sdhci: Add support for hosts that are only capable of 1-bit transfers Some hosts (hardware configurations, or particular SD/MMC slots) may not support 4-bit bus. For example, on MPC8569E-MDS boards we can switch between serial (1-bit only) and nibble (4-bit) modes, thought we have to disable more peripherals to work in 4-bit mode. Along with some small core changes, this patch modifies sdhci-of driver, so that now it looks for "sdhci,1-bit-only" property in the device-tree, and if specified we enable a proper quirk. Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Pierre Ossman <pierre@ossman.eu>
diff --git a/Documentation/powerpc/dts-bindings/fsl/esdhc.txt b/Documentation/powerpc/dts-bindings/fsl/esdhc.txt index 5093ddf..3ed3797 100644 --- a/Documentation/powerpc/dts-bindings/fsl/esdhc.txt +++ b/Documentation/powerpc/dts-bindings/fsl/esdhc.txt
@@ -10,6 +10,8 @@ - interrupts : should contain eSDHC interrupt. - interrupt-parent : interrupt source phandle. - clock-frequency : specifies eSDHC base clock frequency. + - sdhci,1-bit-only : (optional) specifies that a controller can + only handle 1-bit data transfers. Example:
diff --git a/drivers/mmc/host/sdhci-of.c b/drivers/mmc/host/sdhci-of.c index 128c614..d79fa55 100644 --- a/drivers/mmc/host/sdhci-of.c +++ b/drivers/mmc/host/sdhci-of.c
@@ -250,6 +250,9 @@ host->ops = &sdhci_of_data->ops; } + if (of_get_property(np, "sdhci,1-bit-only", NULL)) + host->quirks |= SDHCI_QUIRK_FORCE_1_BIT_DATA; + clk = of_get_property(np, "clock-frequency", &size); if (clk && size == sizeof(*clk) && *clk) of_host->clock = *clk;
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 3856669..c758673 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c
@@ -1761,7 +1761,10 @@ mmc->ops = &sdhci_ops; mmc->f_min = host->max_clk / 256; mmc->f_max = host->max_clk; - mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ; + mmc->caps = MMC_CAP_SDIO_IRQ; + + if (!(host->quirks & SDHCI_QUIRK_FORCE_1_BIT_DATA)) + mmc->caps |= MMC_CAP_4_BIT_DATA; if (caps & SDHCI_CAN_DO_HISPD) mmc->caps |= MMC_CAP_SD_HIGHSPEED;
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 84d1490..5d37dd9 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h
@@ -228,6 +228,8 @@ #define SDHCI_QUIRK_FORCE_BLK_SZ_2048 (1<<20) /* Controller cannot do multi-block transfers */ #define SDHCI_QUIRK_NO_MULTIBLOCK (1<<21) +/* Controller can only handle 1-bit data transfers */ +#define SDHCI_QUIRK_FORCE_1_BIT_DATA (1<<22) int irq; /* Device IRQ */ void __iomem * ioaddr; /* Mapped address */