[RFC PATCH v1 6/6] mtd: spi-nor: introduce support for displaying deprecation message

[Michael Walle]

Hi,

On Wed Apr 17, 2024 at 5:52 PM CEST, Pratyush Yadav wrote:
> On Wed, Apr 17 2024, Michael Walle wrote:
> > On Wed Apr 17, 2024 at 4:36 PM CEST, Pratyush Yadav wrote:
> >> On Fri, Apr 12 2024, Michael Walle wrote:
> >>
> >> > SPI-NOR will automatically detect the attached flash device most of the
> >> > time. We cannot easily find out if boards are using a given flash.
> >> > Therefore, introduce a (temporary) flag to display a message on boot if
> >>
> >> Why temporary? There will always be a need to deprecate one flash or
> >> another. Might as well keep the flag around.
> >
> > Mh, yes I agree. That also means that this flag will not have any
> > users (most) of the time (hopefully ;) ).
> >
> >> Also, this patch/series does not add any users of the deprecated flag.
> >> If you have some flashes in mind, it would be good to add them to the
> >> patch/series.
> >
> > This is just an RFC to see if whether you Tudor agree with me :) But
> > I was about to add it to the evervision/cypress FRAMs.
> >
> >> I like the idea in general. Do you think we should also print a rough
> >> date for the deprecation as well?
> >
> > Might make sense, any suggestions?
>
> How about a simple string to flash_info?

Ahh, I was rather asking if you already had a time frame in mind.

Besides that, should it be a date or a (future) kernel version?
Roughly about two/three kernel releases?

> /**
>  * struct flash_info - SPI NOR flash_info entry.
>  * @id:   pointer to struct spi_nor_id or NULL, which means "no ID" (mostly
>  *        older chips).
>  * @name: (obsolete) the name of the flash. Do not set it for new additions.
>  * @size:           the size of the flash in bytes.
>  * @deprecation_date: The date after which the support for this flash will be
>  *                    removed.
>  * [...]
>  */
> struct flash_info {
> 	char *name;
> 	const struct spi_nor_id *id;
> 	char *deprecation_date;
> 	[...]
> }
>
> And then in everspin.c for example,
>
> 	{
> 		.name = "mr25h128",
> 		.size = SZ_16K,
> 		.sector_size = SZ_16K,
> 		.addr_nbytes = 2,
> 		.flags = SPI_NOR_NO_ERASE | SPI_NOR_NO_FR,
> 		.deprecation_date = "2025-01-01",
> 	}, {
>
> And in spi_nor_get_flash_info() (changed some wording of the message):
>
> 	info = jinfo ?: info;
>
> 	if (info->deprecation_date)
> 		pr_warn("Your board or device tree is using a SPI NOR flash (%s) with\n"
> 			"deprecated driver support. It can be removed in any kernel\n"
> 			"version after %s. If you feel this shouldn't be the case, please contact\n"
> 			"us at linux-mtd at lists.infradead.org\n", info->name,
> 			info->deprecation_date);
>
> 	return info;
>
> This would also remove the need for SPI_NOR_DEPRECATED. But it would
> make the flash_info 4 or 8 bytes larger.
>
> What do you think?

Looks good.

-michael
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