1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * max8660.c  --  Voltage regulation for the Maxim 8660/8661
4  *
5  * based on max1586.c and wm8400-regulator.c
6  *
7  * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
8  *
9  * Some info:
10  *
11  * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
12  *
13  * This chip is a bit nasty because it is a write-only device. Thus, the driver
14  * uses shadow registers to keep track of its values. The main problem appears
15  * to be the initialization: When Linux boots up, we cannot know if the chip is
16  * in the default state or not, so we would have to pass such information in
17  * platform_data. As this adds a bit of complexity to the driver, this is left
18  * out for now until it is really needed.
19  *
20  * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
21  *
22  * If the driver is feature complete, it might be worth to check if one set of
23  * functions for V3-V7 is sufficient. For maximum flexibility during
24  * development, they are separated for now.
25  */
26 
27 #include <linux/module.h>
28 #include <linux/err.h>
29 #include <linux/i2c.h>
30 #include <linux/platform_device.h>
31 #include <linux/regulator/driver.h>
32 #include <linux/slab.h>
33 #include <linux/regulator/max8660.h>
34 #include <linux/of.h>
35 #include <linux/of_device.h>
36 #include <linux/regulator/of_regulator.h>
37 
38 #define MAX8660_DCDC_MIN_UV	 725000
39 #define MAX8660_DCDC_MAX_UV	1800000
40 #define MAX8660_DCDC_STEP	  25000
41 #define MAX8660_DCDC_MAX_SEL	0x2b
42 
43 #define MAX8660_LDO5_MIN_UV	1700000
44 #define MAX8660_LDO5_MAX_UV	2000000
45 #define MAX8660_LDO5_STEP	  25000
46 #define MAX8660_LDO5_MAX_SEL	0x0c
47 
48 #define MAX8660_LDO67_MIN_UV	1800000
49 #define MAX8660_LDO67_MAX_UV	3300000
50 #define MAX8660_LDO67_STEP	 100000
51 #define MAX8660_LDO67_MAX_SEL	0x0f
52 
53 enum {
54 	MAX8660_OVER1,
55 	MAX8660_OVER2,
56 	MAX8660_VCC1,
57 	MAX8660_ADTV1,
58 	MAX8660_ADTV2,
59 	MAX8660_SDTV1,
60 	MAX8660_SDTV2,
61 	MAX8660_MDTV1,
62 	MAX8660_MDTV2,
63 	MAX8660_L12VCR,
64 	MAX8660_FPWM,
65 	MAX8660_N_REGS,	/* not a real register */
66 };
67 
68 struct max8660 {
69 	struct i2c_client *client;
70 	u8 shadow_regs[MAX8660_N_REGS];		/* as chip is write only */
71 };
72 
max8660_write(struct max8660 * max8660,u8 reg,u8 mask,u8 val)73 static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
74 {
75 	static const u8 max8660_addresses[MAX8660_N_REGS] = {
76 	 0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80
77 	};
78 
79 	int ret;
80 	u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
81 
82 	dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
83 			max8660_addresses[reg], reg_val);
84 
85 	ret = i2c_smbus_write_byte_data(max8660->client,
86 			max8660_addresses[reg], reg_val);
87 	if (ret == 0)
88 		max8660->shadow_regs[reg] = reg_val;
89 
90 	return ret;
91 }
92 
93 
94 /*
95  * DCDC functions
96  */
97 
max8660_dcdc_is_enabled(struct regulator_dev * rdev)98 static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
99 {
100 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
101 	u8 val = max8660->shadow_regs[MAX8660_OVER1];
102 	u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
103 
104 	return !!(val & mask);
105 }
106 
max8660_dcdc_enable(struct regulator_dev * rdev)107 static int max8660_dcdc_enable(struct regulator_dev *rdev)
108 {
109 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
110 	u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
111 
112 	return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
113 }
114 
max8660_dcdc_disable(struct regulator_dev * rdev)115 static int max8660_dcdc_disable(struct regulator_dev *rdev)
116 {
117 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
118 	u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
119 
120 	return max8660_write(max8660, MAX8660_OVER1, mask, 0);
121 }
122 
max8660_dcdc_get_voltage_sel(struct regulator_dev * rdev)123 static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
124 {
125 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
126 	u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
127 	u8 selector = max8660->shadow_regs[reg];
128 
129 	return selector;
130 }
131 
max8660_dcdc_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)132 static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
133 					unsigned int selector)
134 {
135 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
136 	u8 reg, bits;
137 	int ret;
138 
139 	reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
