hwmon: pm8921-adc: Add sysfs interface

-Add sysfs interface to read PM8921 HK/XOADC
and thermistor temperature measurements mapped
through MPP's.
-Move PM8921 ADC from directory /drivers/mfd to
/drivers/hwmon for userspace clients to read ADC
through hwmon.

CRs-Fixed: 302365
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>

Conflicts:

	drivers/mfd/Kconfig
diff --git a/drivers/hwmon/msmproc_adc.c b/drivers/hwmon/msmproc_adc.c
new file mode 100644
index 0000000..a0ee748
--- /dev/null
+++ b/drivers/hwmon/msmproc_adc.c
@@ -0,0 +1,614 @@
+/*
+ * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/mfd/pm8xxx/pm8921-adc.h>
+#define KELVINMIL_DEGMIL	273160
+
+static const struct pm8921_adc_map_pt adcmap_batttherm[] = {
+	{41001,	-30},
+	{40017,	-20},
+	{38721,	-10},
+	{37186,	  0},
+	{35554,	 10},
+	{33980,	 20},
+	{33253,	 25},
+	{32580,	 30},
+	{31412,	 40},
+	{30481,	 50},
+	{29759,	 60},
+	{29209,	 70},
+	{28794,	 80}
+};
+
+static const struct pm8921_adc_map_pt adcmap_btm_threshold[] = {
+	{-30,	41001},
+	{-20,	40017},
+	{-10,	38721},
+	{0,	37186},
+	{10,	35554},
+	{11,	35392},
+	{12,	35230},
+	{13,	35070},
+	{14,	34910},
+	{15,	34751},
+	{16,	34594},
+	{17,	34438},
+	{18,	34284},
+	{19,	34131},
+	{20,	33980},
+	{21,	33830},
+	{22,	33683},
+	{23,	33538},
+	{24,	33394},
+	{25,	33253},
+	{26,	33114},
+	{27,	32977},
+	{28,	32842},
+	{29,	32710},
+	{30,	32580},
+	{31,	32452},
+	{32,	32327},
+	{33,	32204},
+	{34,	32084},
+	{35,	31966},
+	{36,	31850},
+	{37,	31737},
+	{38,	31627},
+	{39,	31518},
+	{40,	31412},
+	{41,	31309},
+	{42,	31208},
+	{43,	31109},
+	{44,	31013},
+	{45,	30918},
+	{46,	30827},
+	{47,	30737},
+	{48,	30649},
+	{49,	30564},
+	{50,	30481},
+	{51,	30400},
+	{52,	30321},
+	{53,	30244},
+	{54,	30169},
+	{55,	30096},
+	{56,	30025},
+	{57,	29956},
+	{58,	29889},
+	{59,	29823},
+	{60,	29759},
+	{61,	29697},
+	{62,	29637},
+	{63,	29578},
+	{64,	29521},
+	{65,	29465},
+	{66,	29411},
+	{67,	29359},
+	{68,	29308},
+	{69,	29258},
+	{70,	29209},
+	{71,	29162},
+	{72,	29117},
+	{73,	29072},
+	{74,	29029},
+	{75,	28987},
+	{76,	28946},
+	{77,	28906},
+	{78,	28868},
+	{79,	28830},
+	{80,	28794}
+};
+
+static const struct pm8921_adc_map_pt adcmap_pa_therm[] = {
+	{41350,	-30},
+	{41282,	-29},
+	{41211,	-28},
+	{41137,	-27},
+	{41060,	-26},
+	{40980,	-25},
+	{40897,	-24},
+	{40811,	-23},
+	{40721,	-22},
+	{40629,	-21},
+	{40533,	-20},
+	{40434,	-19},
+	{40331,	-18},
+	{40226,	-17},
+	{40116,	-16},
+	{40004,	-15},
+	{39888,	-14},
+	{39769,	-13},
+	{39647,	-12},
+	{39521,	-11},
+	{39392,	-10},
+	{39260,	-9},
+	{39124,	-8},
+	{38986,	-7},
+	{38845,	-6},
+	{38700,	-5},
+	{38553,	-4},
+	{38403,	-3},
+	{38250,	-2},
+	{38094,	-1},
+	{37936,	0},
+	{37776,	1},
+	{37613,	2},
+	{37448,	3},
+	{37281,	4},
+	{37112,	5},
+	{36942,	6},
+	{36770,	7},
+	{36596,	8},
+	{36421,	9},
+	{36245,	10},
+	{36068,	11},
+	{35890,	12},
+	{35712,	13},
+	{35532,	14},
+	{35353,	15},
+	{35173,	16},
+	{34993,	17},
+	{34813,	18},
+	{34634,	19},
+	{34455,	20},
+	{34276,	21},
+	{34098,	22},
+	{33921,	23},
+	{33745,	24},
+	{33569,	25},
+	{33395,	26},
+	{33223,	27},
+	{33051,	28},
+	{32881,	29},
+	{32713,	30},
+	{32547,	31},
+	{32382,	32},
+	{32219,	33},
+	{32058,	34},
+	{31899,	35},
+	{31743,	36},
+	{31588,	37},
+	{31436,	38},
+	{31285,	39},
+	{31138,	40},
+	{30992,	41},
+	{30849,	42},
+	{30708,	43},
+	{30570,	44},
+	{30434,	45},
+	{30300,	46},
