xref: /linux/drivers/iio/adc/ab8500-gpadc.c (revision 72bea132f3680ee51e7ed2cee62892b6f5121909)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) ST-Ericsson SA 2010
4  *
5  * Author: Arun R Murthy <arun.murthy@stericsson.com>
6  * Author: Daniel Willerud <daniel.willerud@stericsson.com>
7  * Author: Johan Palsson <johan.palsson@stericsson.com>
8  * Author: M'boumba Cedric Madianga
9  * Author: Linus Walleij <linus.walleij@linaro.org>
10  *
11  * AB8500 General Purpose ADC driver. The AB8500 uses reference voltages:
12  * VinVADC, and VADC relative to GND to do its job. It monitors main and backup
13  * battery voltages, AC (mains) voltage, USB cable voltage, as well as voltages
14  * representing the temperature of the chip die and battery, accessory
15  * detection by resistance measurements using relative voltages and GSM burst
16  * information.
17  *
18  * Some of the voltages are measured on external pins on the IC, such as
19  * battery temperature or "ADC aux" 1 and 2. Other voltages are internal rails
20  * from other parts of the ASIC such as main charger voltage, main and battery
21  * backup voltage or USB VBUS voltage. For this reason drivers for other
22  * parts of the system are required to obtain handles to the ADC to do work
23  * for them and the IIO driver provides arbitration among these consumers.
24  */
25 #include <linux/init.h>
26 #include <linux/bits.h>
27 #include <linux/iio/iio.h>
28 #include <linux/iio/sysfs.h>
29 #include <linux/device.h>
30 #include <linux/interrupt.h>
31 #include <linux/spinlock.h>
32 #include <linux/delay.h>
33 #include <linux/pm_runtime.h>
34 #include <linux/platform_device.h>
35 #include <linux/completion.h>
36 #include <linux/regulator/consumer.h>
37 #include <linux/random.h>
38 #include <linux/err.h>
39 #include <linux/slab.h>
40 #include <linux/mfd/abx500.h>
41 #include <linux/mfd/abx500/ab8500.h>
42 
43 /* GPADC register offsets and bit definitions */
44 
45 #define AB8500_GPADC_CTRL1_REG		0x00
46 /* GPADC control register 1 bits */
47 #define AB8500_GPADC_CTRL1_DISABLE		0x00
48 #define AB8500_GPADC_CTRL1_ENABLE		BIT(0)
49 #define AB8500_GPADC_CTRL1_TRIG_ENA		BIT(1)
50 #define AB8500_GPADC_CTRL1_START_SW_CONV	BIT(2)
51 #define AB8500_GPADC_CTRL1_BTEMP_PULL_UP	BIT(3)
52 /* 0 = use rising edge, 1 = use falling edge */
53 #define AB8500_GPADC_CTRL1_TRIG_EDGE		BIT(4)
54 /* 0 = use VTVOUT, 1 = use VRTC as pull-up supply for battery temp NTC */
55 #define AB8500_GPADC_CTRL1_PUPSUPSEL		BIT(5)
56 #define AB8500_GPADC_CTRL1_BUF_ENA		BIT(6)
57 #define AB8500_GPADC_CTRL1_ICHAR_ENA		BIT(7)
58 
59 #define AB8500_GPADC_CTRL2_REG		0x01
60 #define AB8500_GPADC_CTRL3_REG		0x02
61 /*
62  * GPADC control register 2 and 3 bits
63  * the bit layout is the same for SW and HW conversion set-up
64  */
65 #define AB8500_GPADC_CTRL2_AVG_1		0x00
66 #define AB8500_GPADC_CTRL2_AVG_4		BIT(5)
67 #define AB8500_GPADC_CTRL2_AVG_8		BIT(6)
68 #define AB8500_GPADC_CTRL2_AVG_16		(BIT(5) | BIT(6))
69 
70 enum ab8500_gpadc_channel {
71 	AB8500_GPADC_CHAN_UNUSED = 0x00,
72 	AB8500_GPADC_CHAN_BAT_CTRL = 0x01,
73 	AB8500_GPADC_CHAN_BAT_TEMP = 0x02,
74 	/* This is not used on AB8505 */
75 	AB8500_GPADC_CHAN_MAIN_CHARGER = 0x03,
76 	AB8500_GPADC_CHAN_ACC_DET_1 = 0x04,
77 	AB8500_GPADC_CHAN_ACC_DET_2 = 0x05,
78 	AB8500_GPADC_CHAN_ADC_AUX_1 = 0x06,
79 	AB8500_GPADC_CHAN_ADC_AUX_2 = 0x07,
80 	AB8500_GPADC_CHAN_VBAT_A = 0x08,
81 	AB8500_GPADC_CHAN_VBUS = 0x09,
82 	AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT = 0x0a,
83 	AB8500_GPADC_CHAN_USB_CHARGER_CURRENT = 0x0b,
84 	AB8500_GPADC_CHAN_BACKUP_BAT = 0x0c,
85 	/* Only on AB8505 */
86 	AB8505_GPADC_CHAN_DIE_TEMP = 0x0d,
87 	AB8500_GPADC_CHAN_ID = 0x0e,
88 	AB8500_GPADC_CHAN_INTERNAL_TEST_1 = 0x0f,
89 	AB8500_GPADC_CHAN_INTERNAL_TEST_2 = 0x10,
90 	AB8500_GPADC_CHAN_INTERNAL_TEST_3 = 0x11,
91 	/* FIXME: Applicable to all ASIC variants? */
92 	AB8500_GPADC_CHAN_XTAL_TEMP = 0x12,
93 	AB8500_GPADC_CHAN_VBAT_TRUE_MEAS = 0x13,
94 	/* FIXME: Doesn't seem to work with pure AB8500 */
95 	AB8500_GPADC_CHAN_BAT_CTRL_AND_IBAT = 0x1c,
96 	AB8500_GPADC_CHAN_VBAT_MEAS_AND_IBAT = 0x1d,
97 	AB8500_GPADC_CHAN_VBAT_TRUE_MEAS_AND_IBAT = 0x1e,
98 	AB8500_GPADC_CHAN_BAT_TEMP_AND_IBAT = 0x1f,
99 	/*
100 	 * Virtual channel used only for ibat conversion to ampere.
101 	 * Battery current conversion (ibat) cannot be requested as a
102 	 * single conversion but it is always requested in combination
103 	 * with other input requests.
