[PATCH v2] USB: serial: add nt124 usb to serial driver
From: George McCollister
Date: Tue Mar 03 2015 - 12:57:23 EST
This driver is for the NovaTech 124 4x serial expansion board for the
NovaTech OrionLXm.
Firmware source code can be found here:
https://github.com/novatechweb/nt124
Signed-off-by: George McCollister <george.mccollister@xxxxxxxxx>
---
Changes to v1:
- Added description after nt124.c on line 2.
- Removed DRIVER_AUTHOR and DRIVER_DESC, use MODULE macros directly.
- Removed some unnecessary new lines and comments.
- Removed __packed from struct nt124_line_coding.
- Added locking around ctrlin and ctrlout.
- Switch ctrlin and ctrlout from unsigned int to u16.
- Removed serial_transmit and added tx_empty. Use a hybrid
notification/polling method to accurately determine when transmission is
finished while minimizing bus traffic (see comments in the code for
details).
- Removed flowctrl from struct nt124_line_coding.
- Use u16 for request and value, size_t for len arguments of nt124_ctrl_msg()
- Use USB_CTRL_SET_TIMEOUT instead of 5000.
- Use %04x for 16-bit variables and %zu for size_t variables in dev_dbg() and
dev_err().
- Removed use of ?: constructs.
- Removed nt124_set_control, nt124_set_line, nt124_send_break and
- nt124_set_flowctrl macros in favor of calling nt124_ctrl_msg() directly.
- Renamed nt124_process_notify() to nt124_process_status().
- Call usb_serial_handle_dcd_change() unconditionally when DCD has changed.
- Removed in argument list assignments.
- Use usb_translate_errors() in nt124_port_tiocmset().
- Use C_CSTOPB, C_CSIZE, C_PARENB, C_CMSPAR, C_PARODD, C_CRTSCTS macros.
- Raise/lower RTS on !B0/B0.
- Added NT124_BREAK_ON and NT124_BREAK_OFF #defines.
- Change nt124_open() to just call nt124_set_termios() followed by
usb_serial_generic_open().
- Don't set bulk_in_size and bulk_out_size.
- Performed thorough testing.
drivers/usb/serial/Kconfig | 9 +
drivers/usb/serial/Makefile | 1 +
drivers/usb/serial/nt124.c | 501 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 511 insertions(+)
create mode 100644 drivers/usb/serial/nt124.c
diff --git a/drivers/usb/serial/Kconfig b/drivers/usb/serial/Kconfig
index b7cf198..677a26a 100644
--- a/drivers/usb/serial/Kconfig
+++ b/drivers/usb/serial/Kconfig
@@ -510,6 +510,15 @@ config USB_SERIAL_NAVMAN
To compile this driver as a module, choose M here: the
module will be called navman.
+config USB_SERIAL_NT124
+ tristate "USB NovaTech 124 Serial Driver"
+ help
+ Say Y here if you want to use the NovaTech 124 4x USB to serial
+ board.
+
+ To compile this driver as a module, choose M here: the
+ module will be called nt124.
+
config USB_SERIAL_PL2303
tristate "USB Prolific 2303 Single Port Serial Driver"
help
diff --git a/drivers/usb/serial/Makefile b/drivers/usb/serial/Makefile
index 349d9df..f88eaab 100644
--- a/drivers/usb/serial/Makefile
+++ b/drivers/usb/serial/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_USB_SERIAL_MOS7720) += mos7720.o
obj-$(CONFIG_USB_SERIAL_MOS7840) += mos7840.o
obj-$(CONFIG_USB_SERIAL_MXUPORT) += mxuport.o
obj-$(CONFIG_USB_SERIAL_NAVMAN) += navman.o
+obj-$(CONFIG_USB_SERIAL_NT124) += nt124.o
obj-$(CONFIG_USB_SERIAL_OMNINET) += omninet.o
obj-$(CONFIG_USB_SERIAL_OPTICON) += opticon.o
obj-$(CONFIG_USB_SERIAL_OPTION) += option.o
diff --git a/drivers/usb/serial/nt124.c b/drivers/usb/serial/nt124.c
new file mode 100644
index 0000000..d837593
--- /dev/null
+++ b/drivers/usb/serial/nt124.c
@@ -0,0 +1,501 @@
+/*
+ * nt124.c - Driver for nt124 4x serial board based on STM32F103
+ *
+ * Copyright (c) 2014 - 2015 NovaTech LLC
+ *
+ * Portions derived from the cdc-acm driver
+ *
+ * The original intention was to implement a cdc-acm compliant
+ * 4x USB to serial converter in the STM32F103 however several problems arose.
