Add RS485 control for Fintek F81504/508/512
F81504/508/512 can control their RTS with H/W mode.
PCI configuration space for each port is 0x40 + idx * 8 + 7.
When it set with 0x01, it's configured with RS232 mode.
RTS is controlled by MCR.
When it set with 0x11, it's configured with RS485 mode.
RTS is controlled by H/W, RTS low with idle & RX, high with TX.
When it set with 0x31, it's configured with RS485 mode.
RTS is controlled by H/W, RTS high with idle & RX, low with TX.
We will force 0x01 on pci_fintek_setup().
Changelog:
V2
1. change direct bit operation with meaningful define name.
2. due to F81504 series only support SER_RS485_ENABLED &
SER_RS485_RTS_ON_SEND. We'll clean non-support area of
struct serial_rs485.
3. change control method of SER_RS485_RTS_ON_SEND. In our
reference circuit, the transceiver default mode needed
in rx mode with RTS logic high, tx mode with RTS logic low.
If user set to SER_RS485_ENABLED(default), we should set
reg with 0x31. if SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND
will set reg to 0x11.
Signed-off-by: Peter Hung <hpeter+linux_kernel@xxxxxxxxx>
---
drivers/tty/serial/8250/8250_pci.c | 61 ++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index e55f18b..5d16e14 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1685,11 +1685,60 @@ pci_brcm_trumanage_setup(struct serial_private *priv,
return ret;
}
+/* RTS will control by MCR if this bit is 0 */
+#define FINTEK_RTS_CONTROL_BY_HW BIT(4)
+/* only worked with FINTEK_RTS_CONTROL_BY_HW on */
+#define FINTEK_RTS_INVERT BIT(5)
+
+/* We should do proper H/W transceiver setting before change to RS485 mode */
+static int pci_fintek_rs485_config(struct uart_port *port,
+ struct serial_rs485 *rs485)
+{
+ u8 setting;
+ u8 *index = (u8 *) port->private_data;
+ struct pci_dev *pci_dev = container_of(port->dev, struct pci_dev,
+ dev);
+
+ pci_read_config_byte(pci_dev, 0x40 + 8 * *index + 7, &setting);
+
+ if (rs485->flags & SER_RS485_ENABLED)
+ memset(rs485->padding, 0, sizeof(rs485->padding));
+ else
+ memset(rs485, 0, sizeof(*rs485));
+
+ /* F81504/508/512 not support RTS delay before or after send */
+ rs485->flags &= SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND;
+
+ if (rs485->flags & SER_RS485_ENABLED) {
+ /* Enable RTS H/W control mode */
+ setting |= FINTEK_RTS_CONTROL_BY_HW;
+
+ if (rs485->flags & SER_RS485_RTS_ON_SEND) {
+ /* RTS driving high on TX */
+ setting &= ~FINTEK_RTS_INVERT;
+ } else {
+ /* RTS driving low on TX */
+ setting |= FINTEK_RTS_INVERT;
+ }
+
+ rs485->delay_rts_after_send = 0;
+ rs485->delay_rts_before_send = 0;
+ } else {
+ /* Disable RTS H/W control mode */
+ setting &= ~(FINTEK_RTS_CONTROL_BY_HW | FINTEK_RTS_INVERT);
+ }
+
+ pci_write_config_byte(pci_dev, 0x40 + 8 * *index + 7, setting);
+ port->rs485 = *rs485;
+ return 0;
+}
+
static int pci_fintek_setup(struct serial_private *priv,
const struct pciserial_board *board,
struct uart_8250_port *port, int idx)
{
struct pci_dev *pdev = priv->dev;
+ u8 *data;
u8 config_base;
u16 iobase;
@@ -1702,6 +1751,15 @@ static int pci_fintek_setup(struct serial_private *priv,
port->port.iotype = UPIO_PORT;
port->port.iobase = iobase;
+ port->port.rs485_config = pci_fintek_rs485_config;
+
+ data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ /* preserve index in PCI configuration space */
+ *data = idx;
+ port->port.private_data = data;
return 0;
}
@@ -1752,6 +1810,9 @@ static int pci_fintek_init(struct pci_dev *dev)
(u8)((iobase & 0xff00) >> 8));
pci_write_config_byte(dev, config_base + 0x06, dev->irq);
+
+ /* force init to RS232 Mode */
+ pci_write_config_byte(dev, config_base + 0x07, 0x01);
}
return max_port;
--
1.9.1
--
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