1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2014-2016, NVIDIA CORPORATION.  All rights reserved.
4  */
5 
6 #include <linux/module.h>
7 #include <linux/platform_device.h>
8 #include <soc/tegra/fuse.h>
9 
10 #include "soctherm.h"
11 
12 #define NOMINAL_CALIB_FT			105
13 #define NOMINAL_CALIB_CP			25
14 
15 #define FUSE_TSENSOR_CALIB_CP_TS_BASE_MASK	0x1fff
16 #define FUSE_TSENSOR_CALIB_FT_TS_BASE_MASK	(0x1fff << 13)
17 #define FUSE_TSENSOR_CALIB_FT_TS_BASE_SHIFT	13
18 
19 #define FUSE_TSENSOR_COMMON			0x180
20 
21 /*
22  * Tegra210: Layout of bits in FUSE_TSENSOR_COMMON:
23  *    3                   2                   1                   0
24  *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
25  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
26  * |       BASE_FT       |      BASE_CP      | SHFT_FT | SHIFT_CP  |
27  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
28  *
29  * Tegra12x, etc:
30  * In chips prior to Tegra210, this fuse was incorrectly sized as 26 bits,
31  * and didn't hold SHIFT_CP in [31:26]. Therefore these missing six bits
32  * were obtained via the FUSE_SPARE_REALIGNMENT_REG register [5:0].
33  *
34  * FUSE_TSENSOR_COMMON:
35  *    3                   2                   1                   0
36  *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
37  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38  * |-----------| SHFT_FT |       BASE_FT       |      BASE_CP      |
39  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
40  *
41  * FUSE_SPARE_REALIGNMENT_REG:
42  *    3                   2                   1                   0
43  *  1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
44  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
45  * |---------------------------------------------------| SHIFT_CP  |
46  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
47  */
48 
49 #define CALIB_COEFFICIENT 1000000LL
50 
51 /**
52  * div64_s64_precise() - wrapper for div64_s64()
53  * @a:  the dividend
54  * @b:  the divisor
55  *
56  * Implements division with fairly accurate rounding instead of truncation by
57  * shifting the dividend to the left by 16 so that the quotient has a
58  * much higher precision.
59  *
60  * Return: the quotient of a / b.
61  */
div64_s64_precise(s64 a,s32 b)62 static s64 div64_s64_precise(s64 a, s32 b)
63 {
64 	s64 r, al;
65 
66 	/* Scale up for increased precision division */
67 	al = a << 16;
68 
69 	r = div64_s64(al * 2 + 1, 2 * b);
70 	return r >> 16;
71 }
72 
tegra_calc_shared_calib(const struct tegra_soctherm_fuse * tfuse,struct tsensor_shared_calib * shared)73 int tegra_calc_shared_calib(const struct tegra_soctherm_fuse *tfuse,
74 			    struct tsensor_shared_calib *shared)
75 {
76 	u32 val;
77 	s32 shifted_cp, shifted_ft;
78 	int err;
79 
80 	err = tegra_fuse_readl(FUSE_TSENSOR_COMMON, &val);
81 	if (err)
82 		return err;
83 
84 	shared->base_cp = (val & tfuse->fuse_base_cp_mask) >>
85 			  tfuse->fuse_base_cp_shift;
86 	shared->base_ft = (val & tfuse->fuse_base_ft_mask) >>
87 			  tfuse->fuse_base_ft_shift;
88 
89 	shifted_ft = (val & tfuse->fuse_shift_ft_mask) >>
90 		     tfuse->fuse_shift_ft_shift;
91 	shifted_ft = sign_extend32(shifted_ft, 4);
92 
93 	if (tfuse->fuse_spare_realignment) {
94 		err = tegra_fuse_readl(tfuse->fuse_spare_realignment, &val);
95 		if (err)
96 			return err;
97 	}
98 
99 	shifted_cp = sign_extend32(val, 5);
100 
101 	shared->actual_temp_cp = 2 * NOMINAL_CALIB_CP + shifted_cp;
102 	shared->actual_temp_ft = 2 * NOMINAL_CALIB_FT + shifted_ft;
103 
104 	return 0;
105 }
106 
tegra_calc_tsensor_calib(const struct tegra_tsensor * sensor,const struct tsensor_shared_calib * shared,u32 * calibration)107 int tegra_calc_tsensor_calib(const struct tegra_tsensor *sensor,
108 			     const struct tsensor_shared_calib *shared,
109 			     u32 *calibration)
110 {
111 	const struct tegra_tsensor_group *sensor_group;
112 	u32 val, calib;
113 	s32 actual_tsensor_ft, actual_tsensor_cp;
114 	s32 delta_sens, delta_temp;
115 	s32 mult, div;
116 	s16 therma, thermb;
117 	s64 temp;
118 	int err;
119 
120 	sensor_group = sensor->group;
121 
122 	err = tegra_fuse_readl(sensor->calib_fuse_offset, &val);
123 	if (err)
124 		return err;
125 
126 	actual_tsensor_cp = (shared->base_cp * 64) + sign_extend32(val, 12);
127 	val = (val & FUSE_TSENSOR_CALIB_FT_TS_BASE_MASK) >>
128 	      FUSE_TSENSOR_CALIB_FT_TS_BASE_SHIFT;
129 	actual_tsensor_ft = (shared->base_ft * 32) + sign_extend32(val, 12);
130 
131 	delta_sens = actual_tsensor_ft - actual_tsensor_cp;
132 	delta_temp = shared->actual_temp_ft - shared->actual_temp_cp;
133 
134 	mult = sensor_group->pdiv * sensor->config->tsample_ate;
135 	div = sensor->config->tsample * sensor_group->pdiv_ate;
136 
137 	temp = (s64)delta_temp * (1LL << 13) * mult;
138 	therma = div64_s64_precise(temp, (s64)delta_sens * div);
139 
140 	temp = ((s64)actual_tsensor_ft * shared->actual_temp_cp) -
141 		((s64)actual_tsensor_cp * shared->actual_temp_ft);
142 	thermb = div64_s64_precise(temp, delta_sens);
143 
144 	temp = (s64)therma * sensor->fuse_corr_alpha;
145 	therma = div64_s64_precise(temp, CALIB_COEFFICIENT);
146 
147 	temp = (s64)thermb * sensor->fuse_corr_alpha + sensor->fuse_corr_beta;
148 	thermb = div64_s64_precise(temp, CALIB_COEFFICIENT);
149 
150 	calib = ((u16)therma << SENSOR_CONFIG2_THERMA_SHIFT) |
151 		((u16)thermb << SENSOR_CONFIG2_THERMB_SHIFT);
152 
153 	*calibration = calib;
154 
155 	return 0;
156 }
157 
158 MODULE_AUTHOR("Wei Ni <wni@nvidia.com>");
159 MODULE_DESCRIPTION("Tegra SOCTHERM fuse management");
160 MODULE_LICENSE("GPL v2");
161