This patch adds support for the synchronous FIFO mode of the FT232H
serial converter chip.
This might also be extended to be usable with other FTDI chips.
Signed-off-by: Philipp Hachtmann <hachti@xxxxxxxxx>
---
drivers/usb/serial/ftdi_sio.c | 65 +++++++++++++++++++++++++++++++++++++++++--
drivers/usb/serial/ftdi_sio.h | 15 ++++++++++
2 files changed, 78 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 7c6e1de..cacba4a 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -73,7 +73,7 @@ struct ftdi_private {
this value */
int force_rtscts; /* if non-zero, force RTS-CTS to always
be enabled */
-
+ int syncmode; /* FIFO device in synchronous 245 mode */
unsigned int latency; /* latency setting in use */
unsigned short max_packet_size;
struct mutex cfg_lock; /* Avoid mess by parallel calls of config ioctl() and change_speed() */
@@ -1327,6 +1327,36 @@ static int change_speed(struct tty_struct *tty, struct usb_serial_port *port)
return rv;
}
+static int set_syncmode(struct usb_serial_port *port, int enable)
+{
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+
+ __u16 urb_value = 0;
+ int rv = 0;
+
+ enable = enable ? 1 : 0;
+ if (enable == priv->syncmode)
+ return 0;
+
+ priv->syncmode = enable;
+
+ /* FTDI seems to say that the urb_value should be or'ed with 0xff. But
+ * when done this way the port gets quite slow. 0x00 seems to work much
+ * better.
+ */
+ if (enable)
+ urb_value = FTDI_BITMODE_SYNCFIFO << 8 | 0x00;
+
+ rv = usb_control_msg(port->serial->dev,
+ usb_sndctrlpipe(port->serial->dev, 0),
+ FTDI_SIO_SET_BITBANG_REQUEST,
+ FTDI_SIO_SET_BITBANG_REQUEST_TYPE,
+ urb_value, priv->interface,
+ NULL, 0, WDR_SHORT_TIMEOUT);
+
+ return rv;
+}
+
static int write_latency_timer(struct usb_serial_port *port)
{
struct ftdi_private *priv = usb_get_serial_port_data(port);
@@ -1628,6 +1658,32 @@ static ssize_t latency_timer_store(struct device *dev,
}
static DEVICE_ATTR_RW(latency_timer);
+static ssize_t syncmode_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct usb_serial_port *port = to_usb_serial_port(dev);
+ struct ftdi_private *priv = usb_get_serial_port_data(port);
+ return sprintf(buf, "%i\n", priv->syncmode);
+}
+
+static ssize_t syncmode_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *valbuf, size_t count)
+{
+ unsigned long value;
+ int rv;
+ struct usb_serial_port *port = to_usb_serial_port(dev);
+ int ret = kstrtoul(valbuf, 0, &value);
+ if (ret)
+ return -EINVAL;
+
+ rv = set_syncmode(port, value);
+ if (rv < 0)
+ return -EIO;
+ return count;
+}
+static DEVICE_ATTR_RW(syncmode);
+
/* Write an event character directly to the FTDI register. The ASCII
value is in the low 8 bits, with the enable bit in the 9th bit. */
static ssize_t store_event_char(struct device *dev,
@@ -1678,6 +1734,10 @@ static int create_sysfs_attrs(struct usb_serial_port *port)
&dev_attr_latency_timer);
}
}
+ if ((!retval) && priv->chip_type == FT232H) {
+ retval = device_create_file(&port->dev,
+ &dev_attr_syncmode);
+ }
return retval;
}
@@ -1698,7 +1758,8 @@ static void remove_sysfs_attrs(struct usb_serial_port *port)
device_remove_file(&port->dev, &dev_attr_latency_timer);
}
}
-
+ if (priv->chip_type == FT232H)
+ device_remove_file(&port->dev, &dev_attr_syncmode);
}
/*
diff --git a/drivers/usb/serial/ftdi_sio.h b/drivers/usb/serial/ftdi_sio.h
index ed58c6f..04a29f8 100644
--- a/drivers/usb/serial/ftdi_sio.h
+++ b/drivers/usb/serial/ftdi_sio.h
@@ -35,6 +35,7 @@
#define FTDI_SIO_SET_ERROR_CHAR 7 /* Set the error character */
#define FTDI_SIO_SET_LATENCY_TIMER 9 /* Set the latency timer */
#define FTDI_SIO_GET_LATENCY_TIMER 10 /* Get the latency timer */
+#define FTDI_SIO_SET_BITBANG 11 /* Set the bitbang mode */
/* Interface indices for FT2232, FT2232H and FT4232H devices */
#define INTERFACE_A 1
@@ -345,6 +346,20 @@ enum ftdi_sio_baudrate {
*/
/*
+ * FTDI_SIO_SET_BITBANG
+ *
+ * Set the chip's bitbang mode. Used to switch FT232H (which else?) into
+ * synchronous FIFO mode which cannot be configured in the eeprom.
+ *
+ */
+
+#define FTDI_SIO_SET_BITBANG_REQUEST FTDI_SIO_SET_BITBANG
+#define FTDI_SIO_SET_BITBANG_REQUEST_TYPE 0x40
+
+#define FTDI_BITMODE_RESET 0x00 /* Switch back to normal operation */
+#define FTDI_BITMODE_SYNCFIFO 0x40 /* Switch to syncronous FIFO mode */
+
+/*
* FTDI_SIO_SET_EVENT_CHAR
*
* Set the special event character for the specified communications port.
--
2.0.0.rc2
--
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