+ * The STM32F103 didn't have enough end points to implement 4 ports.
+ * CTS control was required by the application.
+ * Accurate notification of transmission completion was required.
+ * RTSCTS flow control support was required.
+ *
+ * The interrupt endpoint was eliminated and the control line information
+ * was moved to the first two bytes of the bulk in endpoint message. CTS
+ * control and mechanisms to enable RTSCTS flow control and deliver TXEMPTY
+ * information were added.
+ *
+ * Firmware source code can be found here:
+ * https://github.com/novatechweb/nt124
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+#include <linux/tty_flip.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <asm/unaligned.h>
+
+#define NT124_VID 0x2aeb
+#define NT124_USB_PID 124
+
+static const struct usb_device_id id_table[] = {
+ { USB_DEVICE(NT124_VID, NT124_USB_PID) },
+ { },
+};
+
+MODULE_DEVICE_TABLE(usb, id_table);
+
+/*
+ * Output control lines.
+ */
+#define NT124_CTRL_DTR 0x01
+#define NT124_CTRL_RTS 0x02
+
+/*
+ * Input control lines and line errors.
+ */
+#define NT124_CTRL_DCD 0x01
+#define NT124_CTRL_DSR 0x02
+#define NT124_CTRL_BRK 0x04
+#define NT124_CTRL_RI 0x08
+#define NT124_CTRL_FRAMING 0x10
+#define NT124_CTRL_PARITY 0x20
+#define NT124_CTRL_OVERRUN 0x40
+#define NT124_CTRL_TXEMPTY 0x80
+#define NT124_CTRL_CTS 0x100
+
+#define USB_NT124_REQ_SET_LINE_CODING 0x20
+#define USB_NT124_REQ_SET_CONTROL_LINE_STATE 0x22
+#define USB_NT124_REQ_SEND_BREAK 0x23
+#define USB_NT124_REQ_SET_FLOW_CONTROL 0x90
+#define USB_NT124_REQ_GET_TXEMPTY 0x91
+
+#define NT124_BREAK_OFF 0x0
+#define NT124_BREAK_ON 0xffff
+
+#define NT124_STOP_BITS_1 0
+#define NT124_STOP_BITS_2 2
+
+#define NT124_PARITY_NONE 0
+#define NT124_PARITY_ODD 1
+#define NT124_PARITY_EVEN 2
+
+#define NT124_RTSCTS_FLOW_CONTROL_OFF 0
+#define NT124_RTSCTS_FLOW_CONTROL_ON 1
+
+struct nt124_line_coding {
+ __le32 dwDTERate;
+ u8 bCharFormat;
+ u8 bParityType;
+ u8 bDataBits;
+};
+
+struct nt124_private {
+ u16 bInterfaceNumber;
+ /* input control lines (DCD, DSR, RI, break, overruns) */
+ u16 ctrlin;
+ /* output control lines (DTR, RTS) */
+ u16 ctrlout;
+ spinlock_t ctrl_lock;
+ struct nt124_line_coding line;
+ bool tx_empty;
+};
+
+static int nt124_ctrl_msg(struct usb_serial_port *port, u16 request, u16 value,
+ void *buf, size_t len)
+{
+ struct nt124_private *priv = usb_get_serial_port_data(port);
+ int retval;
+
+ retval = usb_control_msg(port->serial->dev,
+ usb_sndctrlpipe(port->serial->dev, 0),
+ request, USB_DIR_OUT | USB_TYPE_VENDOR, value,
+ priv->bInterfaceNumber,
+ buf, len, USB_CTRL_SET_TIMEOUT);
+
+ dev_dbg(&port->dev,
+ "%s - rq 0x%04x, val 0x%04x, len %zu, result %d\n",
+ __func__, request, value, len, retval);
+
+ if (retval < 0) {
+ dev_err(&port->dev,
+ "%s - usb_control_msg failed (%d)\n",
+ __func__, retval);
+ return retval;
+ }
+
+ if (retval != len) {
+ dev_err(&port->dev,
+ "%s - short write (%d / %zu)\n",
+ __func__, retval, len);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static void nt124_process_status(struct usb_serial_port *port,
+ struct nt124_private *priv,
+ unsigned char *data)
+{
+ u16 ctrlin;
+ u16 newctrl;
+ unsigned long flags;
+ struct tty_struct *tty;
+
+ newctrl = get_unaligned_le16(data);
+
+ spin_lock_irqsave(&priv->ctrl_lock, flags);
+ ctrlin = priv->ctrlin;
+ priv->ctrlin = newctrl;
+ if (newctrl & NT124_CTRL_TXEMPTY)
