Add callbacks to handle TIOCGRS485 and TIOCSRS485 ioctl
calls in mos7840.c, allowing configuration of the chip's
"scratchpad" register to strobe the DTR line while transmitting.
This functionality is required for RS485 mode on the B&B Electronics
USOPTL4-4P and USOPTL4-2P USB-to-RS485/422 hubs based on this chip.
Signed-off-by: Aaron Marburg <amarburg@xxxxxxxxxxxxxxxxxx>
---
Changes relative to v2:
-- As suggested, implemented handlers for TIOC?RS485 ioctl callbacks
rather than command-line options to enable RS485 configurations.
drivers/usb/serial/mos7840.c | 78 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 78 insertions(+)
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index ed378fb..8a78143 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1977,6 +1977,74 @@ static int mos7840_get_serial_info(struct moschip_port *mos7840_port,
}
/*****************************************************************************
+ * mos7840_get_rs485_info
+ * function to handle RS485 "get" ioctl
+ *****************************************************************************/
+
+static int mos7840_get_rs485_info(struct usb_serial_port *port,
+ struct serial_rs485 __user *retinfo)
+{
+ struct serial_rs485 tmp;
+ int status;
+ __u16 scratchpad;
+
+ if (port == NULL)
+ return -EFAULT;
+
+ if (!retinfo)
+ return -EFAULT;
+
+ memset(&tmp, 0, sizeof(tmp));
+
+ status = mos7840_get_uart_reg(port, SCRATCH_PAD_REGISTER, &scratchpad);
+ if (status < 0) {
+ dev_dbg(&port->dev, "Reading ScratchPad (RS485 config) register failed status=0x%x\n", status);
+ return -EFAULT;
+ }
+
+ tmp.flags |= (scratchpad & 0x80) ? SER_RS485_ENABLED : 0x00;
+ tmp.flags |= (scratchpad & 0x40) ? SER_RS485_RTS_ON_SEND : 0x00;
+
+ if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
+ return -EFAULT;
+
+ return 0;
+}
+
+/*****************************************************************************
+ * mos7840_set_rs485_info
+ * function to handle RS485 "set" ioctl
+ *****************************************************************************/
+
+static int mos7840_set_rs485_info(struct usb_serial_port *port,
+ struct serial_rs485 __user *retinfo)
+{
+ struct serial_rs485 tmp;
+ int status;
+ __u16 scratchpad = 0;
+
+ if (port == NULL)
+ return -EFAULT;
+
+ if (!retinfo)
+ return -EFAULT;
+
+ if (copy_from_user(&tmp, retinfo, sizeof(*retinfo)))
+ return -EFAULT;
+
+ if (tmp.flags & SER_RS485_ENABLED)
+ scratchpad = 0x80 | ((tmp.flags & SER_RS485_RTS_ON_SEND) ? 0x40 : 0x00);
+
+ status = mos7840_set_uart_reg(port, SCRATCH_PAD_REGISTER, scratchpad);
+ if (status < 0) {
+ dev_dbg(&port->dev, "Writing ScratchPad (RS485 config) register failed status=0x%x\n", status);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+/*****************************************************************************
* SerialIoctl
* this function handles any ioctl calls to the driver
*****************************************************************************/
@@ -2010,6 +2078,16 @@ static int mos7840_ioctl(struct tty_struct *tty,
case TIOCSSERIAL:
dev_dbg(&port->dev, "%s TIOCSSERIAL\n", __func__);
break;
+
+ case TIOCGRS485:
+ dev_dbg(&port->dev, "%s TIOCGRS485\n", __func__);
+ return mos7840_get_rs485_info(port, argp);
+
+ case TIOCSRS485:
+ dev_dbg(&port->dev, "%s TIOCSRS485\n", __func__);
+ return mos7840_set_rs485_info(port, argp);
+
+
default:
break;
}
--
1.9.1
--
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