104 	 */
105 	AB8500_GPADC_CHAN_IBAT_VIRTUAL = 0xFF,
106 };
107 
108 #define AB8500_GPADC_AUTO_TIMER_REG	0x03
109 
110 #define AB8500_GPADC_STAT_REG		0x04
111 #define AB8500_GPADC_STAT_BUSY		BIT(0)
112 
113 #define AB8500_GPADC_MANDATAL_REG	0x05
114 #define AB8500_GPADC_MANDATAH_REG	0x06
115 #define AB8500_GPADC_AUTODATAL_REG	0x07
116 #define AB8500_GPADC_AUTODATAH_REG	0x08
117 #define AB8500_GPADC_MUX_CTRL_REG	0x09
118 #define AB8540_GPADC_MANDATA2L_REG	0x09
119 #define AB8540_GPADC_MANDATA2H_REG	0x0A
120 #define AB8540_GPADC_APEAAX_REG		0x10
121 #define AB8540_GPADC_APEAAT_REG		0x11
122 #define AB8540_GPADC_APEAAM_REG		0x12
123 #define AB8540_GPADC_APEAAH_REG		0x13
124 #define AB8540_GPADC_APEAAL_REG		0x14
125 
126 /*
127  * OTP register offsets
128  * Bank : 0x15
129  */
130 #define AB8500_GPADC_CAL_1	0x0F
131 #define AB8500_GPADC_CAL_2	0x10
132 #define AB8500_GPADC_CAL_3	0x11
133 #define AB8500_GPADC_CAL_4	0x12
134 #define AB8500_GPADC_CAL_5	0x13
135 #define AB8500_GPADC_CAL_6	0x14
136 #define AB8500_GPADC_CAL_7	0x15
137 /* New calibration for 8540 */
138 #define AB8540_GPADC_OTP4_REG_7	0x38
139 #define AB8540_GPADC_OTP4_REG_6	0x39
140 #define AB8540_GPADC_OTP4_REG_5	0x3A
141 
142 #define AB8540_GPADC_DIS_ZERO	0x00
143 #define AB8540_GPADC_EN_VBIAS_XTAL_TEMP	0x02
144 
145 /* GPADC constants from AB8500 spec, UM0836 */
146 #define AB8500_ADC_RESOLUTION		1024
147 #define AB8500_ADC_CH_BTEMP_MIN		0
148 #define AB8500_ADC_CH_BTEMP_MAX		1350
149 #define AB8500_ADC_CH_DIETEMP_MIN	0
150 #define AB8500_ADC_CH_DIETEMP_MAX	1350
151 #define AB8500_ADC_CH_CHG_V_MIN		0
152 #define AB8500_ADC_CH_CHG_V_MAX		20030
153 #define AB8500_ADC_CH_ACCDET2_MIN	0
154 #define AB8500_ADC_CH_ACCDET2_MAX	2500
155 #define AB8500_ADC_CH_VBAT_MIN		2300
156 #define AB8500_ADC_CH_VBAT_MAX		4800
157 #define AB8500_ADC_CH_CHG_I_MIN		0
158 #define AB8500_ADC_CH_CHG_I_MAX		1500
159 #define AB8500_ADC_CH_BKBAT_MIN		0
160 #define AB8500_ADC_CH_BKBAT_MAX		3200
161 
162 /* GPADC constants from AB8540 spec */
163 #define AB8500_ADC_CH_IBAT_MIN		(-6000) /* mA range measured by ADC for ibat */
164 #define AB8500_ADC_CH_IBAT_MAX		6000
165 #define AB8500_ADC_CH_IBAT_MIN_V	(-60)	/* mV range measured by ADC for ibat */
166 #define AB8500_ADC_CH_IBAT_MAX_V	60
167 #define AB8500_GPADC_IBAT_VDROP_L	(-56)  /* mV */
168 #define AB8500_GPADC_IBAT_VDROP_H	56
169 
170 /* This is used to not lose precision when dividing to get gain and offset */
171 #define AB8500_GPADC_CALIB_SCALE	1000
172 /*
173  * Number of bits shift used to not lose precision
174  * when dividing to get ibat gain.
175  */
176 #define AB8500_GPADC_CALIB_SHIFT_IBAT	20
177 
178 /* Time in ms before disabling regulator */
179 #define AB8500_GPADC_AUTOSUSPEND_DELAY	1
180 
181 #define AB8500_GPADC_CONVERSION_TIME	500 /* ms */
182 
183 enum ab8500_cal_channels {
184 	AB8500_CAL_VMAIN = 0,
185 	AB8500_CAL_BTEMP,
186 	AB8500_CAL_VBAT,
187 	AB8500_CAL_IBAT,
188 	AB8500_CAL_NR,
189 };
190 
191 /**
192  * struct ab8500_adc_cal_data - Table for storing gain and offset for the
193  * calibrated ADC channels
194  * @gain: Gain of the ADC channel
195  * @offset: Offset of the ADC channel
196  * @otp_calib_hi: Calibration from OTP
197  * @otp_calib_lo: Calibration from OTP
198  */
199 struct ab8500_adc_cal_data {
200 	s64 gain;
201 	s64 offset;
202 	u16 otp_calib_hi;
203 	u16 otp_calib_lo;
204 };
205 
206 /**
207  * struct ab8500_gpadc_chan_info - per-channel GPADC info
208  * @name: name of the channel
209  * @id: the internal AB8500 ID number for the channel
210  * @hardware_control: indicate that we want to use hardware ADC control
211  * on this channel, the default is software ADC control. Hardware control
212  * is normally only used to test the battery voltage during GSM bursts
213  * and needs a hardware trigger on the GPADCTrig pin of the ASIC.
214  * @falling_edge: indicate that we want to trigger on falling edge
215  * rather than rising edge, rising edge is the default
216  * @avg_sample: how many samples to average: must be 1, 4, 8 or 16.
217  * @trig_timer: how long to wait for the trigger, in 32kHz periods:
218  * 0 .. 255 periods
219  */
220 struct ab8500_gpadc_chan_info {
221 	const char *name;
222 	u8 id;
223 	bool hardware_control;
224 	bool falling_edge;
225 	u8 avg_sample;
226 	u8 trig_timer;
227 };
228 
229 /**
230  * struct ab8500_gpadc - AB8500 GPADC device information
231  * @dev: pointer to the containing device
232  * @ab8500: pointer to the parent AB8500 device
233  * @chans: internal per-channel information container
234  * @nchans: number of channels
235  * @complete: pointer to the completion that indicates
236  * the completion of an gpadc conversion cycle
237  * @vddadc: pointer to the regulator supplying VDDADC
238  * @irq_sw: interrupt number that is used by gpadc for software ADC conversion
239  * @irq_hw: interrupt number that is used by gpadc for hardware ADC conversion
240  * @cal_data: array of ADC calibration data structs
241  */
242 struct ab8500_gpadc {
243 	struct device *dev;
244 	struct ab8500 *ab8500;
245 	struct ab8500_gpadc_chan_info *chans;
246 	unsigned int nchans;
247 	struct completion complete;
248 	struct regulator *vddadc;
249 	int irq_sw;
250 	int irq_hw;
251 	struct ab8500_adc_cal_data cal_data[AB8500_CAL_NR];
252 };
253 
254 static struct ab8500_gpadc_chan_info *
255 ab8500_gpadc_get_channel(struct ab8500_gpadc *gpadc, u8 chan)
256 {
257 	struct ab8500_gpadc_chan_info *ch;
258 	int i;
259 
260 	for (i = 0; i < gpadc->nchans; i++) {
261 		ch = &gpadc->chans[i];
262 		if (ch->id == chan)
263 			break;
264 	}
265 	if (i == gpadc->nchans)
266 		return NULL;
267 
268 	return ch;
269 }
270 
271 /**
272  * ab8500_gpadc_ad_to_voltage() - Convert a raw ADC value to a voltage
273  * @gpadc: GPADC instance
274  * @ch: the sampled channel this raw value is coming from
275  * @ad_value: the raw value
276  */
277 static int ab8500_gpadc_ad_to_voltage(struct ab8500_gpadc *gpadc,
278 				      enum ab8500_gpadc_channel ch,
279 				      int ad_value)
280 {
281 	int res;
282 
283 	switch (ch) {
