Re: [PATCH RFC 1/4] spi: spi-mem: Add set_iofv() callback

[Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>]

Hi Biju,

On Wed, Nov 8, 2023 at 6:12 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> As per section 8.14 on the AT25QL128A hardware manual,
> IO0..IO3 must be set to Hi-Z state for this flash for fast read quad IO.
> Snippet from HW manual section 8.14:
> The upper nibble of the Mode(M7-4) controls the length of the next FAST
> Read Quad IO instruction through the inclusion or exclusion of the first
> byte instruction code. The lower nibble bits of the Mode(M3-0) are don't
> care. However, the IO pins must be high-impedance before the falling edge
> of the first data out clock.
>
> Add set_iofv() callback for configuring IO fixed values to control the
> pin state.
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>

Thanks for your patch!

> --- a/drivers/spi/spi-mem.c
> +++ b/drivers/spi/spi-mem.c
> @@ -297,6 +297,26 @@ static void spi_mem_access_end(struct spi_mem *mem)
>                 pm_runtime_put(ctlr->dev.parent);
>  }
>
> +/**
> + * spi_mem_set_iofv() - Set IO fixed values to control the pin state
> + * @mem: the SPI memory
> + * @val: the IO fixed values

Please document the meaning of this value (i.e. what does a
set or cleared bit mean?).

> + *
> + * Set IO fixed values to control the pin state.
> + *
> + * Return: 0 in case of success, a negative error code otherwise.
> + */
> +int spi_mem_set_iofv(struct spi_mem *mem, u32 val)
> +{
> +       struct spi_controller *ctlr = mem->spi->controller;
> +
> +       if (ctlr->mem_ops && ctlr->mem_ops->set_iofv)
> +               return ctlr->mem_ops->set_iofv(mem, val);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_GPL(spi_mem_set_iofv);
> +
>  /**
>   * spi_mem_exec_op() - Execute a memory operation
>   * @mem: the SPI memory

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