From: Leonardo Graboski Veiga <leonardo.veiga@xxxxxxxxxxx> The 1-bit operation mode, enabled by seeting the 'bus-width' property of the device tree 'esdhc' node to <1>, not work while using SD card. The behavior is only noticed when only the data pin 0 is connected to the hardware. A series of kernel errors are printed to the console, all of them returning the following error message followed by some explanation: mmcblk0: error -84 transferring data If four data lines are connected, it ignores the device-tree property and works in 4-bit mode of operation without errors. The hardware used for testing does not support 8-bit mode. Check the 'bus-width' property and if set to <1>, enable the SDHCI_QUIRK_FORCE_1_BIT_DATA quirk. Signed-off-by: Leonardo Graboski Veiga <leonardo.veiga@xxxxxxxxxxx> --- drivers/mmc/host/sdhci-esdhc-imx.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c index c9fbc4c3..88d7d22 100644 --- a/drivers/mmc/host/sdhci-esdhc-imx.c +++ b/drivers/mmc/host/sdhci-esdhc-imx.c @@ -1003,6 +1003,10 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev, host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V; } + if (!of_property_read_u32(np, "bus-width", &boarddata->max_bus_width) + && boarddata->max_bus_width == 1) + host->quirks |= SDHCI_QUIRK_FORCE_1_BIT_DATA; + /* call to generic mmc_of_parse to support additional capabilities */ ret = mmc_of_parse(host->mmc); if (ret) -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