284 	case AB8500_GPADC_CHAN_MAIN_CHARGER:
285 		/* No calibration data available: just interpolate */
286 		if (!gpadc->cal_data[AB8500_CAL_VMAIN].gain) {
287 			res = AB8500_ADC_CH_CHG_V_MIN + (AB8500_ADC_CH_CHG_V_MAX -
288 				AB8500_ADC_CH_CHG_V_MIN) * ad_value /
289 				AB8500_ADC_RESOLUTION;
290 			break;
291 		}
292 		/* Here we can use calibration */
293 		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_VMAIN].gain +
294 			gpadc->cal_data[AB8500_CAL_VMAIN].offset) / AB8500_GPADC_CALIB_SCALE;
295 		break;
296 
297 	case AB8500_GPADC_CHAN_BAT_CTRL:
298 	case AB8500_GPADC_CHAN_BAT_TEMP:
299 	case AB8500_GPADC_CHAN_ACC_DET_1:
300 	case AB8500_GPADC_CHAN_ADC_AUX_1:
301 	case AB8500_GPADC_CHAN_ADC_AUX_2:
302 	case AB8500_GPADC_CHAN_XTAL_TEMP:
303 		/* No calibration data available: just interpolate */
304 		if (!gpadc->cal_data[AB8500_CAL_BTEMP].gain) {
305 			res = AB8500_ADC_CH_BTEMP_MIN + (AB8500_ADC_CH_BTEMP_MAX -
306 				AB8500_ADC_CH_BTEMP_MIN) * ad_value /
307 				AB8500_ADC_RESOLUTION;
308 			break;
309 		}
310 		/* Here we can use calibration */
311 		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_BTEMP].gain +
312 			gpadc->cal_data[AB8500_CAL_BTEMP].offset) / AB8500_GPADC_CALIB_SCALE;
313 		break;
314 
315 	case AB8500_GPADC_CHAN_VBAT_A:
316 	case AB8500_GPADC_CHAN_VBAT_TRUE_MEAS:
317 		/* No calibration data available: just interpolate */
318 		if (!gpadc->cal_data[AB8500_CAL_VBAT].gain) {
319 			res = AB8500_ADC_CH_VBAT_MIN + (AB8500_ADC_CH_VBAT_MAX -
320 				AB8500_ADC_CH_VBAT_MIN) * ad_value /
321 				AB8500_ADC_RESOLUTION;
322 			break;
323 		}
324 		/* Here we can use calibration */
325 		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_VBAT].gain +
326 			gpadc->cal_data[AB8500_CAL_VBAT].offset) / AB8500_GPADC_CALIB_SCALE;
327 		break;
328 
329 	case AB8505_GPADC_CHAN_DIE_TEMP:
330 		res = AB8500_ADC_CH_DIETEMP_MIN +
331 			(AB8500_ADC_CH_DIETEMP_MAX - AB8500_ADC_CH_DIETEMP_MIN) * ad_value /
332 			AB8500_ADC_RESOLUTION;
333 		break;
334 
335 	case AB8500_GPADC_CHAN_ACC_DET_2:
336 		res = AB8500_ADC_CH_ACCDET2_MIN +
337 			(AB8500_ADC_CH_ACCDET2_MAX - AB8500_ADC_CH_ACCDET2_MIN) * ad_value /
338 			AB8500_ADC_RESOLUTION;
339 		break;
340 
341 	case AB8500_GPADC_CHAN_VBUS:
342 		res = AB8500_ADC_CH_CHG_V_MIN +
343 			(AB8500_ADC_CH_CHG_V_MAX - AB8500_ADC_CH_CHG_V_MIN) * ad_value /
344 			AB8500_ADC_RESOLUTION;
345 		break;
346 
347 	case AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT:
348 	case AB8500_GPADC_CHAN_USB_CHARGER_CURRENT:
349 		res = AB8500_ADC_CH_CHG_I_MIN +
350 			(AB8500_ADC_CH_CHG_I_MAX - AB8500_ADC_CH_CHG_I_MIN) * ad_value /
351 			AB8500_ADC_RESOLUTION;
352 		break;
353 
354 	case AB8500_GPADC_CHAN_BACKUP_BAT:
355 		res = AB8500_ADC_CH_BKBAT_MIN +
356 			(AB8500_ADC_CH_BKBAT_MAX - AB8500_ADC_CH_BKBAT_MIN) * ad_value /
357 			AB8500_ADC_RESOLUTION;
358 		break;
359 
360 	case AB8500_GPADC_CHAN_IBAT_VIRTUAL:
361 		/* No calibration data available: just interpolate */
362 		if (!gpadc->cal_data[AB8500_CAL_IBAT].gain) {
363 			res = AB8500_ADC_CH_IBAT_MIN + (AB8500_ADC_CH_IBAT_MAX -
364 				AB8500_ADC_CH_IBAT_MIN) * ad_value /
365 				AB8500_ADC_RESOLUTION;
366 			break;
367 		}
368 		/* Here we can use calibration */
369 		res = (int) (ad_value * gpadc->cal_data[AB8500_CAL_IBAT].gain +
370 				gpadc->cal_data[AB8500_CAL_IBAT].offset)
371 				>> AB8500_GPADC_CALIB_SHIFT_IBAT;
372 		break;
373 
374 	default:
375 		dev_err(gpadc->dev,
376 			"unknown channel ID: %d, not possible to convert\n",
377 			ch);
378 		res = -EINVAL;
379 		break;
380 
381 	}
382 
383 	return res;
384 }
385 
386 static int ab8500_gpadc_read(struct ab8500_gpadc *gpadc,
387 			     const struct ab8500_gpadc_chan_info *ch,
388 			     int *ibat)
389 {
390 	int ret;
391 	int looplimit = 0;
392 	unsigned long completion_timeout;
393 	u8 val;
394 	u8 low_data, high_data, low_data2, high_data2;
395 	u8 ctrl1;
396 	u8 ctrl23;
397 	unsigned int delay_min = 0;
398 	unsigned int delay_max = 0;
399 	u8 data_low_addr, data_high_addr;
400 
401 	if (!gpadc)
402 		return -ENODEV;
403 
404 	/* check if conversion is supported */
405 	if ((gpadc->irq_sw <= 0) && !ch->hardware_control)
406 		return -ENOTSUPP;
407 	if ((gpadc->irq_hw <= 0) && ch->hardware_control)
408 		return -ENOTSUPP;
409 
410 	/* Enable vddadc by grabbing PM runtime */
411 	pm_runtime_get_sync(gpadc->dev);
412 
413 	/* Check if ADC is not busy, lock and proceed */
414 	do {
415 		ret = abx500_get_register_interruptible(gpadc->dev,
416 			AB8500_GPADC, AB8500_GPADC_STAT_REG, &val);
417 		if (ret < 0)
418 			goto out;
419 		if (!(val & AB8500_GPADC_STAT_BUSY))
420 			break;
421 		msleep(20);
422 	} while (++looplimit < 10);
423 	if (looplimit >= 10 && (val & AB8500_GPADC_STAT_BUSY)) {
424 		dev_err(gpadc->dev, "gpadc_conversion: GPADC busy");
425 		ret = -EINVAL;
426 		goto out;
427 	}
428 
429 	/* Enable GPADC */
430 	ctrl1 = AB8500_GPADC_CTRL1_ENABLE;
431 
432 	/* Select the channel source and set average samples */
433 	switch (ch->avg_sample) {
434 	case 1:
435 		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_1;
436 		break;
437 	case 4:
438 		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_4;
439 		break;
440 	case 8:
441 		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_8;
442 		break;
443 	default:
444 		ctrl23 = ch->id | AB8500_GPADC_CTRL2_AVG_16;
445 		break;
446 	}
447 
448 	if (ch->hardware_control) {
449 		ret = abx500_set_register_interruptible(gpadc->dev,
450 				AB8500_GPADC, AB8500_GPADC_CTRL3_REG, ctrl23);
451 		ctrl1 |= AB8500_GPADC_CTRL1_TRIG_ENA;
452 		if (ch->falling_edge)
453 			ctrl1 |= AB8500_GPADC_CTRL1_TRIG_EDGE;
454 	} else {
455 		ret = abx500_set_register_interruptible(gpadc->dev,
456 				AB8500_GPADC, AB8500_GPADC_CTRL2_REG, ctrl23);
457 	}
458 	if (ret < 0) {
459 		dev_err(gpadc->dev,
460 			"gpadc_conversion: set avg samples failed\n");
461 		goto out;
462 	}
463 
464 	/*
465 	 * Enable ADC, buffering, select rising edge and enable ADC path
466 	 * charging current sense if it needed, ABB 3.0 needs some special
467 	 * treatment too.