140 	ret = max8660_write(max8660, reg, 0, selector);
141 	if (ret)
142 		return ret;
143 
144 	/* Select target voltage register and activate regulation */
145 	bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
146 	return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
147 }
148 
149 static struct regulator_ops max8660_dcdc_ops = {
150 	.is_enabled = max8660_dcdc_is_enabled,
151 	.list_voltage = regulator_list_voltage_linear,
152 	.map_voltage = regulator_map_voltage_linear,
153 	.set_voltage_sel = max8660_dcdc_set_voltage_sel,
154 	.get_voltage_sel = max8660_dcdc_get_voltage_sel,
155 };
156 
157 
158 /*
159  * LDO5 functions
160  */
161 
max8660_ldo5_get_voltage_sel(struct regulator_dev * rdev)162 static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
163 {
164 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
165 
166 	u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
167 	return selector;
168 }
169 
max8660_ldo5_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)170 static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
171 					unsigned int selector)
172 {
173 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
174 	int ret;
175 
176 	ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
177 	if (ret)
178 		return ret;
179 
180 	/* Select target voltage register and activate regulation */
181 	return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
182 }
183 
184 static const struct regulator_ops max8660_ldo5_ops = {
185 	.list_voltage = regulator_list_voltage_linear,
186 	.map_voltage = regulator_map_voltage_linear,
187 	.set_voltage_sel = max8660_ldo5_set_voltage_sel,
188 	.get_voltage_sel = max8660_ldo5_get_voltage_sel,
189 };
190 
191 
192 /*
193  * LDO67 functions
194  */
195 
max8660_ldo67_is_enabled(struct regulator_dev * rdev)196 static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
197 {
198 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
199 	u8 val = max8660->shadow_regs[MAX8660_OVER2];
200 	u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
201 
202 	return !!(val & mask);
203 }
204 
max8660_ldo67_enable(struct regulator_dev * rdev)205 static int max8660_ldo67_enable(struct regulator_dev *rdev)
206 {
207 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
208 	u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
209 
210 	return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
211 }
212 
max8660_ldo67_disable(struct regulator_dev * rdev)213 static int max8660_ldo67_disable(struct regulator_dev *rdev)
214 {
215 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
216 	u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
217 
218 	return max8660_write(max8660, MAX8660_OVER2, mask, 0);
219 }
220 
max8660_ldo67_get_voltage_sel(struct regulator_dev * rdev)221 static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
222 {
223 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
224 	u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
225 	u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
226 
227 	return selector;
228 }
229 
max8660_ldo67_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)230 static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
231 					 unsigned int selector)
232 {
233 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
234 
235 	if (rdev_get_id(rdev) == MAX8660_V6)
236 		return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
237 	else
238 		return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
239 				     selector << 4);
240 }
241 
242 static const struct regulator_ops max8660_ldo67_ops = {
243 	.is_enabled = max8660_ldo67_is_enabled,
244 	.enable = max8660_ldo67_enable,
245 	.disable = max8660_ldo67_disable,
246 	.list_voltage = regulator_list_voltage_linear,
247 	.map_voltage = regulator_map_voltage_linear,
248 	.get_voltage_sel = max8660_ldo67_get_voltage_sel,
249 	.set_voltage_sel = max8660_ldo67_set_voltage_sel,
250 };
251 
252 static const struct regulator_desc max8660_reg[] = {
253 	{
254 		.name = "V3(DCDC)",
255 		.id = MAX8660_V3,
256 		.ops = &max8660_dcdc_ops,
257 		.type = REGULATOR_VOLTAGE,
258 		.n_voltages = MAX8660_DCDC_MAX_SEL + 1,
259 		.owner = THIS_MODULE,
260 		.min_uV = MAX8660_DCDC_MIN_UV,
261 		.uV_step = MAX8660_DCDC_STEP,
262 	},
263 	{
264 		.name = "V4(DCDC)",
265 		.id = MAX8660_V4,
266 		.ops = &max8660_dcdc_ops,
267 		.type = REGULATOR_VOLTAGE,
268 		.n_voltages = MAX8660_DCDC_MAX_SEL + 1,
269 		.owner = THIS_MODULE,
270 		.min_uV = MAX8660_DCDC_MIN_UV,
271 		.uV_step = MAX8660_DCDC_STEP,
