hwmon: qpnp-adc: Add PMIC 2.0 ADC bringup fixes

VADC/IADC peripheral is supported from PMIC 2.0 onwards.
Add version check to allow VADC/IADC reads if the
version is supported. Add probe defereal api for clients
who need to know if the ADC driver is ready. There is a
bug where the completion is not initialized. Fix it
by initializing it. Add support to disable the peripheral
after the ADC is read and enable it before starting a
conversion.

Add scaling functions to support reading the die temperature,
XO_THERM, batt_therm and batt_id. Add the ratiometric
calibration routine that uses the vref/gnd for calibration.
The ratiometric calibration is used for calibrating xo_therm,
batt_therm, batt_id.

Update the gain value used for calibration on the IADC
peripheral. PMIC 2.0 IADC peripheral uses 17.857mV instead
of 25mV for its gain calibration.

Change-Id: I2427a0106920557e95fa630554a26b974e4e4e39
Signed-off-by: Siddartha Mohanadoss <smohanad@codeaurora.org>
diff --git a/drivers/hwmon/qpnp-adc-common.c b/drivers/hwmon/qpnp-adc-common.c
index c122270..f908181 100644
--- a/drivers/hwmon/qpnp-adc-common.c
+++ b/drivers/hwmon/qpnp-adc-common.c
@@ -26,6 +26,7 @@
 #include <linux/spmi.h>
 #include <linux/of_irq.h>
 #include <linux/interrupt.h>
+#include <linux/completion.h>
 #include <linux/qpnp/qpnp-adc.h>
 #include <linux/platform_device.h>
 