468 	 */
469 	switch (ch->id) {
470 	case AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT:
471 	case AB8500_GPADC_CHAN_USB_CHARGER_CURRENT:
472 		ctrl1 |= AB8500_GPADC_CTRL1_BUF_ENA |
473 			AB8500_GPADC_CTRL1_ICHAR_ENA;
474 		break;
475 	case AB8500_GPADC_CHAN_BAT_TEMP:
476 		if (!is_ab8500_2p0_or_earlier(gpadc->ab8500)) {
477 			ctrl1 |= AB8500_GPADC_CTRL1_BUF_ENA |
478 				AB8500_GPADC_CTRL1_BTEMP_PULL_UP;
479 			/*
480 			 * Delay might be needed for ABB8500 cut 3.0, if not,
481 			 * remove when hardware will be available
482 			 */
483 			delay_min = 1000; /* Delay in micro seconds */
484 			delay_max = 10000; /* large range optimises sleepmode */
485 			break;
486 		}
487 		fallthrough;
488 	default:
489 		ctrl1 |= AB8500_GPADC_CTRL1_BUF_ENA;
490 		break;
491 	}
492 
493 	/* Write configuration to control register 1 */
494 	ret = abx500_set_register_interruptible(gpadc->dev,
495 		AB8500_GPADC, AB8500_GPADC_CTRL1_REG, ctrl1);
496 	if (ret < 0) {
497 		dev_err(gpadc->dev,
498 			"gpadc_conversion: set Control register failed\n");
499 		goto out;
500 	}
501 
502 	if (delay_min != 0)
503 		usleep_range(delay_min, delay_max);
504 
505 	if (ch->hardware_control) {
506 		/* Set trigger delay timer */
507 		ret = abx500_set_register_interruptible(gpadc->dev,
508 			AB8500_GPADC, AB8500_GPADC_AUTO_TIMER_REG,
509 			ch->trig_timer);
510 		if (ret < 0) {
511 			dev_err(gpadc->dev,
512 				"gpadc_conversion: trig timer failed\n");
513 			goto out;
514 		}
515 		completion_timeout = 2 * HZ;
516 		data_low_addr = AB8500_GPADC_AUTODATAL_REG;
517 		data_high_addr = AB8500_GPADC_AUTODATAH_REG;
518 	} else {
519 		/* Start SW conversion */
520 		ret = abx500_mask_and_set_register_interruptible(gpadc->dev,
521 			AB8500_GPADC, AB8500_GPADC_CTRL1_REG,
522 			AB8500_GPADC_CTRL1_START_SW_CONV,
523 			AB8500_GPADC_CTRL1_START_SW_CONV);
524 		if (ret < 0) {
525 			dev_err(gpadc->dev,
526 				"gpadc_conversion: start s/w conv failed\n");
527 			goto out;
528 		}
529 		completion_timeout = msecs_to_jiffies(AB8500_GPADC_CONVERSION_TIME);
530 		data_low_addr = AB8500_GPADC_MANDATAL_REG;
531 		data_high_addr = AB8500_GPADC_MANDATAH_REG;
532 	}
533 
534 	/* Wait for completion of conversion */
535 	if (!wait_for_completion_timeout(&gpadc->complete,
536 			completion_timeout)) {
537 		dev_err(gpadc->dev,
538 			"timeout didn't receive GPADC conv interrupt\n");
539 		ret = -EINVAL;
540 		goto out;
541 	}
542 
543 	/* Read the converted RAW data */
544 	ret = abx500_get_register_interruptible(gpadc->dev,
545 			AB8500_GPADC, data_low_addr, &low_data);
546 	if (ret < 0) {
547 		dev_err(gpadc->dev,
548 			"gpadc_conversion: read low data failed\n");
549 		goto out;
550 	}
551 
552 	ret = abx500_get_register_interruptible(gpadc->dev,
553 		AB8500_GPADC, data_high_addr, &high_data);
554 	if (ret < 0) {
555 		dev_err(gpadc->dev,
556 			"gpadc_conversion: read high data failed\n");
557 		goto out;
558 	}
559 
560 	/* Check if double conversion is required */
561 	if ((ch->id == AB8500_GPADC_CHAN_BAT_CTRL_AND_IBAT) ||
562 	    (ch->id == AB8500_GPADC_CHAN_VBAT_MEAS_AND_IBAT) ||
563 	    (ch->id == AB8500_GPADC_CHAN_VBAT_TRUE_MEAS_AND_IBAT) ||
564 	    (ch->id == AB8500_GPADC_CHAN_BAT_TEMP_AND_IBAT)) {
565 
566 		if (ch->hardware_control) {
567 			/* not supported */
568 			ret = -ENOTSUPP;
569 			dev_err(gpadc->dev,
570 				"gpadc_conversion: only SW double conversion supported\n");
571 			goto out;
572 		} else {
573 			/* Read the converted RAW data 2 */
574 			ret = abx500_get_register_interruptible(gpadc->dev,
575 				AB8500_GPADC, AB8540_GPADC_MANDATA2L_REG,
576 				&low_data2);
577 			if (ret < 0) {
578 				dev_err(gpadc->dev,
579 					"gpadc_conversion: read sw low data 2 failed\n");
580 				goto out;
581 			}
582 
583 			ret = abx500_get_register_interruptible(gpadc->dev,
584 				AB8500_GPADC, AB8540_GPADC_MANDATA2H_REG,
585 				&high_data2);
586 			if (ret < 0) {
587 				dev_err(gpadc->dev,
588 					"gpadc_conversion: read sw high data 2 failed\n");
589 				goto out;
590 			}
591 			if (ibat != NULL) {
592 				*ibat = (high_data2 << 8) | low_data2;
593 			} else {
594 				dev_warn(gpadc->dev,
595 					"gpadc_conversion: ibat not stored\n");
596 			}
597 
598 		}
599 	}
600 
601 	/* Disable GPADC */
602 	ret = abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
603 		AB8500_GPADC_CTRL1_REG, AB8500_GPADC_CTRL1_DISABLE);
604 	if (ret < 0) {
605 		dev_err(gpadc->dev, "gpadc_conversion: disable gpadc failed\n");
606 		goto out;
607 	}
608 
609 	/* This eventually drops the regulator */
610 	pm_runtime_mark_last_busy(gpadc->dev);
611 	pm_runtime_put_autosuspend(gpadc->dev);
612 
613 	return (high_data << 8) | low_data;
614 
615 out:
616 	/*
617 	 * It has shown to be needed to turn off the GPADC if an error occurs,
618 	 * otherwise we might have problem when waiting for the busy bit in the
619 	 * GPADC status register to go low. In V1.1 there wait_for_completion
620 	 * seems to timeout when waiting for an interrupt.. Not seen in V2.0
621 	 */
622 	(void) abx500_set_register_interruptible(gpadc->dev, AB8500_GPADC,
623 		AB8500_GPADC_CTRL1_REG, AB8500_GPADC_CTRL1_DISABLE);
624 	pm_runtime_put(gpadc->dev);
625 	dev_err(gpadc->dev,
626 		"gpadc_conversion: Failed to AD convert channel %d\n", ch->id);
627 
628 	return ret;
629 }
630 
631 /**
632  * ab8500_bm_gpadcconvend_handler() - isr for gpadc conversion completion
633  * @irq: irq number
634  * @data: pointer to the data passed during request irq
635  *
636  * This is a interrupt service routine for gpadc conversion completion.
