1/*
2 * max8952.c - Voltage and current regulation for the Maxim 8952
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 * MyungJoo Ham <myungjoo.ham@samsung.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 as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20 */
21
22#include <linux/module.h>
23#include <linux/init.h>
24#include <linux/i2c.h>
25#include <linux/err.h>
26#include <linux/platform_device.h>
27#include <linux/regulator/driver.h>
28#include <linux/regulator/max8952.h>
29#include <linux/gpio.h>
30#include <linux/io.h>
31#include <linux/of.h>
32#include <linux/of_gpio.h>
33#include <linux/regulator/of_regulator.h>
34#include <linux/slab.h>
35
36/* Registers */
37enum {
38	MAX8952_REG_MODE0,
39	MAX8952_REG_MODE1,
40	MAX8952_REG_MODE2,
41	MAX8952_REG_MODE3,
42	MAX8952_REG_CONTROL,
43	MAX8952_REG_SYNC,
44	MAX8952_REG_RAMP,
45	MAX8952_REG_CHIP_ID1,
46	MAX8952_REG_CHIP_ID2,
47};
48
49struct max8952_data {
50	struct i2c_client	*client;
51	struct max8952_platform_data *pdata;
52
53	bool vid0;
54	bool vid1;
55};
56
57static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
58{
59	int ret = i2c_smbus_read_byte_data(max8952->client, reg);
60
61	if (ret > 0)
62		ret &= 0xff;
63
64	return ret;
65}
66
67static int max8952_write_reg(struct max8952_data *max8952,
68		u8 reg, u8 value)
69{
70	return i2c_smbus_write_byte_data(max8952->client, reg, value);
71}
72
73static int max8952_list_voltage(struct regulator_dev *rdev,
74		unsigned int selector)
75{
76	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
77
78	if (rdev_get_id(rdev) != 0)
79		return -EINVAL;
80
81	return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
82}
83
84static int max8952_get_voltage_sel(struct regulator_dev *rdev)
85{
86	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
87	u8 vid = 0;
88
89	if (max8952->vid0)
90		vid += 1;
91	if (max8952->vid1)
92		vid += 2;
93
94	return vid;
95}
96
97static int max8952_set_voltage_sel(struct regulator_dev *rdev,
98				   unsigned selector)
99{
100	struct max8952_data *max8952 = rdev_get_drvdata(rdev);
101
102	if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
103			!gpio_is_valid(max8952->pdata->gpio_vid1)) {
104		/* DVS not supported */
105		return -EPERM;
106	}
107
108	max8952->vid0 = selector & 0x1;
109	max8952->vid1 = (selector >> 1) & 0x1;
110	gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
111	gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
112
113	return 0;
114}
115
116static struct regulator_ops max8952_ops = {
117	.list_voltage		= max8952_list_voltage,
118	.get_voltage_sel	= max8952_get_voltage_sel,
119	.set_voltage_sel	= max8952_set_voltage_sel,
120};
121
122static const struct regulator_desc regulator = {
123	.name		= "MAX8952_VOUT",
124	.id		= 0,
125	.n_voltages	= MAX8952_NUM_DVS_MODE,
126	.ops		= &max8952_ops,
127	.type		= REGULATOR_VOLTAGE,
128	.owner		= THIS_MODULE,
129};
130
131#ifdef CONFIG_OF
132static const struct of_device_id max8952_dt_match[] = {
133	{ .compatible = "maxim,max8952" },
134	{},
135};
136MODULE_DEVICE_TABLE(of, max8952_dt_match);
137
138static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
139{
140	struct max8952_platform_data *pd;
141	struct device_node *np = dev->of_node;
142	int ret;
143	int i;
144
145	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
146	if (!pd)
147		return NULL;
148
149	pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0);
150	pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1);
151	pd->gpio_en = of_get_named_gpio(np, "max8952,en-gpio", 0);
152
153	if (of_property_read_u32(np, "max8952,default-mode", &pd->default_mode))
154		dev_warn(dev, "Default mode not specified, assuming 0\n");
155
156	ret = of_property_read_u32_array(np, "max8952,dvs-mode-microvolt",
157					pd->dvs_mode, ARRAY_SIZE(pd->dvs_mode));
158	if (ret) {
159		dev_err(dev, "max8952,dvs-mode-microvolt property not specified");
160		return NULL;
161	}
162
163	for (i = 0; i < ARRAY_SIZE(pd->dvs_mode); ++i) {
164		if (pd->dvs_mode[i] < 770000 || pd->dvs_mode[i] > 1400000) {
165			dev_err(dev, "DVS voltage %d out of range\n", i);
166			return NULL;
167		}
168		pd->dvs_mode[i] = (pd->dvs_mode[i] - 770000) / 10000;
169	}
170
171	if (of_property_read_u32(np, "max8952,sync-freq", &pd->sync_freq))
172		dev_warn(dev, "max8952,sync-freq property not specified, defaulting to 26MHz\n");
173
174	if (of_property_read_u32(np, "max8952,ramp-speed", &pd->ramp_speed))
175		dev_warn(dev, "max8952,ramp-speed property not specified, defaulting to 32mV/us\n");
176
177	pd->reg_data = of_get_regulator_init_data(dev, np, &regulator);
178	if (!pd->reg_data) {
179		dev_err(dev, "Failed to parse regulator init data\n");
180		return NULL;
181	}
182
183	return pd;
184}
185#else
186static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
187{
188	return NULL;
