Re: [PATCH 3/5] mmc: sdhi: Add write16_hook

Magnus Damm
2011-06-21T00:36:03Z

On Tue, Jun 21, 2011 at 8:00 AM, Simon Horman <horms@verge.net.au> wrote:
> Some controllers require waiting for the bus to become idle
> before writing to some registers. I have implemented this
> by adding a hook to sd_ctrl_write16() and implementing
> a hook for SDHI which waits for the bus to become idle.
>
> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> Cc: Magnus Damm <magnus.damm@gmail.com>
> Signed-off-by: Simon Horman <horms@verge.net.au>
>
> ---
>
> Dependencies: "mmc: tmio: Share register access functions"
>
> v2:
> * Include linux/delay.h instead of asm/delay.h
> * Skip write if sh_mobile_sdhi_wait_idle() times out
>  - The bus will probably be in an inconsistent state and writing
>    may lock up the bus
> * Only set hook if TMIO_MMC_HAS_IDLE_WAIT is set in platform data
>  rather than checking for TMIO_MMC_HAS_IDLE_WAIT each time the
>  hook is called.
> ---

Thanks Simon, this version looks much better!

> index 5a90266..0dc9804 100644
> --- a/include/linux/mfd/tmio.h
> +++ b/include/linux/mfd/tmio.h
> @@ -94,6 +101,7 @@ struct tmio_mmc_data {
>        void (*set_pwr)(struct platform_device *host, int state);
>        void (*set_clk_div)(struct platform_device *host, int state);
>        int (*get_cd)(struct platform_device *host);
> +       int (*write16_hook)(struct tmio_mmc_host *host, int addr);
>  };
>
>  static inline void tmio_mmc_cd_wakeup(struct tmio_mmc_data *pdata)

What's the reason behind passing "struct tmio_mmc_host *" as an
argument to the new hook? Performance? All other callbacks seem to
take a "struct platform_device *", so being consistent here may be
good unless it comes with too much overhead.

Thanks,

/ magnus