xref: /linux/drivers/iio/adc/qcom-pm8xxx-xoadc.c (revision b8d312aa075f33282565467662c4628dae0a2aff)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Qualcomm PM8xxx PMIC XOADC driver
4  *
5  * These ADCs are known as HK/XO (house keeping / chrystal oscillator)
6  * "XO" in "XOADC" means Chrystal Oscillator. It's a bunch of
7  * specific-purpose and general purpose ADC converters and channels.
8  *
9  * Copyright (C) 2017 Linaro Ltd.
10  * Author: Linus Walleij <linus.walleij@linaro.org>
11  */
12 
13 #include <linux/iio/iio.h>
14 #include <linux/iio/sysfs.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/regmap.h>
20 #include <linux/init.h>
21 #include <linux/interrupt.h>
22 #include <linux/regulator/consumer.h>
23 
24 #include "qcom-vadc-common.h"
25 
26 /*
27  * Definitions for the "user processor" registers lifted from the v3.4
28  * Qualcomm tree. Their kernel has two out-of-tree drivers for the ADC:
29  * drivers/misc/pmic8058-xoadc.c
30  * drivers/hwmon/pm8xxx-adc.c
31  * None of them contain any complete register specification, so this is
32  * a best effort of combining the information.
33  */
34 
35 /* These appear to be "battery monitor" registers */
36 #define ADC_ARB_BTM_CNTRL1			0x17e
37 #define ADC_ARB_BTM_CNTRL1_EN_BTM		BIT(0)
38 #define ADC_ARB_BTM_CNTRL1_SEL_OP_MODE		BIT(1)
39 #define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL1	BIT(2)
40 #define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL2	BIT(3)
41 #define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL3	BIT(4)
42 #define ADC_ARB_BTM_CNTRL1_MEAS_INTERVAL4	BIT(5)
43 #define ADC_ARB_BTM_CNTRL1_EOC			BIT(6)
44 #define ADC_ARB_BTM_CNTRL1_REQ			BIT(7)
45 
46 #define ADC_ARB_BTM_AMUX_CNTRL			0x17f
47 #define ADC_ARB_BTM_ANA_PARAM			0x180
48 #define ADC_ARB_BTM_DIG_PARAM			0x181
49 #define ADC_ARB_BTM_RSV				0x182
50 #define ADC_ARB_BTM_DATA1			0x183
51 #define ADC_ARB_BTM_DATA0			0x184
52 #define ADC_ARB_BTM_BAT_COOL_THR1		0x185
53 #define ADC_ARB_BTM_BAT_COOL_THR0		0x186
54 #define ADC_ARB_BTM_BAT_WARM_THR1		0x187
55 #define ADC_ARB_BTM_BAT_WARM_THR0		0x188
56 #define ADC_ARB_BTM_CNTRL2			0x18c
57 
58 /* Proper ADC registers */
59 
60 #define ADC_ARB_USRP_CNTRL			0x197
61 #define ADC_ARB_USRP_CNTRL_EN_ARB		BIT(0)
62 #define ADC_ARB_USRP_CNTRL_RSV1			BIT(1)
63 #define ADC_ARB_USRP_CNTRL_RSV2			BIT(2)
64 #define ADC_ARB_USRP_CNTRL_RSV3			BIT(3)
65 #define ADC_ARB_USRP_CNTRL_RSV4			BIT(4)
66 #define ADC_ARB_USRP_CNTRL_RSV5			BIT(5)
67 #define ADC_ARB_USRP_CNTRL_EOC			BIT(6)
68 #define ADC_ARB_USRP_CNTRL_REQ			BIT(7)
69 
70 #define ADC_ARB_USRP_AMUX_CNTRL			0x198
71 /*
72  * The channel mask includes the bits selecting channel mux and prescaler
73  * on PM8058, or channel mux and premux on PM8921.
74  */
75 #define ADC_ARB_USRP_AMUX_CNTRL_CHAN_MASK	0xfc
76 #define ADC_ARB_USRP_AMUX_CNTRL_RSV0		BIT(0)
77 #define ADC_ARB_USRP_AMUX_CNTRL_RSV1		BIT(1)
78 /* On PM8058 this is prescaling, on PM8921 this is premux */
79 #define ADC_ARB_USRP_AMUX_CNTRL_PRESCALEMUX0	BIT(2)
80 #define ADC_ARB_USRP_AMUX_CNTRL_PRESCALEMUX1	BIT(3)
81 #define ADC_ARB_USRP_AMUX_CNTRL_SEL0		BIT(4)
82 #define ADC_ARB_USRP_AMUX_CNTRL_SEL1		BIT(5)
83 #define ADC_ARB_USRP_AMUX_CNTRL_SEL2		BIT(6)
84 #define ADC_ARB_USRP_AMUX_CNTRL_SEL3		BIT(7)
85 #define ADC_AMUX_PREMUX_SHIFT			2
86 #define ADC_AMUX_SEL_SHIFT			4
87 
88 /* We know very little about the bits in this register */
89 #define ADC_ARB_USRP_ANA_PARAM			0x199
90 #define ADC_ARB_USRP_ANA_PARAM_DIS		0xFE
91 #define ADC_ARB_USRP_ANA_PARAM_EN		0xFF
92 
93 #define ADC_ARB_USRP_DIG_PARAM			0x19A
94 #define ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0	BIT(0)
95 #define ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1	BIT(1)
96 #define ADC_ARB_USRP_DIG_PARAM_CLK_RATE0	BIT(2)
97 #define ADC_ARB_USRP_DIG_PARAM_CLK_RATE1	BIT(3)
98 #define ADC_ARB_USRP_DIG_PARAM_EOC		BIT(4)
99 /*
100  * On a later ADC the decimation factors are defined as
101  * 00 = 512, 01 = 1024, 10 = 2048, 11 = 4096 so assume this
102  * holds also for this older XOADC.
