[PATCH V2 2/5] usb: serial: f81534: add auto RTS direction support

["Ji-Ze Hong (Peter Hong)" <hpeter@xxxxxxxxx>]

The F81532/534 had auto RTS direction support for RS485 mode.
We'll read it from internal Flash with address 0x2f01~0x2f04 for 4 ports.
There are 4 conditions below:
	0: F81534_PORT_CONF_RS232.
	1: F81534_PORT_CONF_RS485.
	2: value error, default to F81534_PORT_CONF_RS232.
	3: F81534_PORT_CONF_RS485_INVERT.

F81532/534 Clock register (offset +08h)

Bit0:	UART Enable (always on)
Bit2-1:	Clock source selector
			00: 1.846MHz.
			01: 18.46MHz.
			10: 24MHz.
			11: 14.77MHz.
Bit4:	Auto direction(RTS) control (RTS pin Low when TX)
Bit5:	Invert direction(RTS) when Bit4 enabled (RTS pin high when TX)

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@xxxxxxxxx>
---
V2:
	1: Read the configure data from flash and save it to shadow clock
	   register.

 drivers/usb/serial/f81534.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
index 758ef0424164..8a778bc1d492 100644
--- a/drivers/usb/serial/f81534.c
+++ b/drivers/usb/serial/f81534.c
@@ -98,11 +98,16 @@
 
 #define F81534_DEFAULT_BAUD_RATE	9600
 
+#define F81534_PORT_CONF_RS232		0
+#define F81534_PORT_CONF_RS485		BIT(0)
+#define F81534_PORT_CONF_RS485_INVERT	(BIT(0) | BIT(1))
 #define F81534_PORT_CONF_DISABLE_PORT	BIT(3)
 #define F81534_PORT_CONF_NOT_EXIST_PORT	BIT(7)
 #define F81534_PORT_UNAVAILABLE		\
 	(F81534_PORT_CONF_DISABLE_PORT | F81534_PORT_CONF_NOT_EXIST_PORT)
 
+#define F81534_UART_MODE_MASK		(BIT(0) | BIT(1))
+
 #define F81534_1X_RXTRIGGER		0xc3
 #define F81534_8X_RXTRIGGER		0xcf
 
@@ -115,6 +120,8 @@
  *			01: 18.46MHz.
  *			10: 24MHz.
  *			11: 14.77MHz.
+ * Bit4:	Auto direction(RTS) control (RTS pin Low when TX)
+ * Bit5:	Invert direction(RTS) when Bit4 enabled (RTS pin high when TX)
  */
 
 #define F81534_UART_EN			BIT(0)
@@ -123,6 +130,9 @@
 #define F81534_CLK_24_MHZ		(F81534_UART_EN | BIT(2))
 #define F81534_CLK_14_77_MHZ		(F81534_UART_EN | BIT(1) | BIT(2))
 
+#define F81534_CLK_RS485_MODE		BIT(4)
+#define F81534_CLK_RS485_INVERT		BIT(5)
+
 static const struct usb_device_id f81534_id_table[] = {
 	{ USB_DEVICE(FINTEK_VENDOR_ID_1, FINTEK_DEVICE_ID) },
 	{ USB_DEVICE(FINTEK_VENDOR_ID_2, FINTEK_DEVICE_ID) },
@@ -517,7 +527,8 @@ static int f81534_set_port_config(struct usb_serial_port *port,
 	}
 
 	port_priv->baud_base = baudrate_table[idx];
-	port_priv->shadow_clk = clock_table[idx];
+	port_priv->shadow_clk &= ~F81534_CLK_14_77_MHZ;
+	port_priv->shadow_clk |= clock_table[idx];
 
 	status = f81534_set_port_register(port, F81534_CLOCK_REG,
 			port_priv->shadow_clk);
@@ -1269,9 +1280,12 @@ static void f81534_lsr_worker(struct work_struct *work)
 
 static int f81534_port_probe(struct usb_serial_port *port)
 {
+	struct f81534_serial_private *serial_priv;
 	struct f81534_port_private *port_priv;
 	int ret;
+	u8 value;
 
+	serial_priv = usb_get_serial_data(port->serial);
 	port_priv = devm_kzalloc(&port->dev, sizeof(*port_priv), GFP_KERNEL);
 	if (!port_priv)
 		return -ENOMEM;
@@ -1303,6 +1317,24 @@ static int f81534_port_probe(struct usb_serial_port *port)
 	if (ret)
 		return ret;
 
+	value = serial_priv->conf_data[port_priv->phy_num];
+	switch (value & F81534_UART_MODE_MASK) {
+	case F81534_PORT_CONF_RS485_INVERT:
+		port_priv->shadow_clk = F81534_CLK_RS485_MODE |
+					F81534_CLK_RS485_INVERT;
+		dev_info(&port->dev, "RS485 invert mode.\n");
+		break;
+	case F81534_PORT_CONF_RS485:
+		port_priv->shadow_clk = F81534_CLK_RS485_MODE;
+		dev_info(&port->dev, "RS485 mode.\n");
+		break;
+
+	default:
+	case F81534_PORT_CONF_RS232:
+		dev_info(&port->dev, "RS232 mode.\n");
+		break;
+	}
+
 	return 0;
 }
 
-- 
2.7.4

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