+ priv->tx_empty = true;
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+
+ if (ctrlin & ~newctrl & NT124_CTRL_DCD) {
+ tty = tty_port_tty_get(&port->port);
+ if (tty)
+ usb_serial_handle_dcd_change(port, tty,
+ newctrl & NT124_CTRL_DCD);
+ }
+}
+
+static void nt124_process_read_urb(struct urb *urb)
+{
+ struct usb_serial_port *port = urb->context;
+ struct nt124_private *priv = usb_get_serial_port_data(port);
+ unsigned char *data = (unsigned char *)urb->transfer_buffer;
+ size_t datalen;
+
+ /* The packet should always be at least 2 bytes because status is
+ * included. If it's too short, discard it. */
+ if (urb->actual_length < 2)
+ return;
+
+ nt124_process_status(port, priv, data);
+
+ datalen = urb->actual_length - 2;
+
+ if (!datalen)
+ return;
+
+ tty_insert_flip_string(&port->port, &data[2], datalen);
+ tty_flip_buffer_push(&port->port);
+}
+
+static int nt124_tiocmget(struct tty_struct *tty)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ struct nt124_private *priv = usb_get_serial_port_data(port);
+ int result = 0;
+ unsigned long flags;
+ u16 ctrlout;
+ u16 ctrlin;
+
+ spin_lock_irqsave(&priv->ctrl_lock, flags);
+ ctrlout = priv->ctrlout;
+ ctrlin = priv->ctrlin;
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+
+ if (ctrlout & NT124_CTRL_DTR)
+ result |= TIOCM_DTR;
+
+ if (ctrlout & NT124_CTRL_RTS)
+ result |= TIOCM_RTS;
+
+ if (ctrlin & NT124_CTRL_DSR)
+ result |= TIOCM_DSR;
+
+ if (ctrlin & NT124_CTRL_RI)
+ result |= TIOCM_RI;
+
+ if (ctrlin & NT124_CTRL_DCD)
+ result |= TIOCM_CD;
+
+ if (ctrlin & NT124_CTRL_CTS)
+ result |= TIOCM_CTS;
+
+ return result;
+}
+
+static int nt124_port_tiocmset(struct usb_serial_port *port,
+ unsigned int set, unsigned int clear)
+{
+ struct nt124_private *priv = usb_get_serial_port_data(port);
+ unsigned int newctrl;
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&priv->ctrl_lock, flags);
+ newctrl = priv->ctrlout;
+
+ if (set & TIOCM_DTR)
+ newctrl |= NT124_CTRL_DTR;
+
+ if (set & TIOCM_RTS)
+ newctrl |= NT124_CTRL_RTS;
+
+ if (clear & TIOCM_DTR)
+ newctrl &= ~NT124_CTRL_DTR;
+
+ if (clear & TIOCM_RTS)
+ newctrl &= ~NT124_CTRL_RTS;
+
+ if (priv->ctrlout == newctrl) {
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+ return 0;
+ }
+
+ priv->ctrlout = newctrl;
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+
+ ret = nt124_ctrl_msg(port, USB_NT124_REQ_SET_CONTROL_LINE_STATE,
+ newctrl, NULL, 0);
+
+ return usb_translate_errors(ret);
+}
+
+static int nt124_tiocmset(struct tty_struct *tty,
+ unsigned int set, unsigned int clear)
+{
+ struct usb_serial_port *port = tty->driver_data;
+
+ return nt124_port_tiocmset(port, set, clear);
+}
+
+static void nt124_dtr_rts(struct usb_serial_port *port, int on)
+{
+ if (on)
+ nt124_port_tiocmset(port, TIOCM_DTR | TIOCM_RTS, 0);
+ else
+ nt124_port_tiocmset(port, 0, TIOCM_DTR | TIOCM_RTS);
+}
+
+static void nt124_set_termios(struct tty_struct *tty,
+ struct usb_serial_port *port,
+ struct ktermios *termios_old)
+{
+ struct nt124_private *priv = usb_get_serial_port_data(port);
+ struct ktermios *termios = &tty->termios;
+ struct nt124_line_coding newline;
+ int newctrl;
+ u16 flowcontrol;
+ unsigned long flags;
+
+ newline.dwDTERate = cpu_to_le32(tty_get_baud_rate(tty));
+ if (C_CSTOPB(tty))
+ newline.bCharFormat = NT124_STOP_BITS_2;
+ else
+ newline.bCharFormat = NT124_STOP_BITS_1;
+
+ /* Mark and space parity aren't supported.