103  */
104 #define ADC_ARB_USRP_DIG_PARAM_DEC_RATE0	BIT(5)
105 #define ADC_ARB_USRP_DIG_PARAM_DEC_RATE1	BIT(6)
106 #define ADC_ARB_USRP_DIG_PARAM_EN		BIT(7)
107 #define ADC_DIG_PARAM_DEC_SHIFT			5
108 
109 #define ADC_ARB_USRP_RSV			0x19B
110 #define ADC_ARB_USRP_RSV_RST			BIT(0)
111 #define ADC_ARB_USRP_RSV_DTEST0			BIT(1)
112 #define ADC_ARB_USRP_RSV_DTEST1			BIT(2)
113 #define ADC_ARB_USRP_RSV_OP			BIT(3)
114 #define ADC_ARB_USRP_RSV_IP_SEL0		BIT(4)
115 #define ADC_ARB_USRP_RSV_IP_SEL1		BIT(5)
116 #define ADC_ARB_USRP_RSV_IP_SEL2		BIT(6)
117 #define ADC_ARB_USRP_RSV_TRM			BIT(7)
118 #define ADC_RSV_IP_SEL_SHIFT			4
119 
120 #define ADC_ARB_USRP_DATA0			0x19D
121 #define ADC_ARB_USRP_DATA1			0x19C
122 
123 /**
124  * Physical channels which MUST exist on all PM variants in order to provide
125  * proper reference points for calibration.
126  *
127  * @PM8XXX_CHANNEL_INTERNAL: 625mV reference channel
128  * @PM8XXX_CHANNEL_125V: 1250mV reference channel
129  * @PM8XXX_CHANNEL_INTERNAL_2: 325mV reference channel
130  * @PM8XXX_CHANNEL_MUXOFF: channel to reduce input load on mux, apparently also
131  * measures XO temperature
132  */
133 #define PM8XXX_CHANNEL_INTERNAL		0x0c
134 #define PM8XXX_CHANNEL_125V		0x0d
135 #define PM8XXX_CHANNEL_INTERNAL_2	0x0e
136 #define PM8XXX_CHANNEL_MUXOFF		0x0f
137 
138 /*
139  * PM8058 AMUX premux scaling, two bits. This is done of the channel before
140  * reaching the AMUX.
141  */
142 #define PM8058_AMUX_PRESCALE_0 0x0 /* No scaling on the signal */
143 #define PM8058_AMUX_PRESCALE_1 0x1 /* Unity scaling selected by the user */
144 #define PM8058_AMUX_PRESCALE_1_DIV3 0x2 /* 1/3 prescaler on the input */
145 
146 /* Defines reference voltage for the XOADC */
147 #define AMUX_RSV0 0x0 /* XO_IN/XOADC_GND, special selection to read XO temp */
148 #define AMUX_RSV1 0x1 /* PMIC_IN/XOADC_GND */
149 #define AMUX_RSV2 0x2 /* PMIC_IN/BMS_CSP */
150 #define AMUX_RSV3 0x3 /* not used */
151 #define AMUX_RSV4 0x4 /* XOADC_GND/XOADC_GND */
152 #define AMUX_RSV5 0x5 /* XOADC_VREF/XOADC_GND */
153 #define XOADC_RSV_MAX 5 /* 3 bits 0..7, 3 and 6,7 are invalid */
154 
155 /**
156  * struct xoadc_channel - encodes channel properties and defaults
157  * @datasheet_name: the hardwarename of this channel
158  * @pre_scale_mux: prescale (PM8058) or premux (PM8921) for selecting
159  * this channel. Both this and the amux channel is needed to uniquely
160  * identify a channel. Values 0..3.
161  * @amux_channel: value of the ADC_ARB_USRP_AMUX_CNTRL register for this
162  * channel, bits 4..7, selects the amux, values 0..f
163  * @prescale: the channels have hard-coded prescale ratios defined
164  * by the hardware, this tells us what it is
165  * @type: corresponding IIO channel type, usually IIO_VOLTAGE or
166  * IIO_TEMP
167  * @scale_fn_type: the liner interpolation etc to convert the
168  * ADC code to the value that IIO expects, in uV or millicelsius
169  * etc. This scale function can be pretty elaborate if different
170  * thermistors are connected or other hardware characteristics are
171  * deployed.
172  * @amux_ip_rsv: ratiometric scale value used by the analog muxer: this
173  * selects the reference voltage for ratiometric scaling
174  */
175 struct xoadc_channel {
176 	const char *datasheet_name;
177 	u8 pre_scale_mux:2;
178 	u8 amux_channel:4;
179 	const struct vadc_prescale_ratio prescale;
180 	enum iio_chan_type type;
181 	enum vadc_scale_fn_type scale_fn_type;
182 	u8 amux_ip_rsv:3;
183 };
184 
185 /**
186  * struct xoadc_variant - encodes the XOADC variant characteristics
187  * @name: name of this PMIC variant
188  * @channels: the hardware channels and respective settings and defaults
189  * @broken_ratiometric: if the PMIC has broken ratiometric scaling (this
190  * is a known problem on PM8058)
191  * @prescaling: this variant uses AMUX bits 2 & 3 for prescaling (PM8058)
192  * @second_level_mux: this variant uses AMUX bits 2 & 3 for a second level
193  * mux
194  */
195 struct xoadc_variant {
196 	const char name[16];
197 	const struct xoadc_channel *channels;
198 	bool broken_ratiometric;
199 	bool prescaling;
200 	bool second_level_mux;
201 };
202 
203 /*
204  * XOADC_CHAN macro parameters:
205  * _dname: the name of the channel
206  * _presmux: prescaler (PM8058) or premux (PM8921) setting for this channel
207  * _amux: the value in bits 2..7 of the ADC_ARB_USRP_AMUX_CNTRL register
208  * for this channel. On some PMICs some of the bits select a prescaler, and
209  * on some PMICs some of the bits select various complex multiplex settings.
210  * _type: IIO channel type
211  * _prenum: prescaler numerator (dividend)
212  * _preden: prescaler denominator (divisor)
213  * _scale: scaling function type, this selects how the raw valued is mangled
214  * to output the actual processed measurement
215  * _amip: analog mux input parent when using ratiometric measurements
216  */
217 #define XOADC_CHAN(_dname, _presmux, _amux, _type, _prenum, _preden, _scale, _amip) \
218 	{								\
219 		.datasheet_name = __stringify(_dname),			\
220 		.pre_scale_mux = _presmux,				\
221 		.amux_channel = _amux,					\
222 		.prescale = { .num = _prenum, .den = _preden },		\
223 		.type = _type,						\
224 		.scale_fn_type = _scale,				\
225 		.amux_ip_rsv = _amip,					\
226 	}
227 
228 /*
229  * Taken from arch/arm/mach-msm/board-9615.c in the vendor tree:
230  * TODO: incomplete, needs testing.
