apalis_t30: optional mmc uhs support (v1.1a and later hw)Colibri_T30_LinuxImageV2.3Beta5_20141219Colibri_T20_LinuxImageV2.3Beta5_20141219Apalis_T30_LinuxImageV2.3Beta5_20141219

This patch adds optional UHS support for the 8-bit MMC controller.
Please note that this requires V1.1A or later module hardware plus the
pull-up resistors on the data as well as the command signal lines of
your carrier board need to be removed (e.g. R46 to R54 on our Apalis
Evaluation Board V1.1A). If those pre-requisites are met support can be
enabled using the following kernel command line parameter:

	mmc_uhs=1

1 files changed, 14 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/board-apalis_t30.c b/arch/arm/mach-tegra/board-apalis_t30.c
index d01f420f33c5..ef709c872d17 100644
--- a/arch/arm/mach-tegra/board-apalis_t30.c
+++ b/arch/arm/mach-tegra/board-apalis_t30.c
@@ -622,6 +622,18 @@ static struct platform_device apalis_t30_keys_device = {
 
 /* MMC/SD */
 
+/* To limit the 8-bit MMC slot to 3.3 volt only operation (e.g. no UHS) */
+int g_sdmmc3_uhs = 0;
+
+static int __init enable_mmc_uhs(char *s)
+{
+	if (!(*s) || !strcmp(s, "1"))
+		g_sdmmc3_uhs = 1;
+
+	return 0;
+}
+__setup("mmc_uhs=", enable_mmc_uhs);
+
 static struct tegra_sdhci_platform_data apalis_t30_emmc_platform_data = {
 	.cd_gpio	= -1,
 	.ddr_clk_limit	= 52000000,
@@ -661,6 +673,8 @@ static void __init apalis_t30_sdhci_init(void)
 			&apalis_t30_emmc_platform_data;
 	platform_device_register(&tegra_sdhci_device4);
 
+	if (g_sdmmc3_uhs)
+		apalis_t30_mmccard_platform_data.no_1v8 = 0;
 	tegra_sdhci_device3.dev.platform_data =
 			&apalis_t30_mmccard_platform_data;
 	platform_device_register(&tegra_sdhci_device3);