+	{30169,	47},
+	{30041,	48},
+	{29915,	49},
+	{29791,	50},
+	{29670,	51},
+	{29551,	52},
+	{29435,	53},
+	{29321,	54},
+	{29210,	55},
+	{29101,	56},
+	{28994,	57},
+	{28890,	58},
+	{28788,	59},
+	{28688,	60},
+	{28590,	61},
+	{28495,	62},
+	{28402,	63},
+	{28311,	64},
+	{28222,	65},
+	{28136,	66},
+	{28051,	67},
+	{27968,	68},
+	{27888,	69},
+	{27809,	70},
+	{27732,	71},
+	{27658,	72},
+	{27584,	73},
+	{27513,	74},
+	{27444,	75},
+	{27376,	76},
+	{27310,	77},
+	{27245,	78},
+	{27183,	79},
+	{27121,	80},
+	{27062,	81},
+	{27004,	82},
+	{26947,	83},
+	{26892,	84},
+	{26838,	85},
+	{26785,	86},
+	{26734,	87},
+	{26684,	88},
+	{26636,	89},
+	{26588,	90}
+};
+
+static const struct pm8921_adc_map_pt adcmap_ntcg_104ef_104fb[] = {
+	{696483,	-40960},
+	{649148,	-39936},
+	{605368,	-38912},
+	{564809,	-37888},
+	{527215,	-36864},
+	{492322,	-35840},
+	{460007,	-34816},
+	{429982,	-33792},
+	{402099,	-32768},
+	{376192,	-31744},
+	{352075,	-30720},
+	{329714,	-29696},
+	{308876,	-28672},
+	{289480,	-27648},
+	{271417,	-26624},
+	{254574,	-25600},
+	{238903,	-24576},
+	{224276,	-23552},
+	{210631,	-22528},
+	{197896,	-21504},
+	{186007,	-20480},
+	{174899,	-19456},
+	{164521,	-18432},
+	{154818,	-17408},
+	{145744,	-16384},
+	{137265,	-15360},
+	{129307,	-14336},
+	{121866,	-13312},
+	{114896,	-12288},
+	{108365,	-11264},
+	{102252,	-10240},
+	{96499,		-9216},
+	{91111,		-8192},
+	{86055,		-7168},
+	{81308,		-6144},
+	{76857,		-5120},
+	{72660,		-4096},
+	{68722,		-3072},
+	{65020,		-2048},
+	{61538,		-1024},
+	{58261,		0},
+	{55177,		1024},
+	{52274,		2048},
+	{49538,		3072},
+	{46962,		4096},
+	{44531,		5120},
+	{42243,		6144},
+	{40083,		7168},
+	{38045,		8192},
+	{36122,		9216},
+	{34308,		10240},
+	{32592,		11264},
+	{30972,		12288},
+	{29442,		13312},
+	{27995,		14336},
+	{26624,		15360},
+	{25333,		16384},
+	{24109,		17408},
+	{22951,		18432},
+	{21854,		19456},
+	{20807,		20480},
+	{19831,		21504},
+	{18899,		22528},
+	{18016,		23552},
+	{17178,		24576},
+	{16384,		25600},
+	{15631,		26624},
+	{14916,		27648},
+	{14237,		28672},
+	{13593,		29696},
+	{12976,		30720},
+	{12400,		31744},
+	{11848,		32768},
+	{11324,		33792},
+	{10825,		34816},
+	{10354,		35840},
+	{9900,		36864},
+	{9471,		37888},
+	{9062,		38912},
+	{8674,		39936},
+	{8306,		40960},
+	{7951,		41984},
+	{7616,		43008},
+	{7296,		44032},
+	{6991,		45056},
+	{6701,		46080},
+	{6424,		47104},
+	{6160,		48128},
+	{5908,		49152},
+	{5667,		50176},
+	{5439,		51200},
+	{5219,		52224},
+	{5010,		53248},
+	{4810,		54272},
+	{4619,		55296},
+	{4440,		56320},
+	{4263,		57344},
+	{4097,		58368},
+	{3938,		59392},
+	{3785,		60416},
+	{3637,		61440},
+	{3501,		62464},
+	{3368,		63488},
+	{3240,		64512},
+	{3118,		65536},
+	{2998,		66560},
+	{2889,		67584},
+	{2782,		68608},
+	{2680,		69632},
+	{2581,		70656},
+	{2490,		71680},
+	{2397,		72704},
+	{2310,		73728},
+	{2227,		74752},
+	{2147,		75776},
+	{2064,		76800},
+	{1998,		77824},
+	{1927,		78848},
+	{1860,		79872},
+	{1795,		80896},
+	{1736,		81920},
+	{1673,		82944},
+	{1615,		83968},
+	{1560,		84992},
+	{1507,		86016},
+	{1456,		87040},
+	{1407,		88064},
+	{1360,		89088},
+	{1314,		90112},
+	{1271,		91136},
+	{1228,		92160},
+	{1189,		93184},
+	{1150,		94208},
+	{1112,		95232},
+	{1076,		96256},
+	{1042,		97280},
+	{1008,		98304},
+	{976,		99328},
+	{945,		100352},
+	{915,		101376},
+	{886,		102400},
+	{859,		103424},
