Documentation/hwmon/bt1-pvt.rst

1 .. SPDX-License-Identifier: GPL-2.0-only
3 Kernel driver bt1-pvt
8   * Baikal-T1 PVT sensor (in SoC)
10     Prefix: 'bt1-pvt'
12     Addresses scanned: -
21 -----------
24 embedded into Baikal-T1 process, voltage and temperature sensors. PVT IP-core
25 consists of one temperature and four voltage sensors, which can be used to
26 monitor the chip internal environment like heating, supply voltage and
29 compile-time configurable due to the hardware interface implementation
35 the threshold status bits. Depending on the measurements timeout settings
40 in alarm-less configuration the data conversion is performed by the driver
41 on demand when read operation is requested via corresponding _input-file.
43 Temperature Monitoring
44 ----------------------
46 Temperature is measured with 10-bit resolution and reported in millidegree
47 Celsius. The driver performs all the scaling by itself therefore reports true
48 temperatures that don't need any user-space adjustments. While the data
49 translation formulae isn't linear, which gives us non-linear discreteness,
51 The temperature input is mapped as follows (the last column indicates the input
54 	temp1: CPU embedded diode	-48.38C - +147.438C
56 In case if the alarms kernel config is enabled in the driver the temperature input
60 ------------------
62 The voltage inputs are also sampled with 10-bit resolution and reported in
68 	in0: VDD		(processor core)		0.62V - 1.168V
69 	in1: Low-Vt		(low voltage threshold)		0.62V - 1.168V
70 	in2: High-Vt		(high voltage threshold)	0.62V - 1.168V
71 	in3: Standard-Vt	(standard voltage threshold)	0.62V - 1.168V
77 ----------------
89 temp1_label			RO	CPU Core Temperature sensor.
90 temp1_input			RO	Measured temperature in millidegree
91 					Celsius.
94 temp1_min_alarm			RO	Temperature input alarm. Returns 1 if
95 					temperature input went below min limit,
97 temp1_max_alarm			RO	Temperature input alarm. Returns 1 if
98 					temperature input went above max limit,
100 temp1_offset			RW	Temperature offset in millidegree
101 					Celsius which is added to the
102 					temperature reading by the chip. It can
104 					temperature measurements within 7.130
105 					degrees Celsius.
106 in[0-3]_label			RO	CPU Voltage sensor (either core or
108 in[0-3]_input			RO	Measured voltage in millivolts.
109 in[0-3]_min			RW	Low limit for voltage input.
110 in[0-3]_max			RW	High limit for voltage input.
111 in[0-3]_min_alarm		RO	Voltage input alarm. Returns 1 if
114 in[0-3]_max_alarm		RO	Voltage input alarm. Returns 1 if