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Linux/drivers/regulator/max8660.c

  1 /*
  2  * max8660.c  --  Voltage regulation for the Maxim 8660/8661
  3  *
  4  * based on max1586.c and wm8400-regulator.c
  5  *
  6  * Copyright (C) 2009 Wolfram Sang, Pengutronix e.K.
  7  *
  8  * This program is free software; you can redistribute it and/or modify it
  9  * under the terms of the GNU General Public License as published by the Free
 10  * Software Foundation; version 2 of the License.
 11  *
 12  * This program is distributed in the hope that it will be useful, but WITHOUT
 13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 15  * more details.
 16  *
 17  * You should have received a copy of the GNU General Public License along with
 18  * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 19  * Place, Suite 330, Boston, MA  02111-1307  USA
 20  *
 21  * Some info:
 22  *
 23  * Datasheet: http://datasheets.maxim-ic.com/en/ds/MAX8660-MAX8661.pdf
 24  *
 25  * This chip is a bit nasty because it is a write-only device. Thus, the driver
 26  * uses shadow registers to keep track of its values. The main problem appears
 27  * to be the initialization: When Linux boots up, we cannot know if the chip is
 28  * in the default state or not, so we would have to pass such information in
 29  * platform_data. As this adds a bit of complexity to the driver, this is left
 30  * out for now until it is really needed.
 31  *
 32  * [A|S|M]DTV1 registers are currently not used, but [A|S|M]DTV2.
 33  *
 34  * If the driver is feature complete, it might be worth to check if one set of
 35  * functions for V3-V7 is sufficient. For maximum flexibility during
 36  * development, they are separated for now.
 37  *
 38  */
 39 
 40 #include <linux/module.h>
 41 #include <linux/err.h>
 42 #include <linux/i2c.h>
 43 #include <linux/platform_device.h>
 44 #include <linux/regulator/driver.h>
 45 #include <linux/slab.h>
 46 #include <linux/regulator/max8660.h>
 47 #include <linux/of.h>
 48 #include <linux/of_device.h>
 49 #include <linux/regulator/of_regulator.h>
 50 
 51 #define MAX8660_DCDC_MIN_UV      725000
 52 #define MAX8660_DCDC_MAX_UV     1800000
 53 #define MAX8660_DCDC_STEP         25000
 54 #define MAX8660_DCDC_MAX_SEL    0x2b
 55 
 56 #define MAX8660_LDO5_MIN_UV     1700000
 57 #define MAX8660_LDO5_MAX_UV     2000000
 58 #define MAX8660_LDO5_STEP         25000
 59 #define MAX8660_LDO5_MAX_SEL    0x0c
 60 
 61 #define MAX8660_LDO67_MIN_UV    1800000
 62 #define MAX8660_LDO67_MAX_UV    3300000
 63 #define MAX8660_LDO67_STEP       100000
 64 #define MAX8660_LDO67_MAX_SEL   0x0f
 65 
 66 enum {
 67         MAX8660_OVER1,
 68         MAX8660_OVER2,
 69         MAX8660_VCC1,
 70         MAX8660_ADTV1,
 71         MAX8660_ADTV2,
 72         MAX8660_SDTV1,
 73         MAX8660_SDTV2,
 74         MAX8660_MDTV1,
 75         MAX8660_MDTV2,
 76         MAX8660_L12VCR,
 77         MAX8660_FPWM,
 78         MAX8660_N_REGS, /* not a real register */
 79 };
 80 
 81 struct max8660 {
 82         struct i2c_client *client;
 83         u8 shadow_regs[MAX8660_N_REGS];         /* as chip is write only */
 84 };
 85 
 86 static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
 87 {
 88         static const u8 max8660_addresses[MAX8660_N_REGS] = {
 89          0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80
 90         };
 91 
 92         int ret;
 93         u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
 94 
 95         dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
 96                         max8660_addresses[reg], reg_val);
 97 
 98         ret = i2c_smbus_write_byte_data(max8660->client,
 99                         max8660_addresses[reg], reg_val);
100         if (ret == 0)
101                 max8660->shadow_regs[reg] = reg_val;
102 
103         return ret;
104 }
105 
106 
107 /*
108  * DCDC functions
109  */
110 
111 static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
112 {
113         struct max8660 *max8660 = rdev_get_drvdata(rdev);
114         u8 val = max8660->shadow_regs[MAX8660_OVER1];
115         u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
116 
117         return !!(val & mask);
118 }
119 
120 static int max8660_dcdc_enable(struct regulator_dev *rdev)
121 {
122         struct max8660 *max8660 = rdev_get_drvdata(rdev);
123         u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
124 
125         return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
126 }
127 
128 static int max8660_dcdc_disable(struct regulator_dev *rdev)
129 {
130         struct max8660 *max8660 = rdev_get_drvdata(rdev);
131         u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
132 
133         return max8660_write(max8660, MAX8660_OVER1, mask, 0);
134 }
135 
136 static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
137 {
138         struct max8660 *max8660 = rdev_get_drvdata(rdev);
139         u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
140         u8 selector = max8660->shadow_regs[reg];
141 
142         return selector;
143 }
144 
145 static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
146                                         unsigned int selector)
147 {
148         struct max8660 *max8660 = rdev_get_drvdata(rdev);
