/drivers/regulator/max8649.c

  1/*
  2 * Regulators driver for Maxim max8649
  3 *
  4 * Copyright (C) 2009-2010 Marvell International Ltd.
  5 *      Haojian Zhuang <haojian.zhuang@marvell.com>
  6 *
  7 * This program is free software; you can redistribute it and/or modify
  8 * it under the terms of the GNU General Public License version 2 as
  9 * published by the Free Software Foundation.
 10 */
 11#include <linux/kernel.h>
 12#include <linux/module.h>
 13#include <linux/err.h>
 14#include <linux/i2c.h>
 15#include <linux/platform_device.h>
 16#include <linux/regulator/driver.h>
 17#include <linux/slab.h>
 18#include <linux/regulator/max8649.h>
 19
 20#define MAX8649_DCDC_VMIN	750000		/* uV */
 21#define MAX8649_DCDC_VMAX	1380000		/* uV */
 22#define MAX8649_DCDC_STEP	10000		/* uV */
 23#define MAX8649_VOL_MASK	0x3f
 24
 25/* Registers */
 26#define MAX8649_MODE0		0x00
 27#define MAX8649_MODE1		0x01
 28#define MAX8649_MODE2		0x02
 29#define MAX8649_MODE3		0x03
 30#define MAX8649_CONTROL		0x04
 31#define MAX8649_SYNC		0x05
 32#define MAX8649_RAMP		0x06
 33#define MAX8649_CHIP_ID1	0x08
 34#define MAX8649_CHIP_ID2	0x09
 35
 36/* Bits */
 37#define MAX8649_EN_PD		(1 << 7)
 38#define MAX8649_VID0_PD		(1 << 6)
 39#define MAX8649_VID1_PD		(1 << 5)
 40#define MAX8649_VID_MASK	(3 << 5)
 41
 42#define MAX8649_FORCE_PWM	(1 << 7)
 43#define MAX8649_SYNC_EXTCLK	(1 << 6)
 44
 45#define MAX8649_EXT_MASK	(3 << 6)
 46
 47#define MAX8649_RAMP_MASK	(7 << 5)
 48#define MAX8649_RAMP_DOWN	(1 << 1)
 49
 50struct max8649_regulator_info {
 51	struct regulator_dev	*regulator;
 52	struct i2c_client	*i2c;
 53	struct device		*dev;
 54	struct mutex		io_lock;
 55
 56	int		vol_reg;
 57	unsigned	mode:2;	/* bit[1:0] = VID1, VID0 */
 58	unsigned	extclk_freq:2;
 59	unsigned	extclk:1;
 60	unsigned	ramp_timing:3;
 61	unsigned	ramp_down:1;
 62};
 63
 64/* I2C operations */
 65
 66static inline int max8649_read_device(struct i2c_client *i2c,
 67				      int reg, int bytes, void *dest)
 68{
 69	unsigned char data;
 70	int ret;
 71
 72	data = (unsigned char)reg;
 73	ret = i2c_master_send(i2c, &data, 1);
 74	if (ret < 0)
 75		return ret;
 76	ret = i2c_master_recv(i2c, dest, bytes);
 77	if (ret < 0)
 78		return ret;
 79	return 0;
 80}
 81
 82static inline int max8649_write_device(struct i2c_client *i2c,
 83				       int reg, int bytes, void *src)
 84{
 85	unsigned char buf[bytes + 1];
 86	int ret;
 87
 88	buf[0] = (unsigned char)reg;
 89	memcpy(&buf[1], src, bytes);
 90
 91	ret = i2c_master_send(i2c, buf, bytes + 1);
 92	if (ret < 0)
 93		return ret;
 94	return 0;
 95}
 96
 97static int max8649_reg_read(struct i2c_client *i2c, int reg)
 98{
 99	struct max8649_regulator_info *info = i2c_get_clientdata(i2c);
100	unsigned char data;
101	int ret;
102
103	mutex_lock(&info->io_lock);
104	ret = max8649_read_device(i2c, reg, 1, &data);
105	mutex_unlock(&info->io_lock);
106
107	if (ret < 0)
108		return ret;
109	return (int)data;
110}
111
112static int max8649_set_bits(struct i2c_client *i2c, int reg,
113			    unsigned char mask, unsigned char data)
114{
115	struct max8649_regulator_info *info = i2c_get_clientdata(i2c);
116	unsigned char value;
117	int ret;
118
119	mutex_lock(&info->io_lock);
120	ret = max8649_read_device(i2c, reg, 1, &value);
121	if (ret < 0)
122		goto out;
123	value &= ~mask;
124	value |= data;
125	ret = max8649_write_device(i2c, reg, 1, &value);
126out:
127	mutex_unlock(&info->io_lock);
128	return ret;
129}
130
131static inline int check_range(int min_uV, int max_uV)
132{
133	if ((min_uV < MAX8649_DCDC_VMIN) || (max_uV > MAX8649_DCDC_VMAX)
134		|| (min_uV > max_uV))
135		return -EINVAL;
136	return 0;
137}
138
139static int max8649_list_voltage(struct regulator_dev *rdev, unsigned index)