272 	},
273 	{
274 		.name = "V5(LDO)",
275 		.id = MAX8660_V5,
276 		.ops = &max8660_ldo5_ops,
277 		.type = REGULATOR_VOLTAGE,
278 		.n_voltages = MAX8660_LDO5_MAX_SEL + 1,
279 		.owner = THIS_MODULE,
280 		.min_uV = MAX8660_LDO5_MIN_UV,
281 		.uV_step = MAX8660_LDO5_STEP,
282 	},
283 	{
284 		.name = "V6(LDO)",
285 		.id = MAX8660_V6,
286 		.ops = &max8660_ldo67_ops,
287 		.type = REGULATOR_VOLTAGE,
288 		.n_voltages = MAX8660_LDO67_MAX_SEL + 1,
289 		.owner = THIS_MODULE,
290 		.min_uV = MAX8660_LDO67_MIN_UV,
291 		.uV_step = MAX8660_LDO67_STEP,
292 	},
293 	{
294 		.name = "V7(LDO)",
295 		.id = MAX8660_V7,
296 		.ops = &max8660_ldo67_ops,
297 		.type = REGULATOR_VOLTAGE,
298 		.n_voltages = MAX8660_LDO67_MAX_SEL + 1,
299 		.owner = THIS_MODULE,
300 		.min_uV = MAX8660_LDO67_MIN_UV,
301 		.uV_step = MAX8660_LDO67_STEP,
302 	},
303 };
304 
305 enum {
306 	MAX8660 = 0,
307 	MAX8661 = 1,
308 };
309 
310 #ifdef CONFIG_OF
311 static const struct of_device_id max8660_dt_ids[] = {
312 	{ .compatible = "maxim,max8660", .data = (void *) MAX8660 },
313 	{ .compatible = "maxim,max8661", .data = (void *) MAX8661 },
314 	{ }
315 };
316 MODULE_DEVICE_TABLE(of, max8660_dt_ids);
317 
max8660_pdata_from_dt(struct device * dev,struct device_node ** of_node,struct max8660_platform_data * pdata)318 static int max8660_pdata_from_dt(struct device *dev,
319 				 struct device_node **of_node,
320 				 struct max8660_platform_data *pdata)
321 {
322 	int matched, i;
323 	struct device_node *np;
324 	struct max8660_subdev_data *sub;
325 	struct of_regulator_match rmatch[ARRAY_SIZE(max8660_reg)] = { };
326 
327 	np = of_get_child_by_name(dev->of_node, "regulators");
328 	if (!np) {
329 		dev_err(dev, "missing 'regulators' subnode in DT\n");
330 		return -EINVAL;
331 	}
332 
333 	for (i = 0; i < ARRAY_SIZE(rmatch); i++)
334 		rmatch[i].name = max8660_reg[i].name;
335 
336 	matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
337 	of_node_put(np);
338 	if (matched <= 0)
339 		return matched;
340 
341 	pdata->subdevs = devm_kcalloc(dev,
342 				      matched,
343 				      sizeof(struct max8660_subdev_data),
344 				      GFP_KERNEL);
345 	if (!pdata->subdevs)
346 		return -ENOMEM;
347 
348 	pdata->num_subdevs = matched;
349 	sub = pdata->subdevs;
350 
351 	for (i = 0; i < matched; i++) {
352 		sub->id = i;
353 		sub->name = rmatch[i].name;
354 		sub->platform_data = rmatch[i].init_data;
355 		of_node[i] = rmatch[i].of_node;
356 		sub++;
357 	}
358 
359 	return 0;
360 }
361 #else
max8660_pdata_from_dt(struct device * dev,struct device_node ** of_node,struct max8660_platform_data * pdata)362 static inline int max8660_pdata_from_dt(struct device *dev,
363 					struct device_node **of_node,
364 					struct max8660_platform_data *pdata)
365 {
366 	return 0;
367 }
368 #endif
369 
max8660_probe(struct i2c_client * client,const struct i2c_device_id * i2c_id)370 static int max8660_probe(struct i2c_client *client,
371 				   const struct i2c_device_id *i2c_id)
372 {
373 	struct device *dev = &client->dev;
374 	struct max8660_platform_data pdata_of, *pdata = dev_get_platdata(dev);
375 	struct regulator_config config = { };
376 	struct max8660 *max8660;
377 	int boot_on, i, id, ret = -EINVAL;
378 	struct device_node *of_node[MAX8660_V_END];
379 	unsigned long type;
380 
381 	if (dev->of_node && !pdata) {
382 		const struct of_device_id *id;
383 
384 		id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
385 		if (!id)
386 			return -ENODEV;
387 
388 		ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
389 		if (ret < 0)
390 			return ret;
391 
392 		pdata = &pdata_of;
393 		type = (unsigned long) id->data;
394 	} else {
395 		type = i2c_id->driver_data;
396 		memset(of_node, 0, sizeof(of_node));
397 	}
398 
399 	if (pdata->num_subdevs > MAX8660_V_END) {
400 		dev_err(dev, "Too many regulators found!\n");
401 		return -EINVAL;
402 	}
403 
404 	max8660 = devm_kzalloc(dev, sizeof(struct max8660), GFP_KERNEL);
405 	if (!max8660)
406 		return -ENOMEM;
407 
408 	max8660->client = client;
409 
410 	if (pdata->en34_is_high) {
411 		/* Simulate always on */
412 		max8660->shadow_regs[MAX8660_OVER1] = 5;
413 	} else {
414 		/* Otherwise devices can be toggled via software */
415 		max8660_dcdc_ops.enable = max8660_dcdc_enable;
416 		max8660_dcdc_ops.disable = max8660_dcdc_disable;
417 	}
418 
419 	/*
420 	 * First, set up shadow registers to prevent glitches. As some
421 	 * registers are shared between regulators, everything must be properly
422 	 * set up for all regulators in advance.
