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Linux/drivers/iio/magnetometer/ak8975.c

  1 /*
  2  * A sensor driver for the magnetometer AK8975.
  3  *
  4  * Magnetic compass sensor driver for monitoring magnetic flux information.
  5  *
  6  * Copyright (c) 2010, NVIDIA Corporation.
  7  *
  8  * This program is free software; you can redistribute it and/or modify
  9  * it under the terms of the GNU General Public License as published by
 10  * the Free Software Foundation; either version 2 of the License, or
 11  * (at your option) any later version.
 12  *
 13  * This program is distributed in the hope that it will be useful, but WITHOUT
 14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 16  * more details.
 17  *
 18  * You should have received a copy of the GNU General Public License along
 19  * with this program; if not, write to the Free Software Foundation, Inc.,
 20  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 21  */
 22 
 23 #include <linux/module.h>
 24 #include <linux/kernel.h>
 25 #include <linux/slab.h>
 26 #include <linux/i2c.h>
 27 #include <linux/interrupt.h>
 28 #include <linux/err.h>
 29 #include <linux/mutex.h>
 30 #include <linux/delay.h>
 31 #include <linux/bitops.h>
 32 #include <linux/gpio.h>
 33 #include <linux/of_gpio.h>
 34 #include <linux/acpi.h>
 35 #include <linux/regulator/consumer.h>
 36 #include <linux/pm_runtime.h>
 37 
 38 #include <linux/iio/iio.h>
 39 #include <linux/iio/sysfs.h>
 40 #include <linux/iio/buffer.h>
 41 #include <linux/iio/trigger.h>
 42 #include <linux/iio/trigger_consumer.h>
 43 #include <linux/iio/triggered_buffer.h>
 44 
 45 #include <linux/iio/magnetometer/ak8975.h>
 46 
 47 /*
 48  * Register definitions, as well as various shifts and masks to get at the
 49  * individual fields of the registers.
 50  */
 51 #define AK8975_REG_WIA                  0x00
 52 #define AK8975_DEVICE_ID                0x48
 53 
 54 #define AK8975_REG_INFO                 0x01
 55 
 56 #define AK8975_REG_ST1                  0x02
 57 #define AK8975_REG_ST1_DRDY_SHIFT       0
 58 #define AK8975_REG_ST1_DRDY_MASK        (1 << AK8975_REG_ST1_DRDY_SHIFT)
 59 
 60 #define AK8975_REG_HXL                  0x03
 61 #define AK8975_REG_HXH                  0x04
 62 #define AK8975_REG_HYL                  0x05
 63 #define AK8975_REG_HYH                  0x06
 64 #define AK8975_REG_HZL                  0x07
 65 #define AK8975_REG_HZH                  0x08
 66 #define AK8975_REG_ST2                  0x09
 67 #define AK8975_REG_ST2_DERR_SHIFT       2
 68 #define AK8975_REG_ST2_DERR_MASK        (1 << AK8975_REG_ST2_DERR_SHIFT)
 69 
 70 #define AK8975_REG_ST2_HOFL_SHIFT       3
 71 #define AK8975_REG_ST2_HOFL_MASK        (1 << AK8975_REG_ST2_HOFL_SHIFT)
 72 
 73 #define AK8975_REG_CNTL                 0x0A
 74 #define AK8975_REG_CNTL_MODE_SHIFT      0
 75 #define AK8975_REG_CNTL_MODE_MASK       (0xF << AK8975_REG_CNTL_MODE_SHIFT)
 76 #define AK8975_REG_CNTL_MODE_POWER_DOWN 0x00
 77 #define AK8975_REG_CNTL_MODE_ONCE       0x01
 78 #define AK8975_REG_CNTL_MODE_SELF_TEST  0x08
 79 #define AK8975_REG_CNTL_MODE_FUSE_ROM   0x0F
 80 
 81 #define AK8975_REG_RSVC                 0x0B
 82 #define AK8975_REG_ASTC                 0x0C
 83 #define AK8975_REG_TS1                  0x0D
 84 #define AK8975_REG_TS2                  0x0E
 85 #define AK8975_REG_I2CDIS               0x0F
 86 #define AK8975_REG_ASAX                 0x10
 87 #define AK8975_REG_ASAY                 0x11
 88 #define AK8975_REG_ASAZ                 0x12
 89 
 90 #define AK8975_MAX_REGS                 AK8975_REG_ASAZ
 91 
 92 /*
 93  * AK09912 Register definitions
 94  */
 95 #define AK09912_REG_WIA1                0x00
 96 #define AK09912_REG_WIA2                0x01
 97 #define AK09912_DEVICE_ID               0x04
 98 #define AK09911_DEVICE_ID               0x05
 99 
100 #define AK09911_REG_INFO1               0x02
101 #define AK09911_REG_INFO2               0x03
102 
103 #define AK09912_REG_ST1                 0x10
104 
