On Thu, Feb 29, 2024 at 08:55:11AM +0000, Varshini.Rajendran@xxxxxxxxxxxxx wrote: > Hi Conor, > > On 28/02/24 5:19 pm, Conor Dooley wrote: > > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > > On Wed, Feb 28, 2024 at 07:03:01AM +0000, Varshini.Rajendran@xxxxxxxxxxxxx wrote: > >> Hi Conor, > >> > >> On 25/02/24 1:32 am, Conor Dooley wrote: > >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe > >>> On Fri, Feb 23, 2024 at 10:55:59PM +0530, Varshini Rajendran wrote: > >>>> Add sam9x7 compatible to DT bindings documentation. > >>>> > >>>> Signed-off-by: Varshini Rajendran <varshini.rajendran@xxxxxxxxxxxxx> > >>>> --- > >>>> Changes in v4: > >>>> - Fixed the wrong addition of compatible > >>>> - Added further compatibles that are possible correct (as per DT) > >>>> --- > >>>> .../devicetree/bindings/serial/atmel,at91-usart.yaml | 12 +++++++++--- > >>>> 1 file changed, 9 insertions(+), 3 deletions(-) > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml b/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml > >>>> index 65cb2e5c5eee..30af537e8e81 100644 > >>>> --- a/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml > >>>> +++ b/Documentation/devicetree/bindings/serial/atmel,at91-usart.yaml > >>>> @@ -23,11 +23,17 @@ properties: > >>>> - const: atmel,at91sam9260-dbgu > >>>> - const: atmel,at91sam9260-usart > >>>> - items: > >>>> - - const: microchip,sam9x60-usart > >>>> + - enum: > >>>> + - microchip,sam9x60-usart > >>>> + - microchip,sam9x7-usart > >>>> - const: atmel,at91sam9260-usart > >>>> - items: > >>>> - - const: microchip,sam9x60-dbgu > >>>> - - const: microchip,sam9x60-usart > >>>> + - enum: > >>>> + - microchip,sam9x60-dbgu > >>>> + - microchip,sam9x7-dbgu > >>> > >>>> + - enum: > >>>> + - microchip,sam9x60-usart > >>>> + - microchip,sam9x7-usart > >>> > >>> This doesn't make sense - this enum should be a const. > >>> I don't really understand the idea behind of the original binding here that > >>> allowed: > >>> "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart" > >>> > >>> Specifically, I don't get the purpose of the "microchip,sam9x60-usart". > >>> Either make it > >>> - items: > >>> - enum: > >>> - microchip,sam9x60-dbgu > >>> - microchip,sam9x7-dbgu > >>> - const: microchip,sam9x60-usart > >>> - const: atmel,at91sam9260-dbgu > >>> - const: atmel,at91sam9260-usart > >>> or add > >>> - items: > >>> - const: microchip,sam9x60-dbgu > >>> - const: atmel,at91sam9260-dbgu > >>> - const: atmel,at91sam9260-usart > >>> or explain exactly why this needs to be > >>> "chipa-dgbu", "chipa-usart", "chipb-dbgu", "chipb-dbgu" > >> The compatible has to be "chipa-usart", "chipb-usart", "chipa-dbgu", > >> "chipb-dbgu" for the device to work as a debug console over UART > >> wher the chipa-<periph> is the device specific compatible > >> and the chipb-<periph> is the fallback compatible that the driver > >> actually uses. > > > > This examples why you have "microchip,sam9x60-dbgu", "atmel,at91sam9260-dbgu" > > and "atmel,at91sam9260-usart". > > It does not explain "microchip,sam9x60-usart" though, I don't see what > > purpose that serves. If used as a debug uart, you fall back to the > > sam9260 debug uart compatible and if not you fall back to the sam9260 > > usart compatible. > > > Here, if it is not used as debug uart it has to fallback to the default > usart compatible which in this case should have a device specific > compatible too right? > > The common usart compatible looks as follows, > > compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart"; > > meaning the 1st one is the device specific usart compatible and the 2nd > one is the fallback compatible which the driver actually supports. > > The debug uart looks as follows, > > compatible = "microchip,sam9x60-dbgu", "atmel,at91sam9260-dbgu", > "microchip,sam9x60-usart", "atmel,at91sam9260-usart"; This version here makes a lot more sense than what is currently in use and what is being added in your original patch. I wouldn't object to this being used. > In this case, there is a device specific debug uart compatible, a > fallback tot he debug uart compatible and as you said if not used as a > debug uart it should fallback and work as a normal uart device which has > both a device specific compatible and a fallback to work. > > In case the device specific compatible is supported with some other > features in the driver in the future, the debug uart also should get its > perk. Does this make sense? > > > > In addition, the current setup implies that sam9x60 usart supports all > > the features that the sam9260 debug usart does. I doubt that that is > > true.
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