[PATCH v2] mtd: spi-nor: Add support for N25Q256A13 as N25Q256A

[岩松信洋 / IWAMATSU，NOBUHIRO]

Hi,

Thanks for your review.

> -----Original Message-----
> From: Cyrille Pitchen [mailto:cyrille.pitchen at atmel.com]
> Sent: Monday, January 30, 2017 10:29 PM
> To: 岩松信洋 / IWAMATSU，NOBUHIRO; linux-mtd at lists.infradead.org
> Cc: Marek Vasut; Jagan Teki
> Subject: Re: [PATCH v2] mtd: spi-nor: Add support for N25Q256A13 as N25Q256A
> 
> Hi Nobuhiro,
> 
> Le 27/01/2017 à 02:51, Nobuhiro Iwamatsu a écrit :
> > Add new Micron N25Q256A (N25Q256A13) 256Mbit NOR Flash in the list of
> > supported devices. This chip has the same structure as the N25Q256A
> > but ID is different. And this fixes N25Q256A to N25Q256 to fit chip
> > name to other n25q chip names.
> >
> > Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.kw at hitachi.com>
> > CC: Jagan Teki <jagan at openedev.com>
> > CC: Marek Vasut <marek.vasut at gmail.com>
> > ---
> >  drivers/mtd/spi-nor/spi-nor.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c
> > b/drivers/mtd/spi-nor/spi-nor.c index da7cd69d4857..a2a6922e356f
> > 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -887,7 +887,8 @@ static const struct flash_info spi_nor_ids[] = {
> >  	{ "n25q064a",    INFO(0x20bb17, 0, 64 * 1024,  128, SECT_4K |
> SPI_NOR_QUAD_READ) },
> >  	{ "n25q128a11",  INFO(0x20bb18, 0, 64 * 1024,  256, SECT_4K |
> SPI_NOR_QUAD_READ) },
> >  	{ "n25q128a13",  INFO(0x20ba18, 0, 64 * 1024,  256, SECT_4K |
> SPI_NOR_QUAD_READ) },
> > -	{ "n25q256a",    INFO(0x20ba19, 0, 64 * 1024,  512, SECT_4K |
> SPI_NOR_QUAD_READ) },
> > +	{ "n25q256",     INFO(0x20ba19, 0, 64 * 1024,  512, SECT_4K |
> SPI_NOR_QUAD_READ) },
> > +	{ "n25q256a",    INFO(0x20bb19, 0, 64 * 1024,  512, SECT_4K |
> SPI_NOR_QUAD_READ) },
> 
> This patch changes the association "n25q256a" <-> 20 ba 19: "n25q256a"
> would be now associated to 20 bb 19.
> However some device trees use the "micron,n25q256a" as compatible string:
> - arch/arm/boot/dts/imx6sx-sbd.dts: compatible = "micron,n25q256a",
> "jedec,spi-nor";
> - arch/arm/boot/dts/socfpga_arria5_socdk.dts: compatible = "n25q256a";
> - arch/arm/boot/dts/socfpga_cyclone5_socrates.dts: compatible =
> "n25q256a";
> - arch/arm/boot/dts/imx6ul-14x14-evk.dts: compatible =
> "micron,n25q256a";
> 
> If the actual JEDEC ID read from the Micron SPI memory of one of these boards
> is 20 ba 19 and if you now associate the string "n25q256a" to the different
> JEDEC ID 20 bb 19, then spi_nor_scan() is likely to display the warning
> message during the boot:
> 
> dev_warn(dev, "found %s, expected %s\n", jinfo->name, info->name);
> 
> 
> Displaying such a warning during the boot process would be an unwanted side
> effect of this patch and users may complain or ask why such warning is now
> displayed in the boot log.
> 

I see.

> You may create a new entry for the 20 bb 19 JEDEC ID but I don't think it
> is totally safe to remove the old n25q256a entry.

We can not solve this problem if we use an old DTB, but I think that this
problem can be solved by updating DTS.
In order not to output this warning, I think that it is necessary to change the
DTS of the target boards.
Is this right?

> 
> Best regards,
> 
> Cyrille

Best regards,
  Nobuhiro