On Tue, May 7, 2019 at 12:52 AM Icenowy Zheng <icenowy@xxxxxxx> wrote: > > 在 2019-05-06一的 14:28 +0200，Maxime Ripard写道： > > Hi, > > > > On Sun, May 05, 2019 at 04:22:15PM +0100, Jonathan Cameron wrote: > > > On Fri, 3 May 2019 03:28:07 -0400 > > > Yangtao Li <tiny.windzz@xxxxxxxxx> wrote: > > > > > > > For some SOCs, there are more than one thermal sensor, and there > > > > are > > > > currently four sensors on the A80. So we need to do some work in > > > > order > > > > to support multiple thermal sensors: > > > > > > > > 1) add sensor_count in gpadc_data. > > > > 2) introduce sun4i_sensor_tzd in sun4i_gpadc_iio, to support > > > > multiple > > > > thermal_zone_device and distinguish between different > > > > sensors. > > > > 3) modify read temperature and initialization function. > > > > > > This comment doesn't mention the devm change. If it had it would > > > have > > > raised immediate alarm bells. > > > > > > I'm also not keen on the web of pointers that this driver is > > > steadily > > > evolving. I can't immediately see how to reduce that complexity > > > however. > > > > So I might be responsible for that, and looking back, this has been a > > mistake. > > > > This driver was initally put together to support a controller found > > in > > older (A10 up to A31) Allwinner SoCs. This controller had an ADC > > driver that could be operated as a touchscreen controller, and was > > providing a CPU temperature sensor and a general purpose ADC. > > > > However, we already had a driver for that controller in drivers/input > > to report the CPU temperature, and the one in IIO was introduced to > > support the general purpose ADC (and the CPU temperature). The long > > term goal was to add the touchscreen feature as well eventually so > > that we could remove the one in drivers/input. That didn't happen. > > > > At the same time, the Allwinner hardware slowly evolved to remove the > > touchscreen and ADC features, and only keep the CPU temperature > > readout. It then evolved further on to support multiple temperatures > > (for different clusters, the GPU, and so on). > > > > So, today, we're in a situation where I was pushing everything into > > that IIO drivers since there was similiraties between all the > > generations, but the fact that we have to support so many odd cases > > (DT bindings compatibility, controllers with and without ADC, etc) > > that it becomes a real mess. > > > > And that mess isn't really used by anybody, since we want to have the > > touchscreen. > > > > There's only one SoC that is supported only by that driver, which is > > the A33 that only had a CPU temperature readout, and is still pretty > > similar to the latest SoC from Allwinner (that is supported by this > > series). > > > > I guess, for everyone's sanity and in order to not stall this > > further, > > it would just be better to create an hwmon driver for the A33 (and > > onwards, including the H6) for the SoC that just have the temperature > > readout feature. And for the older SoC, we just keep the older driver > > under input/. Once the A33 is supported, we'll remove the driver in > > IIO (and the related bits in drivers/mfd). a hwmon driver or a thermal driver？ > > I think a thermal driver is better. This is what I hope to see a few months ago. > > Other SoCs' thermal sensor drivers are all thermal drivers. > > > > > Armbian already has a driver for that they never upstreamed iirc, so > > it might be a good starting point, and we would add the support for > > the H6. How does that sound? > > I think the developer abandoned to upstream it because of the previous > problem ;-) > > Maybe it can be taken and add A33&H6 support. If OK, I am going to start some thermal driver work this weekend. : ) Cheers, Yangtao > > > > > Sorry for wasting everybody's time on this. > > > > Maxime > > > > -- > > Maxime Ripard, Bootlin > > Embedded Linux and Kernel engineering > > https://bootlin.com > > _______________________________________________ > > linux-arm-kernel mailing list > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
