[PATCH 12/14] USB: serial: keyspan_pda: clean up comments and whitespace

From: Johan Hovold
Date: Sun Oct 25 2020 - 14:02:12 EST

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In reply to: Johan Hovold: "[PATCH 03/14] USB: serial: keyspan_pda: fix stalled writes"
Next in thread: Sebastian Andrzej Siewior: "Re: [PATCH 00/14] USB: serial: keyspan_pda: fix up write implementation"
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Clean up comment style, remove some stale or redundant comments and drop
superfluous white space.

Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/serial/keyspan_pda.c | 116 +++++++++++++++----------------
1 file changed, 56 insertions(+), 60 deletions(-)

diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c
index f102dbf83492..8df7c54d6986 100644
--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -11,7 +11,6 @@
* driver
*/

-
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
@@ -121,8 +120,10 @@ static void keyspan_pda_request_unthrottle(struct work_struct *work)

dev_dbg(&port->dev, "%s\n", __func__);

- /* ask the device to tell us when the tx buffer becomes
- sufficiently empty */
+ /*
+ * Ask the device to tell us when the tx buffer becomes
+ * sufficiently empty.
+ */
result = usb_control_msg(serial->dev,
usb_sndctrlpipe(serial->dev, 0),
7, /* request_unthrottle */
@@ -208,7 +209,6 @@ static void keyspan_pda_rx_interrupt(struct urb *urb)

keyspan_pda_write_start(port);

- /* queue up a wakeup at scheduler time */
usb_serial_port_softint(port);
break;
default:
@@ -227,31 +227,30 @@ static void keyspan_pda_rx_interrupt(struct urb *urb)
__func__, retval);
}

-
static void keyspan_pda_rx_throttle(struct tty_struct *tty)
{
- /* stop receiving characters. We just turn off the URB request, and
- let chars pile up in the device. If we're doing hardware
- flowcontrol, the device will signal the other end when its buffer
- fills up. If we're doing XON/XOFF, this would be a good time to
- send an XOFF, although it might make sense to foist that off
- upon the device too. */
struct usb_serial_port *port = tty->driver_data;

+ /*
+ * Stop receiving characters. We just turn off the URB request, and
+ * let chars pile up in the device. If we're doing hardware
+ * flowcontrol, the device will signal the other end when its buffer
+ * fills up. If we're doing XON/XOFF, this would be a good time to
+ * send an XOFF, although it might make sense to foist that off upon
+ * the device too.
+ */
usb_kill_urb(port->interrupt_in_urb);
}

-
static void keyspan_pda_rx_unthrottle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
- /* just restart the receive interrupt URB */

+ /* just restart the receive interrupt URB */
if (usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL))
dev_dbg(&port->dev, "usb_submit_urb(read urb) failed\n");
}

-
static speed_t keyspan_pda_setbaud(struct usb_serial *serial, speed_t baud)
{
int rc;
@@ -293,8 +292,6 @@ static speed_t keyspan_pda_setbaud(struct usb_serial *serial, speed_t baud)
baud = 9600;
}

- /* rather than figure out how to sleep while waiting for this
- to complete, I just use the "legacy" API. */
rc = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
0, /* set baud */
USB_TYPE_VENDOR
@@ -307,10 +304,10 @@ static speed_t keyspan_pda_setbaud(struct usb_serial *serial, speed_t baud)
2000); /* timeout */
if (rc < 0)
return 0;
+
return baud;
}

-
static void keyspan_pda_break_ctl(struct tty_struct *tty, int break_state)
{
struct usb_serial_port *port = tty->driver_data;
@@ -322,6 +319,7 @@ static void keyspan_pda_break_ctl(struct tty_struct *tty, int break_state)
value = 1; /* start break */
else
value = 0; /* clear break */
+
result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
4, /* set break */
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
@@ -329,39 +327,35 @@ static void keyspan_pda_break_ctl(struct tty_struct *tty, int break_state)
if (result < 0)
dev_dbg(&port->dev, "%s - error %d from usb_control_msg\n",
__func__, result);
- /* there is something funky about this.. the TCSBRK that 'cu' performs
- ought to translate into a break_ctl(-1),break_ctl(0) pair HZ/4
- seconds apart, but it feels like the break sent isn't as long as it
- is on /dev/ttyS0 */
}

-
static void keyspan_pda_set_termios(struct tty_struct *tty,
struct usb_serial_port *port, struct ktermios *old_termios)
{
struct usb_serial *serial = port->serial;
speed_t speed;

