Date:   Mon, 13 Mar 2023 11:33:04 +0100
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Michael Walle <michael@walle.cc>
Cc:     Luke He <sixuerain@gmail.com>, tudor.ambarus@linaro.org,
        pratyush@kernel.org, richard@nod.at, vigneshr@ti.com,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mtd: spi-nor: Add support for XMC XM25QH256C /
 XM25QU256C / XM25QH512C / XM25QU512C site:
 https://www.xmcwh.com/site/product#
Message-ID: <20230313113304.1611638d@xps-13>
In-Reply-To: <d553beb1c6e38eac748d0b6b62bcd335@walle.cc>
References: <20230313100153.15441-1-sixuerain@gmail.com>
        <d553beb1c6e38eac748d0b6b62bcd335@walle.cc>
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Hi Michael,

michael@walle.cc wrote on Mon, 13 Mar 2023 11:08:15 +0100:

> Hi,
>=20
> please have a look at Documentation/process/submitting-patches.rst
> how to properly format patches. But also see below.
>=20
> Am 2023-03-13 11:01, schrieb Luke He:
> > Signed-off-by: Luke He <sixuerain@gmail.com>
> > ---
> >  drivers/mtd/spi-nor/xmc.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> >=20
> > diff --git a/drivers/mtd/spi-nor/xmc.c b/drivers/mtd/spi-nor/xmc.c
> > index 051411e86339..6db01b80237f 100644
> > --- a/drivers/mtd/spi-nor/xmc.c
> > +++ b/drivers/mtd/spi-nor/xmc.c
> > @@ -16,6 +16,18 @@ static const struct flash_info xmc_nor_parts[] =3D {
> >  	{ "XM25QH128A", INFO(0x207018, 0, 64 * 1024, 256)
> >  		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ |
> >  			      SPI_NOR_QUAD_READ) },
> > +	{ "XM25QH256C", INFO(0x204019, 0, 64 * 1024, 512)
> > +		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ |
> > +			      SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
> > +	{ "XM25QU256C", INFO(0x204119, 0, 64 * 1024, 512)
> > +		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ |
> > +			     SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
> > +	{ "XM25QH512C", INFO(0x204020, 0, 64 * 1024, 1024)
> > +		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ |
> > +			     SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) },
> > +	{ "XM25QU512C", INFO(0x204120, 0, 64 * 1024, 1024)
> > +		NO_SFDP_FLAGS(SECT_4K | SPI_NOR_DUAL_READ |
> > +			     SPI_NOR_QUAD_READ | SPI_NOR_4B_OPCODES) } =20
>=20
> I've just looked at XM25QH256C [1], but I suspect all of these
> flashes supports SFDP, therefore you shouldn't use the NO_SFDP_FLAGS.

I didn't check, do we have a kdoc or something like that which explains
what flags to use and when?

> Then, without any additional flags, there is no need for an entry
> at all, because it should be coverered by the "generic spi-nor"
> driver [2].
>=20
> -michael
>=20
> [1] https://www.xmcwh.com/uploads/198/XM25QH256C_Ver1.8.pdf
> [2] https://elixir.bootlin.com/linux/v6.3-rc2/source/drivers/mtd/spi-nor/=
core.c#L1637


Thanks,
Miqu=C3=A8l