tegra: Use SD write-protect GPIO on Tamonten

GPIO PI6 can be used to obtain the write-protect status of an SD card
inserted into the SD slot.
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>
Acked-by: NStephen Warren <swarren@wwwdotorg.org>
Signed-off-by: NTom Warren <twarren@nvidia.com>

board/avionic-design/common/tamonten.c

@@ -65,6 +65,8 @@ void gpio_early_init(void)
 static void pin_mux_mmc(void)
 {
 	funcmux_select(PERIPH_ID_SDMMC4, FUNCMUX_SDMMC4_ATB_GMA_GME_8_BIT);
+	/* for write-protect GPIO PI6 */
+	pinmux_tristate_disable(PINGRP_ATA);
 	/* for CD GPIO PH2 */
 	pinmux_tristate_disable(PINGRP_ATD);
 }
@@ -76,7 +78,7 @@ int board_mmc_init(bd_t *bd)
 	pin_mux_mmc();
 
 	/* init dev 0, SD slot, with 4-bit bus */
-	tegra2_mmc_init(0, 4, -1, GPIO_PH2);
+	tegra2_mmc_init(0, 4, GPIO_PI6, GPIO_PH2);
 
 	return 0;
 }