105 #define AK09912_REG_ST1_DRDY_SHIFT      0
106 #define AK09912_REG_ST1_DRDY_MASK       (1 << AK09912_REG_ST1_DRDY_SHIFT)
107 
108 #define AK09912_REG_HXL                 0x11
109 #define AK09912_REG_HXH                 0x12
110 #define AK09912_REG_HYL                 0x13
111 #define AK09912_REG_HYH                 0x14
112 #define AK09912_REG_HZL                 0x15
113 #define AK09912_REG_HZH                 0x16
114 #define AK09912_REG_TMPS                0x17
115 
116 #define AK09912_REG_ST2                 0x18
117 #define AK09912_REG_ST2_HOFL_SHIFT      3
118 #define AK09912_REG_ST2_HOFL_MASK       (1 << AK09912_REG_ST2_HOFL_SHIFT)
119 
120 #define AK09912_REG_CNTL1               0x30
121 
122 #define AK09912_REG_CNTL2               0x31
123 #define AK09912_REG_CNTL_MODE_POWER_DOWN        0x00
124 #define AK09912_REG_CNTL_MODE_ONCE      0x01
125 #define AK09912_REG_CNTL_MODE_SELF_TEST 0x10
126 #define AK09912_REG_CNTL_MODE_FUSE_ROM  0x1F
127 #define AK09912_REG_CNTL2_MODE_SHIFT    0
128 #define AK09912_REG_CNTL2_MODE_MASK     (0x1F << AK09912_REG_CNTL2_MODE_SHIFT)
129 
130 #define AK09912_REG_CNTL3               0x32
131 
132 #define AK09912_REG_TS1                 0x33
133 #define AK09912_REG_TS2                 0x34
134 #define AK09912_REG_TS3                 0x35
135 #define AK09912_REG_I2CDIS              0x36
136 #define AK09912_REG_TS4                 0x37
137 
138 #define AK09912_REG_ASAX                0x60
139 #define AK09912_REG_ASAY                0x61
140 #define AK09912_REG_ASAZ                0x62
141 
142 #define AK09912_MAX_REGS                AK09912_REG_ASAZ
143 
144 /*
145  * Miscellaneous values.
146  */
147 #define AK8975_MAX_CONVERSION_TIMEOUT   500
148 #define AK8975_CONVERSION_DONE_POLL_TIME 10
149 #define AK8975_DATA_READY_TIMEOUT       ((100*HZ)/1000)
150 
151 /*
152  * Precalculate scale factor (in Gauss units) for each axis and
153  * store in the device data.
154  *
155  * This scale factor is axis-dependent, and is derived from 3 calibration
156  * factors ASA(x), ASA(y), and ASA(z).
157  *
158  * These ASA values are read from the sensor device at start of day, and
159  * cached in the device context struct.
160  *
161  * Adjusting the flux value with the sensitivity adjustment value should be
162  * done via the following formula:
163  *
164  * Hadj = H * ( ( ( (ASA-128)*0.5 ) / 128 ) + 1 )
165  * where H is the raw value, ASA is the sensitivity adjustment, and Hadj
166  * is the resultant adjusted value.
167  *
168  * We reduce the formula to:
169  *
170  * Hadj = H * (ASA + 128) / 256
171  *
172  * H is in the range of -4096 to 4095.  The magnetometer has a range of
173  * +-1229uT.  To go from the raw value to uT is:
174  *
175  * HuT = H * 1229/4096, or roughly, 3/10.
176  *
177  * Since 1uT = 0.01 gauss, our final scale factor becomes:
178  *
179  * Hadj = H * ((ASA + 128) / 256) * 3/10 * 1/100
180  * Hadj = H * ((ASA + 128) * 0.003) / 256
181  *
182  * Since ASA doesn't change, we cache the resultant scale factor into the
183  * device context in ak8975_setup().
184  *
185  * Given we use IIO_VAL_INT_PLUS_MICRO bit when displaying the scale, we
186  * multiply the stored scale value by 1e6.
187  */
188 static long ak8975_raw_to_gauss(u16 data)
189 {
190         return (((long)data + 128) * 3000) / 256;
191 }
192 
193 /*
194  * For AK8963 and AK09911, same calculation, but the device is less sensitive:
195  *
196  * H is in the range of +-8190.  The magnetometer has a range of
197  * +-4912uT.  To go from the raw value to uT is:
198  *
199  * HuT = H * 4912/8190, or roughly, 6/10, instead of 3/10.
200  */
201 
202 static long ak8963_09911_raw_to_gauss(u16 data)
203 {
204         return (((long)data + 128) * 6000) / 256;
205 }
206 
207 /*
208  * For AK09912, same calculation, except the device is more sensitive:
209  *
210  * H is in the range of -32752 to 32752.  The magnetometer has a range of
211  * +-4912uT.  To go from the raw value to uT is:
212  *
213  * HuT = H * 4912/32752, or roughly, 3/20, instead of 3/10.
