Re: [PATCH v2 07/32] swim: Enable clock divider only where appropriate

[Geert Uytterhoeven]

Hi Finn,

Thanks for your patch!

On Mon, 17 Aug 2026 at 03:55, Finn Thain <fthain@xxxxxxxxxxxxxx> wrote:
> Some models have a 16 MHz FCLK oscillator and others 32 MHz. Put this
> information into the swim device platform_data so that the driver can
> correctly enable the clock divider. When this is enabled incorrectly,
> nothing can be read and failures from the Error Correction Machine are
> flagged in the error register.
>
> This is chip initialization, so do this in swim_floppy_init() rather
> than floppy_open(). Drop the udelay() which was apparently copied and
> pasted from swim3.c, where it relates to interrupts (of which this chip
> has none).

This move should be a separate patch.

> Cc: Joshua Thompson <funaho@xxxxxxxxx>
> Reviewed-by: Laurent Vivier <laurent@xxxxxxxxx>
> Fixes: 8852ecd97488 ("m68k: mac - Add SWIM floppy support")
> Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxx>
> ---
>  arch/m68k/mac/config.c | 31 ++++++++++++++++++++++++++++++-

For the m68k part:
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

> --- a/arch/m68k/mac/config.c
> +++ b/arch/m68k/mac/config.c
> @@ -984,8 +984,37 @@ static int __init mac_platform_init(void)
>                         .start = swim_base,
>                         .end   = swim_base + 0x1FFF,
>                 };
> +               unsigned int data = 0;

Nit: in the absence of a real platform_data structure, please use a
more explanatory name.

Perhaps s/data/s_fclk/, and store S_FCLK_DIV2 or zero?
Or s/data/setup/, and store the full register value?

> --- a/drivers/block/swim.c
> +++ b/drivers/block/swim.c

> @@ -807,8 +806,10 @@ static void swim_set_parameters(struct swim __iomem *base)
>                 swim_write(base, parameter, mem[i]);
>  }
>
> -static int swim_floppy_init(struct swim_priv *swd)
> +static int swim_floppy_init(struct platform_device *pdev)
>  {
> +       struct swim_priv *swd = platform_get_drvdata(pdev);
> +       unsigned int *data = pdev->dev.platform_data;

Likewise.

>         struct queue_limits lim = {
>                 .features               = BLK_FEAT_ROTATIONAL,
>         };
> @@ -816,6 +817,8 @@ static int swim_floppy_init(struct swim_priv *swd)
>         int drive;
>         struct swim __iomem *base = swd->base;
>
> +       swim_write(base, setup, S_IBM_DRIVE | (*data ? S_FCLK_DIV2 : 0));
> +
>         swim_set_parameters(base);
>
>         /* scan floppy drives */

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds