Hi Doug,
This change looks good.
There's comment below.
On Sat, October 19, 2013, Doug Anderson wrote:
> Jaehoon,
>
> On Fri, Oct 18, 2013 at 2:42 AM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
> >> - clk_en_a = mci_readl(host, CLKENA);
> >> + /*
> >> + * Low power mode will stop the card clock when idle. According to the
> >> + * description of the CLKENA register we should disable low power mode
> >> + * for SDIO cards if we need SDIO interrupts to work.
> >> + */
> >> + if (mmc->caps | MMC_CAP_SDIO_IRQ) {
> > mmc->caps & MMC_CAP_SDIO_IRQ?
>
> Wow, that was an embarrassing one. Thanks.
>
> >> + const u32 clken_low_pwr = SDMMC_CLKEN_LOW_PWR << slot->id;
> >> + u32 clk_en_a_old;
> >> + u32 clk_en_a;
> >>
> >> - if (clk_en_a & clken_low_pwr) {
> >> - mci_writel(host, CLKENA, clk_en_a & ~clken_low_pwr);
> >> - mci_send_cmd(slot, SDMMC_CMD_UPD_CLK |
> >> - SDMMC_CMD_PRV_DAT_WAIT, 0);
> >> + clk_en_a_old = mci_readl(host, CLKENA);
> >> +
> >> + if (card->type == MMC_TYPE_SDIO ||
> >> + card->type == MMC_TYPE_SD_COMBO) {
&& card->quirks & MMC_QUIRK_BROKEN_CLK_GATING
How about considering MMC_QUIRK_BROKEN_CLK_GATING?
Some sdio device can work with gating clock.
For this, mmc_fixup_device() should be called prior to init_card() in core(sdio.c).
I guess you found that.
Thanks,
Seungwon Jeon
> >> + set_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);
> >> + clk_en_a = clk_en_a_old & ~clken_low_pwr;
> >> + } else {
> >> + clear_bit(DW_MMC_CARD_NO_LOW_PWR, &slot->flags);
> >> + clk_en_a = clk_en_a_old | clken_low_pwr;
> > When this condition is entered? card->type is always MMC_TYPE_SDIO or MMC_TYPE_SD_COMBO, isn't?
>
> Ugh, that's not intuitive. This callback is only called for SDIO
> cards and not MMC/SD cards? That means if you plug in an SDIO card
> and then eject it and plug in an SD card you won't get to low power.
> Hrm.
>
> I dug around a bit and couldn't find a better way to do this and then
> I realized that the other user of the init_card() callback has the
> same bug, so for the next version of the series I'm proposing a fix
> for mmc core to add this for all types. If you have a better
> suggestion, I'm all ears.
>
> -Doug
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