231  */
232 static const struct xoadc_channel pm8018_xoadc_channels[] = {
233 	XOADC_CHAN(VCOIN, 0x00, 0x00, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
234 	XOADC_CHAN(VBAT, 0x00, 0x01, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
235 	XOADC_CHAN(VPH_PWR, 0x00, 0x02, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
236 	XOADC_CHAN(DIE_TEMP, 0x00, 0x0b, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
237 	/* Used for battery ID or battery temperature */
238 	XOADC_CHAN(AMUX8, 0x00, 0x08, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV2),
239 	XOADC_CHAN(INTERNAL, 0x00, 0x0c, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
240 	XOADC_CHAN(125V, 0x00, 0x0d, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
241 	XOADC_CHAN(MUXOFF, 0x00, 0x0f, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
242 	{ }, /* Sentinel */
243 };
244 
245 /*
246  * Taken from arch/arm/mach-msm/board-8930-pmic.c in the vendor tree:
247  * TODO: needs testing.
248  */
249 static const struct xoadc_channel pm8038_xoadc_channels[] = {
250 	XOADC_CHAN(VCOIN, 0x00, 0x00, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
251 	XOADC_CHAN(VBAT, 0x00, 0x01, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
252 	XOADC_CHAN(DCIN, 0x00, 0x02, IIO_VOLTAGE, 1, 6, SCALE_DEFAULT, AMUX_RSV1),
253 	XOADC_CHAN(ICHG, 0x00, 0x03, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
254 	XOADC_CHAN(VPH_PWR, 0x00, 0x04, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
255 	XOADC_CHAN(AMUX5, 0x00, 0x05, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
256 	XOADC_CHAN(AMUX6, 0x00, 0x06, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
257 	XOADC_CHAN(AMUX7, 0x00, 0x07, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
258 	/* AMUX8 used for battery temperature in most cases */
259 	XOADC_CHAN(AMUX8, 0x00, 0x08, IIO_TEMP, 1, 1, SCALE_THERM_100K_PULLUP, AMUX_RSV2),
260 	XOADC_CHAN(AMUX9, 0x00, 0x09, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
261 	XOADC_CHAN(USB_VBUS, 0x00, 0x0a, IIO_VOLTAGE, 1, 4, SCALE_DEFAULT, AMUX_RSV1),
262 	XOADC_CHAN(DIE_TEMP, 0x00, 0x0b, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
263 	XOADC_CHAN(INTERNAL, 0x00, 0x0c, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
264 	XOADC_CHAN(125V, 0x00, 0x0d, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
265 	XOADC_CHAN(INTERNAL_2, 0x00, 0x0e, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
266 	XOADC_CHAN(MUXOFF, 0x00, 0x0f, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
267 	{ }, /* Sentinel */
268 };
269 
270 /*
271  * This was created by cross-referencing the vendor tree
272  * arch/arm/mach-msm/board-msm8x60.c msm_adc_channels_data[]
273  * with the "channel types" (first field) to find the right
274  * configuration for these channels on an MSM8x60 i.e. PM8058
275  * setup.
276  */
277 static const struct xoadc_channel pm8058_xoadc_channels[] = {
278 	XOADC_CHAN(VCOIN, 0x00, 0x00, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
279 	XOADC_CHAN(VBAT, 0x00, 0x01, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
280 	XOADC_CHAN(DCIN, 0x00, 0x02, IIO_VOLTAGE, 1, 10, SCALE_DEFAULT, AMUX_RSV1),
281 	XOADC_CHAN(ICHG, 0x00, 0x03, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
282 	XOADC_CHAN(VPH_PWR, 0x00, 0x04, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
283 	/*
284 	 * AMUX channels 5 thru 9 are referred to as MPP5 thru MPP9 in
285 	 * some code and documentation. But they are really just 5
286 	 * channels just like any other. They are connected to a switching
287 	 * matrix where they can be routed to any of the MPPs, not just
288 	 * 1-to-1 onto MPP5 thru 9, so naming them MPP5 thru MPP9 is
289 	 * very confusing.
290 	 */
291 	XOADC_CHAN(AMUX5, 0x00, 0x05, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
292 	XOADC_CHAN(AMUX6, 0x00, 0x06, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
293 	XOADC_CHAN(AMUX7, 0x00, 0x07, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
294 	XOADC_CHAN(AMUX8, 0x00, 0x08, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
295 	XOADC_CHAN(AMUX9, 0x00, 0x09, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
296 	XOADC_CHAN(USB_VBUS, 0x00, 0x0a, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
297 	XOADC_CHAN(DIE_TEMP, 0x00, 0x0b, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
298 	XOADC_CHAN(INTERNAL, 0x00, 0x0c, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
299 	XOADC_CHAN(125V, 0x00, 0x0d, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
300 	XOADC_CHAN(INTERNAL_2, 0x00, 0x0e, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
301 	XOADC_CHAN(MUXOFF, 0x00, 0x0f, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
302 	/* There are also "unity" and divided by 3 channels (prescaler) but noone is using them */
303 	{ }, /* Sentinel */
304 };
305 
306 /*
307  * The PM8921 has some pre-muxing on its channels, this comes from the vendor tree
308  * include/linux/mfd/pm8xxx/pm8xxx-adc.h
309  * board-flo-pmic.c (Nexus 7) and board-8064-pmic.c
310  */
311 static const struct xoadc_channel pm8921_xoadc_channels[] = {
