Thread (31 messages) 31 messages, 7 authors, 2014-01-16
STALE4530d

[PATCH] mmc: dw_mmc: fix dw_mci_get_cd

From: zhangfei.gao@linaro.org (zhangfei)
Date: 2014-01-15 13:56:26
Also in: linux-mmc
Subsystem: multimedia card (mmc), secure digital (sd) and sdio subsystem, synopsys designware mmc/sd/sdio driver, the rest · Maintainers: Ulf Hansson, Jaehoon Chung, Shawn Lin, Linus Torvalds


On 01/15/2014 08:26 PM, Seungwon Jeon wrote:
quoted
quoted
quoted
@@ -1033,7 +1033,8 @@ static int dw_mci_get_cd(struct mmc_host *mmc)
   	int present;
   	struct dw_mci_slot *slot = mmc_priv(mmc);
   	struct dw_mci_board *brd = slot->host->pdata;
-	int gpio_cd = !mmc_gpio_get_cd(mmc);
+	struct dw_mci *host = slot->host;
+	int gpio_cd = mmc_gpio_get_cd(mmc);

   	/* Use platform get_cd function, else try onboard card detect */
   	if (brd->quirks & DW_MCI_QUIRK_BROKEN_CARD_DETECTION)
@@ -1041,11 +1042,12 @@ static int dw_mci_get_cd(struct mmc_host *mmc)
   	else if (brd->get_cd)
   		present = !brd->get_cd(slot->id);
   	else if (!IS_ERR_VALUE(gpio_cd))
-		present = !!gpio_cd;
+		present = !gpio_cd;
!!gpio_cd or gpio_cd is correct, isn't it?
No, mmc_gpio_get_cd(mmc) has to revert.
I'm missing something?
If card is detected, mmc_gpio_get_cd() returns non-zero, right?
I guess gpio_cd should be kept.
Hmm, looks you are right.
Though not see clearly mmc_gpio_get_cd declaratoin, other drivers
directly set get_cd as mmc_gpio_get_cd.
.get_cd	= mmc_gpio_get_cd

However, in our board cd =0 when card is deteced while cd=1 when card is
removed.
In order to mmc_gpio_get_cd return 1, MMC_CAP2_CD_ACTIVE_HIGH has to be
set, as well as new property "caps2-mmc-cd-active-low".
--- a/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
+++ b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
@@ -73,6 +73,8 @@ Optional properties:
+* caps2-mmc-cd-active-low: cd pin is low when card active
+
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
+       if (of_find_property(np, "caps2-mmc-cd-active-low", NULL))
+               pdata->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
+
But it looks strange "cd-active-low" describing "CD_ACTIVE_HIGH" flag.
When card active, cd = 0, and ACTIVE_HIGH is required to make
mmc_gpio_get_cd return 1.
int mmc_gpio_get_cd(struct mmc_host *host)
{
        return !gpio_get_value_cansleep(ctx->cd_gpio) ^
                !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH);
}

Thanks
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