214  */
215 static long ak09912_raw_to_gauss(u16 data)
216 {
217         return (((long)data + 128) * 1500) / 256;
218 }
219 
220 /* Compatible Asahi Kasei Compass parts */
221 enum asahi_compass_chipset {
222         AK8975,
223         AK8963,
224         AK09911,
225         AK09912,
226         AK_MAX_TYPE
227 };
228 
229 enum ak_ctrl_reg_addr {
230         ST1,
231         ST2,
232         CNTL,
233         ASA_BASE,
234         MAX_REGS,
235         REGS_END,
236 };
237 
238 enum ak_ctrl_reg_mask {
239         ST1_DRDY,
240         ST2_HOFL,
241         ST2_DERR,
242         CNTL_MODE,
243         MASK_END,
244 };
245 
246 enum ak_ctrl_mode {
247         POWER_DOWN,
248         MODE_ONCE,
249         SELF_TEST,
250         FUSE_ROM,
251         MODE_END,
252 };
253 
254 struct ak_def {
255         enum asahi_compass_chipset type;
256         long (*raw_to_gauss)(u16 data);
257         u16 range;
258         u8 ctrl_regs[REGS_END];
259         u8 ctrl_masks[MASK_END];
260         u8 ctrl_modes[MODE_END];
261         u8 data_regs[3];
262 };
263 
264 static const struct ak_def ak_def_array[AK_MAX_TYPE] = {
265         {
266                 .type = AK8975,
267                 .raw_to_gauss = ak8975_raw_to_gauss,
268                 .range = 4096,
269                 .ctrl_regs = {
270                         AK8975_REG_ST1,
271                         AK8975_REG_ST2,
272                         AK8975_REG_CNTL,
273                         AK8975_REG_ASAX,
274                         AK8975_MAX_REGS},
275                 .ctrl_masks = {
276                         AK8975_REG_ST1_DRDY_MASK,
277                         AK8975_REG_ST2_HOFL_MASK,
278                         AK8975_REG_ST2_DERR_MASK,
279                         AK8975_REG_CNTL_MODE_MASK},
280                 .ctrl_modes = {
281                         AK8975_REG_CNTL_MODE_POWER_DOWN,
282                         AK8975_REG_CNTL_MODE_ONCE,
283                         AK8975_REG_CNTL_MODE_SELF_TEST,
284                         AK8975_REG_CNTL_MODE_FUSE_ROM},
285                 .data_regs = {
286                         AK8975_REG_HXL,
287                         AK8975_REG_HYL,
288                         AK8975_REG_HZL},
289         },
290         {
291                 .type = AK8963,
292                 .raw_to_gauss = ak8963_09911_raw_to_gauss,
293                 .range = 8190,
294                 .ctrl_regs = {
295                         AK8975_REG_ST1,
296                         AK8975_REG_ST2,
297                         AK8975_REG_CNTL,
298                         AK8975_REG_ASAX,
299                         AK8975_MAX_REGS},
300                 .ctrl_masks = {
301                         AK8975_REG_ST1_DRDY_MASK,
302                         AK8975_REG_ST2_HOFL_MASK,
303                         0,
304                         AK8975_REG_CNTL_MODE_MASK},
305                 .ctrl_modes = {
306                         AK8975_REG_CNTL_MODE_POWER_DOWN,
307                         AK8975_REG_CNTL_MODE_ONCE,
308                         AK8975_REG_CNTL_MODE_SELF_TEST,
309                         AK8975_REG_CNTL_MODE_FUSE_ROM},
310                 .data_regs = {
311                         AK8975_REG_HXL,
312                         AK8975_REG_HYL,
313                         AK8975_REG_HZL},
314         },
315         {
316                 .type = AK09911,
317                 .raw_to_gauss = ak8963_09911_raw_to_gauss,
318                 .range = 8192,
319                 .ctrl_regs = {
320                         AK09912_REG_ST1,
321                         AK09912_REG_ST2,
322                         AK09912_REG_CNTL2,
323                         AK09912_REG_ASAX,
324                         AK09912_MAX_REGS},
325                 .ctrl_masks = {
326                         AK09912_REG_ST1_DRDY_MASK,
327                         AK09912_REG_ST2_HOFL_MASK,
328                         0,
329                         AK09912_REG_CNTL2_MODE_MASK},
330                 .ctrl_modes = {
331                         AK09912_REG_CNTL_MODE_POWER_DOWN,
332                         AK09912_REG_CNTL_MODE_ONCE,
333                         AK09912_REG_CNTL_MODE_SELF_TEST,
334                         AK09912_REG_CNTL_MODE_FUSE_ROM},
335                 .data_regs = {
336                         AK09912_REG_HXL,
337                         AK09912_REG_HYL,
338                         AK09912_REG_HZL},
339         },
340         {
341                 .type = AK09912,
342                 .raw_to_gauss = ak09912_raw_to_gauss,
343                 .range = 32752,
344                 .ctrl_regs = {
345                         AK09912_REG_ST1,
346                         AK09912_REG_ST2,
347                         AK09912_REG_CNTL2,
348                         AK09912_REG_ASAX,
349                         AK09912_MAX_REGS},
350                 .ctrl_masks = {
351                         AK09912_REG_ST1_DRDY_MASK,
352                         AK09912_REG_ST2_HOFL_MASK,
353                         0,
354                         AK09912_REG_CNTL2_MODE_MASK},
355                 .ctrl_modes = {
356                         AK09912_REG_CNTL_MODE_POWER_DOWN,
357                         AK09912_REG_CNTL_MODE_ONCE,
358                         AK09912_REG_CNTL_MODE_SELF_TEST,
359                         AK09912_REG_CNTL_MODE_FUSE_ROM},
360                 .data_regs = {
361                         AK09912_REG_HXL,
362                         AK09912_REG_HYL,
363                         AK09912_REG_HZL},
364         }
365 };
366 
367 /*
368  * Per-instance context data for the device.