312 	XOADC_CHAN(VCOIN, 0x00, 0x00, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
313 	XOADC_CHAN(VBAT, 0x00, 0x01, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
314 	XOADC_CHAN(DCIN, 0x00, 0x02, IIO_VOLTAGE, 1, 6, SCALE_DEFAULT, AMUX_RSV1),
315 	/* channel "ICHG" is reserved and not used on PM8921 */
316 	XOADC_CHAN(VPH_PWR, 0x00, 0x04, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
317 	XOADC_CHAN(IBAT, 0x00, 0x05, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
318 	/* CHAN 6 & 7 (MPP1 & MPP2) are reserved for MPP channels on PM8921 */
319 	XOADC_CHAN(BATT_THERM, 0x00, 0x08, IIO_TEMP, 1, 1, SCALE_THERM_100K_PULLUP, AMUX_RSV1),
320 	XOADC_CHAN(BATT_ID, 0x00, 0x09, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
321 	XOADC_CHAN(USB_VBUS, 0x00, 0x0a, IIO_VOLTAGE, 1, 4, SCALE_DEFAULT, AMUX_RSV1),
322 	XOADC_CHAN(DIE_TEMP, 0x00, 0x0b, IIO_TEMP, 1, 1, SCALE_PMIC_THERM, AMUX_RSV1),
323 	XOADC_CHAN(INTERNAL, 0x00, 0x0c, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
324 	XOADC_CHAN(125V, 0x00, 0x0d, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
325 	/* FIXME: look into the scaling of this temperature */
326 	XOADC_CHAN(CHG_TEMP, 0x00, 0x0e, IIO_TEMP, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
327 	XOADC_CHAN(MUXOFF, 0x00, 0x0f, IIO_TEMP, 1, 1, SCALE_XOTHERM, AMUX_RSV0),
328 	/* The following channels have premux bit 0 set to 1 (all end in 4) */
329 	XOADC_CHAN(ATEST_8, 0x01, 0x00, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
330 	/* Set scaling to 1/2 based on the name for these two */
331 	XOADC_CHAN(USB_SNS_DIV20, 0x01, 0x01, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
332 	XOADC_CHAN(DCIN_SNS_DIV20, 0x01, 0x02, IIO_VOLTAGE, 1, 2, SCALE_DEFAULT, AMUX_RSV1),
333 	XOADC_CHAN(AMUX3, 0x01, 0x03, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
334 	XOADC_CHAN(AMUX4, 0x01, 0x04, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
335 	XOADC_CHAN(AMUX5, 0x01, 0x05, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
336 	XOADC_CHAN(AMUX6, 0x01, 0x06, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
337 	XOADC_CHAN(AMUX7, 0x01, 0x07, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
338 	XOADC_CHAN(AMUX8, 0x01, 0x08, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
339 	/* Internal test signals, I think */
340 	XOADC_CHAN(ATEST_1, 0x01, 0x09, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
341 	XOADC_CHAN(ATEST_2, 0x01, 0x0a, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
342 	XOADC_CHAN(ATEST_3, 0x01, 0x0b, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
343 	XOADC_CHAN(ATEST_4, 0x01, 0x0c, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
344 	XOADC_CHAN(ATEST_5, 0x01, 0x0d, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
345 	XOADC_CHAN(ATEST_6, 0x01, 0x0e, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
346 	XOADC_CHAN(ATEST_7, 0x01, 0x0f, IIO_VOLTAGE, 1, 1, SCALE_DEFAULT, AMUX_RSV1),
347 	/* The following channels have premux bit 1 set to 1 (all end in 8) */
348 	/* I guess even ATEST8 will be divided by 3 here */
349 	XOADC_CHAN(ATEST_8, 0x02, 0x00, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
350 	/* I guess div 2 div 3 becomes div 6 */
351 	XOADC_CHAN(USB_SNS_DIV20_DIV3, 0x02, 0x01, IIO_VOLTAGE, 1, 6, SCALE_DEFAULT, AMUX_RSV1),
352 	XOADC_CHAN(DCIN_SNS_DIV20_DIV3, 0x02, 0x02, IIO_VOLTAGE, 1, 6, SCALE_DEFAULT, AMUX_RSV1),
353 	XOADC_CHAN(AMUX3_DIV3, 0x02, 0x03, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
354 	XOADC_CHAN(AMUX4_DIV3, 0x02, 0x04, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
355 	XOADC_CHAN(AMUX5_DIV3, 0x02, 0x05, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
356 	XOADC_CHAN(AMUX6_DIV3, 0x02, 0x06, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
357 	XOADC_CHAN(AMUX7_DIV3, 0x02, 0x07, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
358 	XOADC_CHAN(AMUX8_DIV3, 0x02, 0x08, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
359 	XOADC_CHAN(ATEST_1_DIV3, 0x02, 0x09, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
360 	XOADC_CHAN(ATEST_2_DIV3, 0x02, 0x0a, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
361 	XOADC_CHAN(ATEST_3_DIV3, 0x02, 0x0b, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
362 	XOADC_CHAN(ATEST_4_DIV3, 0x02, 0x0c, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
363 	XOADC_CHAN(ATEST_5_DIV3, 0x02, 0x0d, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
364 	XOADC_CHAN(ATEST_6_DIV3, 0x02, 0x0e, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
365 	XOADC_CHAN(ATEST_7_DIV3, 0x02, 0x0f, IIO_VOLTAGE, 1, 3, SCALE_DEFAULT, AMUX_RSV1),
366 	{ }, /* Sentinel */
367 };
368 
369 /**
370  * struct pm8xxx_chan_info - ADC channel information
371  * @name: name of this channel
372  * @hwchan: pointer to hardware channel information (muxing & scaling settings)
373  * @calibration: whether to use absolute or ratiometric calibration
374  * @scale_fn_type: scaling function type
375  * @decimation: 0,1,2,3
376  * @amux_ip_rsv: ratiometric scale value if using ratiometric
377  * calibration: 0, 1, 2, 4, 5.
