Best Regards Jerry Huang > -----Original Message----- > From: linux-mmc-owner@xxxxxxxxxxxxxxx [mailto:linux-mmc- > owner@xxxxxxxxxxxxxxx] On Behalf Of Girish K S > Sent: Tuesday, October 30, 2012 7:35 PM > To: Huang Changming-R66093 > Cc: linux-mmc@xxxxxxxxxxxxxxx; Huang Changming-R66093; Anton Vorontsov; > Chris Ball > Subject: Re: [PATCH 2/4 v4] MMC/SD: Add callback function to detect card > > 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) { I did this comment: 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. Can't move to other address, because these codes check the card present state. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