637  * Notifies the gpadc completion is completed and the converted raw value
638  * can be read from the registers.
639  * Returns IRQ status(IRQ_HANDLED)
640  */
641 static irqreturn_t ab8500_bm_gpadcconvend_handler(int irq, void *data)
642 {
643 	struct ab8500_gpadc *gpadc = data;
644 
645 	complete(&gpadc->complete);
646 
647 	return IRQ_HANDLED;
648 }
649 
650 static int otp_cal_regs[] = {
651 	AB8500_GPADC_CAL_1,
652 	AB8500_GPADC_CAL_2,
653 	AB8500_GPADC_CAL_3,
654 	AB8500_GPADC_CAL_4,
655 	AB8500_GPADC_CAL_5,
656 	AB8500_GPADC_CAL_6,
657 	AB8500_GPADC_CAL_7,
658 };
659 
660 static int otp4_cal_regs[] = {
661 	AB8540_GPADC_OTP4_REG_7,
662 	AB8540_GPADC_OTP4_REG_6,
663 	AB8540_GPADC_OTP4_REG_5,
664 };
665 
666 static void ab8500_gpadc_read_calibration_data(struct ab8500_gpadc *gpadc)
667 {
668 	int i;
669 	int ret[ARRAY_SIZE(otp_cal_regs)];
670 	u8 gpadc_cal[ARRAY_SIZE(otp_cal_regs)];
671 	int ret_otp4[ARRAY_SIZE(otp4_cal_regs)];
672 	u8 gpadc_otp4[ARRAY_SIZE(otp4_cal_regs)];
673 	int vmain_high, vmain_low;
674 	int btemp_high, btemp_low;
675 	int vbat_high, vbat_low;
676 	int ibat_high, ibat_low;
677 	s64 V_gain, V_offset, V2A_gain, V2A_offset;
678 
679 	/* First we read all OTP registers and store the error code */
680 	for (i = 0; i < ARRAY_SIZE(otp_cal_regs); i++) {
681 		ret[i] = abx500_get_register_interruptible(gpadc->dev,
682 			AB8500_OTP_EMUL, otp_cal_regs[i],  &gpadc_cal[i]);
683 		if (ret[i] < 0) {
684 			/* Continue anyway: maybe the other registers are OK */
685 			dev_err(gpadc->dev, "%s: read otp reg 0x%02x failed\n",
686 				__func__, otp_cal_regs[i]);
687 		} else {
688 			/* Put this in the entropy pool as device-unique */
689 			add_device_randomness(&ret[i], sizeof(ret[i]));
690 		}
691 	}
692 
693 	/*
694 	 * The ADC calibration data is stored in OTP registers.
695 	 * The layout of the calibration data is outlined below and a more
696 	 * detailed description can be found in UM0836
697 	 *
698 	 * vm_h/l = vmain_high/low
699 	 * bt_h/l = btemp_high/low
700 	 * vb_h/l = vbat_high/low
701 	 *
702 	 * Data bits 8500/9540:
703 	 * | 7	   | 6	   | 5	   | 4	   | 3	   | 2	   | 1	   | 0
704 	 * |.......|.......|.......|.......|.......|.......|.......|.......
705 	 * |						   | vm_h9 | vm_h8
706 	 * |.......|.......|.......|.......|.......|.......|.......|.......
707 	 * |		   | vm_h7 | vm_h6 | vm_h5 | vm_h4 | vm_h3 | vm_h2
708 	 * |.......|.......|.......|.......|.......|.......|.......|.......
709 	 * | vm_h1 | vm_h0 | vm_l4 | vm_l3 | vm_l2 | vm_l1 | vm_l0 | bt_h9
710 	 * |.......|.......|.......|.......|.......|.......|.......|.......
711 	 * | bt_h8 | bt_h7 | bt_h6 | bt_h5 | bt_h4 | bt_h3 | bt_h2 | bt_h1
712 	 * |.......|.......|.......|.......|.......|.......|.......|.......
713 	 * | bt_h0 | bt_l4 | bt_l3 | bt_l2 | bt_l1 | bt_l0 | vb_h9 | vb_h8
714 	 * |.......|.......|.......|.......|.......|.......|.......|.......
715 	 * | vb_h7 | vb_h6 | vb_h5 | vb_h4 | vb_h3 | vb_h2 | vb_h1 | vb_h0
716 	 * |.......|.......|.......|.......|.......|.......|.......|.......
717 	 * | vb_l5 | vb_l4 | vb_l3 | vb_l2 | vb_l1 | vb_l0 |
718 	 * |.......|.......|.......|.......|.......|.......|.......|.......
719 	 *
720 	 * Data bits 8540:
721 	 * OTP2
722 	 * | 7	   | 6	   | 5	   | 4	   | 3	   | 2	   | 1	   | 0
723 	 * |.......|.......|.......|.......|.......|.......|.......|.......
724 	 * |
725 	 * |.......|.......|.......|.......|.......|.......|.......|.......
726 	 * | vm_h9 | vm_h8 | vm_h7 | vm_h6 | vm_h5 | vm_h4 | vm_h3 | vm_h2
727 	 * |.......|.......|.......|.......|.......|.......|.......|.......
728 	 * | vm_h1 | vm_h0 | vm_l4 | vm_l3 | vm_l2 | vm_l1 | vm_l0 | bt_h9
729 	 * |.......|.......|.......|.......|.......|.......|.......|.......
730 	 * | bt_h8 | bt_h7 | bt_h6 | bt_h5 | bt_h4 | bt_h3 | bt_h2 | bt_h1
731 	 * |.......|.......|.......|.......|.......|.......|.......|.......
732 	 * | bt_h0 | bt_l4 | bt_l3 | bt_l2 | bt_l1 | bt_l0 | vb_h9 | vb_h8
733 	 * |.......|.......|.......|.......|.......|.......|.......|.......
734 	 * | vb_h7 | vb_h6 | vb_h5 | vb_h4 | vb_h3 | vb_h2 | vb_h1 | vb_h0
735 	 * |.......|.......|.......|.......|.......|.......|.......|.......
736 	 * | vb_l5 | vb_l4 | vb_l3 | vb_l2 | vb_l1 | vb_l0 |
737 	 * |.......|.......|.......|.......|.......|.......|.......|.......