378  */
379 struct pm8xxx_chan_info {
380 	const char *name;
381 	const struct xoadc_channel *hwchan;
382 	enum vadc_calibration calibration;
383 	u8 decimation:2;
384 	u8 amux_ip_rsv:3;
385 };
386 
387 /**
388  * struct pm8xxx_xoadc - state container for the XOADC
389  * @dev: pointer to device
390  * @map: regmap to access registers
391  * @vref: reference voltage regulator
392  * characteristics of the channels, and sensible default settings
393  * @nchans: number of channels, configured by the device tree
394  * @chans: the channel information per-channel, configured by the device tree
395  * @iio_chans: IIO channel specifiers
396  * @graph: linear calibration parameters for absolute and
397  * ratiometric measurements
398  * @complete: completion to indicate end of conversion
399  * @lock: lock to restrict access to the hardware to one client at the time
400  */
401 struct pm8xxx_xoadc {
402 	struct device *dev;
403 	struct regmap *map;
404 	const struct xoadc_variant *variant;
405 	struct regulator *vref;
406 	unsigned int nchans;
407 	struct pm8xxx_chan_info *chans;
408 	struct iio_chan_spec *iio_chans;
409 	struct vadc_linear_graph graph[2];
410 	struct completion complete;
411 	struct mutex lock;
412 };
413 
414 static irqreturn_t pm8xxx_eoc_irq(int irq, void *d)
415 {
416 	struct iio_dev *indio_dev = d;
417 	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
418 
419 	complete(&adc->complete);
420 
421 	return IRQ_HANDLED;
422 }
423 
424 static struct pm8xxx_chan_info *
425 pm8xxx_get_channel(struct pm8xxx_xoadc *adc, u8 chan)
426 {
427 	int i;
428 
429 	for (i = 0; i < adc->nchans; i++) {
430 		struct pm8xxx_chan_info *ch = &adc->chans[i];
431 		if (ch->hwchan->amux_channel == chan)
432 			return ch;
433 	}
434 	return NULL;
435 }
436 
437 static int pm8xxx_read_channel_rsv(struct pm8xxx_xoadc *adc,
438 				   const struct pm8xxx_chan_info *ch,
439 				   u8 rsv, u16 *adc_code,
440 				   bool force_ratiometric)
441 {
442 	int ret;
443 	unsigned int val;
444 	u8 rsvmask, rsvval;
445 	u8 lsb, msb;
446 
447 	dev_dbg(adc->dev, "read channel \"%s\", amux %d, prescale/mux: %d, rsv %d\n",
448 		ch->name, ch->hwchan->amux_channel, ch->hwchan->pre_scale_mux, rsv);
449 
450 	mutex_lock(&adc->lock);
451 
452 	/* Mux in this channel */
453 	val = ch->hwchan->amux_channel << ADC_AMUX_SEL_SHIFT;
454 	val |= ch->hwchan->pre_scale_mux << ADC_AMUX_PREMUX_SHIFT;
455 	ret = regmap_write(adc->map, ADC_ARB_USRP_AMUX_CNTRL, val);
456 	if (ret)
457 		goto unlock;
458 
459 	/* Set up ratiometric scale value, mask off all bits except these */
460 	rsvmask = (ADC_ARB_USRP_RSV_RST | ADC_ARB_USRP_RSV_DTEST0 |
461 		   ADC_ARB_USRP_RSV_DTEST1 | ADC_ARB_USRP_RSV_OP);
462 	if (adc->variant->broken_ratiometric && !force_ratiometric) {
463 		/*
464 		 * Apparently the PM8058 has some kind of bug which is
465 		 * reflected in the vendor tree drivers/misc/pmix8058-xoadc.c
466 		 * which just hardcodes the RSV selector to SEL1 (0x20) for
467 		 * most cases and SEL0 (0x10) for the MUXOFF channel only.
468 		 * If we force ratiometric (currently only done when attempting
469 		 * to do ratiometric calibration) this doesn't seem to work
470 		 * very well and I suspect ratiometric conversion is simply
471 		 * broken or not supported on the PM8058.
472 		 *
473 		 * Maybe IO_SEL2 doesn't exist on PM8058 and bits 4 & 5 select
474 		 * the mode alone.
475 		 *
476 		 * Some PM8058 register documentation would be nice to get
477 		 * this right.
478 		 */
479 		if (ch->hwchan->amux_channel == PM8XXX_CHANNEL_MUXOFF)
480 			rsvval = ADC_ARB_USRP_RSV_IP_SEL0;
481 		else
482 			rsvval = ADC_ARB_USRP_RSV_IP_SEL1;
483 	} else {
484 		if (rsv == 0xff)
485 			rsvval = (ch->amux_ip_rsv << ADC_RSV_IP_SEL_SHIFT) |
486 				ADC_ARB_USRP_RSV_TRM;
487 		else
488 			rsvval = (rsv << ADC_RSV_IP_SEL_SHIFT) |
489 				ADC_ARB_USRP_RSV_TRM;
490 	}
491 
492 	ret = regmap_update_bits(adc->map,
493 				 ADC_ARB_USRP_RSV,
494 				 ~rsvmask,
495 				 rsvval);
496 	if (ret)
497 		goto unlock;
498 
499 	ret = regmap_write(adc->map, ADC_ARB_USRP_ANA_PARAM,
500 			   ADC_ARB_USRP_ANA_PARAM_DIS);
501 	if (ret)
502 		goto unlock;
503 
504 	/* Decimation factor */
505 	ret = regmap_write(adc->map, ADC_ARB_USRP_DIG_PARAM,
506 			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT0 |
507 			   ADC_ARB_USRP_DIG_PARAM_SEL_SHIFT1 |
508 			   ch->decimation << ADC_DIG_PARAM_DEC_SHIFT);
509 	if (ret)
510 		goto unlock;
511 
512 	ret = regmap_write(adc->map, ADC_ARB_USRP_ANA_PARAM,
513 			   ADC_ARB_USRP_ANA_PARAM_EN);
514 	if (ret)
515 		goto unlock;
516 
517 	/* Enable the arbiter, the Qualcomm code does it twice like this */
518 	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL,
519 			   ADC_ARB_USRP_CNTRL_EN_ARB);
520 	if (ret)
521 		goto unlock;
522 	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL,
523 			   ADC_ARB_USRP_CNTRL_EN_ARB);
524 	if (ret)
525 		goto unlock;
526 
527 
528 	/* Fire a request! */
529 	reinit_completion(&adc->complete);
530 	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL,
531 			   ADC_ARB_USRP_CNTRL_EN_ARB |
532 			   ADC_ARB_USRP_CNTRL_REQ);
533 	if (ret)
534 		goto unlock;
535 
536 	/* Next the interrupt occurs */
537 	ret = wait_for_completion_timeout(&adc->complete,
538 					  VADC_CONV_TIME_MAX_US);
539 	if (!ret) {
540 		dev_err(adc->dev, "conversion timed out\n");
541 		ret = -ETIMEDOUT;
542 		goto unlock;
543 	}
544 
545 	ret = regmap_read(adc->map, ADC_ARB_USRP_DATA0, &val);
546 	if (ret)
547 		goto unlock;
548 	lsb = val;
549 	ret = regmap_read(adc->map, ADC_ARB_USRP_DATA1, &val);
550 	if (ret)
551 		goto unlock;
552 	msb = val;
553 	*adc_code = (msb << 8) | lsb;
554 
555 	/* Turn off the ADC by setting the arbiter to 0 twice */
556 	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL, 0);
557 	if (ret)
558 		goto unlock;
559 	ret = regmap_write(adc->map, ADC_ARB_USRP_CNTRL, 0);
560 	if (ret)
561 		goto unlock;
562 
563 unlock:
564 	mutex_unlock(&adc->lock);
565 	return ret;
566 }
567 
568 static int pm8xxx_read_channel(struct pm8xxx_xoadc *adc,
569 			       const struct pm8xxx_chan_info *ch,
570 			       u16 *adc_code)
571 {
572 	/*
573 	 * Normally we just use the ratiometric scale value (RSV) predefined
574 	 * for the channel, but during calibration we need to modify this
575 	 * so this wrapper is a helper hiding the more complex version.
