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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         struct regulator_dev *rdev[];
 85 };
 86 
 87 static int max8660_write(struct max8660 *max8660, u8 reg, u8 mask, u8 val)
 88 {
 89         static const u8 max8660_addresses[MAX8660_N_REGS] =
 90           { 0x10, 0x12, 0x20, 0x23, 0x24, 0x29, 0x2a, 0x32, 0x33, 0x39, 0x80 };
 91 
 92         int ret;
 93         u8 reg_val = (max8660->shadow_regs[reg] & mask) | val;
 94         dev_vdbg(&max8660->client->dev, "Writing reg %02x with %02x\n",
 95                         max8660_addresses[reg], reg_val);
 96 
 97         ret = i2c_smbus_write_byte_data(max8660->client,
 98                         max8660_addresses[reg], reg_val);
 99         if (ret == 0)
100                 max8660->shadow_regs[reg] = reg_val;
101 
102         return ret;
103 }
104 
105 
106 /*
107  * DCDC functions
108  */
109 
110 static int max8660_dcdc_is_enabled(struct regulator_dev *rdev)
111 {
112         struct max8660 *max8660 = rdev_get_drvdata(rdev);
113         u8 val = max8660->shadow_regs[MAX8660_OVER1];
114         u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
115         return !!(val & mask);
116 }
117 
118 static int max8660_dcdc_enable(struct regulator_dev *rdev)
119 {
120         struct max8660 *max8660 = rdev_get_drvdata(rdev);
121         u8 bit = (rdev_get_id(rdev) == MAX8660_V3) ? 1 : 4;
122         return max8660_write(max8660, MAX8660_OVER1, 0xff, bit);
123 }
124 
125 static int max8660_dcdc_disable(struct regulator_dev *rdev)
126 {
127         struct max8660 *max8660 = rdev_get_drvdata(rdev);
128         u8 mask = (rdev_get_id(rdev) == MAX8660_V3) ? ~1 : ~4;
129         return max8660_write(max8660, MAX8660_OVER1, mask, 0);
130 }
131 
132 static int max8660_dcdc_get_voltage_sel(struct regulator_dev *rdev)
133 {
134         struct max8660 *max8660 = rdev_get_drvdata(rdev);
135 
136         u8 reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
137         u8 selector = max8660->shadow_regs[reg];
138         return selector;
139 }
140 
141 static int max8660_dcdc_set_voltage_sel(struct regulator_dev *rdev,
142                                         unsigned int selector)
143 {
144         struct max8660 *max8660 = rdev_get_drvdata(rdev);
145         u8 reg, bits;
146         int ret;
147 
148         reg = (rdev_get_id(rdev) == MAX8660_V3) ? MAX8660_ADTV2 : MAX8660_SDTV2;
149         ret = max8660_write(max8660, reg, 0, selector);
150         if (ret)
151                 return ret;
152 
153         /* Select target voltage register and activate regulation */
154         bits = (rdev_get_id(rdev) == MAX8660_V3) ? 0x03 : 0x30;
155         return max8660_write(max8660, MAX8660_VCC1, 0xff, bits);
156 }
157 
158 static struct regulator_ops max8660_dcdc_ops = {
159         .is_enabled = max8660_dcdc_is_enabled,
160         .list_voltage = regulator_list_voltage_linear,
161         .map_voltage = regulator_map_voltage_linear,
162         .set_voltage_sel = max8660_dcdc_set_voltage_sel,
163         .get_voltage_sel = max8660_dcdc_get_voltage_sel,
164 };
165 
166 
167 /*
168  * LDO5 functions
169  */
170 
171 static int max8660_ldo5_get_voltage_sel(struct regulator_dev *rdev)
172 {
173         struct max8660 *max8660 = rdev_get_drvdata(rdev);
174 
175         u8 selector = max8660->shadow_regs[MAX8660_MDTV2];
176         return selector;
177 }
178 
179 static int max8660_ldo5_set_voltage_sel(struct regulator_dev *rdev,
180                                         unsigned int selector)
181 {
182         struct max8660 *max8660 = rdev_get_drvdata(rdev);
183         int ret;
184 
185         ret = max8660_write(max8660, MAX8660_MDTV2, 0, selector);
186         if (ret)
187                 return ret;
188 
189         /* Select target voltage register and activate regulation */
190         return max8660_write(max8660, MAX8660_VCC1, 0xff, 0xc0);
191 }
192 
193 static struct regulator_ops max8660_ldo5_ops = {
194         .list_voltage = regulator_list_voltage_linear,
195         .map_voltage = regulator_map_voltage_linear,
196         .set_voltage_sel = max8660_ldo5_set_voltage_sel,
197         .get_voltage_sel = max8660_ldo5_get_voltage_sel,
198 };
199 
200 
201 /*
202  * LDO67 functions
203  */
204 
205 static int max8660_ldo67_is_enabled(struct regulator_dev *rdev)
