1 /*
2  * max8660.c  --  Voltage regulation for the Maxim 8660/8661
3  *
4  * based on max1586.c and wm8400-regulator.c
5  *
6  * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the Free
10  * Software Foundation; version 2 of the License.
11  *
12  * This program is distributed in the hope that it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  * more details.
16  *
17  * You should have received a copy of the GNU General Public License along with
18  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
19  * Place, Suite 330, Boston, MA  02111-1307  USA
20  *
21  * Some info:
22  *
23  * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
24  *
25  * This chip is a bit nasty because it is a write-only device. Thus, the driver
26  * uses shadow registers to keep track of its values. The main problem appears
27  * to be the initialization: When Linux boots up, we cannot know if the chip is
28  * in the default state or not, so we would have to pass such information in
29  * platform_data. As this adds a bit of complexity to the driver, this is left
30  * out for now until it is really needed.
31  *
32  * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
33  *
34  * If the driver is feature complete, it might be worth to check if one set of
35  * functions for V3-V7 is sufficient. For maximum flexibility during
36  * development, they are separated for now.
37  *
38  */
39 
40 #include <linux/module.h>
41 #include <linux/err.h>
42 #include <linux/i2c.h>
43 #include <linux/platform_device.h>
44 #include <linux/regulator/driver.h>
45 #include <linux/slab.h>
46 #include <linux/regulator/max8660.h>
47 #include <linux/of.h>
48 #include <linux/of_device.h>
49 #include <linux/regulator/of_regulator.h>
50 
51 #define MAX8660_DCDC_MIN_UV	 725000
52 #define MAX8660_DCDC_MAX_UV	1800000
53 #define MAX8660_DCDC_STEP	  25000
54 #define MAX8660_DCDC_MAX_SEL	0x2b
55 
56 #define MAX8660_LDO5_MIN_UV	1700000
57 #define MAX8660_LDO5_MAX_UV	2000000
58 #define MAX8660_LDO5_STEP	  25000
59 #define MAX8660_LDO5_MAX_SEL	0x0c
60 
61 #define MAX8660_LDO67_MIN_UV	1800000
62 #define MAX8660_LDO67_MAX_UV	3300000
63 #define MAX8660_LDO67_STEP	 100000
64 #define MAX8660_LDO67_MAX_SEL	0x0f
65 
66 enum {
67 	MAX8660_OVER1,
68 	MAX8660_OVER2,
69 	MAX8660_VCC1,
70 	MAX8660_ADTV1,
71 	MAX8660_ADTV2,
72 	MAX8660_SDTV1,
73 	MAX8660_SDTV2,
74 	MAX8660_MDTV1,
75 	MAX8660_MDTV2,
76 	MAX8660_L12VCR,
77 	MAX8660_FPWM,
78 	MAX8660_N_REGS,	/* not a real register */
79 };
80 
81 struct max8660 {
82 	struct i2c_client *client;
83 	u8 shadow_regs[MAX8660_N_REGS];		/* as chip is write only */
84 };
85 
max8660_write(struct max8660 * max8660,u8 reg,u8 mask,u8 val)86 static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
87 {
88 	static const u8 max8660_addresses[MAX8660_N_REGS] = {
89 	 0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80
90 	};
91 
92 	int ret;
93 	u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
94 
95 	dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
96 			max8660_addresses[reg], reg_val);
97 
98 	ret = i2c_smbus_write_byte_data(max8660->client,
99 			max8660_addresses[reg], reg_val);
100 	if (ret == 0)
101 		max8660->shadow_regs[reg] = reg_val;
102 
103 	return ret;
104 }
105 
106 
107 /*
108  * DCDC functions
109  */
110 
max8660_dcdc_is_enabled(struct regulator_dev * rdev)111 static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
112 {
113 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
114 	u8 val = max8660->shadow_regs[MAX8660_OVER1];
115 	u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
116 
117 	return !!(val & mask);
118 }
119 
max8660_dcdc_enable(struct regulator_dev * rdev)120 static int max8660_dcdc_enable(struct regulator_dev *rdev)
121 {
122 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
123 	u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
124 
125 	return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
126 }
127 
max8660_dcdc_disable(struct regulator_dev * rdev)128 static int max8660_dcdc_disable(struct regulator_dev *rdev)
129 {
130 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
131 	u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
132 
133 	return max8660_write(max8660, MAX8660_OVER1, mask, 0);
134 }
135 
max8660_dcdc_get_voltage_sel(struct regulator_dev * rdev)136 static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
137 {
138 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
139 	u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
140 	u8 selector = max8660->shadow_regs[reg];
141 
142 	return selector;
143 }
144 
max8660_dcdc_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)145 static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
