Re: [PATCH v4 3/3] mtd: spi-nor: Add support for IS25LX256 operating in 1S-8S-8S octal read mode

From: Tudor Ambarus <tudor.ambarus@linaro.org>
To: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Cc: greg.malysa@timesys.com,
	Tudor Ambarus <tudor.ambarus@microchip.com>,
	Pratyush Yadav <pratyush@kernel.org>,
	Michael Walle <michael@walle.cc>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	"open list:SPI NOR SUBSYSTEM" <linux-mtd@lists.infradead.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 3/3] mtd: spi-nor: Add support for IS25LX256 operating in 1S-8S-8S octal read mode
Date: Mon, 26 Dec 2022 10:17:07 +0200	[thread overview]
Message-ID: <eafebda5-7342-dfa9-7745-543d5f7d6f3d@linaro.org> (raw)
In-Reply-To: <9927a8c3-40cf-2c69-46c6-f660ff2422b1@linaro.org>

On 26.12.2022 10:04, Tudor Ambarus wrote:
> Hi, Nathan,
> 
> The series is starting to look good, but I'll need another version,
> please.
> 
> On 02.12.2022 15:55, Nathan Barrett-Morrison wrote:
>> This adds the IS25LX256 chip into the ISSI flash_info parts table
> 
> Describe your changes in imperative mood, e.g. "Add support for
> S25LX256" instead of "This adds ..."
> 
> It may worth to re-read
> https://www.kernel.org/doc/html/latest/process/submitting-patches.html
> once in a while.
> 
>>
>> Signed-off-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
>> ---
>>   drivers/mtd/spi-nor/issi.c | 32 ++++++++++++++++++++++++++++++++
>>   1 file changed, 32 insertions(+)
>>
>> diff --git a/drivers/mtd/spi-nor/issi.c b/drivers/mtd/spi-nor/issi.c
>> index 89a66a19d754..362bc3603d8f 100644
>> --- a/drivers/mtd/spi-nor/issi.c
>> +++ b/drivers/mtd/spi-nor/issi.c
>> @@ -29,6 +29,35 @@ static const struct spi_nor_fixups is25lp256_fixups 
>> = {
>>       .post_bfpt = is25lp256_post_bfpt_fixups,
>>   };
>> +static int
>> +is25lx256_post_bfpt_fixups(struct spi_nor *nor,
>> +               const struct sfdp_parameter_header *bfpt_header,
>> +               const struct sfdp_bfpt *bfpt)
>> +{
>> +    /*
>> +     * IS25LX256 supports both 1S-1S-8S and 1S-8S-8S.
>> +     * However, the BFPT does not contain any information denoting this
>> +     * functionality, so the proper fast read opcodes are never setup.
>> +     * We're correcting this issue via the fixup below.  Page program
>> +     * commands are detected and setup properly via the 4BAIT lookup.
>> +     */

Why don't you set the READ support when parsing the 4bait table? We need
to see the SFDP dump to determine how we treat this. I'm not sure a
post_bfpt hook is the right thing to do for this flash.

Thanks,
ta