These changes were made to support a custom board where one PWM output is routed to two fans, each of which has a tachometer signal routed to a GPIO input on the SoC. As the custom board doesn't currently support the latest mainline kernel I've tested these changes on a SanCloud BeagleBone Enhanced using an oscilloscope to check the PWM output and a signal generator to simulate the fan tachometer signals. I've tested variants of the device tree with 0, 1 and 2 fan tachometer inputs configured to ensure the logic in the probe function is correct. The device tree bindings changes have been submitted in a separate series: https://lore.kernel.org/linux-devicetree/20200920180943.352526-1-pbarker@xxxxxxxxxxxx/ These changes can also be pulled from: https://gitlab.com/pbarker.dev/staging/linux.git tag: for-hwmon/pwm-fan-tachometers-v3_2020-12-12 Changes since v2: * Split refactoring and API conversion into a separate patch series which has now been accepted. These changes now use the recommended hwmon API and dynamically allocate struct hwmon_channel_info objects as needed. * Rebased changes on the current HEAD of hwmon-next. Changes since v1: * Split RPM calculation fix into a separate patch which has now been accepted. * Break the changes down into smaller patches so they're easier to review. * Rebased changes on hwmon-next. Paul Barker (2): hwmon: pwm-fan: Store tach data separately hwmon: pwm-fan: Support multiple fan tachometers drivers/hwmon/pwm-fan.c | 111 +++++++++++++++++++++++++--------------- 1 file changed, 69 insertions(+), 42 deletions(-) base-commit: 1a033769a4fe9a86ee791fd553b6a996dd76e026 -- 2.26.2
