| Message ID | 20180307020719.6675-5-andre.przywara@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Mar 07, 2018 at 02:07:18AM +0000, Andre Przywara wrote: > The PWM controllers found in the Allwinner A64, H5 and H6 SoCs are fully > compatible to the PWM controllers found in the A13 and H3. If fully compatible, then shouldn't there be a fallback to one of the existing compatible strings? > Add new compatible strings for those SoCs to the binding document, so > that they can be safely used, together with a fallback string > (preferably "allwinner,sun5i-a13-pwm"). > Add add the optionals "resets" property, needed by the H6. > > Signed-off-by: Andre Przywara <andre.przywara@arm.com> > --- > Documentation/devicetree/bindings/pwm/pwm-sun4i.txt | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt b/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt > index 51ff54c8b8ef..b3a127a0e58c 100644 > --- a/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt > +++ b/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt > @@ -7,11 +7,17 @@ Required properties: > - "allwinner,sun5i-a13-pwm" > - "allwinner,sun7i-a20-pwm" > - "allwinner,sun8i-h3-pwm" > + - "allwinner,sun50i-a64-pwm" > + - "allwinner,sun50i-h5-pwm" > + - "allwinner,sun50i-h6-pwm" > - reg: physical base address and length of the controller's registers > - #pwm-cells: should be 3. See pwm.txt in this directory for a description of > the cells format. > - clocks: From common clock binding, handle to the parent clock. > > +Optional properties: > + - resets: shall be the reset control phandle for the PWM block, if required. > + > Example: > > pwm: pwm@1c20e00 { > -- > 2.14.1 >
Hi, On 08/03/18 02:08, Rob Herring wrote: > On Wed, Mar 07, 2018 at 02:07:18AM +0000, Andre Przywara wrote: >> The PWM controllers found in the Allwinner A64, H5 and H6 SoCs are fully >> compatible to the PWM controllers found in the A13 and H3. > > If fully compatible, then shouldn't there be a fallback to one of the > existing compatible strings? Yes, that was the idea. I was already wondering how we would differentiate that from "real" compatible strings, but couldn't find convincing examples. So should that read: - compatible: should at least contain be one of: - "allwinner,sun4i-a10-pwm" - "allwinner,sun5i-a10s-pwm" - "allwinner,sun5i-a13-pwm" - "allwinner,sun7i-a20-pwm" - "allwinner,sun8i-h3-pwm" May in addition contain one of: - "allwinner,sun50i-a64-pwm" - "allwinner,sun50i-h5-pwm" - "allwinner,sun50i-h6-pwm" And this would possibly need to be amended once we need to actually use one of those strings (to implement a quirk, for instance)? Or is there some other way of reserving those compatible strings, which are not expected to be matched in drivers directly? Cheers, Andre. >> Add new compatible strings for those SoCs to the binding document, so >> that they can be safely used, together with a fallback string >> (preferably "allwinner,sun5i-a13-pwm"). >> Add add the optionals "resets" property, needed by the H6. >> >> Signed-off-by: Andre Przywara <andre.przywara@arm.com> >> --- >> Documentation/devicetree/bindings/pwm/pwm-sun4i.txt | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt b/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt >> index 51ff54c8b8ef..b3a127a0e58c 100644 >> --- a/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt >> +++ b/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt >> @@ -7,11 +7,17 @@ Required properties: >> - "allwinner,sun5i-a13-pwm" >> - "allwinner,sun7i-a20-pwm" >> - "allwinner,sun8i-h3-pwm" >> + - "allwinner,sun50i-a64-pwm" >> + - "allwinner,sun50i-h5-pwm" >> + - "allwinner,sun50i-h6-pwm" >> - reg: physical base address and length of the controller's registers >> - #pwm-cells: should be 3. See pwm.txt in this directory for a description of >> the cells format. >> - clocks: From common clock binding, handle to the parent clock. >> >> +Optional properties: >> + - resets: shall be the reset control phandle for the PWM block, if required. >> + >> Example: >> >> pwm: pwm@1c20e00 { >> -- >> 2.14.1 >>