140{
141	return (MAX8649_DCDC_VMIN + index * MAX8649_DCDC_STEP);
142}
143
144static int max8649_get_voltage(struct regulator_dev *rdev)
145{
146	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
147	unsigned char data;
148	int ret;
149
150	ret = max8649_reg_read(info->i2c, info->vol_reg);
151	if (ret < 0)
152		return ret;
153	data = (unsigned char)ret & MAX8649_VOL_MASK;
154	return max8649_list_voltage(rdev, data);
155}
156
157static int max8649_set_voltage(struct regulator_dev *rdev,
158			       int min_uV, int max_uV, unsigned *selector)
159{
160	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
161	unsigned char data, mask;
162
163	if (check_range(min_uV, max_uV)) {
164		dev_err(info->dev, "invalid voltage range (%d, %d) uV\n",
165			min_uV, max_uV);
166		return -EINVAL;
167	}
168	data = (min_uV - MAX8649_DCDC_VMIN + MAX8649_DCDC_STEP - 1)
169		/ MAX8649_DCDC_STEP;
170	mask = MAX8649_VOL_MASK;
171	*selector = data & mask;
172
173	return max8649_set_bits(info->i2c, info->vol_reg, mask, data);
174}
175
176/* EN_PD means pulldown on EN input */
177static int max8649_enable(struct regulator_dev *rdev)
178{
179	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
180	return max8649_set_bits(info->i2c, MAX8649_CONTROL, MAX8649_EN_PD, 0);
181}
182
183/*
184 * Applied internal pulldown resistor on EN input pin.
185 * If pulldown EN pin outside, it would be better.
186 */
187static int max8649_disable(struct regulator_dev *rdev)
188{
189	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
190	return max8649_set_bits(info->i2c, MAX8649_CONTROL, MAX8649_EN_PD,
191				MAX8649_EN_PD);
192}
193
194static int max8649_is_enabled(struct regulator_dev *rdev)
195{
196	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
197	int ret;
198
199	ret = max8649_reg_read(info->i2c, MAX8649_CONTROL);
200	if (ret < 0)
201		return ret;
202	return !((unsigned char)ret & MAX8649_EN_PD);
203}
204
205static int max8649_enable_time(struct regulator_dev *rdev)
206{
207	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
208	int voltage, rate, ret;
209
210	/* get voltage */
211	ret = max8649_reg_read(info->i2c, info->vol_reg);
212	if (ret < 0)
213		return ret;
214	ret &= MAX8649_VOL_MASK;
215	voltage = max8649_list_voltage(rdev, (unsigned char)ret); /* uV */
216
217	/* get rate */
218	ret = max8649_reg_read(info->i2c, MAX8649_RAMP);
219	if (ret < 0)
220		return ret;
221	ret = (ret & MAX8649_RAMP_MASK) >> 5;
222	rate = (32 * 1000) >> ret;	/* uV/uS */
223
224	return (voltage / rate);
225}
226
227static int max8649_set_mode(struct regulator_dev *rdev, unsigned int mode)
228{
229	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
230
231	switch (mode) {
232	case REGULATOR_MODE_FAST:
233		max8649_set_bits(info->i2c, info->vol_reg, MAX8649_FORCE_PWM,
234				 MAX8649_FORCE_PWM);
235		break;
236	case REGULATOR_MODE_NORMAL:
237		max8649_set_bits(info->i2c, info->vol_reg,
238				 MAX8649_FORCE_PWM, 0);
239		break;
240	default:
241		return -EINVAL;
242	}
243	return 0;
244}
245
246static unsigned int max8649_get_mode(struct regulator_dev *rdev)
247{
248	struct max8649_regulator_info *info = rdev_get_drvdata(rdev);
249	int ret;
250
251	ret = max8649_reg_read(info->i2c, info->vol_reg);
252	if (ret & MAX8649_FORCE_PWM)
253		return REGULATOR_MODE_FAST;
254	return REGULATOR_MODE_NORMAL;
255}
256
257static struct regulator_ops max8649_dcdc_ops = {
258	.set_voltage	= max8649_set_voltage,
259	.get_voltage	= max8649_get_voltage,
260	.list_voltage	= max8649_list_voltage,
261	.enable		= max8649_enable,
262	.disable	= max8649_disable,
263	.is_enabled	= max8649_is_enabled,
264	.enable_time	= max8649_enable_time,
265	.set_mode	= max8649_set_mode,
266	.get_mode	= max8649_get_mode,
267
268};
269
