From: Leonardo Graboski Veiga <leonardo.ve...@toradex.com>
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.ve...@toradex.com>
---
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
