USB: serial: f81534: add auto RTS direction support

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@gmail.com>
[ johan: rename mode-mask define, and only use GENMASK() for masks ]
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c
index cfba054..5caa945 100644 (file)
--- 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_MODE_MASK     GENMASK(1, 0)
 #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_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 +130,8 @@
 #define F81534_CLK_24_MHZ              BIT(2)
 #define F81534_CLK_14_77_MHZ           (BIT(1) | BIT(2))
 #define F81534_CLK_MASK                        GENMASK(2, 1)
+#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) },
@@ -1274,9 +1283,12 @@ 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;
@@ -1309,6 +1321,24 @@ 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_PORT_CONF_MODE_MASK) {
+       case F81534_PORT_CONF_RS485_INVERT:
+               port_priv->shadow_clk |= F81534_CLK_RS485_MODE |
+                                       F81534_CLK_RS485_INVERT;
+               dev_dbg(&port->dev, "RS485 invert mode\n");
+               break;
+       case F81534_PORT_CONF_RS485:
+               port_priv->shadow_clk |= F81534_CLK_RS485_MODE;
+               dev_dbg(&port->dev, "RS485 mode\n");
+               break;
+
+       default:
+       case F81534_PORT_CONF_RS232:
+               dev_dbg(&port->dev, "RS232 mode\n");
+               break;
+       }
+
        return 0;
 }