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Subject: Re: [PATCH 22/24] ARM: at91: sama7: introduce sama7 SoC family
To:     Claudiu Beznea - M18063 <Claudiu.Beznea@microchip.com>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>
CC:     Ludovic Desroches - M43218 <Ludovic.Desroches@microchip.com>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "linux@armlinux.org.uk" <linux@armlinux.org.uk>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Eugen Hristev - M18282 <Eugen.Hristev@microchip.com>
References: <20210331105908.23027-1-claudiu.beznea@microchip.com>
 <20210331105908.23027-23-claudiu.beznea@microchip.com>
 <YGSc1L8yW0KniOsx@piout.net>
 <a908274a-c4d2-faab-54a4-31fd0ffeab7e@microchip.com>
 <21bd4417-a754-8ee6-370e-4fb4e0f1fef9@microchip.com>
From:   Nicolas Ferre <nicolas.ferre@microchip.com>
Organization: microchip
Message-ID: <51dbcf0b-4ee6-10c9-9598-a451cca16905@microchip.com>
Date:   Thu, 8 Apr 2021 17:24:39 +0200
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On 01/04/2021 at 12:24, Claudiu Beznea - M18063 wrote:
> On 01.04.2021 12:38, Claudiu Beznea - M18063 wrote:
>> On 31.03.2021 19:01, Alexandre Belloni wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> On 31/03/2021 13:59:06+0300, Claudiu Beznea wrote:
>>>> From: Eugen Hristev <eugen.hristev@microchip.com>
>>>>
>>>> Introduce new family of SoCs, sama7, and first SoC, sama7g5.
>>>>
>>>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>>>> Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
>>>> ---
>>>>   arch/arm/mach-at91/Makefile |  1 +
>>>>   arch/arm/mach-at91/sama7.c  | 48 +++++++++++++++++++++++++++++++++++++
>>>>   2 files changed, 49 insertions(+)
>>>>   create mode 100644 arch/arm/mach-at91/sama7.c
>>>>
>>>> diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
>>>> index f565490f1b70..6cc6624cddac 100644
>>>> --- a/arch/arm/mach-at91/Makefile
>>>> +++ b/arch/arm/mach-at91/Makefile
>>>> @@ -9,6 +9,7 @@ obj-$(CONFIG_SOC_AT91SAM9)    += at91sam9.o
>>>>   obj-$(CONFIG_SOC_SAM9X60)    += sam9x60.o
>>>>   obj-$(CONFIG_SOC_SAMA5)              += sama5.o
>>>>   obj-$(CONFIG_SOC_SAMV7)              += samv7.o
>>>> +obj-$(CONFIG_SOC_SAMA7)              += sama7.o
>>>>
>>>>   # Power Management
>>>>   obj-$(CONFIG_ATMEL_PM)               += pm.o pm_suspend.o
>>>> diff --git a/arch/arm/mach-at91/sama7.c b/arch/arm/mach-at91/sama7.c
>>>> new file mode 100644
>>>> index 000000000000..e04cadb569ad
>>>> --- /dev/null
>>>> +++ b/arch/arm/mach-at91/sama7.c
>>>> @@ -0,0 +1,48 @@
>>>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>>> +/*
>>>> + * Setup code for SAMA7
>>>> + *
>>>> + * Copyright (C) 2021 Microchip Technology, Inc. and its subsidiaries
>>>> + *
>>>> + */
>>>> +
>>>> +#include <linux/of.h>
>>>> +#include <linux/of_platform.h>
>>>> +
>>>> +#include <asm/mach/arch.h>
>>>> +#include <asm/system_misc.h>
>>>> +
>>>> +#include "generic.h"
>>>> +
>>>> +static void __init sama7_common_init(void)
>>>> +{
>>>> +     of_platform_default_populate(NULL, NULL, NULL);
>>>
>>> Is this necessary? This is left as a workaround for the old SoCs using
>>> pinctrl-at91. I guess this will be using pio4 so this has to be removed.
>>
>> OK, I'll have a look. BTW, SAMA5D2 which is also using PIO4 calls
>> of_platform_default_populate(NULL, NULL, NULL);
> 
> Without this call the PM code (arch/arm/mach-at/pm.c) is not able to locate
> proper DT nodes:
> 
> [    0.194615] at91_pm_backup_init: failed to find securam device!
> [    0.201393] at91_pm_sram_init: failed to find sram device!
> [    0.207449] AT91: PM not supported, due to no SRAM allocated

Okay, so we can't afford removing these calls to sama5d2 and upcoming 
sama7g5 right now.

Is it a common pattern to have to reach DT content in the early stages 
that explicit call to of_platform_default_populate() tries to solve?

Best regards,
   Nicolas


>>>> +}
>>>> +
>>>> +static void __init sama7_dt_device_init(void)
>>>> +{
>>>> +     sama7_common_init();
>>>> +}
>>>> +
>>>> +static const char *const sama7_dt_board_compat[] __initconst = {
>>>> +     "microchip,sama7",
>>>> +     NULL
>>>> +};
>>>> +
>>>> +DT_MACHINE_START(sama7_dt, "Microchip SAMA7")
>>>> +     /* Maintainer: Microchip */
>>>> +     .init_machine   = sama7_dt_device_init,
>>>> +     .dt_compat      = sama7_dt_board_compat,
>>>> +MACHINE_END
>>>> +
>>>> +static const char *const sama7g5_dt_board_compat[] __initconst = {
>>>> +     "microchip,sama7g5",
>>>> +     NULL
>>>> +};
>>>> +
>>>> +DT_MACHINE_START(sama7g5_dt, "Microchip SAMA7G5")
>>>> +     /* Maintainer: Microchip */
>>>> +     .init_machine   = sama7_dt_device_init,
>>>> +     .dt_compat      = sama7g5_dt_board_compat,
>>>> +MACHINE_END
>>>> +
>>>> --
>>>> 2.25.1
>>>>
>>>
>>> --
>>> Alexandre Belloni, co-owner and COO, Bootlin
>>> Embedded Linux and Kernel engineering
>>> https://bootlin.com
>>>
>>
> 


-- 
Nicolas Ferre