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
28 for each sensor the PVT controller supports. The alarms functionality is made
29 compile-time configurable due to the hardware interface implementation
31 sensor at a time. Additional limitation is that the controller performs the
34 must switch from one sensor to another, read converted data and manually check
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
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 ----------------
86 					sensor.
87 temp1_type			RO	Sensor type (always 1 as CPU embedded
89 temp1_label			RO	CPU Core Temperature sensor.
90 temp1_input			RO	Measured temperature in millidegree
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
102 					temperature reading by the chip. It can
104 					temperature measurements within 7.130
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