369  */
370 struct ak8975_data {
371         struct i2c_client       *client;
372         const struct ak_def     *def;
373         struct mutex            lock;
374         u8                      asa[3];
375         long                    raw_to_gauss[3];
376         int                     eoc_gpio;
377         int                     eoc_irq;
378         wait_queue_head_t       data_ready_queue;
379         unsigned long           flags;
380         u8                      cntl_cache;
381         struct iio_mount_matrix orientation;
382         struct regulator        *vdd;
383         struct regulator        *vid;
384 };
385 
386 /* Enable attached power regulator if any. */
387 static int ak8975_power_on(const struct ak8975_data *data)
388 {
389         int ret;
390 
391         ret = regulator_enable(data->vdd);
392         if (ret) {
393                 dev_warn(&data->client->dev,
394                          "Failed to enable specified Vdd supply\n");
395                 return ret;
396         }
397         ret = regulator_enable(data->vid);
398         if (ret) {
399                 dev_warn(&data->client->dev,
400                          "Failed to enable specified Vid supply\n");
401                 return ret;
402         }
403         /*
404          * According to the datasheet the power supply rise time i 200us
405          * and the minimum wait time before mode setting is 100us, in
406          * total 300 us. Add some margin and say minimum 500us here.
407          */
408         usleep_range(500, 1000);
409         return 0;
410 }
411 
412 /* Disable attached power regulator if any. */
413 static void ak8975_power_off(const struct ak8975_data *data)
414 {
415         regulator_disable(data->vid);
416         regulator_disable(data->vdd);
417 }
418 
419 /*
420  * Return 0 if the i2c device is the one we expect.
421  * return a negative error number otherwise
422  */
423 static int ak8975_who_i_am(struct i2c_client *client,
424                            enum asahi_compass_chipset type)
425 {
426         u8 wia_val[2];
427         int ret;
428 
429         /*
430          * Signature for each device:
431          * Device   |  WIA1      |  WIA2
432          * AK09912  |  DEVICE_ID |  AK09912_DEVICE_ID
433          * AK09911  |  DEVICE_ID |  AK09911_DEVICE_ID
434          * AK8975   |  DEVICE_ID |  NA
435          * AK8963   |  DEVICE_ID |  NA
436          */
437         ret = i2c_smbus_read_i2c_block_data_or_emulated(
438                         client, AK09912_REG_WIA1, 2, wia_val);
439         if (ret < 0) {
440                 dev_err(&client->dev, "Error reading WIA\n");
441                 return ret;
442         }
443 
444         if (wia_val[0] != AK8975_DEVICE_ID)
445                 return -ENODEV;
446 
447         switch (type) {
448         case AK8975:
449         case AK8963:
450                 return 0;
451         case AK09911:
452                 if (wia_val[1] == AK09911_DEVICE_ID)
453                         return 0;
454                 break;
455         case AK09912:
456                 if (wia_val[1] == AK09912_DEVICE_ID)
457                         return 0;
458                 break;
459         default:
460                 dev_err(&client->dev, "Type %d unknown\n", type);
461         }
462         return -ENODEV;
463 }
464 
465 /*
466  * Helper function to write to CNTL register.
467  */
468 static int ak8975_set_mode(struct ak8975_data *data, enum ak_ctrl_mode mode)
469 {
470         u8 regval;
471         int ret;
472 
473         regval = (data->cntl_cache & ~data->def->ctrl_masks[CNTL_MODE]) |
474                  data->def->ctrl_modes[mode];
475         ret = i2c_smbus_write_byte_data(data->client,
476                                         data->def->ctrl_regs[CNTL], regval);
477         if (ret < 0) {
478                 return ret;
479         }
480         data->cntl_cache = regval;
481         /* After mode change wait atleast 100us */
482         usleep_range(100, 500);
483 
484         return 0;
485 }
486 
487 /*
488  * Handle data ready irq
489  */
490 static irqreturn_t ak8975_irq_handler(int irq, void *data)
491 {
492         struct ak8975_data *ak8975 = data;
493 
494         set_bit(0, &ak8975->flags);
495         wake_up(&ak8975->data_ready_queue);
496 
497         return IRQ_HANDLED;
498 }
499 
500 /*
501  * Install data ready interrupt handler
502  */
503 static int ak8975_setup_irq(struct ak8975_data *data)
504 {
505         struct i2c_client *client = data->client;
506         int rc;
507         int irq;
508 
509         init_waitqueue_head(&data->data_ready_queue);
510         clear_bit(0, &data->flags);
511         if (client->irq)
512                 irq = client->irq;
513         else
514                 irq = gpio_to_irq(data->eoc_gpio);
515 
516         rc = devm_request_irq(&client->dev, irq, ak8975_irq_handler,
517                               IRQF_TRIGGER_RISING | IRQF_ONESHOT,
518                               dev_name(&client->dev), data);
519         if (rc < 0) {
520                 dev_err(&client->dev,
521                         "irq %d request failed, (gpio %d): %d\n",
522                         irq, data->eoc_gpio, rc);
523                 return rc;
524         }
525 
526         data->eoc_irq = irq;
527 
528         return rc;
529 }
530 
531 
532 /*
533  * Perform some start-of-day setup, including reading the asa calibration
534  * values and caching them.