576 	 */
577 	return pm8xxx_read_channel_rsv(adc, ch, 0xff, adc_code, false);
578 }
579 
580 static int pm8xxx_calibrate_device(struct pm8xxx_xoadc *adc)
581 {
582 	const struct pm8xxx_chan_info *ch;
583 	u16 read_1250v;
584 	u16 read_0625v;
585 	u16 read_nomux_rsv5;
586 	u16 read_nomux_rsv4;
587 	int ret;
588 
589 	adc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;
590 	adc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE;
591 
592 	/* Common reference channel calibration */
593 	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_125V);
594 	if (!ch)
595 		return -ENODEV;
596 	ret = pm8xxx_read_channel(adc, ch, &read_1250v);
597 	if (ret) {
598 		dev_err(adc->dev, "could not read 1.25V reference channel\n");
599 		return -ENODEV;
600 	}
601 	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_INTERNAL);
602 	if (!ch)
603 		return -ENODEV;
604 	ret = pm8xxx_read_channel(adc, ch, &read_0625v);
605 	if (ret) {
606 		dev_err(adc->dev, "could not read 0.625V reference channel\n");
607 		return -ENODEV;
608 	}
609 	if (read_1250v == read_0625v) {
610 		dev_err(adc->dev, "read same ADC code for 1.25V and 0.625V\n");
611 		return -ENODEV;
612 	}
613 
614 	adc->graph[VADC_CALIB_ABSOLUTE].dy = read_1250v - read_0625v;
615 	adc->graph[VADC_CALIB_ABSOLUTE].gnd = read_0625v;
616 
617 	dev_info(adc->dev, "absolute calibration dx = %d uV, dy = %d units\n",
618 		 VADC_ABSOLUTE_RANGE_UV, adc->graph[VADC_CALIB_ABSOLUTE].dy);
619 
620 	/* Ratiometric calibration */
621 	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_MUXOFF);
622 	if (!ch)
623 		return -ENODEV;
624 	ret = pm8xxx_read_channel_rsv(adc, ch, AMUX_RSV5,
625 				      &read_nomux_rsv5, true);
626 	if (ret) {
627 		dev_err(adc->dev, "could not read MUXOFF reference channel\n");
628 		return -ENODEV;
629 	}
630 	ret = pm8xxx_read_channel_rsv(adc, ch, AMUX_RSV4,
631 				      &read_nomux_rsv4, true);
632 	if (ret) {
633 		dev_err(adc->dev, "could not read MUXOFF reference channel\n");
634 		return -ENODEV;
635 	}
636 	adc->graph[VADC_CALIB_RATIOMETRIC].dy =
637 		read_nomux_rsv5 - read_nomux_rsv4;
638 	adc->graph[VADC_CALIB_RATIOMETRIC].gnd = read_nomux_rsv4;
639 
640 	dev_info(adc->dev, "ratiometric calibration dx = %d, dy = %d units\n",
641 		 VADC_RATIOMETRIC_RANGE,
642 		 adc->graph[VADC_CALIB_RATIOMETRIC].dy);
643 
644 	return 0;
645 }
646 
647 static int pm8xxx_read_raw(struct iio_dev *indio_dev,
648 			   struct iio_chan_spec const *chan,
649 			   int *val, int *val2, long mask)
650 {
651 	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
652 	const struct pm8xxx_chan_info *ch;
653 	u16 adc_code;
654 	int ret;
655 
656 	switch (mask) {
657 	case IIO_CHAN_INFO_PROCESSED:
658 		ch = pm8xxx_get_channel(adc, chan->address);
659 		if (!ch) {
660 			dev_err(adc->dev, "no such channel %lu\n",
661 				chan->address);
662 			return -EINVAL;
663 		}
664 		ret = pm8xxx_read_channel(adc, ch, &adc_code);
665 		if (ret)
666 			return ret;
667 
668 		ret = qcom_vadc_scale(ch->hwchan->scale_fn_type,
669 				      &adc->graph[ch->calibration],
670 				      &ch->hwchan->prescale,
671 				      (ch->calibration == VADC_CALIB_ABSOLUTE),
672 				      adc_code, val);
673 		if (ret)
674 			return ret;
675 
676 		return IIO_VAL_INT;
677 	case IIO_CHAN_INFO_RAW:
678 		ch = pm8xxx_get_channel(adc, chan->address);
679 		if (!ch) {
680 			dev_err(adc->dev, "no such channel %lu\n",
681 				chan->address);
682 			return -EINVAL;
683 		}
684 		ret = pm8xxx_read_channel(adc, ch, &adc_code);
685 		if (ret)
686 			return ret;
687 
688 		*val = (int)adc_code;
689 		return IIO_VAL_INT;
690 	default:
691 		return -EINVAL;
692 	}
693 }
694 
695 static int pm8xxx_of_xlate(struct iio_dev *indio_dev,
696 			   const struct of_phandle_args *iiospec)
697 {
698 	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
699 	u8 pre_scale_mux;
700 	u8 amux_channel;
701 	unsigned int i;
702 
703 	/*
704 	 * First cell is prescaler or premux, second cell is analog
705 	 * mux.
