Several drivers have the same device tree parsing code. Create
a common helper function for it.
This patch bases on work done by Sascha Hauer.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 36 ++++++++++++++++++++++++++++++++++++
include/linux/serial_core.h | 5 +++++
2 files changed, 41 insertions(+)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 3a14cccbd7ff..f4e6c8662987 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3026,5 +3026,41 @@ EXPORT_SYMBOL(uart_resume_port);
EXPORT_SYMBOL(uart_add_one_port);
EXPORT_SYMBOL(uart_remove_one_port);
+/**
+ * of_get_rs485_mode() - Implement parsing rs485 properties
+ * @np: uart node
+ * @rs485conf: output parameter
+ *
+ * This function implements the device tree binding described in
+ * Documentation/devicetree/bindings/serial/rs485.txt.
+ */
+void of_get_rs485_mode(struct device_node *np, struct serial_rs485 *rs485conf)
+{
+ u32 rs485_delay[2];
+ int ret;
+
+ ret = of_property_read_u32_array(np, "rs485-rts-delay", rs485_delay, 2);
+ if (!ret) {
+ rs485conf->delay_rts_before_send = rs485_delay[0];
+ rs485conf->delay_rts_after_send = rs485_delay[1];
+ } else {
+ rs485conf->delay_rts_before_send = 0;
+ rs485conf->delay_rts_after_send = 0;
+ }
+
+ /*
+ * clear full-duplex and enabled flags to get to a defined state with
+ * the two following properties.
+ */
+ rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED);
+
+ if (of_property_read_bool(np, "rs485-rx-during-tx"))
+ rs485conf->flags |= SER_RS485_RX_DURING_TX;
+
+ if (of_property_read_bool(np, "linux,rs485-enabled-at-boot-time"))
+ rs485conf->flags |= SER_RS485_ENABLED;
+}
+EXPORT_SYMBOL_GPL(of_get_rs485_mode);
+
MODULE_DESCRIPTION("Serial driver core");
MODULE_LICENSE("GPL");
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 5553e04e59c9..37b044e78333 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -501,4 +501,9 @@ static inline int uart_handle_break(struct uart_port *port)
(cflag) & CRTSCTS || \
!((cflag) & CLOCAL))
+/*
+ * Common device tree parsing helpers
+ */
+void of_get_rs485_mode(struct device_node *np, struct serial_rs485 *rs485conf);
+
#endif /* LINUX_SERIAL_CORE_H */
--
2.11.0
--
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