146 					unsigned int selector)
147 {
148 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
149 	u8 reg, bits;
150 	int ret;
151 
152 	reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
153 	ret = max8660_write(max8660, reg, 0, selector);
154 	if (ret)
155 		return ret;
156 
157 	/* Select target voltage register and activate regulation */
158 	bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
159 	return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
160 }
161 
162 static struct regulator_ops max8660_dcdc_ops = {
163 	.is_enabled = max8660_dcdc_is_enabled,
164 	.list_voltage = regulator_list_voltage_linear,
165 	.map_voltage = regulator_map_voltage_linear,
166 	.set_voltage_sel = max8660_dcdc_set_voltage_sel,
167 	.get_voltage_sel = max8660_dcdc_get_voltage_sel,
168 };
169 
170 
171 /*
172  * LDO5 functions
173  */
174 
max8660_ldo5_get_voltage_sel(struct regulator_dev * rdev)175 static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
176 {
177 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
178 
179 	u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
180 	return selector;
181 }
182 
max8660_ldo5_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)183 static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
184 					unsigned int selector)
185 {
186 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
187 	int ret;
188 
189 	ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
190 	if (ret)
191 		return ret;
192 
193 	/* Select target voltage register and activate regulation */
194 	return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
195 }
196 
197 static const struct regulator_ops max8660_ldo5_ops = {
198 	.list_voltage = regulator_list_voltage_linear,
199 	.map_voltage = regulator_map_voltage_linear,
200 	.set_voltage_sel = max8660_ldo5_set_voltage_sel,
201 	.get_voltage_sel = max8660_ldo5_get_voltage_sel,
202 };
203 
204 
205 /*
206  * LDO67 functions
207  */
208 
max8660_ldo67_is_enabled(struct regulator_dev * rdev)209 static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
210 {
211 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
212 	u8 val = max8660->shadow_regs[MAX8660_OVER2];
213 	u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
214 
215 	return !!(val & mask);
216 }
217 
max8660_ldo67_enable(struct regulator_dev * rdev)218 static int max8660_ldo67_enable(struct regulator_dev *rdev)
219 {
220 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
221 	u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
222 
223 	return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
224 }
225 
max8660_ldo67_disable(struct regulator_dev * rdev)226 static int max8660_ldo67_disable(struct regulator_dev *rdev)
227 {
228 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
229 	u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
230 
231 	return max8660_write(max8660, MAX8660_OVER2, mask, 0);
232 }
233 
max8660_ldo67_get_voltage_sel(struct regulator_dev * rdev)234 static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
235 {
236 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
237 	u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
238 	u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
239 
240 	return selector;
241 }
242 
max8660_ldo67_set_voltage_sel(struct regulator_dev * rdev,unsigned int selector)243 static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
244 					 unsigned int selector)
245 {
246 	struct max8660 *max8660 = rdev_get_drvdata(rdev);
247 
248 	if (rdev_get_id(rdev) == MAX8660_V6)
249 		return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
250 	else
251 		return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
252 				     selector << 4);
253 }
254 
255 static const struct regulator_ops max8660_ldo67_ops = {
256 	.is_enabled = max8660_ldo67_is_enabled,
257 	.enable = max8660_ldo67_enable,
258 	.disable = max8660_ldo67_disable,
259 	.list_voltage = regulator_list_voltage_linear,
260 	.map_voltage = regulator_map_voltage_linear,
261 	.get_voltage_sel = max8660_ldo67_get_voltage_sel,
262 	.set_voltage_sel = max8660_ldo67_set_voltage_sel,
263 };
264 
265 static const struct regulator_desc max8660_reg[] = {
266 	{
267 		.name = "V3(DCDC)",
268 		.id = MAX8660_V3,
269 		.ops = &max8660_dcdc_ops,
270 		.type = REGULATOR_VOLTAGE,
271 		.n_voltages = MAX8660_DCDC_MAX_SEL + 1,
272 		.owner = THIS_MODULE,
273 		.min_uV = MAX8660_DCDC_MIN_UV,
274 		.uV_step = MAX8660_DCDC_STEP,
275 	},
276 	{
277 		.name = "V4(DCDC)",
278 		.id = MAX8660_V4,
279 		.ops = &max8660_dcdc_ops,
280 		.type = REGULATOR_VOLTAGE,
