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mmc: sdhci-of-at91: force card detect value for non removable devices

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When the device is non removable, the card detect signal is often used
for another purpose i.e. muxed to another SoC peripheral or used as a
GPIO. It could lead to wrong behaviors depending the default value of
this signal if not muxed to the SDHCI controller.

Fixes: bb5f8ea4d5 ("mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC")
Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Ludovic Desroches 2017-07-26 16:02:46 +02:00 committed by Ulf Hansson
parent 16f73eb02d
commit 7a1e3f1431
1 changed files with 34 additions and 1 deletions
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35
drivers/mmc/host/sdhci-of-at91.c
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@ -31,6 +31,7 @@
#define SDMMC_MC1R 0x204
#define SDMMC_MC1R_DDR BIT(3)
#define SDMMC_MC1R_FCD BIT(7)
#define SDMMC_CACR 0x230
#define SDMMC_CACR_CAPWREN BIT(0)
#define SDMMC_CACR_KEY (0x46 << 8)
@ -43,6 +44,15 @@ struct sdhci_at91_priv {
struct clk *mainck;
};
static void sdhci_at91_set_force_card_detect(struct sdhci_host *host)
{
u8 mc1r;
mc1r = readb(host->ioaddr + SDMMC_MC1R);
mc1r |= SDMMC_MC1R_FCD;
writeb(mc1r, host->ioaddr + SDMMC_MC1R);
}
static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
{
u16 clk;
@ -110,10 +120,18 @@ void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
sdhci_set_uhs_signaling(host, timing);
}
static void sdhci_at91_reset(struct sdhci_host *host, u8 mask)
{
sdhci_reset(host, mask);
if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
sdhci_at91_set_force_card_detect(host);
}
static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
.set_clock = sdhci_at91_set_clock,
.set_bus_width = sdhci_set_bus_width,
.reset = sdhci_reset,
.reset = sdhci_at91_reset,
.set_uhs_signaling = sdhci_at91_set_uhs_signaling,
.set_power = sdhci_at91_set_power,
};
@ -324,6 +342,21 @@ static int sdhci_at91_probe(struct platform_device *pdev)
host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
}
/*
* If the device attached to the MMC bus is not removable, it is safer
* to set the Force Card Detect bit. People often don't connect the
* card detect signal and use this pin for another purpose. If the card
* detect pin is not muxed to SDHCI controller, a default value is
* used. This value can be different from a SoC revision to another
* one. Problems come when this default value is not card present. To
* avoid this case, if the device is non removable then the card
* detection procedure using the SDMCC_CD signal is bypassed.
* This bit is reset when a software reset for all command is performed
* so we need to implement our own reset function to set back this bit.
*/
if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
sdhci_at91_set_force_card_detect(host);
pm_runtime_put_autosuspend(&pdev->dev);
return 0;