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 */
38 enum {
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
50 struct max8952_data {
51 struct i2c_client *client;
52 struct max8952_platform_data *pdata;
53
54 bool vid0;
55 bool vid1;
56 };
57
max8952_read_reg(struct max8952_data * max8952,u8 reg)58 static 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
max8952_write_reg(struct max8952_data * max8952,u8 reg,u8 value)68 static 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
max8952_list_voltage(struct regulator_dev * rdev,unsigned int selector)74 static 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
max8952_get_voltage_sel(struct regulator_dev * rdev)85 static 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
max8952_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)98 static 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
117 static 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
123 static 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
133 static const struct of_device_id max8952_dt_match[] = {
134 { .compatible = "maxim,max8952" },
135 {},
136 };
137 MODULE_DEVICE_TABLE(of, max8952_dt_match);
138
max8952_parse_dt(struct device * dev)139 static 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, ®ulator);
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
max8952_parse_dt(struct device * dev)186 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
187 {
188 return NULL;
189 }
190 #endif
191
max8952_pmic_probe(struct i2c_client * client,const struct i2c_device_id * i2c_id)192 static 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 gpiod = devm_gpiod_get_optional(&client->dev,
234 "max8952,en",
235 gflags);
236 if (IS_ERR(gpiod))
237 return PTR_ERR(gpiod);
238 if (gpiod)
239 config.ena_gpiod = gpiod;
240
241 rdev = devm_regulator_register(&client->dev, ®ulator, &config);
242 if (IS_ERR(rdev)) {
243 ret = PTR_ERR(rdev);
244 dev_err(&client->dev, "regulator init failed (%d)\n", ret);
245 return ret;
246 }
247
248 max8952->vid0 = pdata->default_mode & 0x1;
249 max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
250
251 if (gpio_is_valid(pdata->gpio_vid0) &&
252 gpio_is_valid(pdata->gpio_vid1)) {
253 unsigned long gpio_flags;
254
255 gpio_flags = max8952->vid0 ?
256 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
257 if (devm_gpio_request_one(&client->dev, pdata->gpio_vid0,
258 gpio_flags, "MAX8952 VID0"))
259 err = 1;
260
261 gpio_flags = max8952->vid1 ?
262 GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
263 if (devm_gpio_request_one(&client->dev, pdata->gpio_vid1,
264 gpio_flags, "MAX8952 VID1"))
265 err = 2;
266 } else
267 err = 3;
268
269 if (err) {
270 dev_warn(&client->dev, "VID0/1 gpio invalid: "
271 "DVS not available.\n");
272 max8952->vid0 = 0;
273 max8952->vid1 = 0;
274 /* Mark invalid */
275 pdata->gpio_vid0 = -1;
276 pdata->gpio_vid1 = -1;
277
278 /* Disable Pulldown of EN only */
279 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
280
281 dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
282 " do not have proper controls.\n");
283 } else {
284 /*
285 * Disable Pulldown on EN, VID0, VID1 to reduce
286 * leakage current of MAX8952 assuming that MAX8952
287 * is turned on (EN==1). Note that without having VID0/1
288 * properly connected, turning pulldown off can be
289 * problematic. Thus, turn this off only when they are
290 * controllable by GPIO.
291 */
292 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
293 }
294
295 max8952_write_reg(max8952, MAX8952_REG_MODE0,
296 (max8952_read_reg(max8952,
297 MAX8952_REG_MODE0) & 0xC0) |
298 (pdata->dvs_mode[0] & 0x3F));
299 max8952_write_reg(max8952, MAX8952_REG_MODE1,
300 (max8952_read_reg(max8952,
301 MAX8952_REG_MODE1) & 0xC0) |
302 (pdata->dvs_mode[1] & 0x3F));
303 max8952_write_reg(max8952, MAX8952_REG_MODE2,
304 (max8952_read_reg(max8952,
305 MAX8952_REG_MODE2) & 0xC0) |
306 (pdata->dvs_mode[2] & 0x3F));
307 max8952_write_reg(max8952, MAX8952_REG_MODE3,
308 (max8952_read_reg(max8952,
309 MAX8952_REG_MODE3) & 0xC0) |
310 (pdata->dvs_mode[3] & 0x3F));
311
312 max8952_write_reg(max8952, MAX8952_REG_SYNC,
313 (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
314 ((pdata->sync_freq & 0x3) << 6));
315 max8952_write_reg(max8952, MAX8952_REG_RAMP,
316 (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
317 ((pdata->ramp_speed & 0x7) << 5));
318
319 i2c_set_clientdata(client, max8952);
320
321 return 0;
322 }
323
324 static const struct i2c_device_id max8952_ids[] = {
325 { "max8952", 0 },
326 { },
327 };
328 MODULE_DEVICE_TABLE(i2c, max8952_ids);
329
330 static struct i2c_driver max8952_pmic_driver = {
331 .probe = max8952_pmic_probe,
332 .driver = {
333 .name = "max8952",
334 .of_match_table = of_match_ptr(max8952_dt_match),
335 },
336 .id_table = max8952_ids,
337 };
338
max8952_pmic_init(void)339 static int __init max8952_pmic_init(void)
340 {
341 return i2c_add_driver(&max8952_pmic_driver);
342 }
343 subsys_initcall(max8952_pmic_init);
344
max8952_pmic_exit(void)345 static void __exit max8952_pmic_exit(void)
346 {
347 i2c_del_driver(&max8952_pmic_driver);
348 }
349 module_exit(max8952_pmic_exit);
350
351 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
352 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
353 MODULE_LICENSE("GPL");
354