281 		.n_voltages = MAX8660_DCDC_MAX_SEL + 1,
282 		.owner = THIS_MODULE,
283 		.min_uV = MAX8660_DCDC_MIN_UV,
284 		.uV_step = MAX8660_DCDC_STEP,
285 	},
286 	{
287 		.name = "V5(LDO)",
288 		.id = MAX8660_V5,
289 		.ops = &max8660_ldo5_ops,
290 		.type = REGULATOR_VOLTAGE,
291 		.n_voltages = MAX8660_LDO5_MAX_SEL + 1,
292 		.owner = THIS_MODULE,
293 		.min_uV = MAX8660_LDO5_MIN_UV,
294 		.uV_step = MAX8660_LDO5_STEP,
295 	},
296 	{
297 		.name = "V6(LDO)",
298 		.id = MAX8660_V6,
299 		.ops = &max8660_ldo67_ops,
300 		.type = REGULATOR_VOLTAGE,
301 		.n_voltages = MAX8660_LDO67_MAX_SEL + 1,
302 		.owner = THIS_MODULE,
303 		.min_uV = MAX8660_LDO67_MIN_UV,
304 		.uV_step = MAX8660_LDO67_STEP,
305 	},
306 	{
307 		.name = "V7(LDO)",
308 		.id = MAX8660_V7,
309 		.ops = &max8660_ldo67_ops,
310 		.type = REGULATOR_VOLTAGE,
311 		.n_voltages = MAX8660_LDO67_MAX_SEL + 1,
312 		.owner = THIS_MODULE,
313 		.min_uV = MAX8660_LDO67_MIN_UV,
314 		.uV_step = MAX8660_LDO67_STEP,
315 	},
316 };
317 
318 enum {
319 	MAX8660 = 0,
320 	MAX8661 = 1,
321 };
322 
323 #ifdef CONFIG_OF
324 static const struct of_device_id max8660_dt_ids[] = {
325 	{ .compatible = "maxim,max8660", .data = (void *) MAX8660 },
326 	{ .compatible = "maxim,max8661", .data = (void *) MAX8661 },
327 	{ }
328 };
329 MODULE_DEVICE_TABLE(of, max8660_dt_ids);
330 
max8660_pdata_from_dt(struct device * dev,struct device_node ** of_node,struct max8660_platform_data * pdata)331 static int max8660_pdata_from_dt(struct device *dev,
332 				 struct device_node **of_node,
333 				 struct max8660_platform_data *pdata)
334 {
335 	int matched, i;
336 	struct device_node *np;
337 	struct max8660_subdev_data *sub;
338 	struct of_regulator_match rmatch[ARRAY_SIZE(max8660_reg)] = { };
339 
340 	np = of_get_child_by_name(dev->of_node, "regulators");
341 	if (!np) {
342 		dev_err(dev, "missing 'regulators' subnode in DT\n");
343 		return -EINVAL;
344 	}
345 
346 	for (i = 0; i < ARRAY_SIZE(rmatch); i++)
347 		rmatch[i].name = max8660_reg[i].name;
348 
349 	matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
350 	of_node_put(np);
351 	if (matched <= 0)
352 		return matched;
353 
354 	pdata->subdevs = devm_kcalloc(dev,
355 				      matched,
356 				      sizeof(struct max8660_subdev_data),
357 				      GFP_KERNEL);
358 	if (!pdata->subdevs)
359 		return -ENOMEM;
360 
361 	pdata->num_subdevs = matched;
362 	sub = pdata->subdevs;
363 
364 	for (i = 0; i < matched; i++) {
365 		sub->id = i;
366 		sub->name = rmatch[i].name;
367 		sub->platform_data = rmatch[i].init_data;
368 		of_node[i] = rmatch[i].of_node;
369 		sub++;
370 	}
371 
372 	return 0;
373 }
374 #else
max8660_pdata_from_dt(struct device * dev,struct device_node ** of_node,struct max8660_platform_data * pdata)375 static inline int max8660_pdata_from_dt(struct device *dev,
376 					struct device_node **of_node,
377 					struct max8660_platform_data *pdata)
378 {
379 	return 0;
380 }
381 #endif
382 
max8660_probe(struct i2c_client * client,const struct i2c_device_id * i2c_id)383 static int max8660_probe(struct i2c_client *client,
384 				   const struct i2c_device_id *i2c_id)
385 {
386 	struct device *dev = &client->dev;
387 	struct max8660_platform_data pdata_of, *pdata = dev_get_platdata(dev);
388 	struct regulator_config config = { };
389 	struct max8660 *max8660;
390 	int boot_on, i, id, ret = -EINVAL;
391 	struct device_node *of_node[MAX8660_V_END];
392 	unsigned long type;
393 
394 	if (dev->of_node && !pdata) {
395 		const struct of_device_id *id;
396 
397 		id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
398 		if (!id)
399 			return -ENODEV;
400 
401 		ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
402 		if (ret < 0)
403 			return ret;
404 
405 		pdata = &pdata_of;
406 		type = (unsigned long) id->data;
407 	} else {
408 		type = i2c_id->driver_data;
409 		memset(of_node, 0, sizeof(of_node));
410 	}
411 
412 	if (pdata->num_subdevs > MAX8660_V_END) {
413 		dev_err(dev, "Too many regulators found!\n");
414 		return -EINVAL;
415 	}
416 
417 	max8660 = devm_kzalloc(dev, sizeof(struct max8660), GFP_KERNEL);
418 	if (!max8660)
419 		return -ENOMEM;
420 
421 	max8660->client = client;
422 
423 	if (pdata->en34_is_high) {
424 		/* Simulate always on */
425 		max8660->shadow_regs[MAX8660_OVER1] = 5;
426 	} else {
427 		/* Otherwise devices can be toggled via software */
428 		max8660_dcdc_ops.enable = max8660_dcdc_enable;
429 		max8660_dcdc_ops.disable = max8660_dcdc_disable;
430 	}
431 
432 	/*
433 	 * First, set up shadow registers to prevent glitches. As some
434 	 * registers are shared between regulators, everything must be properly
435 	 * set up for all regulators in advance.