@@ -33,6 +34,491 @@
 #define QPNP_VADC_MIN_ADC_CODE			0x6000
 /* Max ADC code represents full-scale range of 1.8V */
 #define QPNP_VADC_MAX_ADC_CODE			0xA800
+#define KELVINMIL_DEGMIL	273160
+
+/* Units for temperature below (on x axis) is in 0.1DegC as
+   required by the battery driver. Note the resolution used
+   here to compute the table was done for DegC to milli-volts.
+   In consideration to limit the size of the table for the given
+   temperature range below, the result is linearly interpolated
+   and provided to the battery driver in the units desired for
+   their framework which is 0.1DegC. True resolution of 0.1DegC
+   will result in the below table size to increase by 10 times */
+static const struct qpnp_vadc_map_pt adcmap_btm_threshold[] = {
+	{-300,	1642},
+	{-200,	1544},
+	{-100,	1414},
+	{0,	1260},
+	{10,	1244},
+	{20,	1228},
+	{30,	1212},
+	{40,	1195},
+	{50,	1179},
+	{60,	1162},
+	{70,	1146},
+	{80,	1129},
+	{90,	1113},
+	{100,	1097},
+	{110,	1080},
+	{120,	1064},
+	{130,	1048},
+	{140,	1032},
+	{150,	1016},
+	{160,	1000},
+	{170,	985},
+	{180,	969},
+	{190,	954},
+	{200,	939},
+	{210,	924},
+	{220,	909},
+	{230,	894},
+	{240,	880},
+	{250,	866},
+	{260,	852},
+	{270,	838},
+	{280,	824},
+	{290,	811},
+	{300,	798},
+	{310,	785},
+	{320,	773},
+	{330,	760},
+	{340,	748},
+	{350,	736},
+	{360,	725},
+	{370,	713},
+	{380,	702},
+	{390,	691},
+	{400,	681},
+	{410,	670},
+	{420,	660},
+	{430,	650},
+	{440,	640},
+	{450,	631},
+	{460,	622},
+	{470,	613},
+	{480,	604},
+	{490,	595},
+	{500,	587},
+	{510,	579},
+	{520,	571},
+	{530,	563},
+	{540,	556},
+	{550,	548},
+	{560,	541},
+	{570,	534},
+	{580,	527},
+	{590,	521},
+	{600,	514},
+	{610,	508},
+	{620,	502},
+	{630,	496},
+	{640,	490},
+	{650,	485},
+	{660,	281},
+	{670,	274},
+	{680,	267},
+	{690,	260},
+	{700,	254},
+	{710,	247},
+	{720,	241},
+	{730,	235},
+	{740,	229},
+	{750,	224},
+	{760,	218},
+	{770,	213},
+	{780,	208},
+	{790,	203}
+};
+
+static const struct qpnp_vadc_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 qpnp_adc_map_linear(const struct qpnp_vadc_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;
+}
+
+static int32_t qpnp_adc_map_batt_therm(const struct qpnp_vadc_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].y < pts[1].y)
+			descending = 0;
+	}
+
+	while (i < tablesize) {
+		if ((descending == 1) && (pts[i].y < input)) {
+			/* table entry is less than measured
+				value and table is descending, stop */
+			break;
+		} else if ((descending == 0) && (pts[i].y > input)) {
+			/* table entry is greater than measured
+				value and table is ascending, stop */
+			break;
+		} else {
+			i++;
+		}
+	}
+
+	if (i == 0) {
+		*output = pts[0].x;
+	} else if (i == tablesize) {
+		*output = pts[tablesize-1].x;
+	} else {
+		/* result is between search_index and search_index-1 */
+		/* interpolate linearly */
+		*output = (((int32_t) ((pts[i].x - pts[i-1].x)*
+			(input - pts[i-1].y))/
+			(pts[i].y - pts[i-1].y))+
+			pts[i-1].x);
+	}
+
+	return 0;
+}
+
+static int64_t qpnp_adc_scale_ratiometric_calib(int32_t adc_code,
+		const struct qpnp_adc_properties *adc_properties,
+		const struct qpnp_vadc_chan_properties *chan_properties)
+{
+	int64_t adc_voltage = 0;
+	bool negative_offset = 0;
+
+	if (!chan_properties || !chan_properties->offset_gain_numerator ||
+		!chan_properties->offset_gain_denominator || !adc_properties)
+		return -EINVAL;
+
+	adc_voltage = (adc_code -
+		chan_properties->adc_graph[CALIB_RATIOMETRIC].adc_gnd)
+		* adc_properties->adc_vdd_reference;
+	if (adc_voltage < 0) {
+		negative_offset = 1;
+		adc_voltage = -adc_voltage;
+	}
+	do_div(adc_voltage,
+		chan_properties->adc_graph[CALIB_RATIOMETRIC].dy);
+	if (negative_offset)
+		adc_voltage = -adc_voltage;
+
+	return adc_voltage;
+}
+
+int32_t qpnp_adc_scale_pmic_therm(int32_t adc_code,