270static struct regulator_desc dcdc_desc = {
271	.name		= "max8649",
272	.ops		= &max8649_dcdc_ops,
273	.type		= REGULATOR_VOLTAGE,
274	.n_voltages	= 1 << 6,
275	.owner		= THIS_MODULE,
276};
277
278static int __devinit max8649_regulator_probe(struct i2c_client *client,
279					     const struct i2c_device_id *id)
280{
281	struct max8649_platform_data *pdata = client->dev.platform_data;
282	struct max8649_regulator_info *info = NULL;
283	unsigned char data;
284	int ret;
285
286	info = kzalloc(sizeof(struct max8649_regulator_info), GFP_KERNEL);
287	if (!info) {
288		dev_err(&client->dev, "No enough memory\n");
289		return -ENOMEM;
290	}
291
292	info->i2c = client;
293	info->dev = &client->dev;
294	mutex_init(&info->io_lock);
295	i2c_set_clientdata(client, info);
296
297	info->mode = pdata->mode;
298	switch (info->mode) {
299	case 0:
300		info->vol_reg = MAX8649_MODE0;
301		break;
302	case 1:
303		info->vol_reg = MAX8649_MODE1;
304		break;
305	case 2:
306		info->vol_reg = MAX8649_MODE2;
307		break;
308	case 3:
309		info->vol_reg = MAX8649_MODE3;
310		break;
311	default:
312		break;
313	}
314
315	ret = max8649_reg_read(info->i2c, MAX8649_CHIP_ID1);
316	if (ret < 0) {
317		dev_err(info->dev, "Failed to detect ID of MAX8649:%d\n",
318			ret);
319		goto out;
320	}
321	dev_info(info->dev, "Detected MAX8649 (ID:%x)\n", ret);
322
323	/* enable VID0 & VID1 */
324	max8649_set_bits(info->i2c, MAX8649_CONTROL, MAX8649_VID_MASK, 0);
325
326	/* enable/disable external clock synchronization */
327	info->extclk = pdata->extclk;
328	data = (info->extclk) ? MAX8649_SYNC_EXTCLK : 0;
329	max8649_set_bits(info->i2c, info->vol_reg, MAX8649_SYNC_EXTCLK, data);
330	if (info->extclk) {
331		/* set external clock frequency */
332		info->extclk_freq = pdata->extclk_freq;
333		max8649_set_bits(info->i2c, MAX8649_SYNC, MAX8649_EXT_MASK,
334				 info->extclk_freq << 6);
335	}
336
337	if (pdata->ramp_timing) {
338		info->ramp_timing = pdata->ramp_timing;
339		max8649_set_bits(info->i2c, MAX8649_RAMP, MAX8649_RAMP_MASK,
340				 info->ramp_timing << 5);
341	}
342
343	info->ramp_down = pdata->ramp_down;
344	if (info->ramp_down) {
345		max8649_set_bits(info->i2c, MAX8649_RAMP, MAX8649_RAMP_DOWN,
346				 MAX8649_RAMP_DOWN);
347	}
348
349	info->regulator = regulator_register(&dcdc_desc, &client->dev,
350					     pdata->regulator, info);
351	if (IS_ERR(info->regulator)) {
352		dev_err(info->dev, "failed to register regulator %s\n",
353			dcdc_desc.name);
354		ret = PTR_ERR(info->regulator);
355		goto out;
356	}
357
358	dev_info(info->dev, "Max8649 regulator device is detected.\n");
359	return 0;
360out:
361	kfree(info);
362	return ret;
363}
364
365static int __devexit max8649_regulator_remove(struct i2c_client *client)
366{
367	struct max8649_regulator_info *info = i2c_get_clientdata(client);
368
369	if (info) {
370		if (info->regulator)
371			regulator_unregister(info->regulator);
372		kfree(info);
373	}
374
375	return 0;
376}
377
378static const struct i2c_device_id max8649_id[] = {
379	{ "max8649", 0 },
380	{ }
381};
382MODULE_DEVICE_TABLE(i2c, max8649_id);
383
384static struct i2c_driver max8649_driver = {
385	.probe		= max8649_regulator_probe,
386	.remove		= __devexit_p(max8649_regulator_remove),
387	.driver		= {
388		.name	= "max8649",
389	},
390	.id_table	= max8649_id,
391};
392
393static int __init max8649_init(void)
394{
395	return i2c_add_driver(&max8649_driver);
396}
397subsys_initcall(max8649_init);
398
399static void __exit max8649_exit(void)
400{
401	i2c_del_driver(&max8649_driver);
402}
403module_exit(max8649_exit);
404
405/* Module information */
406MODULE_DESCRIPTION("MAXIM 8649 voltage regulator driver");
407MODULE_AUTHOR("Haojian Zhuang <haojian.zhuang@marvell.com>");
408MODULE_LICENSE("GPL");
409