add module to switch kernel serial console to headphone jack

[ms2-kexec] / headphone_cons.c

diff --git a/headphone_cons.c b/headphone_cons.c
new file mode 100644 (file)
index 0000000..edf8d16
--- /dev/null
+++ b/headphone_cons.c
@@ -0,0 +1,39 @@
+/*
+ * Provide kernel console on headphone jack
+ */
+
+#include <linux/module.h>
+#include <linux/gpio_mapping.h>
+#include <linux/gpio.h>
+
+/*
+ * int add_preferred_console(char *name, int idx, char *options)
+ * c0069208 T add_preferred_console
+ */
+
+static int (*add_preferred_console)(char *, int, char*) = (int (*)(char*, int, char*))0xc0069208;
+
+static int __init headphone_cons_init(void)
+{
+       int hs_switch;
+
+       /* Get the headset switch gpio number from devtree */
+       hs_switch = get_gpio_by_name("headset_uart_switch");
+       if (hs_switch < 0)
+               return -EINVAL;
+
+       /* configure headset switch gpio as output and
+          direction based on devtree setting */
+       gpio_request(hs_switch, "mapphone audio headset uart switch");
+
+       /* route kernel uart out headset jack */
+       gpio_direction_output(hs_switch, 0);
+
+       add_preferred_console("ttyS", 1, "115200");
+       return 0;
+}
+
+module_init(headphone_cons_init);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Gernoth <michael@gernoth.net>");