On 22 January 2016 at 10:45, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> In the future sdhci will be a library. When that happens
> a callback will be needed to allow drivers easily to override
> the standard way of determining whether a card is present.
There's already a ->get_cd() callback in the struct mmc_host_ops.
By turning sdhci into a library, each sdhci variant should decide
whether they want to use a default "sdhci_get_cd()" version, rely on
slot-gpio or implement their own.
I don't understand why we need a specific sdhci callback to deal with
this, it doesn't make sense to me.
> That is needed because functions like sdhci_request() also
> check the card presence.
Why does sdhci do that? Is that because some variants needs it or
because of all?
Reading a state of a GPIO pin before every request doesn't come
without a cost in performance. My point is, it should only be done
when *really* needed.
Again, by having sdhci to become a library each variant should decide
what's needed for them.
>
> The get_cd callback is being added now to facilitate
> a bug fix, for which subsequent patches are provided.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # v4.4+
> ---
> drivers/mmc/host/sdhci.c | 6 +++++-
> drivers/mmc/host/sdhci.h | 1 +
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index d622435d1bcc..535236084b27 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1612,7 +1612,7 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>
> static int sdhci_do_get_cd(struct sdhci_host *host)
> {
> - int gpio_cd = mmc_gpio_get_cd(host->mmc);
> + int gpio_cd;
>
> if (host->flags & SDHCI_DEVICE_DEAD)
> return 0;
> @@ -1621,10 +1621,14 @@ static int sdhci_do_get_cd(struct sdhci_host *host)
> if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
> return 1;
>
> + if (host->ops->get_cd)
> + return host->ops->get_cd(host);
> +
> /*
> * Try slot gpio detect, if defined it take precedence
> * over build in controller functionality
> */
> + gpio_cd = mmc_gpio_get_cd(host->mmc);
> if (!IS_ERR_VALUE(gpio_cd))
> return !!gpio_cd;
>
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 7654ae5d2b4e..a6c2cd8ef0b2 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -552,6 +552,7 @@ struct sdhci_ops {
> struct mmc_card *card,
> unsigned int max_dtr, int host_drv,
> int card_drv, int *drv_type);
> + int (*get_cd)(struct sdhci_host *host);
> };
>
> #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
> --
> 1.9.1
>
Can you please try to fix this without adding a new callback!? I know,
it requires some more efforts but for sure it's doable.
Kind regards
Uffe
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