149         u8 reg, bits;
150         int ret;
151 
152         reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
153         ret = max8660_write(max8660, reg, 0, selector);
154         if (ret)
155                 return ret;
156 
157         /* Select target voltage register and activate regulation */
158         bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
159         return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
160 }
161 
162 static struct regulator_ops max8660_dcdc_ops = {
163         .is_enabled = max8660_dcdc_is_enabled,
164         .list_voltage = regulator_list_voltage_linear,
165         .map_voltage = regulator_map_voltage_linear,
166         .set_voltage_sel = max8660_dcdc_set_voltage_sel,
167         .get_voltage_sel = max8660_dcdc_get_voltage_sel,
168 };
169 
170 
171 /*
172  * LDO5 functions
173  */
174 
175 static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
176 {
177         struct max8660 *max8660 = rdev_get_drvdata(rdev);
178 
179         u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
180         return selector;
181 }
182 
183 static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
184                                         unsigned int selector)
185 {
186         struct max8660 *max8660 = rdev_get_drvdata(rdev);
187         int ret;
188 
189         ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
190         if (ret)
191                 return ret;
192 
193         /* Select target voltage register and activate regulation */
194         return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
195 }
196 
197 static struct regulator_ops max8660_ldo5_ops = {
198         .list_voltage = regulator_list_voltage_linear,
199         .map_voltage = regulator_map_voltage_linear,
200         .set_voltage_sel = max8660_ldo5_set_voltage_sel,
201         .get_voltage_sel = max8660_ldo5_get_voltage_sel,
202 };
203 
204 
205 /*
206  * LDO67 functions
207  */
208 
209 static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
210 {
211         struct max8660 *max8660 = rdev_get_drvdata(rdev);
212         u8 val = max8660->shadow_regs[MAX8660_OVER2];
213         u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
214 
215         return !!(val & mask);
216 }
217 
218 static int max8660_ldo67_enable(struct regulator_dev *rdev)
219 {
220         struct max8660 *max8660 = rdev_get_drvdata(rdev);
221         u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
222 
223         return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
224 }
225 
226 static int max8660_ldo67_disable(struct regulator_dev *rdev)
227 {
228         struct max8660 *max8660 = rdev_get_drvdata(rdev);
229         u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
230 
231         return max8660_write(max8660, MAX8660_OVER2, mask, 0);
232 }
233 
234 static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
235 {
236         struct max8660 *max8660 = rdev_get_drvdata(rdev);
237         u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
238         u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
239 
240         return selector;
241 }
242 
243 static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
244                                          unsigned int selector)
245 {
246         struct max8660 *max8660 = rdev_get_drvdata(rdev);
247 
248         if (rdev_get_id(rdev) == MAX8660_V6)
249                 return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
250         else
251                 return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
252                                      selector << 4);
253 }
254 
255 static struct regulator_ops max8660_ldo67_ops = {
256         .is_enabled = max8660_ldo67_is_enabled,
257         .enable = max8660_ldo67_enable,
258         .disable = max8660_ldo67_disable,
259         .list_voltage = regulator_list_voltage_linear,
260         .map_voltage = regulator_map_voltage_linear,
261         .get_voltage_sel = max8660_ldo67_get_voltage_sel,
262         .set_voltage_sel = max8660_ldo67_set_voltage_sel,
263 };
264 
265 static const struct regulator_desc max8660_reg[] = {
266         {
267                 .name = "V3(DCDC)",
268                 .id = MAX8660_V3,
269                 .ops = &max8660_dcdc_ops,
270                 .type = REGULATOR_VOLTAGE,
271                 .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
272                 .owner = THIS_MODULE,
273                 .min_uV = MAX8660_DCDC_MIN_UV,
274                 .uV_step = MAX8660_DCDC_STEP,
275         },
276         {
277                 .name = "V4(DCDC)",
278                 .id = MAX8660_V4,
279                 .ops = &max8660_dcdc_ops,
280                 .type = REGULATOR_VOLTAGE,
281                 .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
282                 .owner = THIS_MODULE,
283                 .min_uV = MAX8660_DCDC_MIN_UV,
284                 .uV_step = MAX8660_DCDC_STEP,
285         },
286         {
287                 .name = "V5(LDO)",
288                 .id = MAX8660_V5,
289                 .ops = &max8660_ldo5_ops,
290                 .type = REGULATOR_VOLTAGE,
291                 .n_voltages = MAX8660_LDO5_MAX_SEL + 1,
292                 .owner = THIS_MODULE,