535  */
536 static int ak8975_setup(struct i2c_client *client)
537 {
538         struct iio_dev *indio_dev = i2c_get_clientdata(client);
539         struct ak8975_data *data = iio_priv(indio_dev);
540         int ret;
541 
542         /* Write the fused rom access mode. */
543         ret = ak8975_set_mode(data, FUSE_ROM);
544         if (ret < 0) {
545                 dev_err(&client->dev, "Error in setting fuse access mode\n");
546                 return ret;
547         }
548 
549         /* Get asa data and store in the device data. */
550         ret = i2c_smbus_read_i2c_block_data_or_emulated(
551                         client, data->def->ctrl_regs[ASA_BASE],
552                         3, data->asa);
553         if (ret < 0) {
554                 dev_err(&client->dev, "Not able to read asa data\n");
555                 return ret;
556         }
557 
558         /* After reading fuse ROM data set power-down mode */
559         ret = ak8975_set_mode(data, POWER_DOWN);
560         if (ret < 0) {
561                 dev_err(&client->dev, "Error in setting power-down mode\n");
562                 return ret;
563         }
564 
565         if (data->eoc_gpio > 0 || client->irq > 0) {
566                 ret = ak8975_setup_irq(data);
567                 if (ret < 0) {
568                         dev_err(&client->dev,
569                                 "Error setting data ready interrupt\n");
570                         return ret;
571                 }
572         }
573 
574         data->raw_to_gauss[0] = data->def->raw_to_gauss(data->asa[0]);
575         data->raw_to_gauss[1] = data->def->raw_to_gauss(data->asa[1]);
576         data->raw_to_gauss[2] = data->def->raw_to_gauss(data->asa[2]);
577 
578         return 0;
579 }
580 
581 static int wait_conversion_complete_gpio(struct ak8975_data *data)
582 {
583         struct i2c_client *client = data->client;
584         u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
585         int ret;
586 
587         /* Wait for the conversion to complete. */
588         while (timeout_ms) {
589                 msleep(AK8975_CONVERSION_DONE_POLL_TIME);
590                 if (gpio_get_value(data->eoc_gpio))
591                         break;
592                 timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
593         }
594         if (!timeout_ms) {
595                 dev_err(&client->dev, "Conversion timeout happened\n");
596                 return -EINVAL;
597         }
598 
599         ret = i2c_smbus_read_byte_data(client, data->def->ctrl_regs[ST1]);
600         if (ret < 0)
601                 dev_err(&client->dev, "Error in reading ST1\n");
602 
603         return ret;
604 }
605 
606 static int wait_conversion_complete_polled(struct ak8975_data *data)
607 {
608         struct i2c_client *client = data->client;
609         u8 read_status;
610         u32 timeout_ms = AK8975_MAX_CONVERSION_TIMEOUT;
611         int ret;
612 
613         /* Wait for the conversion to complete. */
614         while (timeout_ms) {
615                 msleep(AK8975_CONVERSION_DONE_POLL_TIME);
616                 ret = i2c_smbus_read_byte_data(client,
617                                                data->def->ctrl_regs[ST1]);
618                 if (ret < 0) {
619                         dev_err(&client->dev, "Error in reading ST1\n");
620                         return ret;
621                 }
622                 read_status = ret;
623                 if (read_status)
624                         break;
625                 timeout_ms -= AK8975_CONVERSION_DONE_POLL_TIME;
626         }
627         if (!timeout_ms) {
628                 dev_err(&client->dev, "Conversion timeout happened\n");
629                 return -EINVAL;
630         }
631 
632         return read_status;
633 }
634 
635 /* Returns 0 if the end of conversion interrupt occured or -ETIME otherwise */
636 static int wait_conversion_complete_interrupt(struct ak8975_data *data)
637 {
638         int ret;
639 
640         ret = wait_event_timeout(data->data_ready_queue,
641                                  test_bit(0, &data->flags),
642                                  AK8975_DATA_READY_TIMEOUT);
643         clear_bit(0, &data->flags);
644 
645         return ret > 0 ? 0 : -ETIME;
646 }
647 
648 static int ak8975_start_read_axis(struct ak8975_data *data,
649                                   const struct i2c_client *client)
650 {
651         /* Set up the device for taking a sample. */
652         int ret = ak8975_set_mode(data, MODE_ONCE);
653 
654         if (ret < 0) {
655                 dev_err(&client->dev, "Error in setting operating mode\n");
656                 return ret;
657         }
658 
659         /* Wait for the conversion to complete. */
660         if (data->eoc_irq)
661                 ret = wait_conversion_complete_interrupt(data);
662         else if (gpio_is_valid(data->eoc_gpio))
663                 ret = wait_conversion_complete_gpio(data);
664         else
665                 ret = wait_conversion_complete_polled(data);
666         if (ret < 0)
667                 return ret;
668 
669         /* This will be executed only for non-interrupt based waiting case */
670         if (ret & data->def->ctrl_masks[ST1_DRDY]) {
671                 ret = i2c_smbus_read_byte_data(client,
672                                                data->def->ctrl_regs[ST2]);
673                 if (ret < 0) {
674                         dev_err(&client->dev, "Error in reading ST2\n");
675                         return ret;
676                 }
677                 if (ret & (data->def->ctrl_masks[ST2_DERR] |
678                            data->def->ctrl_masks[ST2_HOFL])) {
