On Fri, 11 Jun 2021, at 01:53, Rob Herring wrote: > On Tue, Jun 08, 2021 at 06:25:37PM +0800, Steven Lee wrote: > > AST2600 SoC has 2 SGPIO master interfaces one with 128 pins another one > > with 80 pins. Add ast2600-sgpiom0-80 and ast2600-sgpiom-128 compatibles > > and update descriptions to introduce the max number of available gpio > > pins that AST2600 supported. > > > > Signed-off-by: Steven Lee <steven_lee@xxxxxxxxxxxxxx> > > Reviewed-by: Andrew Jeffery <andrew@xxxxxxxx> > > --- > > Documentation/devicetree/bindings/gpio/aspeed,sgpio.yaml | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/gpio/aspeed,sgpio.yaml b/Documentation/devicetree/bindings/gpio/aspeed,sgpio.yaml > > index b2ae211411ff..0e42eded3c1e 100644 > > --- a/Documentation/devicetree/bindings/gpio/aspeed,sgpio.yaml > > +++ b/Documentation/devicetree/bindings/gpio/aspeed,sgpio.yaml > > @@ -10,9 +10,10 @@ maintainers: > > - Andrew Jeffery <andrew@xxxxxxxx> > > > > description: > > - This SGPIO controller is for ASPEED AST2500 SoC, it supports up to 80 full > > - featured Serial GPIOs. Each of the Serial GPIO pins can be programmed to > > - support the following options > > + This SGPIO controller is for ASPEED AST2400, AST2500 and AST2600 SoC, > > + AST2600 have two sgpio master one with 128 pins another one with 80 pins, > > + AST2500/AST2400 have one sgpio master with 80 pins. Each of the Serial > > + GPIO pins can be programmed to support the following options > > - Support interrupt option for each input port and various interrupt > > sensitivity option (level-high, level-low, edge-high, edge-low) > > - Support reset tolerance option for each output port > > @@ -25,6 +26,8 @@ properties: > > enum: > > - aspeed,ast2400-sgpio > > - aspeed,ast2500-sgpio > > + - aspeed,ast2600-sgpiom-80 > > + - aspeed,ast2600-sgpiom-128 > > If the number of GPIOs is the only difference, then I don't think you > should get rid of ngpios. It's one thing if it varies from one SoC to > the next, but if something is per instance we should have a property. > There are two issues: 1. The maximum number of GPIOs supported by the controller 2. The maximum number of GPIOs supported by the platform These are different because of what the controller does - here's some previous discussion on the topic: https://lore.kernel.org/linux-gpio/f2875111-9ba9-43b7-b2a4-d00c8725f5a0@xxxxxxxxxxxxxxxx/ We've used ngpios to describe 2; this decision was made prior to the 2600 design - the SGPIO controller for both the 2400 and 2500 supported a maximum of 80 GPIOs. With the 2600 we have to differentiate between the two SGPIO controllers because they support a different maximum number of GPIOs. The proposed approach of different compatibles keeps the behaviour of ngpios the same across all controller implementations. Cheers, Andrew
