On 30 October 2012 13:42, <r66093@xxxxxxxxxxxxx> wrote:
> From: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
>
> In order to check whether the card has been removed, the function
> mmc_send_status() will send command CMD13 to card and ask the card
> to send its status register to sdhc driver, which will generate
> many interrupts repeatedly and make the system performance bad.
>
> Therefore, add callback function get_cd() to check whether
> the card has been removed when the driver has this callback function.
>
> If the card is present, 1 will return, if the card is absent, 0 will return.
> If the controller will not support this feature, -ENOSYS will return.
>
> Signed-off-by: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
> CC: Anton Vorontsov <cbouatmailru@xxxxxxxxx>
> CC: Chris Ball <cjb@xxxxxxxxxx>
> ---
> changes for v2:
> - when controller don't support get_cd, return -ENOSYS
> - add the CC
> changes for v3:
> - enalbe the controller clock in platform, instead of core
> changes for v4:
> - move the detect code to core.c according to the new structure
>
> drivers/mmc/core/core.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 9c162cd..6412355 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2073,7 +2073,7 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
>
> int _mmc_detect_card_removed(struct mmc_host *host)
> {
> - int ret;
> + int ret = -ENOSYS;
>
> if ((host->caps & MMC_CAP_NONREMOVABLE) || !host->bus_ops->alive)
> return 0;
> @@ -2081,7 +2081,13 @@ int _mmc_detect_card_removed(struct mmc_host *host)
> if (!host->card || mmc_card_removed(host->card))
> return 1;
>
> - ret = host->bus_ops->alive(host);
> + if (host->ops->get_cd) {
> + ret = host->ops->get_cd(host);
> + if (ret >= 0)
> + ret = !ret;
> + }
> + if (ret < 0)
> + ret = host->bus_ops->alive(host);
why should we check for negative here? can move this code into else
path of if (host->ops->get_cd).
> if (ret) {
> mmc_card_set_removed(host->card);
> pr_debug("%s: card remove detected\n", mmc_hostname(host));
> --
> 1.7.9.5
>
>
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