706 	 */
707 	if (iiospec->args_count != 2) {
708 		dev_err(&indio_dev->dev, "wrong number of arguments for %pOFn need 2 got %d\n",
709 			iiospec->np,
710 			iiospec->args_count);
711 		return -EINVAL;
712 	}
713 	pre_scale_mux = (u8)iiospec->args[0];
714 	amux_channel = (u8)iiospec->args[1];
715 	dev_dbg(&indio_dev->dev, "pre scale/mux: %02x, amux: %02x\n",
716 		pre_scale_mux, amux_channel);
717 
718 	/* We need to match exactly on the prescale/premux and channel */
719 	for (i = 0; i < adc->nchans; i++)
720 		if (adc->chans[i].hwchan->pre_scale_mux == pre_scale_mux &&
721 		    adc->chans[i].hwchan->amux_channel == amux_channel)
722 			return i;
723 
724 	return -EINVAL;
725 }
726 
727 static const struct iio_info pm8xxx_xoadc_info = {
728 	.of_xlate = pm8xxx_of_xlate,
729 	.read_raw = pm8xxx_read_raw,
730 };
731 
732 static int pm8xxx_xoadc_parse_channel(struct device *dev,
733 				      struct device_node *np,
734 				      const struct xoadc_channel *hw_channels,
735 				      struct iio_chan_spec *iio_chan,
736 				      struct pm8xxx_chan_info *ch)
737 {
738 	const char *name = np->name;
739 	const struct xoadc_channel *hwchan;
740 	u32 pre_scale_mux, amux_channel;
741 	u32 rsv, dec;
742 	int ret;
743 	int chid;
744 
745 	ret = of_property_read_u32_index(np, "reg", 0, &pre_scale_mux);
746 	if (ret) {
747 		dev_err(dev, "invalid pre scale/mux number %s\n", name);
748 		return ret;
749 	}
750 	ret = of_property_read_u32_index(np, "reg", 1, &amux_channel);
751 	if (ret) {
752 		dev_err(dev, "invalid amux channel number %s\n", name);
753 		return ret;
754 	}
755 
756 	/* Find the right channel setting */
757 	chid = 0;
758 	hwchan = &hw_channels[0];
759 	while (hwchan && hwchan->datasheet_name) {
760 		if (hwchan->pre_scale_mux == pre_scale_mux &&
761 		    hwchan->amux_channel == amux_channel)
762 			break;
763 		hwchan++;
764 		chid++;
765 	}
766 	/* The sentinel does not have a name assigned */
767 	if (!hwchan->datasheet_name) {
768 		dev_err(dev, "could not locate channel %02x/%02x\n",
769 			pre_scale_mux, amux_channel);
770 		return -EINVAL;
771 	}
772 	ch->name = name;
773 	ch->hwchan = hwchan;
774 	/* Everyone seems to use absolute calibration except in special cases */
775 	ch->calibration = VADC_CALIB_ABSOLUTE;
776 	/* Everyone seems to use default ("type 2") decimation */
777 	ch->decimation = VADC_DEF_DECIMATION;
778 
779 	if (!of_property_read_u32(np, "qcom,ratiometric", &rsv)) {
780 		ch->calibration = VADC_CALIB_RATIOMETRIC;
781 		if (rsv > XOADC_RSV_MAX) {
782 			dev_err(dev, "%s too large RSV value %d\n", name, rsv);
783 			return -EINVAL;
784 		}
785 		if (rsv == AMUX_RSV3) {
786 			dev_err(dev, "%s invalid RSV value %d\n", name, rsv);
787 			return -EINVAL;
788 		}
789 	}
790 
791 	/* Optional decimation, if omitted we use the default */
792 	ret = of_property_read_u32(np, "qcom,decimation", &dec);
793 	if (!ret) {
794 		ret = qcom_vadc_decimation_from_dt(dec);
795 		if (ret < 0) {
796 			dev_err(dev, "%s invalid decimation %d\n",
797 				name, dec);
798 			return ret;
799 		}
800 		ch->decimation = ret;
801 	}
802 
803 	iio_chan->channel = chid;
804 	iio_chan->address = hwchan->amux_channel;
805 	iio_chan->datasheet_name = hwchan->datasheet_name;
806 	iio_chan->type = hwchan->type;
807 	/* All channels are raw or processed */
808 	iio_chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
809 		BIT(IIO_CHAN_INFO_PROCESSED);
810 	iio_chan->indexed = 1;
811 
812 	dev_dbg(dev, "channel [PRESCALE/MUX: %02x AMUX: %02x] \"%s\" "
813 		"ref voltage: %d, decimation %d "
814 		"prescale %d/%d, scale function %d\n",
815 		hwchan->pre_scale_mux, hwchan->amux_channel, ch->name,
816 		ch->amux_ip_rsv, ch->decimation, hwchan->prescale.num,
817 		hwchan->prescale.den, hwchan->scale_fn_type);
818 
819 	return 0;
820 }
821 
822 static int pm8xxx_xoadc_parse_channels(struct pm8xxx_xoadc *adc,
823 				       struct device_node *np)
824 {
825 	struct device_node *child;
826 	struct pm8xxx_chan_info *ch;
827 	int ret;
828 	int i;
829 
830 	adc->nchans = of_get_available_child_count(np);
831 	if (!adc->nchans) {
832 		dev_err(adc->dev, "no channel children\n");
833 		return -ENODEV;
834 	}
835 	dev_dbg(adc->dev, "found %d ADC channels\n", adc->nchans);
836 
837 	adc->iio_chans = devm_kcalloc(adc->dev, adc->nchans,
838 				      sizeof(*adc->iio_chans), GFP_KERNEL);
839 	if (!adc->iio_chans)
840 		return -ENOMEM;
841 
842 	adc->chans = devm_kcalloc(adc->dev, adc->nchans,
843 				  sizeof(*adc->chans), GFP_KERNEL);
844 	if (!adc->chans)
845 		return -ENOMEM;
846 
847 	i = 0;
848 	for_each_available_child_of_node(np, child) {
849 		ch = &adc->chans[i];
850 		ret = pm8xxx_xoadc_parse_channel(adc->dev, child,
851 						 adc->variant->channels,
852 						 &adc->iio_chans[i],
853 						 ch);
854 		if (ret) {
