Re: [PATCH 2/4] arm: dts: add support for Laird WB50N cpu module and DVK

[Nicolas Ferre <nicolas.ferre@microchip.com>]

On 14/06/2018 at 11:50, Alexandre Belloni wrote:
> On 14/06/2018 09:51:55+0100, Ben Whitten wrote:
>> Signed-off-by: Ben Whitten <ben.whitten@lairdtech.com>
>> ---
>>   arch/arm/boot/dts/Makefile        |   3 +-
>>   arch/arm/boot/dts/at91-wb50n.dts  | 116 ++++++++++++++++++++++
>>   arch/arm/boot/dts/at91-wb50n.dtsi | 202 ++++++++++++++++++++++++++++++++++++++
>>   3 files changed, 320 insertions(+), 1 deletion(-)
>>   create mode 100644 arch/arm/boot/dts/at91-wb50n.dts
>>   create mode 100644 arch/arm/boot/dts/at91-wb50n.dtsi
>>
>> diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
>> index 1ee94ee..fd5f8a6 100644
>> --- a/arch/arm/boot/dts/Makefile
>> +++ b/arch/arm/boot/dts/Makefile
>> @@ -61,7 +61,8 @@ dtb-$(CONFIG_SOC_SAM_V7) += \
>>   	at91-sama5d4_ma5d4evk.dtb \
>>   	at91-sama5d4_xplained.dtb \
>>   	at91-sama5d4ek.dtb \
>> -	at91-vinco.dtb
>> +	at91-vinco.dtb \
>> +	at91-wb50n.dtb
> 
> I know we have been bad at this but this should be
> at91-<soc>-<board>.dtb so at91-sama5d31-wb50n.dtb

See new message by Alexandre.

Actually, the current convention is explained here:
https://elixir.bootlin.com/linux/latest/source/Documentation/arm/Microchip/README#L159

>>   dtb-$(CONFIG_ARCH_ATLAS6) += \
>>   	atlas6-evb.dtb
>>   dtb-$(CONFIG_ARCH_ATLAS7) += \
>> diff --git a/arch/arm/boot/dts/at91-wb50n.dts b/arch/arm/boot/dts/at91-wb50n.dts
>> new file mode 100644
>> index 0000000..ee4f823
>> --- /dev/null
>> +++ b/arch/arm/boot/dts/at91-wb50n.dts
>> @@ -0,0 +1,116 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * at91-wb50n.dts - Device Tree file for wb50n evaluation board
>> + *
>> + *  Copyright (C) 2018 Laird
>> + *
>> + */
>> +
>> +/dts-v1/;
>> +#include "at91-wb50n.dtsi"
>> +
>> +/ {
>> +	model = "Laird Workgroup Bridge 50N - Atmel SAMA5D";
>> +	compatible = "laird,wb50n", "atmel,sama5d31", "atmel,sama5d3", "atmel,sama5";
>> +
>> +	ahb {
>> +		apb {
>> +			watchdog@fffffe40 {
> 
> I don't mind if you want to have a preparation patch adding the
> necessary labels in the soc dtsi so you don't have to reproduce the
> ahb/apb hierarchy here.

I agree: +1

>> +	ahb {
>> +		apb {
>> +			pinctrl@fffff200 {
> 
> Ditto
> 
>> +				board {
>> +					pinctrl_mmc0_cd: mmc0_cd {
>> +						atmel,pins = <AT91_PIOC 26 AT91_PERIPH_GPIO AT91_PINCTRL_PULL_UP_DEGLITCH>; /* PC26 GPIO with pullup deglitch */
>> +					};
>> +
>> +					pinctrl_usba_vbus: usba_vbus {
>> +						atmel,pins = <AT91_PIOB 13 AT91_PERIPH_GPIO AT91_PINCTRL_DEGLITCH>; /* PB13 GPIO with deglitch */
>> +					};
>> +				};
>> +			};
>> +		};
>> +	};
>> +};
>> +
>> +&slow_osc {
>> +	atmel,osc-bypass;
>> +};
> 
> After the clock binding rework, this will have to be moved to the pmc
> node (the rework is not posted, this is just to remind me that this will
> have to be done).
> 
>> +
>> +&usart1_clk {
>> +	atmel,clk-output-range = <0 132000000>;
>> +};
> 
> The datasheet explicitly states that 66 MHz is the maximum allowed
> frequency for the USART. Note that the new binding will not allow you to
> do that.
> 
> However, I see the table disappeared from the latest datasheet. Maybe
> Nicolas can comment on that?

You're right, 66 MHz is the maximum frequency for all USART and UART on 
this sama5d3 SoC.

The disappearing of this table is a bug in the latest datasheet. I can 
see that the one "11121B–ATARM–08-Mar-13" still have it. I report this 
issue to the team in charge of datasheets (it will be certainly fixed 
for next release of this document).

Best regards,
-- 
Nicolas Ferre