679                         dev_err(&client->dev, "ST2 status error 0x%x\n", ret);
680                         return -EINVAL;
681                 }
682         }
683 
684         return 0;
685 }
686 
687 /* Retrieve raw flux value for one of the x, y, or z axis.  */
688 static int ak8975_read_axis(struct iio_dev *indio_dev, int index, int *val)
689 {
690         struct ak8975_data *data = iio_priv(indio_dev);
691         const struct i2c_client *client = data->client;
692         const struct ak_def *def = data->def;
693         u16 buff;
694         int ret;
695 
696         pm_runtime_get_sync(&data->client->dev);
697 
698         mutex_lock(&data->lock);
699 
700         ret = ak8975_start_read_axis(data, client);
701         if (ret)
702                 goto exit;
703 
704         ret = i2c_smbus_read_i2c_block_data_or_emulated(
705                         client, def->data_regs[index],
706                         sizeof(buff), (u8*)&buff);
707         if (ret < 0)
708                 goto exit;
709 
710         mutex_unlock(&data->lock);
711 
712         pm_runtime_mark_last_busy(&data->client->dev);
713         pm_runtime_put_autosuspend(&data->client->dev);
714 
715         /* Swap bytes and convert to valid range. */
716         buff = le16_to_cpu(buff);
717         *val = clamp_t(s16, buff, -def->range, def->range);
718         return IIO_VAL_INT;
719 
720 exit:
721         mutex_unlock(&data->lock);
722         dev_err(&client->dev, "Error in reading axis\n");
723         return ret;
724 }
725 
726 static int ak8975_read_raw(struct iio_dev *indio_dev,
727                            struct iio_chan_spec const *chan,
728                            int *val, int *val2,
729                            long mask)
730 {
731         struct ak8975_data *data = iio_priv(indio_dev);
732 
733         switch (mask) {
734         case IIO_CHAN_INFO_RAW:
735                 return ak8975_read_axis(indio_dev, chan->address, val);
736         case IIO_CHAN_INFO_SCALE:
737                 *val = 0;
738                 *val2 = data->raw_to_gauss[chan->address];
739                 return IIO_VAL_INT_PLUS_MICRO;
740         }
741         return -EINVAL;
742 }
743 
744 static const struct iio_mount_matrix *
745 ak8975_get_mount_matrix(const struct iio_dev *indio_dev,
746                         const struct iio_chan_spec *chan)
747 {
748         return &((struct ak8975_data *)iio_priv(indio_dev))->orientation;
749 }
750 
751 static const struct iio_chan_spec_ext_info ak8975_ext_info[] = {
752         IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8975_get_mount_matrix),
753         { },
754 };
755 
756 #define AK8975_CHANNEL(axis, index)                                     \
757         {                                                               \
758                 .type = IIO_MAGN,                                       \
759                 .modified = 1,                                          \
760                 .channel2 = IIO_MOD_##axis,                             \
761                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
762                              BIT(IIO_CHAN_INFO_SCALE),                  \
763                 .address = index,                                       \
764                 .scan_index = index,                                    \
765                 .scan_type = {                                          \
766                         .sign = 's',                                    \
767                         .realbits = 16,                                 \
768                         .storagebits = 16,                              \
769                         .endianness = IIO_CPU                           \
770                 },                                                      \
771                 .ext_info = ak8975_ext_info,                            \
772         }
773 
774 static const struct iio_chan_spec ak8975_channels[] = {
775         AK8975_CHANNEL(X, 0), AK8975_CHANNEL(Y, 1), AK8975_CHANNEL(Z, 2),
776         IIO_CHAN_SOFT_TIMESTAMP(3),
777 };
778 
779 static const unsigned long ak8975_scan_masks[] = { 0x7, 0 };
780 
781 static const struct iio_info ak8975_info = {
782         .read_raw = &ak8975_read_raw,
783         .driver_module = THIS_MODULE,
784 };
785 
786 static const struct acpi_device_id ak_acpi_match[] = {
787         {"AK8975", AK8975},
788         {"AK8963", AK8963},
789         {"INVN6500", AK8963},
790         {"AK09911", AK09911},
791         {"AK09912", AK09912},
792         { },
793 };
794 MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
795 
796 static const char *ak8975_match_acpi_device(struct device *dev,
797                                             enum asahi_compass_chipset *chipset)
798 {
799         const struct acpi_device_id *id;
800 
801         id = acpi_match_device(dev->driver->acpi_match_table, dev);
802         if (!id)
803                 return NULL;
804         *chipset = (int)id->driver_data;
805 
806         return dev_name(dev);
807 }
808 
809 static void ak8975_fill_buffer(struct iio_dev *indio_dev)
810 {
811         struct ak8975_data *data = iio_priv(indio_dev);
812         const struct i2c_client *client = data->client;
813         const struct ak_def *def = data->def;
814         int ret;
815         s16 buff[8]; /* 3 x 16 bits axis values + 1 aligned 64 bits timestamp */
816 
817         mutex_lock(&data->lock);
818 
819         ret = ak8975_start_read_axis(data, client);
820         if (ret)
821                 goto unlock;
822 
823         /*
824          * For each axis, read the flux value from the appropriate register
825          * (the register is specified in the iio device attributes).
