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Linux/drivers/regulator/max8952.c

  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 */
 37 enum {
 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 
 49 struct max8952_data {
 50         struct i2c_client       *client;
 51         struct max8952_platform_data *pdata;
 52 
 53         bool vid0;
 54         bool vid1;
 55 };
 56 
 57 static 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 
 67 static 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 
 73 static 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 
 84 static 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 
 97 static 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 
116 static 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 
122 static 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
132 static const struct of_device_id max8952_dt_match[] = {
133         { .compatible = "maxim,max8952" },
134         {},
135 };
136 MODULE_DEVICE_TABLE(of, max8952_dt_match);
137 
138 static 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);
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
186 static struct max8952_platform_data *max8952_parse_dt(struct device *dev)
187 {
188         return NULL;
189 }
190 #endif
191 
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 
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 (pdata->reg_data->constraints.boot_on)
229                 config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
230 
231         rdev = devm_regulator_register(&client->dev, &regulator, &config);
232 
233         if (IS_ERR(rdev)) {
234                 ret = PTR_ERR(rdev);
235                 dev_err(&client->dev, "regulator init failed (%d)\n", ret);
236                 return ret;
237         }
238 
239         max8952->vid0 = pdata->default_mode & 0x1;
240         max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
241 
242         if (gpio_is_valid(pdata->gpio_vid0) &&
243                         gpio_is_valid(pdata->gpio_vid1)) {
244                 if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
245                         gpio_direction_output(pdata->gpio_vid0,
246                                         (pdata->default_mode) & 0x1);
247                 else
248                         err = 1;
249 
250                 if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
251                         gpio_direction_output(pdata->gpio_vid1,
252                                 (pdata->default_mode >> 1) & 0x1);
253                 else {
254                         if (!err)
255                                 gpio_free(pdata->gpio_vid0);
256                         err = 2;
257                 }
258 
259         } else
260                 err = 3;
261 
262         if (err) {
263                 dev_warn(&client->dev, "VID0/1 gpio invalid: "
264                                 "DVS not available.\n");
265                 max8952->vid0 = 0;
266                 max8952->vid1 = 0;
267                 /* Mark invalid */
268                 pdata->gpio_vid0 = -1;
269                 pdata->gpio_vid1 = -1;
270 
271                 /* Disable Pulldown of EN only */
272                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
273 
274                 dev_err(&client->dev, "DVS modes disabled because VID0 and VID1"
275                                 " do not have proper controls.\n");
276         } else {
277                 /*
278                  * Disable Pulldown on EN, VID0, VID1 to reduce
279                  * leakage current of MAX8952 assuming that MAX8952
280                  * is turned on (EN==1). Note that without having VID0/1
281                  * properly connected, turning pulldown off can be
282                  * problematic. Thus, turn this off only when they are
283                  * controllable by GPIO.
284                  */
285                 max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
286         }
287 
288         max8952_write_reg(max8952, MAX8952_REG_MODE0,
289                         (max8952_read_reg(max8952,
290                                           MAX8952_REG_MODE0) & 0xC0) |
291                         (pdata->dvs_mode[0] & 0x3F));
292         max8952_write_reg(max8952, MAX8952_REG_MODE1,
293                         (max8952_read_reg(max8952,
294                                           MAX8952_REG_MODE1) & 0xC0) |
295                         (pdata->dvs_mode[1] & 0x3F));
296         max8952_write_reg(max8952, MAX8952_REG_MODE2,
297                         (max8952_read_reg(max8952,
298                                           MAX8952_REG_MODE2) & 0xC0) |
299                         (pdata->dvs_mode[2] & 0x3F));
300         max8952_write_reg(max8952, MAX8952_REG_MODE3,
301                         (max8952_read_reg(max8952,
302                                           MAX8952_REG_MODE3) & 0xC0) |
303                         (pdata->dvs_mode[3] & 0x3F));
304 
305         max8952_write_reg(max8952, MAX8952_REG_SYNC,
306                         (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
307                         ((pdata->sync_freq & 0x3) << 6));
308         max8952_write_reg(max8952, MAX8952_REG_RAMP,
309                         (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
310                         ((pdata->ramp_speed & 0x7) << 5));
311 
312         i2c_set_clientdata(client, max8952);
313 
314         return 0;
315 }
316 
317 static int max8952_pmic_remove(struct i2c_client *client)
318 {
319         struct max8952_data *max8952 = i2c_get_clientdata(client);
320         struct max8952_platform_data *pdata = max8952->pdata;
321 
322         gpio_free(pdata->gpio_vid0);
323         gpio_free(pdata->gpio_vid1);
324         return 0;
325 }
326 
327 static const struct i2c_device_id max8952_ids[] = {
328         { "max8952", 0 },
329         { },
330 };
331 MODULE_DEVICE_TABLE(i2c, max8952_ids);
332 
333 static struct i2c_driver max8952_pmic_driver = {
334         .probe          = max8952_pmic_probe,
335         .remove         = max8952_pmic_remove,
336         .driver         = {
337                 .name   = "max8952",
338                 .of_match_table = of_match_ptr(max8952_dt_match),
339         },
340         .id_table       = max8952_ids,
341 };
342 
343 static int __init max8952_pmic_init(void)
344 {
345         return i2c_add_driver(&max8952_pmic_driver);
346 }
347 subsys_initcall(max8952_pmic_init);
348 
349 static void __exit max8952_pmic_exit(void)
350 {
351         i2c_del_driver(&max8952_pmic_driver);
352 }
353 module_exit(max8952_pmic_exit);
354 
355 MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
356 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
357 MODULE_LICENSE("GPL");
358 

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