206 {
207         struct max8660 *max8660 = rdev_get_drvdata(rdev);
208         u8 val = max8660->shadow_regs[MAX8660_OVER2];
209         u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
210         return !!(val & mask);
211 }
212 
213 static int max8660_ldo67_enable(struct regulator_dev *rdev)
214 {
215         struct max8660 *max8660 = rdev_get_drvdata(rdev);
216         u8 bit = (rdev_get_id(rdev) == MAX8660_V6) ? 2 : 4;
217         return max8660_write(max8660, MAX8660_OVER2, 0xff, bit);
218 }
219 
220 static int max8660_ldo67_disable(struct regulator_dev *rdev)
221 {
222         struct max8660 *max8660 = rdev_get_drvdata(rdev);
223         u8 mask = (rdev_get_id(rdev) == MAX8660_V6) ? ~2 : ~4;
224         return max8660_write(max8660, MAX8660_OVER2, mask, 0);
225 }
226 
227 static int max8660_ldo67_get_voltage_sel(struct regulator_dev *rdev)
228 {
229         struct max8660 *max8660 = rdev_get_drvdata(rdev);
230 
231         u8 shift = (rdev_get_id(rdev) == MAX8660_V6) ? 0 : 4;
232         u8 selector = (max8660->shadow_regs[MAX8660_L12VCR] >> shift) & 0xf;
233         return selector;
234 }
235 
236 static int max8660_ldo67_set_voltage_sel(struct regulator_dev *rdev,
237                                          unsigned int selector)
238 {
239         struct max8660 *max8660 = rdev_get_drvdata(rdev);
240 
241         if (rdev_get_id(rdev) == MAX8660_V6)
242                 return max8660_write(max8660, MAX8660_L12VCR, 0xf0, selector);
243         else
244                 return max8660_write(max8660, MAX8660_L12VCR, 0x0f,
245                                      selector << 4);
246 }
247 
248 static struct regulator_ops max8660_ldo67_ops = {
249         .is_enabled = max8660_ldo67_is_enabled,
250         .enable = max8660_ldo67_enable,
251         .disable = max8660_ldo67_disable,
252         .list_voltage = regulator_list_voltage_linear,
253         .map_voltage = regulator_map_voltage_linear,
254         .get_voltage_sel = max8660_ldo67_get_voltage_sel,
255         .set_voltage_sel = max8660_ldo67_set_voltage_sel,
256 };
257 
258 static const struct regulator_desc max8660_reg[] = {
259         {
260                 .name = "V3(DCDC)",
261                 .id = MAX8660_V3,
262                 .ops = &max8660_dcdc_ops,
263                 .type = REGULATOR_VOLTAGE,
264                 .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
265                 .owner = THIS_MODULE,
266                 .min_uV = MAX8660_DCDC_MIN_UV,
267                 .uV_step = MAX8660_DCDC_STEP,
268         },
269         {
270                 .name = "V4(DCDC)",
271                 .id = MAX8660_V4,
272                 .ops = &max8660_dcdc_ops,
273                 .type = REGULATOR_VOLTAGE,
274                 .n_voltages = MAX8660_DCDC_MAX_SEL + 1,
275                 .owner = THIS_MODULE,
276                 .min_uV = MAX8660_DCDC_MIN_UV,
277                 .uV_step = MAX8660_DCDC_STEP,
278         },
279         {
280                 .name = "V5(LDO)",
281                 .id = MAX8660_V5,
282                 .ops = &max8660_ldo5_ops,
283                 .type = REGULATOR_VOLTAGE,
284                 .n_voltages = MAX8660_LDO5_MAX_SEL + 1,
285                 .owner = THIS_MODULE,
286                 .min_uV = MAX8660_LDO5_MIN_UV,
287                 .uV_step = MAX8660_LDO5_STEP,
288         },
289         {
290                 .name = "V6(LDO)",
291                 .id = MAX8660_V6,
292                 .ops = &max8660_ldo67_ops,
293                 .type = REGULATOR_VOLTAGE,
294                 .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
295                 .owner = THIS_MODULE,
296                 .min_uV = MAX8660_LDO67_MIN_UV,
297                 .uV_step = MAX8660_LDO67_STEP,
298         },
299         {
300                 .name = "V7(LDO)",
301                 .id = MAX8660_V7,
302                 .ops = &max8660_ldo67_ops,
303                 .type = REGULATOR_VOLTAGE,
304                 .n_voltages = MAX8660_LDO67_MAX_SEL + 1,
305                 .owner = THIS_MODULE,
306                 .min_uV = MAX8660_LDO67_MIN_UV,
307                 .uV_step = MAX8660_LDO67_STEP,
308         },
309 };
310 
311 enum {
312         MAX8660 = 0,
313         MAX8661 = 1,
314 };
315 
316 #ifdef CONFIG_OF
317 static const struct of_device_id max8660_dt_ids[] = {
