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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: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>
This commit is contained in:
Anton Vorontsov 2009-06-18 00:14:08 +04:00 committed by Pierre Ossman
parent 04ac2f46d6
commit 5fe23c7f51
4 changed files with 11 additions and 1 deletions
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2
Documentation/powerpc/dts-bindings/fsl/esdhc.txt
View File

@ -10,6 +10,8 @@ Required properties:
- interrupts : should contain eSDHC interrupt. - interrupts : should contain eSDHC interrupt.
- interrupt-parent : interrupt source phandle. - interrupt-parent : interrupt source phandle.
- clock-frequency : specifies eSDHC base clock frequency. - clock-frequency : specifies eSDHC base clock frequency.
- sdhci,1-bit-only : (optional) specifies that a controller can
only handle 1-bit data transfers.
Example: Example:

3
drivers/mmc/host/sdhci-of.c
View File

@ -250,6 +250,9 @@ static int __devinit sdhci_of_probe(struct of_device *ofdev,
host->ops = &sdhci_of_data->ops; 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); clk = of_get_property(np, "clock-frequency", &size);
if (clk && size == sizeof(*clk) && *clk) if (clk && size == sizeof(*clk) && *clk)
of_host->clock = *clk; of_host->clock = *clk;

5
drivers/mmc/host/sdhci.c
View File

@ -1761,7 +1761,10 @@ int sdhci_add_host(struct sdhci_host *host)
mmc->ops = &sdhci_ops; mmc->ops = &sdhci_ops;
mmc->f_min = host->max_clk / 256; mmc->f_min = host->max_clk / 256;
mmc->f_max = host->max_clk; 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) if (caps & SDHCI_CAN_DO_HISPD)
mmc->caps |= MMC_CAP_SD_HIGHSPEED; mmc->caps |= MMC_CAP_SD_HIGHSPEED;

2
drivers/mmc/host/sdhci.h
View File

@ -228,6 +228,8 @@ struct sdhci_host {
#define SDHCI_QUIRK_FORCE_BLK_SZ_2048 (1<<20) #define SDHCI_QUIRK_FORCE_BLK_SZ_2048 (1<<20)
/* Controller cannot do multi-block transfers */ /* Controller cannot do multi-block transfers */
#define SDHCI_QUIRK_NO_MULTIBLOCK (1<<21) #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 */ int irq; /* Device IRQ */
void __iomem * ioaddr; /* Mapped address */ void __iomem * ioaddr; /* Mapped address */