From 74d1e007915fab590f8be9dc647b19511260210c Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Fri, 25 May 2018 21:24:35 +0200 Subject: hwmon: Add support for RPi voltage sensor MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently there is no easy way to detect undervoltage conditions on a remote Raspberry Pi. This hwmon driver retrieves the state of the undervoltage sensor via mailbox interface. The handling based on Noralf's modifications to the downstream firmware driver. In case of an undervoltage condition only an entry is written to the kernel log. CC: "Noralf Trønnes" Signed-off-by: Stefan Wahren Signed-off-by: Eric Anholt Acked-by: Guenter Roeck --- Documentation/hwmon/raspberrypi-hwmon | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 Documentation/hwmon/raspberrypi-hwmon (limited to 'Documentation/hwmon') diff --git a/Documentation/hwmon/raspberrypi-hwmon b/Documentation/hwmon/raspberrypi-hwmon new file mode 100644 index 000000000000..3c92e2cb52d6 --- /dev/null +++ b/Documentation/hwmon/raspberrypi-hwmon @@ -0,0 +1,22 @@ +Kernel driver raspberrypi-hwmon +=============================== + +Supported boards: + * Raspberry Pi A+ (via GPIO on SoC) + * Raspberry Pi B+ (via GPIO on SoC) + * Raspberry Pi 2 B (via GPIO on SoC) + * Raspberry Pi 3 B (via GPIO on port expander) + * Raspberry Pi 3 B+ (via PMIC) + +Author: Stefan Wahren + +Description +----------- + +This driver periodically polls a mailbox property of the VC4 firmware to detect +undervoltage conditions. + +Sysfs entries +------------- + +in0_lcrit_alarm Undervoltage alarm -- cgit