855 			of_node_put(child);
856 			return ret;
857 		}
858 		i++;
859 	}
860 
861 	/* Check for required channels */
862 	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_125V);
863 	if (!ch) {
864 		dev_err(adc->dev, "missing 1.25V reference channel\n");
865 		return -ENODEV;
866 	}
867 	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_INTERNAL);
868 	if (!ch) {
869 		dev_err(adc->dev, "missing 0.625V reference channel\n");
870 		return -ENODEV;
871 	}
872 	ch = pm8xxx_get_channel(adc, PM8XXX_CHANNEL_MUXOFF);
873 	if (!ch) {
874 		dev_err(adc->dev, "missing MUXOFF reference channel\n");
875 		return -ENODEV;
876 	}
877 
878 	return 0;
879 }
880 
881 static int pm8xxx_xoadc_probe(struct platform_device *pdev)
882 {
883 	const struct xoadc_variant *variant;
884 	struct pm8xxx_xoadc *adc;
885 	struct iio_dev *indio_dev;
886 	struct device_node *np = pdev->dev.of_node;
887 	struct regmap *map;
888 	struct device *dev = &pdev->dev;
889 	int ret;
890 
891 	variant = of_device_get_match_data(dev);
892 	if (!variant)
893 		return -ENODEV;
894 
895 	indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
896 	if (!indio_dev)
897 		return -ENOMEM;
898 	platform_set_drvdata(pdev, indio_dev);
899 
900 	adc = iio_priv(indio_dev);
901 	adc->dev = dev;
902 	adc->variant = variant;
903 	init_completion(&adc->complete);
904 	mutex_init(&adc->lock);
905 
906 	ret = pm8xxx_xoadc_parse_channels(adc, np);
907 	if (ret)
908 		return ret;
909 
910 	map = dev_get_regmap(dev->parent, NULL);
911 	if (!map) {
912 		dev_err(dev, "parent regmap unavailable.\n");
913 		return -ENXIO;
914 	}
915 	adc->map = map;
916 
917 	/* Bring up regulator */
918 	adc->vref = devm_regulator_get(dev, "xoadc-ref");
919 	if (IS_ERR(adc->vref)) {
920 		dev_err(dev, "failed to get XOADC VREF regulator\n");
921 		return PTR_ERR(adc->vref);
922 	}
923 	ret = regulator_enable(adc->vref);
924 	if (ret) {
925 		dev_err(dev, "failed to enable XOADC VREF regulator\n");
926 		return ret;
927 	}
928 
929 	ret = devm_request_threaded_irq(dev, platform_get_irq(pdev, 0),
930 			pm8xxx_eoc_irq, NULL, 0, variant->name, indio_dev);
931 	if (ret) {
932 		dev_err(dev, "unable to request IRQ\n");
933 		goto out_disable_vref;
934 	}
935 
936 	indio_dev->dev.parent = dev;
937 	indio_dev->dev.of_node = np;
938 	indio_dev->name = variant->name;
939 	indio_dev->modes = INDIO_DIRECT_MODE;
940 	indio_dev->info = &pm8xxx_xoadc_info;
941 	indio_dev->channels = adc->iio_chans;
942 	indio_dev->num_channels = adc->nchans;
943 
944 	ret = iio_device_register(indio_dev);
945 	if (ret)
946 		goto out_disable_vref;
947 
948 	ret = pm8xxx_calibrate_device(adc);
949 	if (ret)
950 		goto out_unreg_device;
951 
952 	dev_info(dev, "%s XOADC driver enabled\n", variant->name);
953 
954 	return 0;
955 
956 out_unreg_device:
957 	iio_device_unregister(indio_dev);
958 out_disable_vref:
959 	regulator_disable(adc->vref);
960 
961 	return ret;
962 }
963 
964 static int pm8xxx_xoadc_remove(struct platform_device *pdev)
965 {
966 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
967 	struct pm8xxx_xoadc *adc = iio_priv(indio_dev);
968 
969 	iio_device_unregister(indio_dev);
970 
971 	regulator_disable(adc->vref);
972 
973 	return 0;
974 }
975 
976 static const struct xoadc_variant pm8018_variant = {
977 	.name = "PM8018-XOADC",
978 	.channels = pm8018_xoadc_channels,
979 };
980 
981 static const struct xoadc_variant pm8038_variant = {
982 	.name = "PM8038-XOADC",
983 	.channels = pm8038_xoadc_channels,
984 };
985 
986 static const struct xoadc_variant pm8058_variant = {
987 	.name = "PM8058-XOADC",
988 	.channels = pm8058_xoadc_channels,
989 	.broken_ratiometric = true,
990 	.prescaling = true,
991 };
992 
993 static const struct xoadc_variant pm8921_variant = {
994 	.name = "PM8921-XOADC",
995 	.channels = pm8921_xoadc_channels,
996 	.second_level_mux = true,
997 };
998 
999 static const struct of_device_id pm8xxx_xoadc_id_table[] = {
1000 	{
1001 		.compatible = "qcom,pm8018-adc",
1002 		.data = &pm8018_variant,
1003 	},
1004 	{
1005 		.compatible = "qcom,pm8038-adc",
1006 		.data = &pm8038_variant,
1007 	},
1008 	{
1009 		.compatible = "qcom,pm8058-adc",
1010 		.data = &pm8058_variant,
1011 	},
1012 	{
1013 		.compatible = "qcom,pm8921-adc",
1014 		.data = &pm8921_variant,
1015 	},
1016 	{ },
1017 };
1018 MODULE_DEVICE_TABLE(of, pm8xxx_xoadc_id_table);
1019 
1020 static struct platform_driver pm8xxx_xoadc_driver = {
1021 	.driver		= {
1022 		.name	= "pm8xxx-adc",
1023 		.of_match_table = pm8xxx_xoadc_id_table,
1024 	},
1025 	.probe		= pm8xxx_xoadc_probe,
1026 	.remove		= pm8xxx_xoadc_remove,
1027 };
1028 module_platform_driver(pm8xxx_xoadc_driver);
1029 
1030 MODULE_DESCRIPTION("PM8xxx XOADC driver");
1031 MODULE_LICENSE("GPL v2");
1032 MODULE_ALIAS("platform:pm8xxx-xoadc");
1033