Commit 5fe23c7f authored by Anton Vorontsov's avatar Anton Vorontsov Committed by Pierre Ossman
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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: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: default avatarPierre Ossman <pierre@ossman.eu>
parent 04ac2f46

Documentation/powerpc/dts-bindings/fsl/esdhc.txt

+2 −0
Original line number Diff line number Diff line
@@ -10,6 +10,8 @@ Required properties: 
  - 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:

drivers/mmc/host/sdhci-of.c

+3 −0
Original line number Diff line number Diff line
@@ -250,6 +250,9 @@ static int __devinit sdhci_of_probe(struct of_device *ofdev, 
		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;

drivers/mmc/host/sdhci.c

+4 −1
Original line number Diff line number Diff line
@@ -1761,7 +1761,10 @@ int sdhci_add_host(struct sdhci_host *host) 
	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;

drivers/mmc/host/sdhci.h

+2 −0
Original line number Diff line number Diff line
@@ -228,6 +228,8 @@ struct sdhci_host { 
#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 */

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