738 	 *
739 	 * Data bits 8540:
740 	 * OTP4
741 	 * | 7	   | 6	   | 5	   | 4	   | 3	   | 2	   | 1	   | 0
742 	 * |.......|.......|.......|.......|.......|.......|.......|.......
743 	 * |					   | ib_h9 | ib_h8 | ib_h7
744 	 * |.......|.......|.......|.......|.......|.......|.......|.......
745 	 * | ib_h6 | ib_h5 | ib_h4 | ib_h3 | ib_h2 | ib_h1 | ib_h0 | ib_l5
746 	 * |.......|.......|.......|.......|.......|.......|.......|.......
747 	 * | ib_l4 | ib_l3 | ib_l2 | ib_l1 | ib_l0 |
748 	 *
749 	 *
750 	 * Ideal output ADC codes corresponding to injected input voltages
751 	 * during manufacturing is:
752 	 *
753 	 * vmain_high: Vin = 19500mV / ADC ideal code = 997
754 	 * vmain_low:  Vin = 315mV   / ADC ideal code = 16
755 	 * btemp_high: Vin = 1300mV  / ADC ideal code = 985
756 	 * btemp_low:  Vin = 21mV    / ADC ideal code = 16
757 	 * vbat_high:  Vin = 4700mV  / ADC ideal code = 982
758 	 * vbat_low:   Vin = 2380mV  / ADC ideal code = 33
759 	 */
760 
761 	if (is_ab8540(gpadc->ab8500)) {
762 		/* Calculate gain and offset for VMAIN if all reads succeeded*/
763 		if (!(ret[1] < 0 || ret[2] < 0)) {
764 			vmain_high = (((gpadc_cal[1] & 0xFF) << 2) |
765 				((gpadc_cal[2] & 0xC0) >> 6));
766 			vmain_low = ((gpadc_cal[2] & 0x3E) >> 1);
767 
768 			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_hi =
769 				(u16)vmain_high;
770 			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_lo =
771 				(u16)vmain_low;
772 
773 			gpadc->cal_data[AB8500_CAL_VMAIN].gain = AB8500_GPADC_CALIB_SCALE *
774 				(19500 - 315) / (vmain_high - vmain_low);
775 			gpadc->cal_data[AB8500_CAL_VMAIN].offset = AB8500_GPADC_CALIB_SCALE *
776 				19500 - (AB8500_GPADC_CALIB_SCALE * (19500 - 315) /
777 				(vmain_high - vmain_low)) * vmain_high;
778 		} else {
779 			gpadc->cal_data[AB8500_CAL_VMAIN].gain = 0;
780 		}
781 
782 		/* Read IBAT calibration Data */
783 		for (i = 0; i < ARRAY_SIZE(otp4_cal_regs); i++) {
784 			ret_otp4[i] = abx500_get_register_interruptible(
785 					gpadc->dev, AB8500_OTP_EMUL,
786 					otp4_cal_regs[i],  &gpadc_otp4[i]);
787 			if (ret_otp4[i] < 0)
788 				dev_err(gpadc->dev,
789 					"%s: read otp4 reg 0x%02x failed\n",
790 					__func__, otp4_cal_regs[i]);
791 		}
792 
793 		/* Calculate gain and offset for IBAT if all reads succeeded */
794 		if (!(ret_otp4[0] < 0 || ret_otp4[1] < 0 || ret_otp4[2] < 0)) {
795 			ibat_high = (((gpadc_otp4[0] & 0x07) << 7) |
796 				((gpadc_otp4[1] & 0xFE) >> 1));
797 			ibat_low = (((gpadc_otp4[1] & 0x01) << 5) |
798 				((gpadc_otp4[2] & 0xF8) >> 3));
799 
800 			gpadc->cal_data[AB8500_CAL_IBAT].otp_calib_hi =
801 				(u16)ibat_high;
802 			gpadc->cal_data[AB8500_CAL_IBAT].otp_calib_lo =
803 				(u16)ibat_low;
804 
805 			V_gain = ((AB8500_GPADC_IBAT_VDROP_H - AB8500_GPADC_IBAT_VDROP_L)
806 				<< AB8500_GPADC_CALIB_SHIFT_IBAT) / (ibat_high - ibat_low);
807 
808 			V_offset = (AB8500_GPADC_IBAT_VDROP_H << AB8500_GPADC_CALIB_SHIFT_IBAT) -
809 				(((AB8500_GPADC_IBAT_VDROP_H - AB8500_GPADC_IBAT_VDROP_L) <<
810 				AB8500_GPADC_CALIB_SHIFT_IBAT) / (ibat_high - ibat_low))
811 				* ibat_high;
812 			/*
813 			 * Result obtained is in mV (at a scale factor),
814 			 * we need to calculate gain and offset to get mA
815 			 */
816 			V2A_gain = (AB8500_ADC_CH_IBAT_MAX - AB8500_ADC_CH_IBAT_MIN)/
817 				(AB8500_ADC_CH_IBAT_MAX_V - AB8500_ADC_CH_IBAT_MIN_V);
818 			V2A_offset = ((AB8500_ADC_CH_IBAT_MAX_V * AB8500_ADC_CH_IBAT_MIN -
819 				AB8500_ADC_CH_IBAT_MAX * AB8500_ADC_CH_IBAT_MIN_V)
820 				<< AB8500_GPADC_CALIB_SHIFT_IBAT)
821 				/ (AB8500_ADC_CH_IBAT_MAX_V - AB8500_ADC_CH_IBAT_MIN_V);
822 
823 			gpadc->cal_data[AB8500_CAL_IBAT].gain =
824 				V_gain * V2A_gain;
825 			gpadc->cal_data[AB8500_CAL_IBAT].offset =
826 				V_offset * V2A_gain + V2A_offset;
827 		} else {
828 			gpadc->cal_data[AB8500_CAL_IBAT].gain = 0;
829 		}
830 	} else {
831 		/* Calculate gain and offset for VMAIN if all reads succeeded */
832 		if (!(ret[0] < 0 || ret[1] < 0 || ret[2] < 0)) {
833 			vmain_high = (((gpadc_cal[0] & 0x03) << 8) |
834 				((gpadc_cal[1] & 0x3F) << 2) |
835 				((gpadc_cal[2] & 0xC0) >> 6));
836 			vmain_low = ((gpadc_cal[2] & 0x3E) >> 1);
837 
838 			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_hi =
839 				(u16)vmain_high;
840 			gpadc->cal_data[AB8500_CAL_VMAIN].otp_calib_lo =
841 				(u16)vmain_low;
842 
843 			gpadc->cal_data[AB8500_CAL_VMAIN].gain = AB8500_GPADC_CALIB_SCALE *
844 				(19500 - 315) / (vmain_high - vmain_low);
845 
846 			gpadc->cal_data[AB8500_CAL_VMAIN].offset = AB8500_GPADC_CALIB_SCALE *
847 				19500 - (AB8500_GPADC_CALIB_SCALE * (19500 - 315) /
848 				(vmain_high - vmain_low)) * vmain_high;
849 		} else {
850 			gpadc->cal_data[AB8500_CAL_VMAIN].gain = 0;
851 		}
852 	}
853 
854 	/* Calculate gain and offset for BTEMP if all reads succeeded */
855 	if (!(ret[2] < 0 || ret[3] < 0 || ret[4] < 0)) {
856 		btemp_high = (((gpadc_cal[2] & 0x01) << 9) |
857 			(gpadc_cal[3] << 1) | ((gpadc_cal[4] & 0x80) >> 7));
858 		btemp_low = ((gpadc_cal[4] & 0x7C) >> 2);
859 
860 		gpadc->cal_data[AB8500_CAL_BTEMP].otp_calib_hi = (u16)btemp_high;
861 		gpadc->cal_data[AB8500_CAL_BTEMP].otp_calib_lo = (u16)btemp_low;
862 
863 		gpadc->cal_data[AB8500_CAL_BTEMP].gain =
