Add a hwmon driver that reports fan and temperature readings from the ChromeOS Embedded controller. There was an earlier effort in 2017 to add such a driver [0], but there was no followup after v1. The new driver is complete reimplementation based on newer APIs and with more features (temp sensor names). It only works on LPC-connected ECs, as only those implement direct memory-map access. For other busses the data would need to be read with a command. Adding some helpers was discussed in the previous patchset [1]. The EC protocols also support reading and writing fan curves but that is not implemented. Tested on a Framework 13 AMD, Firmware 3.05. [0] https://lore.kernel.org/all/1491602410-31518-1-git-send-email-moritz.fischer@xxxxxxxxx/ [1] https://lore.kernel.org/all/ac61bfca-bfa0-143b-c9ca-365b8026ce8d@xxxxxxxxxxxx/ To: Jean Delvare <jdelvare@xxxxxxxx> To: Guenter Roeck <linux@xxxxxxxxxxxx> To: Benson Leung <bleung@xxxxxxxxxxxx> To: Lee Jones <lee@xxxxxxxxxx> To: Tzung-Bi Shih <tzungbi@xxxxxxxxxx> Cc: Guenter Roeck <groeck@xxxxxxxxxxxx> Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: linux-hwmon@xxxxxxxxxxxxxxx Cc: chrome-platform@xxxxxxxxxxxxxxx Cc: Dustin Howett <dustin@xxxxxxxxxx> Cc: Mario Limonciello <mario.limonciello@xxxxxxx> Cc: Moritz Fischer <mdf@xxxxxxxxxx> Cc: Stephen Horvath <s.horvath@xxxxxxxxxxxxxx> Cc: Rajas Paranjpe <paranjperajas@xxxxxxxxx> Changes in v3: - Drop Mario's Reviewed-by tag, as the code has changed - Introduce cros_ec_cmd_readmem() for non-LPC compatibility - Report fault state for fans and temp sensors - Avoid adding unnecessary space characters to channel label - Drop thermal_version from priv data - Read fans during probing only once - Don't include linux/kernel.h - Move _read_temp_sensor_info to similar functions - Insert MFD entry alphabetically - Link to v2: https://lore.kernel.org/r/20240507-cros_ec-hwmon-v2-0-1222c5fca0f7@xxxxxxxxxxxxxx Changes in v2: - drop unnecessary range checks (Guenter) - only validate thermal_version during probing - reorder some variable declarations - validate thermal_version directly in cros_ec_hwmon_probe (Mario) - drop return value from probe_temp_sensors as it can't fail anymore - fail with -ENODEV if cmd_readmem is missing to avoid spurious warnings - Link to v1: https://lore.kernel.org/r/20240507-cros_ec-hwmon-v1-0-2c47c5ce8e85@xxxxxxxxxxxxxx --- Thomas Weißschuh (3): platform/chrome: cros_ec_proto: Introduce cros_ec_cmd_readmem() hwmon: add ChromeOS EC driver mfd: cros_ec: Register hardware monitoring subdevice Documentation/hwmon/cros_ec_hwmon.rst | 26 +++ Documentation/hwmon/index.rst | 1 + MAINTAINERS | 8 + drivers/hwmon/Kconfig | 11 ++ drivers/hwmon/Makefile | 1 + drivers/hwmon/cros_ec_hwmon.c | 291 ++++++++++++++++++++++++++++ drivers/mfd/cros_ec_dev.c | 1 + drivers/platform/chrome/cros_ec_proto.c | 27 +++ include/linux/platform_data/cros_ec_proto.h | 2 + 9 files changed, 368 insertions(+) --- base-commit: 2bfcfd584ff5ccc8bb7acde19b42570414bf880b change-id: 20240506-cros_ec-hwmon-24634b07cf6f Best regards, -- Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