+ * Use the old setting or no parity if termios_old isn't available. */
+ if (C_PARENB(tty) && C_CMSPAR(tty)) {
+ termios->c_cflag &= ~(PARENB | PARODD | CMSPAR);
+ if (termios_old)
+ termios->c_cflag |= termios_old->c_cflag &
+ (PARENB | PARODD | CMSPAR);
+ }
+
+ if (C_PARENB(tty)) {
+ if (C_PARODD(tty))
+ newline.bParityType = NT124_PARITY_ODD;
+ else
+ newline.bParityType = NT124_PARITY_EVEN;
+ } else {
+ newline.bParityType = NT124_PARITY_NONE;
+ }
+
+ /* 5 and 6 databits aren't supported.
+ * Use the old setting or 8 databits if termios_old isn't available. */
+ if (C_CSIZE(tty) == CS5 || C_CSIZE(tty) == CS6) {
+ termios->c_cflag &= ~CSIZE;
+ if (termios_old)
+ termios->c_cflag |= termios_old->c_cflag & CSIZE;
+ else
+ termios->c_cflag |= CS8;
+ }
+
+ switch (C_CSIZE(tty)) {
+ case CS7:
+ newline.bDataBits = 7;
+ break;
+ case CS8:
+ default:
+ newline.bDataBits = 8;
+ break;
+ }
+
+ spin_lock_irqsave(&priv->ctrl_lock, flags);
+ newctrl = priv->ctrlout;
+ if (C_BAUD(tty) == B0) {
+ newline.dwDTERate = priv->line.dwDTERate;
+ newctrl &= ~(NT124_CTRL_DTR | NT124_CTRL_RTS);
+ } else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
+ newctrl |= NT124_CTRL_DTR | NT124_CTRL_RTS;
+ }
+
+ if (newctrl != priv->ctrlout) {
+ priv->ctrlout = newctrl;
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+ nt124_ctrl_msg(port, USB_NT124_REQ_SET_CONTROL_LINE_STATE,
+ newctrl, NULL, 0);
+ } else
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+
+ if (memcmp(&priv->line, &newline, sizeof(newline))) {
+ memcpy(&priv->line, &newline, sizeof(newline));
+ dev_dbg(&port->dev, "%s - set line: %u %u %u %u\n",
+ __func__,
+ le32_to_cpu(newline.dwDTERate),
+ newline.bCharFormat, newline.bParityType,
+ newline.bDataBits);
+ nt124_ctrl_msg(port, USB_NT124_REQ_SET_LINE_CODING, 0,
+ &priv->line, sizeof(priv->line));
+ }
+
+ if (!termios_old ||
+ C_CRTSCTS(tty) != (termios_old->c_cflag & CRTSCTS)) {
+ if (C_CRTSCTS(tty))
+ flowcontrol = NT124_RTSCTS_FLOW_CONTROL_ON;
+ else
+ flowcontrol = NT124_RTSCTS_FLOW_CONTROL_OFF;
+ nt124_ctrl_msg(port, USB_NT124_REQ_SET_FLOW_CONTROL,
+ flowcontrol, NULL, 0);
+ }
+}
+
+static bool nt124_tx_empty(struct usb_serial_port *port)
+{
+ struct nt124_private *priv = usb_get_serial_port_data(port);
+ u8 tx_empty;
+ int retval;
+ unsigned long flags;
+ bool result;
+
+ /* If tx_empty has already been marked false there is no need to poll
+ * for it's value since we can rely on a bulk in empty notification.