864 			AB8500_GPADC_CALIB_SCALE * (1300 - 21) / (btemp_high - btemp_low);
865 		gpadc->cal_data[AB8500_CAL_BTEMP].offset = AB8500_GPADC_CALIB_SCALE * 1300 -
866 			(AB8500_GPADC_CALIB_SCALE * (1300 - 21) / (btemp_high - btemp_low))
867 			* btemp_high;
868 	} else {
869 		gpadc->cal_data[AB8500_CAL_BTEMP].gain = 0;
870 	}
871 
872 	/* Calculate gain and offset for VBAT if all reads succeeded */
873 	if (!(ret[4] < 0 || ret[5] < 0 || ret[6] < 0)) {
874 		vbat_high = (((gpadc_cal[4] & 0x03) << 8) | gpadc_cal[5]);
875 		vbat_low = ((gpadc_cal[6] & 0xFC) >> 2);
876 
877 		gpadc->cal_data[AB8500_CAL_VBAT].otp_calib_hi = (u16)vbat_high;
878 		gpadc->cal_data[AB8500_CAL_VBAT].otp_calib_lo = (u16)vbat_low;
879 
880 		gpadc->cal_data[AB8500_CAL_VBAT].gain = AB8500_GPADC_CALIB_SCALE *
881 			(4700 - 2380) /	(vbat_high - vbat_low);
882 		gpadc->cal_data[AB8500_CAL_VBAT].offset = AB8500_GPADC_CALIB_SCALE * 4700 -
883 			(AB8500_GPADC_CALIB_SCALE * (4700 - 2380) /
884 			(vbat_high - vbat_low)) * vbat_high;
885 	} else {
886 		gpadc->cal_data[AB8500_CAL_VBAT].gain = 0;
887 	}
888 }
889 
890 static int ab8500_gpadc_read_raw(struct iio_dev *indio_dev,
891 				 struct iio_chan_spec const *chan,
892 				 int *val, int *val2, long mask)
893 {
894 	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
895 	const struct ab8500_gpadc_chan_info *ch;
896 	int raw_val;
897 	int processed;
898 
899 	ch = ab8500_gpadc_get_channel(gpadc, chan->address);
900 	if (!ch) {
901 		dev_err(gpadc->dev, "no such channel %lu\n",
902 			chan->address);
903 		return -EINVAL;
904 	}
905 
906 	raw_val = ab8500_gpadc_read(gpadc, ch, NULL);
907 	if (raw_val < 0)
908 		return raw_val;
909 
910 	if (mask == IIO_CHAN_INFO_RAW) {
911 		*val = raw_val;
912 		return IIO_VAL_INT;
913 	}
914 
915 	if (mask == IIO_CHAN_INFO_PROCESSED) {
916 		processed = ab8500_gpadc_ad_to_voltage(gpadc, ch->id, raw_val);
917 		if (processed < 0)
918 			return processed;
919 
920 		/* Return millivolt or milliamps or millicentigrades */
921 		*val = processed;
922 		return IIO_VAL_INT;
923 	}
924 
925 	return -EINVAL;
926 }
927 
928 static int ab8500_gpadc_fwnode_xlate(struct iio_dev *indio_dev,
929 				     const struct fwnode_reference_args *iiospec)
930 {
931 	int i;
932 
933 	for (i = 0; i < indio_dev->num_channels; i++)
934 		if (indio_dev->channels[i].channel == iiospec->args[0])
935 			return i;
936 
937 	return -EINVAL;
938 }
939 
940 static const struct iio_info ab8500_gpadc_info = {
941 	.fwnode_xlate = ab8500_gpadc_fwnode_xlate,
942 	.read_raw = ab8500_gpadc_read_raw,
943 };
944 
945 static int ab8500_gpadc_runtime_suspend(struct device *dev)
946 {
947 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
948 	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
949 
950 	regulator_disable(gpadc->vddadc);
951 
952 	return 0;
953 }
954 
955 static int ab8500_gpadc_runtime_resume(struct device *dev)
956 {
957 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
958 	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
959 	int ret;
960 
961 	ret = regulator_enable(gpadc->vddadc);
962 	if (ret)
963 		dev_err(dev, "Failed to enable vddadc: %d\n", ret);
964 
965 	return ret;
966 }
967 
968 /**
969  * ab8500_gpadc_parse_channel() - process devicetree channel configuration
970  * @dev: pointer to containing device
971  * @fwnode: fw node for the channel to configure
972  * @ch: channel info to fill in
973  * @iio_chan: IIO channel specification to fill in
974  *
975  * The devicetree will set up the channel for use with the specific device,
976  * and define usage for things like AUX GPADC inputs more precisely.
977  */
978 static int ab8500_gpadc_parse_channel(struct device *dev,
979 				      struct fwnode_handle *fwnode,
980 				      struct ab8500_gpadc_chan_info *ch,
981 				      struct iio_chan_spec *iio_chan)
982 {
983 	const char *name = fwnode_get_name(fwnode);
984 	u32 chan;
985 	int ret;
986 
987 	ret = fwnode_property_read_u32(fwnode, "reg", &chan);
988 	if (ret) {
989 		dev_err(dev, "invalid channel number %s\n", name);
990 		return ret;
991 	}
992 	if (chan > AB8500_GPADC_CHAN_BAT_TEMP_AND_IBAT) {
993 		dev_err(dev, "%s channel number out of range %d\n", name, chan);
994 		return -EINVAL;
995 	}
996 
997 	iio_chan->channel = chan;
998 	iio_chan->datasheet_name = name;
999 	iio_chan->indexed = 1;
1000 	iio_chan->address = chan;
1001 	iio_chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
1002 		BIT(IIO_CHAN_INFO_PROCESSED);
1003 	/* Most are voltages (also temperatures), some are currents */
1004 	if ((chan == AB8500_GPADC_CHAN_MAIN_CHARGER_CURRENT) ||
1005 	    (chan == AB8500_GPADC_CHAN_USB_CHARGER_CURRENT))
1006 		iio_chan->type = IIO_CURRENT;
1007 	else
1008 		iio_chan->type = IIO_VOLTAGE;
1009 
1010 	ch->id = chan;
1011 
1012 	/* Sensible defaults */
1013 	ch->avg_sample = 16;
1014 	ch->hardware_control = false;
1015 	ch->falling_edge = false;
1016 	ch->trig_timer = 0;
1017 
1018 	return 0;
1019 }
1020 
1021 /**
1022  * ab8500_gpadc_parse_channels() - Parse the GPADC channels from DT
1023  * @gpadc: the GPADC to configure the channels for
1024  * @chans: the IIO channels we parsed
1025  * @nchans: the number of IIO channels we parsed
1026  */
1027 static int ab8500_gpadc_parse_channels(struct ab8500_gpadc *gpadc,
