[PATCH 3/3] mtd: spinand: winbond: Clarify when to enable the HS bit

[Michael Nazzareno Trimarchi]

Hi

On Fri, Apr 3, 2026 at 6:17 PM Miquel Raynal <miquel.raynal at bootlin.com> wrote:
>
> Above 104MHz when in fast dual or quad I/O reads, the delay between
> address and data cycles is too short. It is possible to reach higher
> frequencies, up to 166MHz, by adding a few more dummy cycles through the
> setting of the HS bit. Improve the condition for enabling this bit, and
> also make sure we set it at soon as we go over 104MHz.
>
> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
> ---
> This is a port from Linux.
> ---
>  drivers/mtd/nand/spi/winbond.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mtd/nand/spi/winbond.c b/drivers/mtd/nand/spi/winbond.c
> index 79c3354efb65..accb46dfeb03 100644
> --- a/drivers/mtd/nand/spi/winbond.c
> +++ b/drivers/mtd/nand/spi/winbond.c
> @@ -261,16 +261,19 @@ static int w25n0xjw_hs_cfg(struct spinand_device *spinand)
>         u8 sr4;
>         int ret;
>
> +       /*
> +        * SDR dual and quad I/O operations over 104MHz require the HS bit to
> +        * enable a few more dummy cycles.
> +        */
>         op = spinand->op_templates.read_cache;
>         if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
>                 hs = false;
> -       else if (op->cmd.buswidth == 1 && op->addr.buswidth == 1 &&
> -                op->dummy.buswidth == 1 && op->data.buswidth == 1)
> +       else if (op->cmd.buswidth != 1 || op->addr.buswidth != 1)
> +               hs = false;
> +       else if (op->max_freq && op->max_freq <= 104 * HZ_PER_MHZ)
>                 hs = false;
> -       else if (!op->max_freq)
> -               hs = true;
>         else
> -               hs = false;
> +               hs = true;
>

Reviewed-by: Michael Trimarchi <michael at amarulasolutions.com>


>         ret = spinand_read_reg_op(spinand, W25N0XJW_SR4, &sr4);
>         if (ret)
>
> --
> 2.53.0
>


-- 
Michael Nazzareno Trimarchi
Co-Founder & Chief Executive Officer
M. +39 347 913 2170
michael at amarulasolutions.com
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