826          */
827         ret = i2c_smbus_read_i2c_block_data_or_emulated(client,
828                                                         def->data_regs[0],
829                                                         3 * sizeof(buff[0]),
830                                                         (u8 *)buff);
831         if (ret < 0)
832                 goto unlock;
833 
834         mutex_unlock(&data->lock);
835 
836         /* Clamp to valid range. */
837         buff[0] = clamp_t(s16, le16_to_cpu(buff[0]), -def->range, def->range);
838         buff[1] = clamp_t(s16, le16_to_cpu(buff[1]), -def->range, def->range);
839         buff[2] = clamp_t(s16, le16_to_cpu(buff[2]), -def->range, def->range);
840 
841         iio_push_to_buffers_with_timestamp(indio_dev, buff,
842                                            iio_get_time_ns(indio_dev));
843         return;
844 
845 unlock:
846         mutex_unlock(&data->lock);
847         dev_err(&client->dev, "Error in reading axes block\n");
848 }
849 
850 static irqreturn_t ak8975_handle_trigger(int irq, void *p)
851 {
852         const struct iio_poll_func *pf = p;
853         struct iio_dev *indio_dev = pf->indio_dev;
854 
855         ak8975_fill_buffer(indio_dev);
856         iio_trigger_notify_done(indio_dev->trig);
857         return IRQ_HANDLED;
858 }
859 
860 static int ak8975_probe(struct i2c_client *client,
861                         const struct i2c_device_id *id)
862 {
863         struct ak8975_data *data;
864         struct iio_dev *indio_dev;
865         int eoc_gpio;
866         int err;
867         const char *name = NULL;
868         enum asahi_compass_chipset chipset = AK_MAX_TYPE;
869         const struct ak8975_platform_data *pdata =
870                 dev_get_platdata(&client->dev);
871 
872         /* Grab and set up the supplied GPIO. */
873         if (pdata)
874                 eoc_gpio = pdata->eoc_gpio;
875         else if (client->dev.of_node)
876                 eoc_gpio = of_get_gpio(client->dev.of_node, 0);
877         else
878                 eoc_gpio = -1;
879 
880         if (eoc_gpio == -EPROBE_DEFER)
881                 return -EPROBE_DEFER;
882 
883         /* We may not have a GPIO based IRQ to scan, that is fine, we will
884            poll if so */
885         if (gpio_is_valid(eoc_gpio)) {
886                 err = devm_gpio_request_one(&client->dev, eoc_gpio,
887                                                         GPIOF_IN, "ak_8975");
888                 if (err < 0) {
889                         dev_err(&client->dev,
890                                 "failed to request GPIO %d, error %d\n",
891                                                         eoc_gpio, err);
892                         return err;
893                 }
894         }
895 
896         /* Register with IIO */
897         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
898         if (indio_dev == NULL)
899                 return -ENOMEM;
900 
901         data = iio_priv(indio_dev);
902         i2c_set_clientdata(client, indio_dev);
903 
904         data->client = client;
905         data->eoc_gpio = eoc_gpio;
906         data->eoc_irq = 0;
907 
908         if (!pdata) {
909                 err = of_iio_read_mount_matrix(&client->dev,
910                                                "mount-matrix",
911                                                &data->orientation);
912                 if (err)
913                         return err;
914         } else
915                 data->orientation = pdata->orientation;
916 
917         /* id will be NULL when enumerated via ACPI */
918         if (id) {
919                 chipset = (enum asahi_compass_chipset)(id->driver_data);
920                 name = id->name;
921         } else if (ACPI_HANDLE(&client->dev)) {
922                 name = ak8975_match_acpi_device(&client->dev, &chipset);
923                 if (!name)
924                         return -ENODEV;
925         } else
926                 return -ENOSYS;
927 
928         if (chipset >= AK_MAX_TYPE) {
929                 dev_err(&client->dev, "AKM device type unsupported: %d\n",
930                         chipset);
931                 return -ENODEV;
932         }
933 
934         data->def = &ak_def_array[chipset];
935 
936         /* Fetch the regulators */
937         data->vdd = devm_regulator_get(&client->dev, "vdd");
938         if (IS_ERR(data->vdd))
939                 return PTR_ERR(data->vdd);
940         data->vid = devm_regulator_get(&client->dev, "vid");
941         if (IS_ERR(data->vid))
942                 return PTR_ERR(data->vid);
943 
944         err = ak8975_power_on(data);
945         if (err)
946                 return err;
947 
948         err = ak8975_who_i_am(client, data->def->type);
949         if (err < 0) {
950                 dev_err(&client->dev, "Unexpected device\n");
951                 goto power_off;
952         }
953         dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
954 
955         /* Perform some basic start-of-day setup of the device. */
956         err = ak8975_setup(client);
957         if (err < 0) {
958                 dev_err(&client->dev, "%s initialization fails\n", name);
959                 goto power_off;
960         }
961 
962         mutex_init(&data->lock);
963         indio_dev->dev.parent = &client->dev;
964         indio_dev->channels = ak8975_channels;
965         indio_dev->num_channels = ARRAY_SIZE(ak8975_channels);
966         indio_dev->info = &ak8975_info;
967         indio_dev->available_scan_masks = ak8975_scan_masks;
968         indio_dev->modes = INDIO_DIRECT_MODE;
969         indio_dev->name = name;
970 
971         err = iio_triggered_buffer_setup(indio_dev, NULL, ak8975_handle_trigger,
972                                          NULL);
973         if (err) {
974                 dev_err(&client->dev, "triggered buffer setup failed\n");
975                 goto power_off;
976         }
977 
978         err = iio_device_register(indio_dev);
979         if (err) {
980                 dev_err(&client->dev, "device register failed\n");
981                 goto cleanup_buffer;
982         }
983 
984         /* Enable runtime PM */
985         pm_runtime_get_noresume(&client->dev);
986         pm_runtime_set_active(&client->dev);
987         pm_runtime_enable(&client->dev);
988         /*
989          * The device comes online in 500us, so add two orders of magnitude
990          * of delay before autosuspending: 50 ms.
