xref: /linux/drivers/iio/adc/qcom-vadc-common.c (revision e9f0878c4b2004ac19581274c1ae4c61ae3ca70e)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bug.h>
3 #include <linux/kernel.h>
4 #include <linux/bitops.h>
5 #include <linux/math64.h>
6 #include <linux/log2.h>
7 #include <linux/err.h>
8 #include <linux/module.h>
9 
10 #include "qcom-vadc-common.h"
11 
12 /* Voltage to temperature */
13 static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {
14 	{1758,	-40},
15 	{1742,	-35},
16 	{1719,	-30},
17 	{1691,	-25},
18 	{1654,	-20},
19 	{1608,	-15},
20 	{1551,	-10},
21 	{1483,	-5},
22 	{1404,	0},
23 	{1315,	5},
24 	{1218,	10},
25 	{1114,	15},
26 	{1007,	20},
27 	{900,	25},
28 	{795,	30},
29 	{696,	35},
30 	{605,	40},
31 	{522,	45},
32 	{448,	50},
33 	{383,	55},
34 	{327,	60},
35 	{278,	65},
36 	{237,	70},
37 	{202,	75},
38 	{172,	80},
39 	{146,	85},
40 	{125,	90},
41 	{107,	95},
42 	{92,	100},
43 	{79,	105},
44 	{68,	110},
45 	{59,	115},
46 	{51,	120},
47 	{44,	125}
48 };
49 
50 static int qcom_vadc_map_voltage_temp(const struct vadc_map_pt *pts,
51 				      u32 tablesize, s32 input, s64 *output)
52 {
53 	bool descending = 1;
54 	u32 i = 0;
55 
56 	if (!pts)
57 		return -EINVAL;
58 
59 	/* Check if table is descending or ascending */
60 	if (tablesize > 1) {
61 		if (pts[0].x < pts[1].x)
62 			descending = 0;
63 	}
64 
65 	while (i < tablesize) {
66 		if ((descending) && (pts[i].x < input)) {
67 			/* table entry is less than measured*/
68 			 /* value and table is descending, stop */
69 			break;
70 		} else if ((!descending) &&
71 				(pts[i].x > input)) {
72 			/* table entry is greater than measured*/
73 			/*value and table is ascending, stop */
74 			break;
75 		}
76 		i++;
77 	}
78 
79 	if (i == 0) {
80 		*output = pts[0].y;
81 	} else if (i == tablesize) {
82 		*output = pts[tablesize - 1].y;
83 	} else {
84 		/* result is between search_index and search_index-1 */
85 		/* interpolate linearly */
86 		*output = (((s32)((pts[i].y - pts[i - 1].y) *
87 			(input - pts[i - 1].x)) /
88 			(pts[i].x - pts[i - 1].x)) +
89 			pts[i - 1].y);
90 	}
91 
92 	return 0;
93 }
94 
95 static void qcom_vadc_scale_calib(const struct vadc_linear_graph *calib_graph,
96 				  u16 adc_code,
97 				  bool absolute,
98 				  s64 *scale_voltage)
99 {
100 	*scale_voltage = (adc_code - calib_graph->gnd);
101 	*scale_voltage *= calib_graph->dx;
102 	*scale_voltage = div64_s64(*scale_voltage, calib_graph->dy);
103 	if (absolute)
104 		*scale_voltage += calib_graph->dx;
105 
106 	if (*scale_voltage < 0)
107 		*scale_voltage = 0;
108 }
109 
110 static int qcom_vadc_scale_volt(const struct vadc_linear_graph *calib_graph,
111 				const struct vadc_prescale_ratio *prescale,
112 				bool absolute, u16 adc_code,
113 				int *result_uv)
114 {
115 	s64 voltage = 0, result = 0;
116 
117 	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
118 
119 	voltage = voltage * prescale->den;
120 	result = div64_s64(voltage, prescale->num);
121 	*result_uv = result;
122 
123 	return 0;
124 }
125 
126 static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,
127 				 const struct vadc_prescale_ratio *prescale,
128 				 bool absolute, u16 adc_code,
129 				 int *result_mdec)
130 {
131 	s64 voltage = 0, result = 0;
132 	int ret;
133 
134 	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
135 
136 	if (absolute)
137 		voltage = div64_s64(voltage, 1000);
138 
139 	ret = qcom_vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
140 					 ARRAY_SIZE(adcmap_100k_104ef_104fb),
141 					 voltage, &result);
142 	if (ret)
143 		return ret;
144 
145 	result *= 1000;
146 	*result_mdec = result;
147 
148 	return 0;
149 }
150 
151 static int qcom_vadc_scale_die_temp(const struct vadc_linear_graph *calib_graph,
152 				    const struct vadc_prescale_ratio *prescale,
153 				    bool absolute,
154 				    u16 adc_code, int *result_mdec)
155 {
156 	s64 voltage = 0;
157 	u64 temp; /* Temporary variable for do_div */
158 
159 	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
160 
161 	if (voltage > 0) {
162 		temp = voltage * prescale->den;
163 		do_div(temp, prescale->num * 2);
164 		voltage = temp;
165 	} else {
166 		voltage = 0;
167 	}
168 
169 	voltage -= KELVINMIL_CELSIUSMIL;
170 	*result_mdec = voltage;
171 
172 	return 0;
173 }
174 
175 static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,
176 				    const struct vadc_prescale_ratio *prescale,
177 				    bool absolute,
178 				    u16 adc_code, int *result_mdec)
179 {
180 	s64 voltage = 0, result = 0;
181 
182 	qcom_vadc_scale_calib(calib_graph, adc_code, absolute, &voltage);
183 
184 	voltage = voltage * prescale->den;
185 	voltage = div64_s64(voltage, prescale->num);
186 	voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));
187 	voltage = (voltage + PMI_CHG_SCALE_2);
188 	result =  div64_s64(voltage, 1000000);
189 	*result_mdec = result;
190 
191 	return 0;
192 }
193 
194 int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
195 		    const struct vadc_linear_graph *calib_graph,
196 		    const struct vadc_prescale_ratio *prescale,
197 		    bool absolute,
198 		    u16 adc_code, int *result)
199 {
200 	switch (scaletype) {
201 	case SCALE_DEFAULT:
202 		return qcom_vadc_scale_volt(calib_graph, prescale,
203 					    absolute, adc_code,
204 					    result);
205 	case SCALE_THERM_100K_PULLUP:
206 	case SCALE_XOTHERM:
207 		return qcom_vadc_scale_therm(calib_graph, prescale,
208 					     absolute, adc_code,
209 					     result);
210 	case SCALE_PMIC_THERM:
211 		return qcom_vadc_scale_die_temp(calib_graph, prescale,
212 						absolute, adc_code,
213 						result);
214 	case SCALE_PMI_CHG_TEMP:
215 		return qcom_vadc_scale_chg_temp(calib_graph, prescale,
216 						absolute, adc_code,
217 						result);
218 	default:
219 		return -EINVAL;
220 	}
221 }
222 EXPORT_SYMBOL(qcom_vadc_scale);
223 
224 int qcom_vadc_decimation_from_dt(u32 value)
225 {
226 	if (!is_power_of_2(value) || value < VADC_DECIMATION_MIN ||
227 	    value > VADC_DECIMATION_MAX)
228 		return -EINVAL;
229 
230 	return __ffs64(value / VADC_DECIMATION_MIN);
231 }
232 EXPORT_SYMBOL(qcom_vadc_decimation_from_dt);
233 
234 MODULE_LICENSE("GPL v2");
235 MODULE_DESCRIPTION("Qualcomm ADC common functionality");
236