423 	 */
424 	max8660->shadow_regs[MAX8660_ADTV1] =
425 		max8660->shadow_regs[MAX8660_ADTV2] =
426 		max8660->shadow_regs[MAX8660_SDTV1] =
427 		max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
428 	max8660->shadow_regs[MAX8660_MDTV1] =
429 		max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
430 
431 	for (i = 0; i < pdata->num_subdevs; i++) {
432 
433 		if (!pdata->subdevs[i].platform_data)
434 			boot_on = false;
435 		else
436 			boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
437 
438 		switch (pdata->subdevs[i].id) {
439 		case MAX8660_V3:
440 			if (boot_on)
441 				max8660->shadow_regs[MAX8660_OVER1] |= 1;
442 			break;
443 
444 		case MAX8660_V4:
445 			if (boot_on)
446 				max8660->shadow_regs[MAX8660_OVER1] |= 4;
447 			break;
448 
449 		case MAX8660_V5:
450 			break;
451 
452 		case MAX8660_V6:
453 			if (boot_on)
454 				max8660->shadow_regs[MAX8660_OVER2] |= 2;
455 			break;
456 
457 		case MAX8660_V7:
458 			if (type == MAX8661) {
459 				dev_err(dev, "Regulator not on this chip!\n");
460 				return -EINVAL;
461 			}
462 
463 			if (boot_on)
464 				max8660->shadow_regs[MAX8660_OVER2] |= 4;
465 			break;
466 
467 		default:
468 			dev_err(dev, "invalid regulator %s\n",
469 				 pdata->subdevs[i].name);
470 			return ret;
471 		}
472 	}
473 
474 	/* Finally register devices */
475 	for (i = 0; i < pdata->num_subdevs; i++) {
476 		struct regulator_dev *rdev;
477 
478 		id = pdata->subdevs[i].id;
479 
480 		config.dev = dev;
481 		config.init_data = pdata->subdevs[i].platform_data;
482 		config.of_node = of_node[i];
483 		config.driver_data = max8660;
484 
485 		rdev = devm_regulator_register(&client->dev,
486 						  &max8660_reg[id], &config);
487 		if (IS_ERR(rdev)) {
488 			dev_err(&client->dev, "failed to register %s\n",
489 				max8660_reg[id].name);
490 			return PTR_ERR(rdev);
491 		}
492 	}
493 
494 	i2c_set_clientdata(client, max8660);
495 	return 0;
496 }
497 
498 static const struct i2c_device_id max8660_id[] = {
499 	{ .name = "max8660", .driver_data = MAX8660 },
500 	{ .name = "max8661", .driver_data = MAX8661 },
501 	{ }
502 };
503 MODULE_DEVICE_TABLE(i2c, max8660_id);
504 
505 static struct i2c_driver max8660_driver = {
506 	.probe = max8660_probe,
507 	.driver		= {
508 		.name	= "max8660",
509 	},
510 	.id_table	= max8660_id,
511 };
512 
max8660_init(void)513 static int __init max8660_init(void)
514 {
515 	return i2c_add_driver(&max8660_driver);
516 }
517 subsys_initcall(max8660_init);
518 
max8660_exit(void)519 static void __exit max8660_exit(void)
520 {
521 	i2c_del_driver(&max8660_driver);
522 }
523 module_exit(max8660_exit);
524 
525 /* Module information */
526 MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
527 MODULE_AUTHOR("Wolfram Sang");
528 MODULE_LICENSE("GPL v2");
529