293                 .min_uV = MAX8660_LDO5_MIN_UV,
294                 .uV_step = MAX8660_LDO5_STEP,
295         },
296         {
297                 .name = "V6(LDO)",
298                 .id = MAX8660_V6,
299                 .ops = &max8660_ldo67_ops,
300                 .type = REGULATOR_VOLTAGE,
301                 .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
302                 .owner = THIS_MODULE,
303                 .min_uV = MAX8660_LDO67_MIN_UV,
304                 .uV_step = MAX8660_LDO67_STEP,
305         },
306         {
307                 .name = "V7(LDO)",
308                 .id = MAX8660_V7,
309                 .ops = &max8660_ldo67_ops,
310                 .type = REGULATOR_VOLTAGE,
311                 .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
312                 .owner = THIS_MODULE,
313                 .min_uV = MAX8660_LDO67_MIN_UV,
314                 .uV_step = MAX8660_LDO67_STEP,
315         },
316 };
317 
318 enum {
319         MAX8660 = 0,
320         MAX8661 = 1,
321 };
322 
323 #ifdef CONFIG_OF
324 static const struct of_device_id max8660_dt_ids[] = {
325         { .compatible = "maxim,max8660", .data = (void *) MAX8660 },
326         { .compatible = "maxim,max8661", .data = (void *) MAX8661 },
327         { }
328 };
329 MODULE_DEVICE_TABLE(of, max8660_dt_ids);
330 
331 static int max8660_pdata_from_dt(struct device *dev,
332                                  struct device_node **of_node,
333                                  struct max8660_platform_data *pdata)
334 {
335         int matched, i;
336         struct device_node *np;
337         struct max8660_subdev_data *sub;
338         struct of_regulator_match rmatch[ARRAY_SIZE(max8660_reg)];
339 
340         np = of_get_child_by_name(dev->of_node, "regulators");
341         if (!np) {
342                 dev_err(dev, "missing 'regulators' subnode in DT\n");
343                 return -EINVAL;
344         }
345 
346         for (i = 0; i < ARRAY_SIZE(rmatch); i++)
347                 rmatch[i].name = max8660_reg[i].name;
348 
349         matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
350         of_node_put(np);
351         if (matched <= 0)
352                 return matched;
353 
354         pdata->subdevs = devm_kzalloc(dev, sizeof(struct max8660_subdev_data) *
355                                                 matched, GFP_KERNEL);
356         if (!pdata->subdevs)
357                 return -ENOMEM;
358 
359         pdata->num_subdevs = matched;
360         sub = pdata->subdevs;
361 
362         for (i = 0; i < matched; i++) {
363                 sub->id = i;
364                 sub->name = rmatch[i].name;
365                 sub->platform_data = rmatch[i].init_data;
366                 of_node[i] = rmatch[i].of_node;
367                 sub++;
368         }
369 
370         return 0;
371 }
372 #else
373 static inline int max8660_pdata_from_dt(struct device *dev,
374                                         struct device_node **of_node,
375                                         struct max8660_platform_data *pdata)
376 {
377         return 0;
378 }
379 #endif
380 
381 static int max8660_probe(struct i2c_client *client,
382                                    const struct i2c_device_id *i2c_id)
383 {
384         struct device *dev = &client->dev;
385         struct max8660_platform_data *pdata = dev_get_platdata(dev);
386         struct regulator_config config = { };
387         struct max8660 *max8660;
388         int boot_on, i, id, ret = -EINVAL;
389         struct device_node *of_node[MAX8660_V_END];
390         unsigned long type;
391 
392         if (dev->of_node && !pdata) {
393                 const struct of_device_id *id;
394                 struct max8660_platform_data pdata_of;
395 
396                 id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
397                 if (!id)
398                         return -ENODEV;
399 
400                 ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
401                 if (ret < 0)
402                         return ret;
403 
404                 pdata = &pdata_of;
405                 type = (unsigned long) id->data;
406         } else {
407                 type = i2c_id->driver_data;
408                 memset(of_node, 0, sizeof(of_node));
409         }
410 
411         if (pdata->num_subdevs > MAX8660_V_END) {
412                 dev_err(dev, "Too many regulators found!\n");
413                 return -EINVAL;
414         }
415 
416         max8660 = devm_kzalloc(dev, sizeof(struct max8660), GFP_KERNEL);
417         if (!max8660)
418                 return -ENOMEM;
419 
420         max8660->client = client;
421 
422         if (pdata->en34_is_high) {
423                 /* Simulate always on */
424                 max8660->shadow_regs[MAX8660_OVER1] = 5;
425         } else {
426                 /* Otherwise devices can be toggled via software */
427                 max8660_dcdc_ops.enable = max8660_dcdc_enable;
428                 max8660_dcdc_ops.disable = max8660_dcdc_disable;
429         }
430 
431         /*
432          * First, set up shadow registers to prevent glitches. As some
433          * registers are shared between regulators, everything must be properly
434          * set up for all regulators in advance.
