1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Generic ADC thermal driver
*
* Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
*
* Author: Laxman Dewangan <ldewangan@nvidia.com>
*/
#include <linux/iio/consumer.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/thermal.h>
#include "thermal_hwmon.h"
struct gadc_thermal_info {
struct device *dev;
struct thermal_zone_device *tz_dev;
struct iio_channel *channel;
s32 *lookup_table;
int nlookup_table;
};
static int gadc_thermal_adc_to_temp(struct gadc_thermal_info *gti, int val)
{
int temp, temp_hi, temp_lo, adc_hi, adc_lo;
int i;
if (!gti->lookup_table)
return val;
for (i = 0; i < gti->nlookup_table; i++) {
if (val >= gti->lookup_table[2 * i + 1])
break;
}
if (i == 0) {
temp = gti->lookup_table[0];
} else if (i >= gti->nlookup_table) {
temp = gti->lookup_table[2 * (gti->nlookup_table - 1)];
} else {
adc_hi = gti->lookup_table[2 * i - 1];
adc_lo = gti->lookup_table[2 * i + 1];
temp_hi = gti->lookup_table[2 * i - 2];
temp_lo = gti->lookup_table[2 * i];
temp = temp_hi + mult_frac(temp_lo - temp_hi, val - adc_hi,
adc_lo - adc_hi);
}
return temp;
}
static int gadc_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
{
struct gadc_thermal_info *gti = thermal_zone_device_priv(tz);
int val;
int ret;
ret = iio_read_channel_processed(gti->channel, &val);
if (ret < 0)
return ret;
*temp = gadc_thermal_adc_to_temp(gti, val);
return 0;
}
static const struct thermal_zone_device_ops gadc_thermal_ops = {
.get_temp = gadc_thermal_get_temp,
};
static int gadc_thermal_read_linear_lookup_table(struct device *dev,
struct gadc_thermal_info *gti)
{
struct device_node *np = dev->of_node;
enum iio_chan_type chan_type;
int ntable;
int ret;
ntable = of_property_count_elems_of_size(np, "temperature-lookup-table",
sizeof(u32));
if (ntable <= 0) {
ret = iio_get_channel_type(gti->channel, &chan_type);
if (ret || chan_type != IIO_TEMP)
dev_notice(dev,
"no lookup table, assuming DAC channel returns milliCelcius\n");
return 0;
}
if (ntable % 2) {
dev_err(dev, "Pair of temperature vs ADC read value missing\n");
return -EINVAL;
}
gti->lookup_table = devm_kcalloc(dev,
ntable, sizeof(*gti->lookup_table),
GFP_KERNEL);
if (!gti->lookup_table)
return -ENOMEM;
ret = of_property_read_u32_array(np, "temperature-lookup-table",
(u32 *)gti->lookup_table, ntable);
if (ret < 0) {
dev_err(dev, "Failed to read temperature lookup table: %d\n",
ret);
return ret;
}
gti->nlookup_table = ntable / 2;
return 0;
}
static int gadc_thermal_probe(struct platform_device *pdev)
{
struct gadc_thermal_info *gti;
int ret;
if (!pdev->dev.of_node) {
dev_err(&pdev->dev, "Only DT based supported\n");
return -ENODEV;
}
gti = devm_kzalloc(&pdev->dev, sizeof(*gti), GFP_KERNEL);
if (!gti)
return -ENOMEM;
gti->channel = devm_iio_channel_get(&pdev->dev, "sensor-channel");
if (IS_ERR(gti->channel)) {
ret = PTR_ERR(gti->channel);
if (ret != -EPROBE_DEFER)
dev_err(&pdev->dev, "IIO channel not found: %d\n", ret);
return ret;
}
ret = gadc_thermal_read_linear_lookup_table(&pdev->dev, gti);
if (ret < 0)
return ret;
gti->dev = &pdev->dev;
gti->tz_dev = devm_thermal_of_zone_register(&pdev->dev, 0, gti,
&gadc_thermal_ops);
if (IS_ERR(gti->tz_dev)) {
ret = PTR_ERR(gti->tz_dev);
if (ret != -EPROBE_DEFER)
dev_err(&pdev->dev,
"Thermal zone sensor register failed: %d\n",
ret);
return ret;
}
devm_thermal_add_hwmon_sysfs(&pdev->dev, gti->tz_dev);
return 0;
}
static const struct of_device_id of_adc_thermal_match[] = {
{ .compatible = "generic-adc-thermal", },
{},
};
MODULE_DEVICE_TABLE(of, of_adc_thermal_match);
static struct platform_driver gadc_thermal_driver = {
.driver = {
.name = "generic-adc-thermal",
.of_match_table = of_adc_thermal_match,
},
.probe = gadc_thermal_probe,
};
module_platform_driver(gadc_thermal_driver);
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_DESCRIPTION("Generic ADC thermal driver using IIO framework with DT");
MODULE_LICENSE("GPL v2");
|
