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Commit 5fe23c7f51def59f66bc6aeee988ef1a467a2c8c

Authored by Anton Vorontsov
Committed by Pierre Ossman
1 parent 04ac2f46d6
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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>

Showing 4 changed files with 11 additions and 1 deletions Side-by-side Diff

Documentation/powerpc/dts-bindings/fsl/esdhc.txt
Diff comments   View file @ 5fe23c7
... ... @@ -10,6 +10,8 @@
10 10 - interrupts : should contain eSDHC interrupt.
11 11 - interrupt-parent : interrupt source phandle.
12 12 - clock-frequency : specifies eSDHC base clock frequency.
  13 + - sdhci,1-bit-only : (optional) specifies that a controller can
  14 + only handle 1-bit data transfers.
13 15  
14 16 Example:
15 17  
drivers/mmc/host/sdhci-of.c
Diff comments   View file @ 5fe23c7
... ... @@ -250,6 +250,9 @@
250 250 host->ops = &sdhci_of_data->ops;
251 251 }
252 252  
  253 + if (of_get_property(np, "sdhci,1-bit-only", NULL))
  254 + host->quirks |= SDHCI_QUIRK_FORCE_1_BIT_DATA;
  255 +
253 256 clk = of_get_property(np, "clock-frequency", &size);
254 257 if (clk && size == sizeof(*clk) && *clk)
255 258 of_host->clock = *clk;
drivers/mmc/host/sdhci.c
Diff comments   View file @ 5fe23c7
... ... @@ -1761,7 +1761,10 @@
1761 1761 mmc->ops = &sdhci_ops;
1762 1762 mmc->f_min = host->max_clk / 256;
1763 1763 mmc->f_max = host->max_clk;
1764   - mmc->caps = MMC_CAP_4_BIT_DATA | MMC_CAP_SDIO_IRQ;
  1764 + mmc->caps = MMC_CAP_SDIO_IRQ;
  1765 +
  1766 + if (!(host->quirks & SDHCI_QUIRK_FORCE_1_BIT_DATA))
  1767 + mmc->caps |= MMC_CAP_4_BIT_DATA;
1765 1768  
1766 1769 if (caps & SDHCI_CAN_DO_HISPD)
1767 1770 mmc->caps |= MMC_CAP_SD_HIGHSPEED;
drivers/mmc/host/sdhci.h
Diff comments   View file @ 5fe23c7
... ... @@ -228,6 +228,8 @@
228 228 #define SDHCI_QUIRK_FORCE_BLK_SZ_2048 (1<<20)
229 229 /* Controller cannot do multi-block transfers */
230 230 #define SDHCI_QUIRK_NO_MULTIBLOCK (1<<21)
  231 +/* Controller can only handle 1-bit data transfers */
  232 +#define SDHCI_QUIRK_FORCE_1_BIT_DATA (1<<22)
231 233  
232 234 int irq; /* Device IRQ */
233 235 void __iomem * ioaddr; /* Mapped address */