435          */
436         max8660->shadow_regs[MAX8660_ADTV1] =
437                 max8660->shadow_regs[MAX8660_ADTV2] =
438                 max8660->shadow_regs[MAX8660_SDTV1] =
439                 max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
440         max8660->shadow_regs[MAX8660_MDTV1] =
441                 max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
442 
443         for (i = 0; i < pdata->num_subdevs; i++) {
444 
445                 if (!pdata->subdevs[i].platform_data)
446                         return ret;
447 
448                 boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
449 
450                 switch (pdata->subdevs[i].id) {
451                 case MAX8660_V3:
452                         if (boot_on)
453                                 max8660->shadow_regs[MAX8660_OVER1] |= 1;
454                         break;
455 
456                 case MAX8660_V4:
457                         if (boot_on)
458                                 max8660->shadow_regs[MAX8660_OVER1] |= 4;
459                         break;
460 
461                 case MAX8660_V5:
462                         break;
463 
464                 case MAX8660_V6:
465                         if (boot_on)
466                                 max8660->shadow_regs[MAX8660_OVER2] |= 2;
467                         break;
468 
469                 case MAX8660_V7:
470                         if (type == MAX8661) {
471                                 dev_err(dev, "Regulator not on this chip!\n");
472                                 return -EINVAL;
473                         }
474 
475                         if (boot_on)
476                                 max8660->shadow_regs[MAX8660_OVER2] |= 4;
477                         break;
478 
479                 default:
480                         dev_err(dev, "invalid regulator %s\n",
481                                  pdata->subdevs[i].name);
482                         return ret;
483                 }
484         }
485 
486         /* Finally register devices */
487         for (i = 0; i < pdata->num_subdevs; i++) {
488                 struct regulator_dev *rdev;
489 
490                 id = pdata->subdevs[i].id;
491 
492                 config.dev = dev;
493                 config.init_data = pdata->subdevs[i].platform_data;
494                 config.of_node = of_node[i];
495                 config.driver_data = max8660;
496 
497                 rdev = devm_regulator_register(&client->dev,
498                                                   &max8660_reg[id], &config);
499                 if (IS_ERR(rdev)) {
500                         ret = PTR_ERR(rdev);
501                         dev_err(&client->dev, "failed to register %s\n",
502                                 max8660_reg[id].name);
503                         return PTR_ERR(rdev);
504                 }
505         }
506 
507         i2c_set_clientdata(client, max8660);
508         return 0;
509 }
510 
511 static const struct i2c_device_id max8660_id[] = {
512         { .name = "max8660", .driver_data = MAX8660 },
513         { .name = "max8661", .driver_data = MAX8661 },
514         { }
515 };
516 MODULE_DEVICE_TABLE(i2c, max8660_id);
517 
518 static struct i2c_driver max8660_driver = {
519         .probe = max8660_probe,
520         .driver         = {
521                 .name   = "max8660",
522                 .owner  = THIS_MODULE,
523         },
524         .id_table       = max8660_id,
525 };
526 
527 static int __init max8660_init(void)
528 {
529         return i2c_add_driver(&max8660_driver);
530 }
531 subsys_initcall(max8660_init);
532 
533 static void __exit max8660_exit(void)
534 {
535         i2c_del_driver(&max8660_driver);
536 }
537 module_exit(max8660_exit);
538 
539 /* Module information */
540 MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
541 MODULE_AUTHOR("Wolfram Sang");
542 MODULE_LICENSE("GPL v2");
543 

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