Messages in this thread | | | Date | Thu, 21 Aug 2014 08:39:43 -0700 | Subject | Re: [PATCH 1/4] ARM: rockchip: rk3288: Switch to use the proper PWM IP | From | Doug Anderson <> |
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Thierry and Heiko
On Wed, Aug 20, 2014 at 11:24 PM, Thierry Reding <thierry.reding@gmail.com> wrote: > On Wed, Aug 20, 2014 at 08:55:09AM -0700, Doug Anderson wrote: >> On Wed, Aug 20, 2014 at 8:38 AM, Thierry Reding <thierry.reding@gmail.com> wrote: > [...] >> > Looking at the register offsets in the device tree that seems likely. At >> > least PWMs 0 and 1 as well as 2 and 3 seem like they could be in the >> > same IP block. Their placement in the register map is somewhat strange: >> > >> > pwm0: pwm@20030000 { >> > ... >> > reg = <0x20030000 0x10>; >> > ... >> > clocks = <&cru PCLK_PWM01>; >> > ... >> > }; >> > >> > pwm1: pwm@20030010 { >> > ... >> > reg = <0x20030010 0x10>; >> > ... >> > clocks = <&cru PCLK_PWM01>; >> > ... >> > }; >> > >> > ... >> > >> > pwm2: pwm@20050020 { >> > ... >> > reg = <0x20050020 0x10>; >> > ... >> > clocks = <&cru PCLK_PWM23>; >> > ... >> > }; >> > >> > pwm3: pwm@20050030 { >> > ... >> > reg = <0x20050030 0x10>; >> > ... >> > clocks = <&cru PCLK_PWM23>; >> > ... >> > }; >> >> Ah, you're looking at "rk3xxx.dtsi". That doesn't apply to rk3288 >> (the downsides of trying to guess ahead of time what SoC vendors will >> name new models). >> >> In rk3288 they have the same clocks. See patch #3 in this series. >> >> >> > The clocks would also indicate that there are actually two blocks. I >> > seem to remember a discussion about whether to handle them as a single >> > block or two/four, but I can't seem to find a reference to it. Maybe I'm >> > confusing it with another driver. >> >> At this point it seems like the choice has already been made to handle >> them as separate PWMs. I can change this choice if you want... > > Well, looking at patch 3/4 this really does seem to be one single block > providing four PWM channels, so the right thing to do would be to > represent it in one device tree node. But I'll leave it up to Heiko to > decide how he wants to handle this. > > One downside of describing it as one device is that it would make the > pinmux handling slightly more difficult, since presumably you'd only > want to apply the pinmux settings when a channel is actually being used. > Currently the pinmux doesn't apply as long as the device remains > disabled in device tree (though enabling it doesn't necessarily mean > that it's being used). > > Like I said, it's up to Heiko to decide whether it's worth making this > change (and it'd make sense to apply it to existing DTS files > retroactively) or better to keep what we have.
Please let me know if you'd like me to spin. Otherwise I'll assume this is OK as is.
-Doug
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