On Thu, Mar 8, 2018 at 3:09 AM, Andre Przywara <andre.przywara@arm.com> wrote: > Hi, > > On 08/03/18 02:08, Rob Herring wrote: >> On Wed, Mar 07, 2018 at 02:07:18AM +0000, Andre Przywara wrote: >>> The PWM controllers found in the Allwinner A64, H5 and H6 SoCs are fully >>> compatible to the PWM controllers found in the A13 and H3. >> >> If fully compatible, then shouldn't there be a fallback to one of the >> existing compatible strings? > > Yes, that was the idea. I was already wondering how we would > differentiate that from "real" compatible strings, but couldn't find > convincing examples. So should that read: > > - compatible: should at least contain be one of: > - "allwinner,sun4i-a10-pwm" > - "allwinner,sun5i-a10s-pwm" > - "allwinner,sun5i-a13-pwm" > - "allwinner,sun7i-a20-pwm" > - "allwinner,sun8i-h3-pwm" > May in addition contain one of: > - "allwinner,sun50i-a64-pwm" > - "allwinner,sun50i-h5-pwm" > - "allwinner,sun50i-h6-pwm" I can't validate a dts is correct with it written like this. Just list each valid combination on each line: "allwinner,sun8i-h3-pwm", "allwinner,sun50i-h6-pwm" (Assuming "allwinner,sun50i-h6-pwm" was the first implementation and h3 has the same block). > And this would possibly need to be amended once we need to actually use > one of those strings (to implement a quirk, for instance)? The most specific compatible provides that. The driver matches on the least specific one until you have a quirk to implement. > Or is there some other way of reserving those compatible strings, which > are not expected to be matched in drivers directly? The binding should just list all that are appropriate from the start and the driver is free to match on which ever string it wants. Rob
Hi, On 08/03/18 14:37, Rob Herring wrote: > On Thu, Mar 8, 2018 at 3:09 AM, Andre Przywara <andre.przywara@arm.com> wrote: >> Hi, >> >> On 08/03/18 02:08, Rob Herring wrote: >>> On Wed, Mar 07, 2018 at 02:07:18AM +0000, Andre Przywara wrote: >>>> The PWM controllers found in the Allwinner A64, H5 and H6 SoCs are fully >>>> compatible to the PWM controllers found in the A13 and H3. >>> >>> If fully compatible, then shouldn't there be a fallback to one of the >>> existing compatible strings? >> >> Yes, that was the idea. I was already wondering how we would >> differentiate that from "real" compatible strings, but couldn't find >> convincing examples. So should that read: >> >> - compatible: should at least contain be one of: >> - "allwinner,sun4i-a10-pwm" >> - "allwinner,sun5i-a10s-pwm" >> - "allwinner,sun5i-a13-pwm" >> - "allwinner,sun7i-a20-pwm" >> - "allwinner,sun8i-h3-pwm" >> May in addition contain one of: >> - "allwinner,sun50i-a64-pwm" >> - "allwinner,sun50i-h5-pwm" >> - "allwinner,sun50i-h6-pwm" > > I can't validate a dts is correct with it written like this. Just list > each valid combination on each line: > > "allwinner,sun8i-h3-pwm", "allwinner,sun50i-h6-pwm" > > (Assuming "allwinner,sun50i-h6-pwm" was the first implementation and > h3 has the same block). Ah, OK, that's makes some sense. I didn't find too many examples outside of root compatible nodes in the binding docs, but I will use that. >> And this would possibly need to be amended once we need to actually use >> one of those strings (to implement a quirk, for instance)? > > The most specific compatible provides that. The driver matches on the > least specific one until you have a quirk to implement. Yeah, I was just wondering how a (non-Linux) driver author would induce what strings are actually needed just by reading the binding. But enumerating the combinations explicitly should solve this. Thanks! Andre. >> Or is there some other way of reserving those compatible strings, which >> are not expected to be matched in drivers directly? > > The binding should just list all that are appropriate from the start > and the driver is free to match on which ever string it wants. > > Rob >
diff --git a/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt b/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt index 51ff54c8b8ef..b3a127a0e58c 100644 --- a/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt +++ b/Documentation/devicetree/bindings/pwm/pwm-sun4i.txt @@ -7,11 +7,17 @@ Required properties: - "allwinner,sun5i-a13-pwm" - "allwinner,sun7i-a20-pwm" - "allwinner,sun8i-h3-pwm" + - "allwinner,sun50i-a64-pwm" + - "allwinner,sun50i-h5-pwm" + - "allwinner,sun50i-h6-pwm" - reg: physical base address and length of the controller's registers - #pwm-cells: should be 3. See pwm.txt in this directory for a description of the cells format. - clocks: From common clock binding, handle to the parent clock. +Optional properties: + - resets: shall be the reset control phandle for the PWM block, if required. + Example: pwm: pwm@1c20e00 {
The PWM controllers found in the Allwinner A64, H5 and H6 SoCs are fully compatible to the PWM controllers found in the A13 and H3. Add new compatible strings for those SoCs to the binding document, so that they can be safely used, together with a fallback string (preferably "allwinner,sun5i-a13-pwm"). Add add the optionals "resets" property, needed by the H6. Signed-off-by: Andre Przywara <andre.przywara@arm.com> --- Documentation/devicetree/bindings/pwm/pwm-sun4i.txt | 6 ++++++ 1 file changed, 6 insertions(+)