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
66enum {
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
81struct max8660 {
82	struct i2c_client *client;
83	u8 shadow_regs[MAX8660_N_REGS];		/* as chip is write only */
84};
85
86static 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
111static 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
120static 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
128static 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
136static 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
145static 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
162static 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
175static 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
183static 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
197static 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
209static 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
218static 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
226static 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
234static 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
243static 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
255static 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
265static 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
318enum {
319	MAX8660 = 0,
320	MAX8661 = 1,
321};
322
323#ifdef CONFIG_OF
324static const struct of_device_id max8660_dt_ids[] = {
325	{ .compatible = "maxim,max8660", .data = (void *) MAX8660 },
326	{ .compatible = "maxim,max8661", .data = (void *) MAX8661 },
327	{ }
328};
329MODULE_DEVICE_TABLE(of, max8660_dt_ids);
330
331static 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_kzalloc(dev, sizeof(struct max8660_subdev_data) *
355						matched, GFP_KERNEL);
356	if (!pdata->subdevs)
357		return -ENOMEM;
358
359	pdata->num_subdevs = matched;
360	sub = pdata->subdevs;
361
362	for (i = 0; i < matched; i++) {
363		sub->id = i;
364		sub->name = rmatch[i].name;
365		sub->platform_data = rmatch[i].init_data;
366		of_node[i] = rmatch[i].of_node;
367		sub++;
368	}
369
370	return 0;
371}
372#else
373static inline int max8660_pdata_from_dt(struct device *dev,
374					struct device_node **of_node,
375					struct max8660_platform_data *pdata)
376{
377	return 0;
378}
379#endif
380
381static int max8660_probe(struct i2c_client *client,
382				   const struct i2c_device_id *i2c_id)
383{
384	struct device *dev = &client->dev;
385	struct max8660_platform_data pdata_of, *pdata = dev_get_platdata(dev);
386	struct regulator_config config = { };
387	struct max8660 *max8660;
388	int boot_on, i, id, ret = -EINVAL;
389	struct device_node *of_node[MAX8660_V_END];
390	unsigned long type;
391
392	if (dev->of_node && !pdata) {
393		const struct of_device_id *id;
394
395		id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
396		if (!id)
397			return -ENODEV;
398
399		ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
400		if (ret < 0)
401			return ret;
402
403		pdata = &pdata_of;
404		type = (unsigned long) id->data;
405	} else {
406		type = i2c_id->driver_data;
407		memset(of_node, 0, sizeof(of_node));
408	}
409
410	if (pdata->num_subdevs > MAX8660_V_END) {
411		dev_err(dev, "Too many regulators found!\n");
412		return -EINVAL;
413	}
414
415	max8660 = devm_kzalloc(dev, sizeof(struct max8660), GFP_KERNEL);
416	if (!max8660)
417		return -ENOMEM;
418
419	max8660->client = client;
420
421	if (pdata->en34_is_high) {
422		/* Simulate always on */
423		max8660->shadow_regs[MAX8660_OVER1] = 5;
424	} else {
425		/* Otherwise devices can be toggled via software */
426		max8660_dcdc_ops.enable = max8660_dcdc_enable;
427		max8660_dcdc_ops.disable = max8660_dcdc_disable;
428	}
429
430	/*
431	 * First, set up shadow registers to prevent glitches. As some
432	 * registers are shared between regulators, everything must be properly
433	 * set up for all regulators in advance.
434	 */
435	max8660->shadow_regs[MAX8660_ADTV1] =
436		max8660->shadow_regs[MAX8660_ADTV2] =
437		max8660->shadow_regs[MAX8660_SDTV1] =
438		max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
439	max8660->shadow_regs[MAX8660_MDTV1] =
440		max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
441
442	for (i = 0; i < pdata->num_subdevs; i++) {
443
444		if (!pdata->subdevs[i].platform_data)
445			boot_on = false;
446		else
447			boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
448
449		switch (pdata->subdevs[i].id) {
450		case MAX8660_V3:
451			if (boot_on)
452				max8660->shadow_regs[MAX8660_OVER1] |= 1;
453			break;
454
455		case MAX8660_V4:
456			if (boot_on)
457				max8660->shadow_regs[MAX8660_OVER1] |= 4;
458			break;
459
460		case MAX8660_V5:
461			break;
462
463		case MAX8660_V6:
464			if (boot_on)
465				max8660->shadow_regs[MAX8660_OVER2] |= 2;
466			break;
467
468		case MAX8660_V7:
469			if (type == MAX8661) {
470				dev_err(dev, "Regulator not on this chip!\n");
471				return -EINVAL;
472			}
473
474			if (boot_on)
475				max8660->shadow_regs[MAX8660_OVER2] |= 4;
476			break;
477
478		default:
479			dev_err(dev, "invalid regulator %s\n",
480				 pdata->subdevs[i].name);
481			return ret;
482		}
483	}
484
485	/* Finally register devices */
486	for (i = 0; i < pdata->num_subdevs; i++) {
487		struct regulator_dev *rdev;
488
489		id = pdata->subdevs[i].id;
490
491		config.dev = dev;
492		config.init_data = pdata->subdevs[i].platform_data;
493		config.of_node = of_node[i];
494		config.driver_data = max8660;
495
496		rdev = devm_regulator_register(&client->dev,
497						  &max8660_reg[id], &config);
498		if (IS_ERR(rdev)) {
499			ret = PTR_ERR(rdev);
500			dev_err(&client->dev, "failed to register %s\n",
501				max8660_reg[id].name);
502			return PTR_ERR(rdev);
503		}
504	}
505
506	i2c_set_clientdata(client, max8660);
507	return 0;
508}
509
510static const struct i2c_device_id max8660_id[] = {
511	{ .name = "max8660", .driver_data = MAX8660 },
512	{ .name = "max8661", .driver_data = MAX8661 },
513	{ }
514};
515MODULE_DEVICE_TABLE(i2c, max8660_id);
516
517static struct i2c_driver max8660_driver = {
518	.probe = max8660_probe,
519	.driver		= {
520		.name	= "max8660",
521		.owner	= THIS_MODULE,
522	},
523	.id_table	= max8660_id,
524};
525
526static int __init max8660_init(void)
527{
528	return i2c_add_driver(&max8660_driver);
529}
530subsys_initcall(max8660_init);
531
532static void __exit max8660_exit(void)
533{
534	i2c_del_driver(&max8660_driver);
535}
536module_exit(max8660_exit);
537
538/* Module information */
539MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
540MODULE_AUTHOR("Wolfram Sang");
541MODULE_LICENSE("GPL v2");
542