Hi Maxime, On 15/05/2017 11:11, Maxime Ripard wrote: > On Mon, May 15, 2017 at 09:39:02AM +0200, Quentin Schulz wrote: >> For the sake of DT binding stability, this IIO driver is a child of an >> MFD driver for Allwinner A10, A13 and A31 because there already exists a >> DT binding for this IP. The MFD driver has a DT node but the IIO driver >> does not. >> >> The IIO device registers the temperature sensor in the thermal framework >> using the DT node of the parent, the MFD device, so the thermal >> framework could match the phandle to the MFD device in the DT and the >> struct device used to register in the thermal framework. >> >> devm_thermal_zone_of_sensor_register was previously used to register the >> thermal sensor with the parent struct device of the IIO device, >> representing the MFD device. By doing so, we registered actually the >> parent in the devm routine and not the actual IIO device. >> >> This lead to the devm unregister function not being called when the IIO >> module driver is removed. It resulted in the thermal framework still >> polling the get_temp function of the IIO module while the device doesn't >> exist anymore, thus generated a kernel panic. >> >> Use the non-devm function instead and do the unregister manually in the >> remove function. >> >> Fixes: d1caa9905538 ("iio: adc: add support for Allwinner SoCs ADC") >> >> Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxxxxxxxxx> >> Reported-by: Corentin Labbe <clabbe.montjoie@xxxxxxxxx> >> --- [...] >> @@ -688,6 +687,12 @@ static int sun4i_gpadc_remove(struct platform_device *pdev) >> >> pm_runtime_put(&pdev->dev); >> pm_runtime_disable(&pdev->dev); >> + >> + if (pdev->dev.of_node) >> + thermal_zone_of_sensor_unregister(&pdev->dev, info->tzd); >> + else >> + thermal_zone_of_sensor_unregister(pdev->dev.parent, info->tzd); >> + > > Can't we just store the device used to create the zone in the > structure as well, that would avoid that non-trivial logic. > Yes we could. I've that same condition in the probe function, if pdev->dev.of_node then I continue in the probe dedicated to device probed from DT, or I continue with the probe dedicated to device probed via MFD. The thermal_zone_of_sensor_register is different in those two functions, thus, I thought that it would make more sense to replicate the same condition in the remove to make the relation between the device used in thermal_zone_of_sensor_register and unregister clear. That's just a matter of taste for me, so I'm definitely ok to write a v2 for this change. Thanks, Quentin -- Quentin Schulz, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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