318         { .compatible = "maxim,max8660", .data = (void *) MAX8660 },
319         { .compatible = "maxim,max8661", .data = (void *) MAX8661 },
320         { }
321 };
322 MODULE_DEVICE_TABLE(of, max8660_dt_ids);
323 
324 static int max8660_pdata_from_dt(struct device *dev,
325                                  struct device_node **of_node,
326                                  struct max8660_platform_data *pdata)
327 {
328         int matched, i;
329         struct device_node *np;
330         struct max8660_subdev_data *sub;
331         struct of_regulator_match rmatch[ARRAY_SIZE(max8660_reg)];
332 
333         np = of_find_node_by_name(dev->of_node, "regulators");
334         if (!np) {
335                 dev_err(dev, "missing 'regulators' subnode in DT\n");
336                 return -EINVAL;
337         }
338 
339         for (i = 0; i < ARRAY_SIZE(rmatch); i++)
340                 rmatch[i].name = max8660_reg[i].name;
341 
342         matched = of_regulator_match(dev, np, rmatch, ARRAY_SIZE(rmatch));
343         if (matched <= 0)
344                 return matched;
345 
346         pdata->subdevs = devm_kzalloc(dev, sizeof(struct max8660_subdev_data) *
347                                                 matched, GFP_KERNEL);
348         if (!pdata->subdevs)
349                 return -ENOMEM;
350 
351         pdata->num_subdevs = matched;
352         sub = pdata->subdevs;
353 
354         for (i = 0; i < matched; i++) {
355                 sub->id = i;
356                 sub->name = rmatch[i].name;
357                 sub->platform_data = rmatch[i].init_data;
358                 of_node[i] = rmatch[i].of_node;
359                 sub++;
360         }
361 
362         return 0;
363 }
364 #else
365 static inline int max8660_pdata_from_dt(struct device *dev,
366                                         struct device_node **of_node,
367                                         struct max8660_platform_data *pdata)
368 {
369         return 0;
370 }
371 #endif
372 
373 static int max8660_probe(struct i2c_client *client,
374                                    const struct i2c_device_id *i2c_id)
375 {
376         struct regulator_dev **rdev;
377         struct device *dev = &client->dev;
378         struct max8660_platform_data *pdata = dev_get_platdata(dev);
379         struct regulator_config config = { };
380         struct max8660 *max8660;
381         int boot_on, i, id, ret = -EINVAL;
382         struct device_node *of_node[MAX8660_V_END];
383         unsigned long type;
384 
385         if (dev->of_node && !pdata) {
386                 const struct of_device_id *id;
387                 struct max8660_platform_data pdata_of;
388 
389                 id = of_match_device(of_match_ptr(max8660_dt_ids), dev);
390                 if (!id)
391                         return -ENODEV;
392 
393                 ret = max8660_pdata_from_dt(dev, of_node, &pdata_of);
394                 if (ret < 0)
395                         return ret;
396 
397                 pdata = &pdata_of;
398                 type = (unsigned long) id->data;
399         } else {
400                 type = i2c_id->driver_data;
401                 memset(of_node, 0, sizeof(of_node));
402         }
403 
404         if (pdata->num_subdevs > MAX8660_V_END) {
405                 dev_err(dev, "Too many regulators found!\n");
406                 return -EINVAL;
407         }
408 
409         max8660 = devm_kzalloc(dev, sizeof(struct max8660) +
410                         sizeof(struct regulator_dev *) * MAX8660_V_END,
411                         GFP_KERNEL);
412         if (!max8660)
413                 return -ENOMEM;
414 
415         max8660->client = client;
416         rdev = max8660->rdev;
417 
418         if (pdata->en34_is_high) {
419                 /* Simulate always on */
420                 max8660->shadow_regs[MAX8660_OVER1] = 5;
421         } else {
422                 /* Otherwise devices can be toggled via software */
423                 max8660_dcdc_ops.enable = max8660_dcdc_enable;
424                 max8660_dcdc_ops.disable = max8660_dcdc_disable;
425         }
426 
427         /*
428          * First, set up shadow registers to prevent glitches. As some
429          * registers are shared between regulators, everything must be properly
430          * set up for all regulators in advance.
