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/gpio/consumer.h>
31#include <linux/io.h>
32#include <linux/of.h>
33#include <linux/of_gpio.h>
34#include <linux/regulator/of_regulator.h>
35#include <linux/slab.h>
36
37/* Registers */
38enum {
39 MAX8952_REG_MODE0,
40 MAX8952_REG_MODE1,
41 MAX8952_REG_MODE2,
42 MAX8952_REG_MODE3,
43 MAX8952_REG_CONTROL,
44 MAX8952_REG_SYNC,
45 MAX8952_REG_RAMP,
46 MAX8952_REG_CHIP_ID1,
47 MAX8952_REG_CHIP_ID2,
48};
49
50struct max8952_data {
51 struct i2c_client *client;
52 struct max8952_platform_data *pdata;
53
54 bool vid0;
55 bool vid1;
56};
57
58static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
59{
60 int ret = i2c_smbus_read_byte_data(max8952->client, reg);
61
62 if (ret > 0)
63 ret &= 0xff;
64
65 return ret;
66}
67
68static int max8952_write_reg(struct max8952_data *max8952,
69 u8 reg, u8 value)
70{
71 return i2c_smbus_write_byte_data(max8952->client, reg, value);
72}
73
74static int max8952_list_voltage(struct regulator_dev *rdev,
75 unsigned int selector)
76{
77 struct max8952_data *max8952 = rdev_get_drvdata(rdev);
78
79 if (rdev_get_id(rdev) != 0)
80 return -EINVAL;
81
82 return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
83}
84
85static int max8952_get_voltage_sel(struct regulator_dev *rdev)
86{
87 struct max8952_data *max8952 = rdev_get_drvdata(rdev);
88 u8 vid = 0;
89
90 if (max8952->vid0)
91 vid += 1;
92 if (max8952->vid1)
93 vid += 2;
94
95 return vid;
96}
97
98static int max8952_set_voltage_sel(struct regulator_dev *rdev,
99 unsigned selector)
100{
101 struct max8952_data *max8952 = rdev_get_drvdata(rdev);
102
103 if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
104 !gpio_is_valid(max8952->pdata->gpio_vid1)) {
105 /* DVS not supported */
106 return -EPERM;
107 }
108
109 max8952->vid0 = selector & 0x1;
110 max8952->vid1 = (selector >> 1) & 0x1;
111 gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
112 gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
113
114 return 0;
115}
116
117static const struct regulator_ops max8952_ops = {
118 .list_voltage = max8952_list_voltage,
119 .get_voltage_sel = max8952_get_voltage_sel,
120 .set_voltage_sel = max8952_set_voltage_sel,
121};
122
123static const struct regulator_desc regulator = {
124 .name = "MAX8952_VOUT",
125 .id = 0,
126 .n_voltages = MAX8952_NUM_DVS_MODE,
127 .ops = &max8952_ops,
128 .type = REGULATOR_VOLTAGE,
129 .owner = THIS_MODULE,
130};
131
132#ifdef CONFIG_OF
133static const struct of_device_id max8952_dt_match[] = {
134 { .compatible = "maxim,max8952" },
135 {},
136};
137MODULE_DEVICE_TABLE(of, max8952_dt_match);
138
139static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
140{
141 struct max8952_platform_data *pd;
142 struct device_node *np = dev->of_node;
143 int ret;
144 int i;
145
146 pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
147 if (!pd)
148 return NULL;
149
150 pd->gpio_vid0 = of_get_named_gpio(np, "max8952,vid-gpios", 0);
151 pd->gpio_vid1 = of_get_named_gpio(np, "max8952,vid-gpios", 1);
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 struct gpio_desc *gpiod;
201 enum gpiod_flags gflags;
202
203 int ret = 0, err = 0;
204
205 if (client->dev.of_node)
206 pdata = max8952_parse_dt(&client->dev);
207
208 if (!pdata) {
209 dev_err(&client->dev, "Require the platform data\n");
210 return -EINVAL;
211 }
212
213 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
214 return -EIO;
215
216 max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
217 GFP_KERNEL);
218 if (!max8952)
219 return -ENOMEM;
220
221 max8952->client = client;
222 max8952->pdata = pdata;
223
224 config.dev = &client->dev;
225 config.init_data = pdata->reg_data;
226 config.driver_data = max8952;
227 config.of_node = client->dev.of_node;
228
229 if (pdata->reg_data->constraints.boot_on)
230 gflags = GPIOD_OUT_HIGH;
231 else
232 gflags = GPIOD_OUT_LOW;
233 gflags |= GPIOD_FLAGS_BIT_NONEXCLUSIVE;
234 /*
235 * Do not use devm* here: the regulator core takes over the
236 * lifecycle management of the GPIO descriptor.