+		const struct qpnp_adc_properties *adc_properties,
+		const struct qpnp_vadc_chan_properties *chan_properties,
+		struct qpnp_vadc_result *adc_chan_result)
+{
+	int64_t pmic_voltage = 0;
+	bool negative_offset = 0;
+
+	if (!chan_properties || !chan_properties->offset_gain_numerator ||
+		!chan_properties->offset_gain_denominator || !adc_properties
+		|| !adc_chan_result)
+		return -EINVAL;
+
+	pmic_voltage = (adc_code -
+		chan_properties->adc_graph[CALIB_ABSOLUTE].adc_gnd)
+		* chan_properties->adc_graph[CALIB_ABSOLUTE].dx;
+	if (pmic_voltage < 0) {
+		negative_offset = 1;
+		pmic_voltage = -pmic_voltage;
+	}
+	do_div(pmic_voltage,
+		chan_properties->adc_graph[CALIB_ABSOLUTE].dy);
+	if (negative_offset)
+		pmic_voltage = -pmic_voltage;
+	pmic_voltage += chan_properties->adc_graph[CALIB_ABSOLUTE].dx;
+
+	if (pmic_voltage > 0) {
+		/* 2mV/K */
+		adc_chan_result->measurement = pmic_voltage*
+			chan_properties->offset_gain_denominator;
+
+		do_div(adc_chan_result->measurement,
+			chan_properties->offset_gain_numerator * 2);
+	} else {
+		adc_chan_result->measurement = 0;
+	}
+	/* Change to .001 deg C */
+	adc_chan_result->measurement -= KELVINMIL_DEGMIL;
+	adc_chan_result->physical = (int32_t)adc_chan_result->measurement;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qpnp_adc_scale_pmic_therm);
+
+/* Scales the ADC code to 0.001 degrees C using the map
+ * table for the XO thermistor.
+ */
+int32_t qpnp_adc_tdkntcg_therm(int32_t adc_code,
+		const struct qpnp_adc_properties *adc_properties,
+		const struct qpnp_vadc_chan_properties *chan_properties,
+		struct qpnp_vadc_result *adc_chan_result)
+{
+	int64_t xo_thm = 0;
+
+	if (!chan_properties || !chan_properties->offset_gain_numerator ||
+		!chan_properties->offset_gain_denominator || !adc_properties
+		|| !adc_chan_result)
+		return -EINVAL;
+
+	xo_thm = qpnp_adc_scale_ratiometric_calib(adc_code,
+			adc_properties, chan_properties);
+	xo_thm <<= 4;
+	qpnp_adc_map_linear(adcmap_ntcg_104ef_104fb,
+		ARRAY_SIZE(adcmap_ntcg_104ef_104fb),
+		xo_thm, &adc_chan_result->physical);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qpnp_adc_tdkntcg_therm);
+
+int32_t qpnp_adc_scale_batt_therm(int32_t adc_code,
+		const struct qpnp_adc_properties *adc_properties,
+		const struct qpnp_vadc_chan_properties *chan_properties,
+		struct qpnp_vadc_result *adc_chan_result)
+{
+	int64_t bat_voltage = 0;
+
+	bat_voltage = qpnp_adc_scale_ratiometric_calib(adc_code,
+			adc_properties, chan_properties);
+
+	return qpnp_adc_map_batt_therm(
+			adcmap_btm_threshold,
+			ARRAY_SIZE(adcmap_btm_threshold),
+			bat_voltage,
+			&adc_chan_result->physical);
+}
+EXPORT_SYMBOL_GPL(qpnp_adc_scale_batt_therm);
+
+int32_t qpnp_adc_scale_batt_id(int32_t adc_code,
+		const struct qpnp_adc_properties *adc_properties,
+		const struct qpnp_vadc_chan_properties *chan_properties,
+		struct qpnp_vadc_result *adc_chan_result)
+{
+	int64_t batt_id_voltage = 0;
+
+	batt_id_voltage = qpnp_adc_scale_ratiometric_calib(adc_code,
+			adc_properties, chan_properties);
+	adc_chan_result->physical = batt_id_voltage;
+	adc_chan_result->physical = adc_chan_result->measurement;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qpnp_adc_scale_batt_id);
 
 int32_t qpnp_adc_scale_default(int32_t adc_code,
 		const struct qpnp_adc_properties *adc_properties,
@@ -203,7 +689,7 @@
 				"qcom,calibration-type", NULL);
 		if (!strncmp(calibration_param, "absolute", 8))
 			calib_type = CALIB_ABSOLUTE;
-		else if (!strncmp(calibration_param, "historical", 9))
+		else if (!strncmp(calibration_param, "ratiometric", 11))
 			calib_type = CALIB_RATIOMETRIC;
 		else {
 			pr_err("%s: Invalid calibration property\n", __func__);
@@ -252,6 +738,8 @@
 		return -ENXIO;
 	}
 
+	init_completion(&adc_qpnp->adc_rslt_completion);
+
 	mutex_init(&adc_qpnp->adc_lock);
 
 	return 0;