991          */
992         pm_runtime_set_autosuspend_delay(&client->dev, 50);
993         pm_runtime_use_autosuspend(&client->dev);
994         pm_runtime_put(&client->dev);
995 
996         return 0;
997 
998 cleanup_buffer:
999         iio_triggered_buffer_cleanup(indio_dev);
1000 power_off:
1001         ak8975_power_off(data);
1002         return err;
1003 }
1004 
1005 static int ak8975_remove(struct i2c_client *client)
1006 {
1007         struct iio_dev *indio_dev = i2c_get_clientdata(client);
1008         struct ak8975_data *data = iio_priv(indio_dev);
1009 
1010         pm_runtime_get_sync(&client->dev);
1011         pm_runtime_put_noidle(&client->dev);
1012         pm_runtime_disable(&client->dev);
1013         iio_device_unregister(indio_dev);
1014         iio_triggered_buffer_cleanup(indio_dev);
1015         ak8975_set_mode(data, POWER_DOWN);
1016         ak8975_power_off(data);
1017 
1018         return 0;
1019 }
1020 
1021 #ifdef CONFIG_PM
1022 static int ak8975_runtime_suspend(struct device *dev)
1023 {
1024         struct i2c_client *client = to_i2c_client(dev);
1025         struct iio_dev *indio_dev = i2c_get_clientdata(client);
1026         struct ak8975_data *data = iio_priv(indio_dev);
1027         int ret;
1028 
1029         /* Set the device in power down if it wasn't already */
1030         ret = ak8975_set_mode(data, POWER_DOWN);
1031         if (ret < 0) {
1032                 dev_err(&client->dev, "Error in setting power-down mode\n");
1033                 return ret;
1034         }
1035         /* Next cut the regulators */
1036         ak8975_power_off(data);
1037 
1038         return 0;
1039 }
1040 
1041 static int ak8975_runtime_resume(struct device *dev)
1042 {
1043         struct i2c_client *client = to_i2c_client(dev);
1044         struct iio_dev *indio_dev = i2c_get_clientdata(client);
1045         struct ak8975_data *data = iio_priv(indio_dev);
1046         int ret;
1047 
1048         /* Take up the regulators */
1049         ak8975_power_on(data);
1050         /*
1051          * We come up in powered down mode, the reading routines will
1052          * put us in the mode to read values later.
1053          */
1054         ret = ak8975_set_mode(data, POWER_DOWN);
1055         if (ret < 0) {
1056                 dev_err(&client->dev, "Error in setting power-down mode\n");
1057                 return ret;
1058         }
1059 
1060         return 0;
1061 }
1062 #endif /* CONFIG_PM */
1063 
1064 static const struct dev_pm_ops ak8975_dev_pm_ops = {
1065         SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
1066                                 pm_runtime_force_resume)
1067         SET_RUNTIME_PM_OPS(ak8975_runtime_suspend,
1068                            ak8975_runtime_resume, NULL)
1069 };
1070 
1071 static const struct i2c_device_id ak8975_id[] = {
1072         {"ak8975", AK8975},
1073         {"ak8963", AK8963},
1074         {"AK8963", AK8963},
1075         {"ak09911", AK09911},
1076         {"ak09912", AK09912},
1077         {}
1078 };
1079 
1080 MODULE_DEVICE_TABLE(i2c, ak8975_id);
1081 
1082 static const struct of_device_id ak8975_of_match[] = {
1083         { .compatible = "asahi-kasei,ak8975", },
1084         { .compatible = "ak8975", },
1085         { .compatible = "asahi-kasei,ak8963", },
1086         { .compatible = "ak8963", },
1087         { .compatible = "asahi-kasei,ak09911", },
1088         { .compatible = "ak09911", },
1089         { .compatible = "asahi-kasei,ak09912", },
1090         { .compatible = "ak09912", },
1091         {}
1092 };
1093 MODULE_DEVICE_TABLE(of, ak8975_of_match);
1094 
1095 static struct i2c_driver ak8975_driver = {
1096         .driver = {
1097                 .name   = "ak8975",
1098                 .pm = &ak8975_dev_pm_ops,
1099                 .of_match_table = of_match_ptr(ak8975_of_match),
1100                 .acpi_match_table = ACPI_PTR(ak_acpi_match),
1101         },
1102         .probe          = ak8975_probe,
1103         .remove         = ak8975_remove,
1104         .id_table       = ak8975_id,
1105 };
1106 module_i2c_driver(ak8975_driver);
1107 
1108 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1109 MODULE_DESCRIPTION("AK8975 magnetometer driver");
1110 MODULE_LICENSE("GPL");
1111 

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