431          */
432         max8660->shadow_regs[MAX8660_ADTV1] =
433                 max8660->shadow_regs[MAX8660_ADTV2] =
434                 max8660->shadow_regs[MAX8660_SDTV1] =
435                 max8660->shadow_regs[MAX8660_SDTV2] = 0x1b;
436         max8660->shadow_regs[MAX8660_MDTV1] =
437                 max8660->shadow_regs[MAX8660_MDTV2] = 0x04;
438 
439         for (i = 0; i < pdata->num_subdevs; i++) {
440 
441                 if (!pdata->subdevs[i].platform_data)
442                         return ret;
443 
444                 boot_on = pdata->subdevs[i].platform_data->constraints.boot_on;
445 
446                 switch (pdata->subdevs[i].id) {
447                 case MAX8660_V3:
448                         if (boot_on)
449                                 max8660->shadow_regs[MAX8660_OVER1] |= 1;
450                         break;
451 
452                 case MAX8660_V4:
453                         if (boot_on)
454                                 max8660->shadow_regs[MAX8660_OVER1] |= 4;
455                         break;
456 
457                 case MAX8660_V5:
458                         break;
459 
460                 case MAX8660_V6:
461                         if (boot_on)
462                                 max8660->shadow_regs[MAX8660_OVER2] |= 2;
463                         break;
464 
465                 case MAX8660_V7:
466                         if (type == MAX8661) {
467                                 dev_err(dev, "Regulator not on this chip!\n");
468                                 return -EINVAL;
469                         }
470 
471                         if (boot_on)
472                                 max8660->shadow_regs[MAX8660_OVER2] |= 4;
473                         break;
474 
475                 default:
476                         dev_err(dev, "invalid regulator %s\n",
477                                  pdata->subdevs[i].name);
478                         return ret;
479                 }
480         }
481 
482         /* Finally register devices */
483         for (i = 0; i < pdata->num_subdevs; i++) {
484 
485                 id = pdata->subdevs[i].id;
486 
487                 config.dev = dev;
488                 config.init_data = pdata->subdevs[i].platform_data;
489                 config.of_node = of_node[i];
490                 config.driver_data = max8660;
491 
492                 rdev[i] = devm_regulator_register(&client->dev,
493                                                   &max8660_reg[id], &config);
494                 if (IS_ERR(rdev[i])) {
495                         ret = PTR_ERR(rdev[i]);
496                         dev_err(&client->dev, "failed to register %s\n",
497                                 max8660_reg[id].name);
498                         return PTR_ERR(rdev[i]);
499                 }
500         }
501 
502         i2c_set_clientdata(client, max8660);
503         return 0;
504 }
505 
506 static const struct i2c_device_id max8660_id[] = {
507         { .name = "max8660", .driver_data = MAX8660 },
508         { .name = "max8661", .driver_data = MAX8661 },
509         { }
510 };
511 MODULE_DEVICE_TABLE(i2c, max8660_id);
512 
513 static struct i2c_driver max8660_driver = {
514         .probe = max8660_probe,
515         .driver         = {
516                 .name   = "max8660",
517                 .owner  = THIS_MODULE,
518         },
519         .id_table       = max8660_id,
520 };
521 
522 static int __init max8660_init(void)
523 {
524         return i2c_add_driver(&max8660_driver);
525 }
526 subsys_initcall(max8660_init);
527 
528 static void __exit max8660_exit(void)
529 {
530         i2c_del_driver(&max8660_driver);
531 }
532 module_exit(max8660_exit);
533 
534 /* Module information */
535 MODULE_DESCRIPTION("MAXIM 8660/8661 voltage regulator driver");
536 MODULE_AUTHOR("Wolfram Sang");
537 MODULE_LICENSE("GPL v2");
538 

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