[PATCH] ARM: dts: at91: sam9x60: fix the SOC detection
Conor Dooley
conor at kernel.org
Wed Jul 12 12:42:00 PDT 2023
On Wed, Jul 12, 2023 at 09:30:33PM +0200, Alexandre Belloni wrote:
> On 12/07/2023 19:43:51+0100, Conor Dooley wrote:
> > On Wed, Jul 12, 2023 at 03:30:42PM +0530, Durai Manickam KR wrote:
> > > Remove the dbgu compatible strings in the UART submodule of the
> > > flexcom for the proper SOC detection.
> >
> > I am afraid that I do not understand what this means. The first
> > compatible, before and after your patch, is a sam9x60 one, so I don't
> > see how the SoC comes into it. Grepping to try and understand:
> > rg microchip,sam9x60-usart drivers/
> >
> > rg microchip,sam9x60-dbgu drivers/
> >
> > rg atmel,at91sam9260-dbgu drivers/
> > drivers/soc/atmel/soc.c
> > 259: "atmel,at91sam9260-dbgu");
> >
> > rg atmel,at91sam9260-usart drivers/
> > drivers/tty/serial/atmel_serial.c
> > 2723:OF_EARLYCON_DECLARE(atmel_serial, "atmel,at91sam9260-usart",
> >
> > drivers/mfd/at91-usart.c
> > 50: { .compatible = "atmel,at91sam9260-usart" },
> >
> > It looks like you are trying to avoid the atmel soc driver from
> > detecting the atmel,at91sam9260-dbgu compatible?
> > Is this not actually compatible with the sam9260's debug uart?
> >
> > Please try to explain things in more detail so that people unfamiliar
> > with at91 hardware are not confused. As an outsider, removing
> > compatibles to fix detection seems like it would not work - the sam9x60
> > compatibles are first in the list. To me it seems like this removes,
> > rather than fixes detection, and to fix detection you would need to
> > make some changes to the driver?
> >
> > Also, the binding says:
> > - items:
> > - const: microchip,sam9x60-dbgu
> > - const: microchip,sam9x60-usart
> > - const: atmel,at91sam9260-dbgu
> > - const: atmel,at91sam9260-usart
> >
> > Your patch here makes the dts non-compliant with the bindings, as far as
> > I can tell, so you will need to go and modify the bindings to do this
> > either way.
>
> There can be only one dbgu on a SoC and it has the chipid register. It
> has always been wrong to have a dbgu compatible on the flexcom uart as
> they are not dbgu.
Ahh, thanks for the explanation. Sounds like stuff that might be obvious
to those working on arm stuff all the time, but not all of those CCed on
the patch ;)
The correct thing to do would seem to be updating the dt-binding to
something that permits what is listed below, or just removing the second
compatible, to leave "microchip,sam9x60-usart" in isolation, since that
is permitted also.
> Anyway, my advice has always been that you must not do chipid detection
> on at91 because there is no point in doing it because you need to have
> a correct dts to be able to find the dbgu chipid register so you either
> you already know what you are running on or you are going to read bogus
> registers anyway.
I won't claim to have an opinion on any of that, but sounds like you'd
be better off just reading the board/SoC level compatibles to figure out
what you are running on...
Thanks,
Conor.
> > > Fixes: 99c808335877 (ARM: dts: at91: sam9x60: Add missing flexcom definitions)
> > > Signed-off-by: Durai Manickam KR <durai.manickamkr at microchip.com>
> > > ---
> > > arch/arm/boot/dts/microchip/sam9x60.dtsi | 26 ++++++++++++------------
> > > 1 file changed, 13 insertions(+), 13 deletions(-)
> > >
> > > diff --git a/arch/arm/boot/dts/microchip/sam9x60.dtsi b/arch/arm/boot/dts/microchip/sam9x60.dtsi
> > > index 8b53997675e7..73d570a17269 100644
> > > --- a/arch/arm/boot/dts/microchip/sam9x60.dtsi
> > > +++ b/arch/arm/boot/dts/microchip/sam9x60.dtsi
> > > @@ -172,7 +172,7 @@ flx4: flexcom at f0000000 {
> > > status = "disabled";
> > >
> > > uart4: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <13 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -240,7 +240,7 @@ flx5: flexcom at f0004000 {
> > > status = "disabled";
> > >
> > > uart5: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > atmel,usart-mode = <AT91_USART_MODE_SERIAL>;
> > > interrupts = <14 IRQ_TYPE_LEVEL_HIGH 7>;
> > > @@ -370,7 +370,7 @@ flx11: flexcom at f0020000 {
> > > status = "disabled";
> > >
> > > uart11: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <32 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -419,7 +419,7 @@ flx12: flexcom at f0024000 {
> > > status = "disabled";
> > >
> > > uart12: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <33 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -576,7 +576,7 @@ flx6: flexcom at f8010000 {
> > > status = "disabled";
> > >
> > > uart6: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <9 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -625,7 +625,7 @@ flx7: flexcom at f8014000 {
> > > status = "disabled";
> > >
> > > uart7: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <10 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -674,7 +674,7 @@ flx8: flexcom at f8018000 {
> > > status = "disabled";
> > >
> > > uart8: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <11 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -723,7 +723,7 @@ flx0: flexcom at f801c000 {
> > > status = "disabled";
> > >
> > > uart0: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <5 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -791,7 +791,7 @@ flx1: flexcom at f8020000 {
> > > status = "disabled";
> > >
> > > uart1: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <6 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -859,7 +859,7 @@ flx2: flexcom at f8024000 {
> > > status = "disabled";
> > >
> > > uart2: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <7 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -927,7 +927,7 @@ flx3: flexcom at f8028000 {
> > > status = "disabled";
> > >
> > > uart3: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <8 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -1050,7 +1050,7 @@ flx9: flexcom at f8040000 {
> > > status = "disabled";
> > >
> > > uart9: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <15 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > @@ -1099,7 +1099,7 @@ flx10: flexcom at f8044000 {
> > > status = "disabled";
> > >
> > > uart10: serial at 200 {
> > > - compatible = "microchip,sam9x60-dbgu", "microchip,sam9x60-usart", "atmel,at91sam9260-dbgu", "atmel,at91sam9260-usart";
> > > + compatible = "microchip,sam9x60-usart", "atmel,at91sam9260-usart";
> > > reg = <0x200 0x200>;
> > > interrupts = <16 IRQ_TYPE_LEVEL_HIGH 7>;
> > > dmas = <&dma0
> > > --
> > > 2.25.1
> > >
>
>
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
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