+ * In the common situation of tcdrain() being called after transmitting
+ * we prevent a considerable amount of bus traffic. */
+ spin_lock_irqsave(&priv->ctrl_lock, flags);
+ if (!priv->tx_empty) {
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+ return false;
+ }
+
+ /* Set tx_empty to false, since it can only set it to true below
+ * there is no possibility to lose a tx_empty notification from the
+ * bulk in packet while the lock isn't held */
+ priv->tx_empty = false;
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+
+ retval = usb_control_msg(port->serial->dev,
+ usb_rcvctrlpipe(port->serial->dev, 0),
+ USB_NT124_REQ_GET_TXEMPTY,
+ USB_DIR_IN | USB_TYPE_VENDOR,
+ 0,
+ priv->bInterfaceNumber,
+ &tx_empty,
+ sizeof(tx_empty),
+ USB_CTRL_SET_TIMEOUT);
+ if (retval < 0) {
+ dev_err(&port->dev,
+ "%s - usb_control_msg failed (%d)\n",
+ __func__, retval);
+ return true;
+ }
+
+ if (retval != sizeof(tx_empty)) {
+ dev_err(&port->dev,
+ "%s - short read (%d / %zu)\n",
+ __func__, retval, sizeof(tx_empty));
+ return true;
+ }
+
+ spin_lock_irqsave(&priv->ctrl_lock, flags);
+ if (tx_empty)
+ priv->tx_empty = true;
+ result = priv->tx_empty;
+ spin_unlock_irqrestore(&priv->ctrl_lock, flags);
+
+ return result;
+}
+
+static void nt124_break_ctl(struct tty_struct *tty, int state)
+{
+ struct usb_serial_port *port = tty->driver_data;
+ int retval;
+ u16 val;
+
+ if (state)
+ val = NT124_BREAK_ON;
+ else
+ val = NT124_BREAK_OFF;
+
+ retval = nt124_ctrl_msg(port, USB_NT124_REQ_SEND_BREAK, val, NULL, 0);
+ if (retval < 0)
+ dev_err(&port->dev, "%s - send break failed\n", __func__);
+}
+
+static int nt124_open(struct tty_struct *tty,
+ struct usb_serial_port *port)
+{
+ nt124_set_termios(tty, port, NULL);
+
+ return usb_serial_generic_open(tty, port);
+}
+
+static int nt124_port_probe(struct usb_serial_port *port)
+{
+ struct usb_interface *interface = port->serial->interface;
+ struct usb_host_interface *cur_altsetting = interface->cur_altsetting;
+ struct nt124_private *priv;
+
+ priv = devm_kzalloc(&port->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ spin_lock_init(&priv->ctrl_lock);
+ priv->bInterfaceNumber = cur_altsetting->desc.bInterfaceNumber;
+ priv->tx_empty = true;
+
+ usb_set_serial_port_data(port, priv);
+
+ return 0;
+}
+
+static struct usb_serial_driver nt124_device = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "nt124",
+ },
+ .id_table = id_table,
+ .num_ports = 1,
+ .open = nt124_open,
+ .process_read_urb = nt124_process_read_urb,
+ .tx_empty = nt124_tx_empty,
+ .throttle = usb_serial_generic_throttle,
+ .unthrottle = usb_serial_generic_unthrottle,
+ .set_termios = nt124_set_termios,
+ .tiocmget = nt124_tiocmget,
+ .tiocmset = nt124_tiocmset,
+ .dtr_rts = nt124_dtr_rts,
+ .break_ctl = nt124_break_ctl,
+ .port_probe = nt124_port_probe,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+ &nt124_device, NULL
+};
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_AUTHOR("George McCollister <george.mccollister@xxxxxxxxx>");
+MODULE_DESCRIPTION("nt124 USB serial driver");
+MODULE_LICENSE("GPL");
--
2.2.2
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