436 	 */
437 	max8660->shadow_regs[MAX8660_ADTV1] =
438 		max8660->shadow_regs[MAX8660_ADTV2] =
439 		max8660->shadow_regs[MAX8660_SDTV1] =
440 		max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
441 	max8660->shadow_regs[MAX8660_MDTV1] =
442 		max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
443 
444 	for (i = 0; i < pdata->num_subdevs; i++) {
445 
446 		if (!pdata->subdevs[i].platform_data)
447 			boot_on = false;
448 		else
449 			boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
450 
451 		switch (pdata->subdevs[i].id) {
452 		case MAX8660_V3:
453 			if (boot_on)
454 				max8660->shadow_regs[MAX8660_OVER1] |= 1;
455 			break;
456 
457 		case MAX8660_V4:
458 			if (boot_on)
459 				max8660->shadow_regs[MAX8660_OVER1] |= 4;
460 			break;
461 
462 		case MAX8660_V5:
463 			break;
464 
465 		case MAX8660_V6:
466 			if (boot_on)
467 				max8660->shadow_regs[MAX8660_OVER2] |= 2;
468 			break;
469 
470 		case MAX8660_V7:
471 			if (type == MAX8661) {
472 				dev_err(dev, "Regulator not on this chip!\n");
473 				return -EINVAL;
474 			}
475 
476 			if (boot_on)
477 				max8660->shadow_regs[MAX8660_OVER2] |= 4;
478 			break;
479 
480 		default:
481 			dev_err(dev, "invalid regulator %s\n",
482 				 pdata->subdevs[i].name);
483 			return ret;
484 		}
485 	}
486 
487 	/* Finally register devices */
488 	for (i = 0; i < pdata->num_subdevs; i++) {
489 		struct regulator_dev *rdev;
490 
491 		id = pdata->subdevs[i].id;
492 
493 		config.dev = dev;
494 		config.init_data = pdata->subdevs[i].platform_data;
495 		config.of_node = of_node[i];
496 		config.driver_data = max8660;
497 
498 		rdev = devm_regulator_register(&client->dev,
499 						  &max8660_reg[id], &config);
500 		if (IS_ERR(rdev)) {
501 			ret = PTR_ERR(rdev);
502 			dev_err(&client->dev, "failed to register %s\n",
503 				max8660_reg[id].name);
504 			return PTR_ERR(rdev);
505 		}
506 	}
507 
508 	i2c_set_clientdata(client, max8660);
509 	return 0;
510 }
511 
512 static const struct i2c_device_id max8660_id[] = {
513 	{ .name = "max8660", .driver_data = MAX8660 },
514 	{ .name = "max8661", .driver_data = MAX8661 },
515 	{ }
516 };
517 MODULE_DEVICE_TABLE(i2c, max8660_id);
518 
519 static struct i2c_driver max8660_driver = {
520 	.probe = max8660_probe,
521 	.driver		= {
522 		.name	= "max8660",
523 	},
524 	.id_table	= max8660_id,
525 };
526 
max8660_init(void)527 static int __init max8660_init(void)
528 {
529 	return i2c_add_driver(&max8660_driver);
530 }
531 subsys_initcall(max8660_init);
532 
max8660_exit(void)533 static void __exit max8660_exit(void)
534 {
535 	i2c_del_driver(&max8660_driver);
536 }
537 module_exit(max8660_exit);
538 
539 /* Module information */
540 MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
541 MODULE_AUTHOR("Wolfram Sang");
542 MODULE_LICENSE("GPL v2");
543