+	{832,		104448},
+	{807,		105472},
+	{782,		106496},
+	{756,		107520},
+	{735,		108544},
+	{712,		109568},
+	{691,		110592},
+	{670,		111616},
+	{650,		112640},
+	{631,		113664},
+	{612,		114688},
+	{594,		115712},
+	{577,		116736},
+	{560,		117760},
+	{544,		118784},
+	{528,		119808},
+	{513,		120832},
+	{498,		121856},
+	{483,		122880},
+	{470,		123904},
+	{457,		124928},
+	{444,		125952},
+	{431,		126976},
+	{419,		128000}
+};
+
+static int32_t pm8921_adc_map_linear(const struct pm8921_adc_map_pt *pts,
+		uint32_t tablesize, int32_t input, int64_t *output)
+{
+	bool descending = 1;
+	uint32_t i = 0;
+
+	if ((pts == NULL) || (output == NULL))
+		return -EINVAL;
+
+	/* Check if table is descending or ascending */
+	if (tablesize > 1) {
+		if (pts[0].x < pts[1].x)
+			descending = 0;
+	}
+
+	while (i < tablesize) {
+		if ((descending == 1) && (pts[i].x < input)) {
+			/* table entry is less than measured
+				value and table is descending, stop */
+			break;
+		} else if ((descending == 0) &&
+				(pts[i].x > input)) {
+			/* table entry is greater than measured
+				value and table is ascending, stop */
+			break;
+		} else {
+			i++;
+		}
+	}
+
+	if (i == 0)
+		*output = pts[0].y;
+	else if (i == tablesize)
+		*output = pts[tablesize-1].y;
+	else {
+		/* result is between search_index and search_index-1 */
+		/* interpolate linearly */
+		*output = (((int32_t) ((pts[i].y - pts[i-1].y)*
+			(input - pts[i-1].x))/
+			(pts[i].x - pts[i-1].x))+
+			pts[i-1].y);
+	}
+
+	return 0;
+}
+
+int32_t pm8921_adc_scale_default(int32_t adc_code,
+		const struct pm8921_adc_properties *adc_properties,
+		const struct pm8921_adc_chan_properties *chan_properties,
+		struct pm8921_adc_chan_result *adc_chan_result)
+{
+	bool negative_rawfromoffset = 0;
+	int32_t rawfromoffset = 0;
+
+	if (!chan_properties || !chan_properties->offset_gain_numerator ||
+		!chan_properties->offset_gain_denominator || !adc_properties
+		|| !adc_chan_result)
+		return -EINVAL;
+
+	rawfromoffset = adc_code -
+			chan_properties->adc_graph[ADC_CALIB_ABSOLUTE].offset;
+
+	adc_chan_result->adc_code = adc_code;
+	if (rawfromoffset < 0) {
+		if (adc_properties->bipolar) {
+			rawfromoffset = -rawfromoffset;
+			negative_rawfromoffset = 1;
+		} else {
+			rawfromoffset = 0;
+		}
+	}
+
+	if (rawfromoffset >= 1 << adc_properties->bitresolution)
+		rawfromoffset = (1 << adc_properties->bitresolution) - 1;
+
+	adc_chan_result->measurement = (int64_t)rawfromoffset *
+		chan_properties->adc_graph[ADC_CALIB_ABSOLUTE].dx *
+				chan_properties->offset_gain_denominator;
+
+	/* do_div only perform positive integer division! */
+	do_div(adc_chan_result->measurement,
+		chan_properties->adc_graph[ADC_CALIB_ABSOLUTE].dy *
+				chan_properties->offset_gain_numerator);
+
+	if (negative_rawfromoffset)
+		adc_chan_result->measurement = -adc_chan_result->measurement;
+
+	/* Note: adc_chan_result->measurement is in the unit of
+	 * adc_properties.adc_reference. For generic channel processing,
+	 * channel measurement is a scale/ratio relative to the adc
+	 * reference input */
+	adc_chan_result->physical = (int32_t) adc_chan_result->measurement;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm8921_adc_scale_default);
+
+int32_t pm8921_adc_scale_batt_therm(int32_t adc_code,
+		const struct pm8921_adc_properties *adc_properties,
+		const struct pm8921_adc_chan_properties *chan_properties,
