1 .. SPDX-License-Identifier: GPL-2.0-only
2
3 Kernel driver bt1-pvt
4 =====================
5
6 Supported chips:
7
8 * Baikal-T1 PVT sensor (in SoC)
9
10 Prefix: 'bt1-pvt'
11
12 Addresses scanned: -
13
14 Datasheet: Provided by BAIKAL ELECTRONICS
15
16 Authors:
17 Maxim Kaurkin <maxim.kaurkin@baikalelectron
18 Serge Semin <Sergey.Semin@baikalelectronics
19
20 Description
21 -----------
22
23 This driver implements support for the hardwar
24 embedded into Baikal-T1 process, voltage and t
25 consists of one temperature and four voltage s
26 monitor the chip internal environment like hea
27 transistors performance. The driver can option
28 for each sensor the PVT controller supports. T
29 compile-time configurable due to the hardware
30 peculiarity, which is connected with an abilit
31 sensor at a time. Additional limitation is tha
32 thresholds checking synchronously with the dat
33 these in order to have the hwmon alarms automa
34 must switch from one sensor to another, read c
35 the threshold status bits. Depending on the me
36 (update_interval sysfs node value) this design
37 the system performance. So in case if alarms a
38 design it's recommended to have them disabled
39 periodically raised to get the data cache/alar
40 in alarm-less configuration the data conversio
41 on demand when read operation is requested via
42
43 Temperature Monitoring
44 ----------------------
45
46 Temperature is measured with 10-bit resolution
47 Celsius. The driver performs all the scaling b
48 temperatures that don't need any user-space ad
49 translation formulae isn't linear, which gives
50 it's close to one, but giving a bit better acc
51 The temperature input is mapped as follows (th
52 ranges)::
53
54 temp1: CPU embedded diode -48.38
55
56 In case if the alarms kernel config is enabled
57 has associated min and max limits which trigge
58
59 Voltage Monitoring
60 ------------------
61
62 The voltage inputs are also sampled with 10-bi
63 millivolts. But in this case the data translat
64 provides a constant measurements discreteness.
65 performed by the driver, so returning true mil
66 mapped as follows (the last column indicates t
67
68 in0: VDD (processor cor
69 in1: Low-Vt (low voltage t
70 in2: High-Vt (high voltage
71 in3: Standard-Vt (standard volt
72
73 In case if the alarms config is enabled in the
74 have associated min and max limits which trigg
75
76 Sysfs Attributes
77 ----------------
78
79 Following is a list of all sysfs attributes th
80 permissions and a short description:
81
82 =============================== ======= ======
83 Name Perm Descri
84 =============================== ======= ======
85 update_interval RW Measur
86 sensor
87 temp1_type RO Sensor
88 diode)
89 temp1_label RO CPU Co
90 temp1_input RO Measur
91 Celsiu
92 temp1_min RW Low li
93 temp1_max RW High l
94 temp1_min_alarm RO Temper
95 temper
96 0 othe
97 temp1_max_alarm RO Temper
98 temper
99 0 othe
100 temp1_offset RW Temper
101 Celsiu
102 temper
103 be use
104 temper
105 degree
106 in[0-3]_label RO CPU Vo
107 low/hi
108 in[0-3]_input RO Measur
109 in[0-3]_min RW Low li
110 in[0-3]_max RW High l
111 in[0-3]_min_alarm RO Voltag
112 voltag
113 0 othe
114 in[0-3]_max_alarm RO Voltag
115 voltag
116 0 othe
117 =============================== ======= ======
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