power Protector Driver");
335MODULE_LICENSE("GPL");