Shawn,

+/* mmc */
+static void __init mx28evk_mmc_slot_poweron(int gpio)
+{
+	int ret;
+
+	ret = gpio_request(gpio, "mmc-slot-power");
+	if (ret) {
+		pr_err("Failed to request gpio mmc-slot-power: %d\n", ret);
+		return;
+	}
+
+	ret = gpio_direction_output(gpio, 0);
+	if (ret) {
+		pr_err("Failed to drive gpio mmc-slot-power: %d\n", ret);
+		return;
+	}
+}

Minor nit: You could use gpio_request_one(), and doing so maybe even get rid of
this function and simply do it the init-function. The advantage would be, that
you can name the two GPIOs independently.

Regards,

   Wolfram

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