Re: [PATCH v2 2/2] mtd: spi-nor: Add Renesas AT25QL128A serial nor flash

From: <Tudor.Ambarus@microchip.com>
To: <biju.das.jz@bp.renesas.com>, <p.yadav@ti.com>,
	<miquel.raynal@bootlin.com>, <richard@nod.at>, <vigneshr@ti.com>
Cc: <michael@walle.cc>, <Nicolas.Ferre@microchip.com>,
	<alexandre.belloni@bootlin.com>, <Claudiu.Beznea@microchip.com>,
	<linux-mtd@lists.infradead.org>,
	<linux-arm-kernel@lists.infradead.org>, <geert+renesas@glider.be>,
	<Chris.Paterson2@renesas.com>, <biju.das@bp.renesas.com>,
	<prabhakar.mahadev-lad.rj@bp.renesas.com>,
	<linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH v2 2/2] mtd: spi-nor: Add Renesas AT25QL128A serial nor flash
Date: Thu, 21 Jul 2022 08:28:43 +0000	[thread overview]
Message-ID: <7aa7de93-23f0-c94a-bfc3-e79321cdc1f9@microchip.com> (raw)
In-Reply-To: <20220715105716.2415068-3-biju.das.jz@bp.renesas.com>

On 7/15/22 13:57, Biju Das wrote:

Hi, Biju!

> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Add support for Renesas AT25QL128A serial nor flash.
> Details of flash chip can be found here [1]
> 
> [1] https://www.dialog-semiconductor.com/sites/default/files/2022-04/DS-AT25QL128A-129F-022022.pdf
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
> $ xxd -p sfdp
> 53464450060101ff00060110300000ff1f00010280000001ffffffffffff
> ffffffffffffffffffffffffffffffffffffe520f1ffffffff0744eb086b
> 083b80bbfeffffffffff00ffffff42eb0c200f5210d800ff3362d5008429
> 01ceeca1073d7a757a75f7a2d55c19f61cffe810c080ffffffffffffffff
> ffffffffffffffff501650190000ffff
> 
> $ md5sum /sys/devices/platform/soc/10060000.spi/rpc-if-spi/spi_master/spi1/spi1.0/spi-nor/sfdp
> 23e3ec56b5b8f986d0488ba4727239dd  /sys/devices/platform/soc/10060000.spi/rpc-if-spi/spi_master/spi1/spi1.0/spi-nor/sfdp
> $ cat /sys/devices/platform/soc/10060000.spi/rpc-if-spi/spi_master/spi1/spi1.0/spi-nor/jedec_id
> 1f4218
> $ cat /sys/devices/platform/soc/10060000.spi/rpc-if-spi/spi_master/spi1/spi1.0/spi-nor/partname
> at25ql128a
> $ cat /sys/devices/platform/soc/10060000.spi/rpc-if-spi/spi_master/spi1/spi1.0/spi-nor/manufacturer
> atmel
> v2->v1:
>  * Added flash definitions into Atmel table.
> RFC->v1:
>  * Moved the flash definitions to atmel.c
>  * Remove macro related to locking as it is untested.
>  * Replaced INFO macro with SNOR_ID3
> 
> RFC:
>  * https://patchwork.kernel.org/project/linux-renesas-soc/patch/20220501185512.51158-1-biju.das.jz@bp.renesas.com/
> ---
>  drivers/mtd/spi-nor/atmel.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/mtd/spi-nor/atmel.c b/drivers/mtd/spi-nor/atmel.c
> index 656dd80a0be7..80c24d138b27 100644
> --- a/drivers/mtd/spi-nor/atmel.c
> +++ b/drivers/mtd/spi-nor/atmel.c
> @@ -186,6 +186,7 @@ static const struct flash_info atmel_nor_parts[] = {
>                 .fixups = &atmel_nor_global_protection_fixups },
>         { "at25sl321",  INFO(0x1f4216, 0, 64 * 1024, 64)
>                 NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> +       { "at25ql128a", SNOR_ID3(0x1f4218) },

As the flash is defined now, all its characteristics can be discovered by
parsing SFDP. So instead of adding a new flash_info entry in the already
big array that we have, I would like us to focus more on a generic flash
driver which acts as a backup when the flash is not found in the flash_info
array. We can discover the flash particularities by parsing SFDP and we can
probe the flash based on that. Michael has already suggested this, would you
please help review it?

https://lore.kernel.org/lkml/20220513133520.3945820-1-michael@walle.cc/

>         { "at26f004",   INFO(0x1f0400, 0, 64 * 1024,  8)
>                 NO_SFDP_FLAGS(SECT_4K) },
>         { "at26df081a", INFO(0x1f4501, 0, 64 * 1024, 16)
> --
> 2.25.1
> 

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