189}
190#endif
191
192static int max8952_pmic_probe(struct i2c_client *client,
193		const struct i2c_device_id *i2c_id)
194{
195	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
196	struct max8952_platform_data *pdata = dev_get_platdata(&client->dev);
197	struct regulator_config config = { };
198	struct max8952_data *max8952;
199	struct regulator_dev *rdev;
200
201	int ret = 0, err = 0;
202
203	if (client->dev.of_node)
204		pdata = max8952_parse_dt(&client->dev);
205
206	if (!pdata) {
207		dev_err(&client->dev, "Require the platform data\n");
208		return -EINVAL;
209	}
210
211	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
212		return -EIO;
213
214	max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
215			       GFP_KERNEL);
216	if (!max8952)
217		return -ENOMEM;
218
219	max8952->client = client;
220	max8952->pdata = pdata;
221
222	config.dev = &client->dev;
223	config.init_data = pdata->reg_data;
224	config.driver_data = max8952;
225	config.of_node = client->dev.of_node;
226
227	config.ena_gpio = pdata->gpio_en;
228	if (client->dev.of_node)
229		config.ena_gpio_initialized = true;
230	if (pdata->reg_data->constraints.boot_on)
231		config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
232
233	rdev = devm_regulator_register(&client->dev, &regulator, &config);
234	if (IS_ERR(rdev)) {
235		ret = PTR_ERR(rdev);
236		dev_err(&client->dev, "regulator init failed (%d)\n", ret);
237		return ret;
238	}
239
240	max8952->vid0 = pdata->default_mode & 0x1;
241	max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
242
243	if (gpio_is_valid(pdata->gpio_vid0) &&
244			gpio_is_valid(pdata->gpio_vid1)) {
245		unsigned long gpio_flags;
246
247		gpio_flags = max8952->vid0 ?
248			     GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
249		if (devm_gpio_request_one(&client->dev, pdata->gpio_vid0,
250					  gpio_flags, "MAX8952 VID0"))
251			err = 1;
252
253		gpio_flags = max8952->vid1 ?
254			     GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
255		if (devm_gpio_request_one(&client->dev, pdata->gpio_vid1,
256					  gpio_flags, "MAX8952 VID1"))
257			err = 2;
258	} else
259		err = 3;
260
261	if (err) {
262		dev_warn(&client->dev, "VID0/1 gpio invalid: "
263				"DVS not available.\n");
264		max8952->vid0 = 0;
265		max8952->vid1 = 0;
266		/* Mark invalid */
267		pdata->gpio_vid0 = -1;
268		pdata->gpio_vid1 = -1;
269
270		/* Disable Pulldown of EN only */
271		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
272
273		dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
274				" do not have proper controls.\n");
275	} else {
276		/*
277		 * Disable Pulldown on EN, VID0, VID1 to reduce
278		 * leakage current of MAX8952 assuming that MAX8952
279		 * is turned on (EN==1). Note that without having VID0/1
280		 * properly connected, turning pulldown off can be
281		 * problematic. Thus, turn this off only when they are
282		 * controllable by GPIO.
283		 */
284		max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
285	}
286
287	max8952_write_reg(max8952, MAX8952_REG_MODE0,
288			(max8952_read_reg(max8952,
289					  MAX8952_REG_MODE0) & 0xC0) |
290			(pdata->dvs_mode[0] & 0x3F));
291	max8952_write_reg(max8952, MAX8952_REG_MODE1,
292			(max8952_read_reg(max8952,
293					  MAX8952_REG_MODE1) & 0xC0) |
294			(pdata->dvs_mode[1] & 0x3F));
295	max8952_write_reg(max8952, MAX8952_REG_MODE2,
296			(max8952_read_reg(max8952,
297					  MAX8952_REG_MODE2) & 0xC0) |
298			(pdata->dvs_mode[2] & 0x3F));
299	max8952_write_reg(max8952, MAX8952_REG_MODE3,
300			(max8952_read_reg(max8952,
301					  MAX8952_REG_MODE3) & 0xC0) |
302			(pdata->dvs_mode[3] & 0x3F));
303
304	max8952_write_reg(max8952, MAX8952_REG_SYNC,
305			(max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
306			((pdata->sync_freq & 0x3) << 6));
307	max8952_write_reg(max8952, MAX8952_REG_RAMP,
308			(max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
309			((pdata->ramp_speed & 0x7) << 5));
310
311	i2c_set_clientdata(client, max8952);
312
313	return 0;
314}
315
316static const struct i2c_device_id max8952_ids[] = {
317	{ "max8952", 0 },
318	{ },
319};
320MODULE_DEVICE_TABLE(i2c, max8952_ids);
321
322static struct i2c_driver max8952_pmic_driver = {
323	.probe		= max8952_pmic_probe,
324	.driver		= {
325		.name	= "max8952",
326		.of_match_table = of_match_ptr(max8952_dt_match),
327	},
328	.id_table	= max8952_ids,
329};
330
331static int __init max8952_pmic_init(void)
332{
333	return i2c_add_driver(&max8952_pmic_driver);
334}
335subsys_initcall(max8952_pmic_init);
336
337static void __exit max8952_pmic_exit(void)
338{
339	i2c_del_driver(&max8952_pmic_driver);
340}
341module_exit(max8952_pmic_exit);
342
343MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
344MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
345MODULE_LICENSE("GPL");
346