+		struct pm8921_adc_chan_result *adc_chan_result)
+{
+	/* convert mV ---> degC using the table */
+	return pm8921_adc_map_linear(
+			adcmap_batttherm,
+			ARRAY_SIZE(adcmap_batttherm),
+			adc_code,
+			&adc_chan_result->physical);
+}
+EXPORT_SYMBOL_GPL(pm8921_adc_scale_batt_therm);
+
+int32_t pm8921_adc_scale_pa_therm(int32_t adc_code,
+		const struct pm8921_adc_properties *adc_properties,
+		const struct pm8921_adc_chan_properties *chan_properties,
+		struct pm8921_adc_chan_result *adc_chan_result)
+{
+	/* convert mV ---> degC using the table */
+	return pm8921_adc_map_linear(
+			adcmap_pa_therm,
+			ARRAY_SIZE(adcmap_pa_therm),
+			adc_code,
+			&adc_chan_result->physical);
+}
+EXPORT_SYMBOL_GPL(pm8921_adc_scale_pa_therm);
+
+int32_t pm8921_adc_scale_pmic_therm(int32_t adc_code,
+		const struct pm8921_adc_properties *adc_properties,
+		const struct pm8921_adc_chan_properties *chan_properties,
+		struct pm8921_adc_chan_result *adc_chan_result)
+{
+	int32_t rawfromoffset;
+
+	if (!chan_properties || !chan_properties->offset_gain_numerator ||
+		!chan_properties->offset_gain_denominator || !adc_properties
+		|| !adc_chan_result)
+		return -EINVAL;
+
+	adc_chan_result->adc_code = adc_code;
+	rawfromoffset = adc_code -
+			chan_properties->adc_graph[ADC_CALIB_ABSOLUTE].offset;
+	if (rawfromoffset > 0) {
+		if (rawfromoffset >= 1 << adc_properties->bitresolution)
+			rawfromoffset = (1 << adc_properties->bitresolution)
+									- 1;
+		/* 2mV/K */
+		adc_chan_result->measurement = (int64_t)rawfromoffset*
+			chan_properties->adc_graph[ADC_CALIB_ABSOLUTE].dx *
+			chan_properties->offset_gain_denominator * 1000;
+
+		do_div(adc_chan_result->measurement,
+			chan_properties->adc_graph[ADC_CALIB_ABSOLUTE].dy *
+			chan_properties->offset_gain_numerator*2);
+	} else {
+		adc_chan_result->measurement = 0;
+	}
+	/* Note: adc_chan_result->measurement is in the unit of
+		adc_properties.adc_reference */
+	adc_chan_result->physical = (int32_t)adc_chan_result->measurement;
+	/* Change to .001 deg C */
+	adc_chan_result->physical -= KELVINMIL_DEGMIL;
+	adc_chan_result->measurement <<= 1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm8921_adc_scale_pmic_therm);
+
+/* Scales the ADC code to 0.001 degrees C using the map
+ * table for the XO thermistor.
+ */
+int32_t pm8921_adc_tdkntcg_therm(int32_t adc_code,
+		const struct pm8921_adc_properties *adc_properties,
+		const struct pm8921_adc_chan_properties *chan_properties,
+		struct pm8921_adc_chan_result *adc_chan_result)
+{
+	int32_t rt_r25;
+	int32_t offset = chan_properties->adc_graph[ADC_CALIB_ABSOLUTE].offset;
+
+	rt_r25 = adc_code - offset;
+
+	pm8921_adc_map_linear(adcmap_ntcg_104ef_104fb,
+		ARRAY_SIZE(adcmap_ntcg_104ef_104fb),
+		rt_r25, &adc_chan_result->physical);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm8921_adc_tdkntcg_therm);
+
+int32_t pm8921_adc_batt_scaler(struct pm8921_adc_arb_btm_param *btm_param)
+{
+	int rc;
+
+	rc = pm8921_adc_map_linear(
+		adcmap_btm_threshold,
+		ARRAY_SIZE(adcmap_btm_threshold),
+		btm_param->low_thr_temp,
+		&btm_param->low_thr_voltage);
+
+	if (!rc) {
+		rc = pm8921_adc_map_linear(
+			adcmap_btm_threshold,
+			ARRAY_SIZE(adcmap_btm_threshold),
+			btm_param->high_thr_temp,
+			&btm_param->high_thr_voltage);
+	}
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(pm8921_adc_batt_scaler);