Re: [PATCH v2] mtd: nand: spi: rework detect procedure for different read id op

From: Chuanhong Guo
Date: Fri Jan 10 2020 - 02:34:41 EST


Hi!

On Fri, Jan 10, 2020 at 2:59 PM Boris Brezillon
<boris.brezillon@xxxxxxxxxxxxx> wrote:
> [...]
> > + ret = spinand_read_id_op(spinand, 1, 0, id);
> > + if (ret)
> > + return ret;
> > + ret = spinand_manufacturer_match(spinand,
> > + SPINAND_READID_METHOD_OPCODE_ADDR);
> > + if (!ret)
> > + return 0;
> > +
> > + ret = spinand_read_id_op(spinand, 0, 1, id);
>
> Hm, we should probably do only one of each read_id and iterate over all
> manufacturers/chips each time instead of doing 3 read_ids per
> manufacturer.

This actually do the former instead of the latter. Maybe the function
names are a bit
misleading. spinand_manufacturer_match iterates over all manufacturers
in one call,
and spinand_manufacturer_detect is called once in spinand_detect.
Do you have suggestions on function naming?

> [...]
> > + * SPINAND_READID_METHOD_OPCODE_DUMMY: chip id is returned after
> > + * read_id opcode + 1 dummy byte.
> > + */
> > +struct spinand_devid {
> > + u16 id;
>
> Can we make that field an array of u8?
>
> const u8 *id;
>
> > + u8 len;
> > + enum spinand_readid_method method;
> > +};
> [...]
> >
> > +#define SPINAND_ID(__id, __len, __method) \
> > + { \
> > + .id = __id, \
> > + .len = __len, \
> > + .method = __method, \
> > + }
>
> That one can be turned into
>
> #define SPINAND_ID(__method, ...) \
> { \
> .id = (const u8[]){ __VA_ARGS }, \
> .len = sizeof((u8[]){ __VA_ARGS }), \
> .method = __method, \
> }

Wow. I never thought of this cool trick. I'll give it a try.

Regards,
Chuanhong Guo