237 */
238 gpiod = gpiod_get_optional(&client->dev,
239 "max8952,en",
240 gflags);
241 if (IS_ERR(gpiod))
242 return PTR_ERR(gpiod);
243 if (gpiod)
244 config.ena_gpiod = gpiod;
245
246 rdev = devm_regulator_register(&client->dev, &regulator, &config);
247 if (IS_ERR(rdev)) {
248 ret = PTR_ERR(rdev);
249 dev_err(&client->dev, "regulator init failed (%d)\n", ret);
250 return ret;
251 }
252
253 max8952->vid0 = pdata->default_mode & 0x1;
254 max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
255
256 if (gpio_is_valid(pdata->gpio_vid0) &&
257 gpio_is_valid(pdata->gpio_vid1)) {
258 unsigned long gpio_flags;
259
260 gpio_flags = max8952->vid0 ?
261 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
262 if (devm_gpio_request_one(&client->dev, pdata->gpio_vid0,
263 gpio_flags, "MAX8952 VID0"))
264 err = 1;
265
266 gpio_flags = max8952->vid1 ?
267 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
268 if (devm_gpio_request_one(&client->dev, pdata->gpio_vid1,
269 gpio_flags, "MAX8952 VID1"))
270 err = 2;
271 } else
272 err = 3;
273
274 if (err) {
275 dev_warn(&client->dev, "VID0/1 gpio invalid: "
276 "DVS not available.\n");
277 max8952->vid0 = 0;
278 max8952->vid1 = 0;
279 /* Mark invalid */
280 pdata->gpio_vid0 = -1;
281 pdata->gpio_vid1 = -1;
282
283 /* Disable Pulldown of EN only */
284 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
285
286 dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
287 " do not have proper controls.\n");
288 } else {
289 /*
290 * Disable Pulldown on EN, VID0, VID1 to reduce
291 * leakage current of MAX8952 assuming that MAX8952
292 * is turned on (EN==1). Note that without having VID0/1
293 * properly connected, turning pulldown off can be
294 * problematic. Thus, turn this off only when they are
295 * controllable by GPIO.
296 */
297 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
298 }
299
300 max8952_write_reg(max8952, MAX8952_REG_MODE0,
301 (max8952_read_reg(max8952,
302 MAX8952_REG_MODE0) & 0xC0) |
303 (pdata->dvs_mode[0] & 0x3F));
304 max8952_write_reg(max8952, MAX8952_REG_MODE1,
305 (max8952_read_reg(max8952,
306 MAX8952_REG_MODE1) & 0xC0) |
307 (pdata->dvs_mode[1] & 0x3F));
308 max8952_write_reg(max8952, MAX8952_REG_MODE2,
309 (max8952_read_reg(max8952,
310 MAX8952_REG_MODE2) & 0xC0) |
311 (pdata->dvs_mode[2] & 0x3F));
312 max8952_write_reg(max8952, MAX8952_REG_MODE3,
313 (max8952_read_reg(max8952,
314 MAX8952_REG_MODE3) & 0xC0) |
315 (pdata->dvs_mode[3] & 0x3F));
316
317 max8952_write_reg(max8952, MAX8952_REG_SYNC,
318 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
319 ((pdata->sync_freq & 0x3) << 6));
320 max8952_write_reg(max8952, MAX8952_REG_RAMP,
321 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
322 ((pdata->ramp_speed & 0x7) << 5));
323
324 i2c_set_clientdata(client, max8952);
325
326 return 0;
327}
328
329static const struct i2c_device_id max8952_ids[] = {
330 { "max8952", 0 },
331 { },
332};
333MODULE_DEVICE_TABLE(i2c, max8952_ids);
334
335static struct i2c_driver max8952_pmic_driver = {
336 .probe = max8952_pmic_probe,
337 .driver = {
338 .name = "max8952",
339 .of_match_table = of_match_ptr(max8952_dt_match),
340 },
341 .id_table = max8952_ids,
342};
343
344static int __init max8952_pmic_init(void)
345{
346 return i2c_add_driver(&max8952_pmic_driver);
347}
348subsys_initcall(max8952_pmic_init);
349
350static void __exit max8952_pmic_exit(void)
351{
352 i2c_del_driver(&max8952_pmic_driver);
353}
354module_exit(max8952_pmic_exit);
355
356MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
357MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
358MODULE_LICENSE("GPL");
359