devicetrees may have a linux,stdout-path property in the chosen
node describing the console device. This adds a helper function
to match a device against this property so a driver can call
add_preferred_console for a matching device.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 30 ++++++++++++++++++++++++++++++
include/linux/serial_core.h | 3 +++
2 files changed, 33 insertions(+)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index a21dc8e..f4a9f26 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -33,6 +33,7 @@
#include <linux/serial_core.h>
#include <linux/delay.h>
#include <linux/mutex.h>
+#include <linux/of.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
@@ -2540,6 +2541,35 @@ void uart_insert_char(struct uart_port *port, unsigned int status,
}
EXPORT_SYMBOL_GPL(uart_insert_char);
+#ifdef CONFIG_OF
+/**
+ * of_uart_is_stdoutpath - check if this device matches the linux,stdout-path
+ * property
+ *
+ * Check if this device matches the linux,stdout-path property
+ * in the chosen node. return true if yes, false otherwise.
+ */
+int of_uart_is_stdoutpath(struct device *dev)
+{
+ struct device_node *dn;
+ const char *name;
+
+ name = of_get_property(of_chosen, "linux,stdout-path", NULL);
+ if (name == NULL)
+ return 0;
+
+ dn = of_find_node_by_path(name);
+ if (!dn)
+ return 0;
+
+ if (dn == dev->of_node)
+ return 1;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_uart_is_stdoutpath);
+#endif
+
EXPORT_SYMBOL(uart_write_wakeup);
EXPORT_SYMBOL(uart_register_driver);
EXPORT_SYMBOL(uart_unregister_driver);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 0253c20..35a61f6 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -560,6 +560,9 @@ static inline int uart_handle_break(struct uart_port *port)
(cflag) & CRTSCTS || \
!((cflag) & CLOCAL))
+/* check if a device matches the linux,stdout-path property */
+int of_uart_is_stdoutpath(struct device *dev);
+
#endif
#endif /* LINUX_SERIAL_CORE_H */
--
1.7.10.4
--
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