From: Thierry Reding <treding@nvidia.com>
The PWM controller found on Tegra264 is largely compatible with the one
on prior generations, but it comes with some extra features, hence a new
compatible string is needed.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---
Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml | 2 ++
1 file changed, 2 insertions(+)
diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml
index 41cea4979132..15706d2a808d 100644
--- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml
+++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml
@@ -16,6 +16,8 @@ properties:
- enum:
- nvidia,tegra20-pwm
- nvidia,tegra186-pwm
+ - nvidia,tegra194-pwm
+ - nvidia,tegra264-pwm
- items:
- enum:
--
2.53.0On Wed, Mar 25, 2026 at 07:16:59PM +0900, Mikko Perttunen wrote: > From: Thierry Reding <treding@nvidia.com> > > The PWM controller found on Tegra264 is largely compatible with the one > on prior generations, but it comes with some extra features, hence a new > compatible string is needed. Same comments as before. Best regards, Krzysztof
On Wed, Mar 25, 2026 at 07:16:59PM +0900, Mikko Perttunen wrote: > From: Thierry Reding <treding@nvidia.com> > > The PWM controller found on Tegra264 is largely compatible with the one > on prior generations, but it comes with some extra features, hence a new > compatible string is needed. > > Signed-off-by: Thierry Reding <treding@nvidia.com> > Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com> > --- > Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > index 41cea4979132..15706d2a808d 100644 > --- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > @@ -16,6 +16,8 @@ properties: > - enum: > - nvidia,tegra20-pwm > - nvidia,tegra186-pwm > + - nvidia,tegra194-pwm > + - nvidia,tegra264-pwm I think this was lost during the earlier conversation we had on the split of these patches. Krzysztof had pointed out that tegra194-pwm is now a duplicate entry. I don't know exactly how it ended up like this, but I'm pretty sure what I meant was: - items: - const: tegra264-pwm - const: tegra194-pwm This mirrors the fact that this is in fact backwards-compatible with Tegra194 but also has additional features that we need the Tegra264 compatible string for. Krzysztof also requested that we drop the latter part of, or reword, the commit message because we always want the compatible string to be added, regardless of backwards-compatibility, etc. So I think maybe something like this would be better for the commit message: The PWM controller found on Tegra264 is largely compatible with the one on prior generations, but it comes with some extra features. The new Tegra264-specific compatible string can be used to distinguish between the feature sets. Thierry
On Wed, Mar 25, 2026 at 03:22:13PM +0100, Thierry Reding wrote: > On Wed, Mar 25, 2026 at 07:16:59PM +0900, Mikko Perttunen wrote: > > From: Thierry Reding <treding@nvidia.com> > > > > The PWM controller found on Tegra264 is largely compatible with the one > > on prior generations, but it comes with some extra features, hence a new > > compatible string is needed. > > > > Signed-off-by: Thierry Reding <treding@nvidia.com> > > Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com> > > --- > > Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > index 41cea4979132..15706d2a808d 100644 > > --- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > @@ -16,6 +16,8 @@ properties: > > - enum: > > - nvidia,tegra20-pwm > > - nvidia,tegra186-pwm > > + - nvidia,tegra194-pwm > > + - nvidia,tegra264-pwm > > I think this was lost during the earlier conversation we had on the > split of these patches. Krzysztof had pointed out that tegra194-pwm is > now a duplicate entry. I don't know exactly how it ended up like this, > but I'm pretty sure what I meant was: > > - items: > - const: tegra264-pwm > - const: tegra194-pwm > > This mirrors the fact that this is in fact backwards-compatible with > Tegra194 but also has additional features that we need the Tegra264 > compatible string for. If the devices are compatible. You have quite a lot of differences in the driver, so the question is whether driver will work fine when bound via old interface. This was EXACTLY explained in DTS101 last year. I really focused on that because after repeating for few years and two previous speeches people still claim compatibility is something else. :( Best regards, Krzysztof
On 2026-03-25 15:22 +0100, Thierry Reding wrote: > On Wed, Mar 25, 2026 at 07:16:59PM +0900, Mikko Perttunen wrote: > > From: Thierry Reding <treding@nvidia.com> > > > > The PWM controller found on Tegra264 is largely compatible with the one > > on prior generations, but it comes with some extra features, hence a new > > compatible string is needed. > > > > Signed-off-by: Thierry Reding <treding@nvidia.com> > > Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com> > > --- > > Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > index 41cea4979132..15706d2a808d 100644 > > --- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > @@ -16,6 +16,8 @@ properties: > > - enum: > > - nvidia,tegra20-pwm > > - nvidia,tegra186-pwm > > + - nvidia,tegra194-pwm > > + - nvidia,tegra264-pwm > > I think this was lost during the earlier conversation we had on the > split of these patches. Krzysztof had pointed out that tegra194-pwm is > now a duplicate entry. I don't know exactly how it ended up like this, > but I'm pretty sure what I meant was: > > - items: > - const: tegra264-pwm > - const: tegra194-pwm Ah, I see now. > > This mirrors the fact that this is in fact backwards-compatible with > Tegra194 but also has additional features that we need the Tegra264 > compatible string for. The Tegra264 PWM controller is in fact not backwards compatible with Tegra194. It is close but not quite. I will drop the duplicate tegra194 compatible string and update the commit message accordingly. Mikko > > Krzysztof also requested that we drop the latter part of, or reword, the > commit message because we always want the compatible string to be added, > regardless of backwards-compatibility, etc. > > So I think maybe something like this would be better for the commit > message: > > The PWM controller found on Tegra264 is largely compatible with the one > on prior generations, but it comes with some extra features. The new > Tegra264-specific compatible string can be used to distinguish between > the feature sets. > > Thierry
On Thu, Mar 26, 2026 at 09:47:30AM +0900, Mikko Perttunen wrote: > On 2026-03-25 15:22 +0100, Thierry Reding wrote: > > On Wed, Mar 25, 2026 at 07:16:59PM +0900, Mikko Perttunen wrote: > > > From: Thierry Reding <treding@nvidia.com> > > > > > > The PWM controller found on Tegra264 is largely compatible with the one > > > on prior generations, but it comes with some extra features, hence a new > > > compatible string is needed. > > > > > > Signed-off-by: Thierry Reding <treding@nvidia.com> > > > Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com> > > > --- > > > Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml | 2 ++ > > > 1 file changed, 2 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > > index 41cea4979132..15706d2a808d 100644 > > > --- a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > > +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.yaml > > > @@ -16,6 +16,8 @@ properties: > > > - enum: > > > - nvidia,tegra20-pwm > > > - nvidia,tegra186-pwm > > > + - nvidia,tegra194-pwm > > > + - nvidia,tegra264-pwm > > > > I think this was lost during the earlier conversation we had on the > > split of these patches. Krzysztof had pointed out that tegra194-pwm is > > now a duplicate entry. I don't know exactly how it ended up like this, > > but I'm pretty sure what I meant was: > > > > - items: > > - const: tegra264-pwm > > - const: tegra194-pwm > > Ah, I see now. > > > > > This mirrors the fact that this is in fact backwards-compatible with > > Tegra194 but also has additional features that we need the Tegra264 > > compatible string for. > > The Tegra264 PWM controller is in fact not backwards compatible with > Tegra194. It is close but not quite. I will drop the duplicate tegra194 > compatible string and update the commit message accordingly. Ah... I remembered this wrongly. Yes, since the enable bit was moved to a different register, we cannot claim backwards-compatibility. Thierry
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