1028 				       struct iio_chan_spec **chans_parsed,
1029 				       unsigned int *nchans_parsed)
1030 {
1031 	struct fwnode_handle *child;
1032 	struct ab8500_gpadc_chan_info *ch;
1033 	struct iio_chan_spec *iio_chans;
1034 	unsigned int nchans;
1035 	int i;
1036 
1037 	nchans = device_get_child_node_count(gpadc->dev);
1038 	if (!nchans) {
1039 		dev_err(gpadc->dev, "no channel children\n");
1040 		return -ENODEV;
1041 	}
1042 	dev_info(gpadc->dev, "found %d ADC channels\n", nchans);
1043 
1044 	iio_chans = devm_kcalloc(gpadc->dev, nchans,
1045 				 sizeof(*iio_chans), GFP_KERNEL);
1046 	if (!iio_chans)
1047 		return -ENOMEM;
1048 
1049 	gpadc->chans = devm_kcalloc(gpadc->dev, nchans,
1050 				    sizeof(*gpadc->chans), GFP_KERNEL);
1051 	if (!gpadc->chans)
1052 		return -ENOMEM;
1053 
1054 	i = 0;
1055 	device_for_each_child_node(gpadc->dev, child) {
1056 		struct iio_chan_spec *iio_chan;
1057 		int ret;
1058 
1059 		ch = &gpadc->chans[i];
1060 		iio_chan = &iio_chans[i];
1061 
1062 		ret = ab8500_gpadc_parse_channel(gpadc->dev, child, ch,
1063 						 iio_chan);
1064 		if (ret) {
1065 			fwnode_handle_put(child);
1066 			return ret;
1067 		}
1068 		i++;
1069 	}
1070 	gpadc->nchans = nchans;
1071 	*chans_parsed = iio_chans;
1072 	*nchans_parsed = nchans;
1073 
1074 	return 0;
1075 }
1076 
1077 static int ab8500_gpadc_probe(struct platform_device *pdev)
1078 {
1079 	struct ab8500_gpadc *gpadc;
1080 	struct iio_dev *indio_dev;
1081 	struct device *dev = &pdev->dev;
1082 	struct iio_chan_spec *iio_chans;
1083 	unsigned int n_iio_chans;
1084 	int ret;
1085 
1086 	indio_dev = devm_iio_device_alloc(dev, sizeof(*gpadc));
1087 	if (!indio_dev)
1088 		return -ENOMEM;
1089 
1090 	platform_set_drvdata(pdev, indio_dev);
1091 	gpadc = iio_priv(indio_dev);
1092 
1093 	gpadc->dev = dev;
1094 	gpadc->ab8500 = dev_get_drvdata(dev->parent);
1095 
1096 	ret = ab8500_gpadc_parse_channels(gpadc, &iio_chans, &n_iio_chans);
1097 	if (ret)
1098 		return ret;
1099 
1100 	gpadc->irq_sw = platform_get_irq_byname(pdev, "SW_CONV_END");
1101 	if (gpadc->irq_sw < 0)
1102 		return gpadc->irq_sw;
1103 
1104 	if (is_ab8500(gpadc->ab8500)) {
1105 		gpadc->irq_hw = platform_get_irq_byname(pdev, "HW_CONV_END");
1106 		if (gpadc->irq_hw < 0)
1107 			return gpadc->irq_hw;
1108 	} else {
1109 		gpadc->irq_hw = 0;
1110 	}
1111 
1112 	/* Initialize completion used to notify completion of conversion */
1113 	init_completion(&gpadc->complete);
1114 
1115 	/* Request interrupts */
1116 	ret = devm_request_threaded_irq(dev, gpadc->irq_sw, NULL,
1117 		ab8500_bm_gpadcconvend_handler,	IRQF_NO_SUSPEND | IRQF_ONESHOT,
1118 		"ab8500-gpadc-sw", gpadc);
1119 	if (ret < 0) {
1120 		dev_err(dev,
1121 			"failed to request sw conversion irq %d\n",
1122 			gpadc->irq_sw);
1123 		return ret;
1124 	}
1125 
1126 	if (gpadc->irq_hw) {
1127 		ret = devm_request_threaded_irq(dev, gpadc->irq_hw, NULL,
1128 			ab8500_bm_gpadcconvend_handler,	IRQF_NO_SUSPEND | IRQF_ONESHOT,
1129 			"ab8500-gpadc-hw", gpadc);
1130 		if (ret < 0) {
1131 			dev_err(dev,
1132 				"Failed to request hw conversion irq: %d\n",
1133 				gpadc->irq_hw);
1134 			return ret;
1135 		}
1136 	}
1137 
1138 	/* The VTVout LDO used to power the AB8500 GPADC */
1139 	gpadc->vddadc = devm_regulator_get(dev, "vddadc");
1140 	if (IS_ERR(gpadc->vddadc))
1141 		return dev_err_probe(dev, PTR_ERR(gpadc->vddadc),
1142 				     "failed to get vddadc\n");
1143 
1144 	ret = regulator_enable(gpadc->vddadc);
1145 	if (ret) {
1146 		dev_err(dev, "failed to enable vddadc: %d\n", ret);
1147 		return ret;
1148 	}
1149 
1150 	/* Enable runtime PM */
1151 	pm_runtime_get_noresume(dev);
1152 	pm_runtime_set_active(dev);
1153 	pm_runtime_enable(dev);
1154 	pm_runtime_set_autosuspend_delay(dev, AB8500_GPADC_AUTOSUSPEND_DELAY);
1155 	pm_runtime_use_autosuspend(dev);
1156 
1157 	ab8500_gpadc_read_calibration_data(gpadc);
1158 
1159 	pm_runtime_put(dev);
1160 
1161 	indio_dev->name = "ab8500-gpadc";
1162 	indio_dev->modes = INDIO_DIRECT_MODE;
1163 	indio_dev->info = &ab8500_gpadc_info;
1164 	indio_dev->channels = iio_chans;
1165 	indio_dev->num_channels = n_iio_chans;
1166 
1167 	ret = devm_iio_device_register(dev, indio_dev);
1168 	if (ret)
1169 		goto out_dis_pm;
1170 
1171 	return 0;
1172 
1173 out_dis_pm:
1174 	pm_runtime_get_sync(dev);
1175 	pm_runtime_put_noidle(dev);
1176 	pm_runtime_disable(dev);
1177 	regulator_disable(gpadc->vddadc);
1178 
1179 	return ret;
1180 }
1181 
1182 static void ab8500_gpadc_remove(struct platform_device *pdev)
1183 {
1184 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
1185 	struct ab8500_gpadc *gpadc = iio_priv(indio_dev);
1186 
1187 	pm_runtime_get_sync(gpadc->dev);
1188 	pm_runtime_put_noidle(gpadc->dev);
1189 	pm_runtime_disable(gpadc->dev);
1190 	regulator_disable(gpadc->vddadc);
1191 }
1192 
1193 static DEFINE_RUNTIME_DEV_PM_OPS(ab8500_gpadc_pm_ops,
1194 				 ab8500_gpadc_runtime_suspend,
1195 				 ab8500_gpadc_runtime_resume, NULL);
1196 
1197 static struct platform_driver ab8500_gpadc_driver = {
1198 	.probe = ab8500_gpadc_probe,
1199 	.remove_new = ab8500_gpadc_remove,
1200 	.driver = {
1201 		.name = "ab8500-gpadc",
1202 		.pm = pm_ptr(&ab8500_gpadc_pm_ops),
1203 	},
1204 };
1205 builtin_platform_driver(ab8500_gpadc_driver);
1206