- /* cflag specifies lots of stuff: number of stop bits, parity, number
- of data bits, baud. What can the device actually handle?:
- CSTOPB (1 stop bit or 2)
- PARENB (parity)
- CSIZE (5bit .. 8bit)
- There is minimal hw support for parity (a PSW bit seems to hold the
- parity of whatever is in the accumulator). The UART either deals
- with 10 bits (start, 8 data, stop) or 11 bits (start, 8 data,
- 1 special, stop). So, with firmware changes, we could do:
- 8N1: 10 bit
- 8N2: 11 bit, extra bit always (mark?)
- 8[EOMS]1: 11 bit, extra bit is parity
- 7[EOMS]1: 10 bit, b0/b7 is parity
- 7[EOMS]2: 11 bit, b0/b7 is parity, extra bit always (mark?)
-
- HW flow control is dictated by the tty->termios.c_cflags & CRTSCTS
- bit.
-
- For now, just do baud. */
-
+ /*
+ * cflag specifies lots of stuff: number of stop bits, parity, number
+ * of data bits, baud. What can the device actually handle?:
+ * CSTOPB (1 stop bit or 2)
+ * PARENB (parity)
+ * CSIZE (5bit .. 8bit)
+ * There is minimal hw support for parity (a PSW bit seems to hold the
+ * parity of whatever is in the accumulator). The UART either deals
+ * with 10 bits (start, 8 data, stop) or 11 bits (start, 8 data,
+ * 1 special, stop). So, with firmware changes, we could do:
+ * 8N1: 10 bit
+ * 8N2: 11 bit, extra bit always (mark?)
+ * 8[EOMS]1: 11 bit, extra bit is parity
+ * 7[EOMS]1: 10 bit, b0/b7 is parity
+ * 7[EOMS]2: 11 bit, b0/b7 is parity, extra bit always (mark?)
+ *
+ * HW flow control is dictated by the tty->termios.c_cflags & CRTSCTS
+ * bit.
+ *
+ * For now, just do baud.
+ */
speed = tty_get_baud_rate(tty);
speed = keyspan_pda_setbaud(serial, speed);

@@ -370,17 +364,19 @@ static void keyspan_pda_set_termios(struct tty_struct *tty,
/* It hasn't changed so.. */
speed = tty_termios_baud_rate(old_termios);
}
- /* Only speed can change so copy the old h/w parameters
- then encode the new speed */
+ /*
+ * Only speed can change so copy the old h/w parameters then encode
+ * the new speed.
+ */
tty_termios_copy_hw(&tty->termios, old_termios);
tty_encode_baud_rate(tty, speed, speed);
}

-
-/* modem control pins: DTR and RTS are outputs and can be controlled.
- DCD, RI, DSR, CTS are inputs and can be read. All outputs can also be
- read. The byte passed is: DTR(b7) DCD RI DSR CTS RTS(b2) unused unused */
-
+/*
+ * Modem control pins: DTR and RTS are outputs and can be controlled.
+ * DCD, RI, DSR, CTS are inputs and can be read. All outputs can also be
+ * read. The byte passed is: DTR(b7) DCD RI DSR CTS RTS(b2) unused unused.
+ */
static int keyspan_pda_get_modem_info(struct usb_serial *serial,
unsigned char *value)
{
@@ -404,7 +400,6 @@ static int keyspan_pda_get_modem_info(struct usb_serial *serial,
return rc;
}

-
static int keyspan_pda_set_modem_info(struct usb_serial *serial,
unsigned char value)
{
@@ -480,10 +475,11 @@ static int keyspan_pda_write_start(struct usb_serial_port *port)
* unthrottle work is scheduled).
*/

- /* we might block because of:
- the TX urb is in-flight (wait until it completes)
- the device is full (wait until it says there is room)
- */
+ /*
+ * We might block because of:
+ * the TX urb is in-flight (wait until it completes)
+ * the device is full (wait until it says there is room)
+ */
spin_lock_irqsave(&port->lock, flags);

room = priv->tx_room;
@@ -542,7 +538,6 @@ static void keyspan_pda_write_bulk_callback(struct urb *urb)

keyspan_pda_write_start(port);

- /* queue up a wakeup at scheduler time */
usb_serial_port_softint(port);
}

@@ -591,7 +586,6 @@ static int keyspan_pda_open(struct tty_struct *tty,
priv->tx_room = rc;
spin_unlock_irq(&port->lock);

- /*Start reading from the device*/
rc = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
if (rc) {
dev_dbg(&port->dev, "%s - usb_submit_urb(read int) failed\n", __func__);
@@ -648,10 +642,12 @@ static int keyspan_pda_fake_startup(struct usb_serial *serial)
return -ENOENT;
}

- /* after downloading firmware Renumeration will occur in a
- moment and the new device will bind to the real driver */
+ /*
+ * After downloading firmware renumeration will occur in a moment and
+ * the new device will bind to the real driver.
+ */

- /* we want this device to fail to have a driver assigned to it. */
+ /* We want this device to fail to have a driver assigned to it. */
return 1;
}

@@ -711,7 +707,7 @@ static struct usb_serial_driver keyspan_pda_device = {
.open = keyspan_pda_open,
.close = keyspan_pda_close,
.write = keyspan_pda_write,
- .write_bulk_callback = keyspan_pda_write_bulk_callback,
+ .write_bulk_callback = keyspan_pda_write_bulk_callback,
.read_int_callback = keyspan_pda_rx_interrupt,
.throttle = keyspan_pda_rx_throttle,
.unthrottle = keyspan_pda_rx_unthrottle,
--
2.26.2

Next message: Dwaipayan Ray: "Re: [PATCH v5] checkpatch: extend attributes check to handle more patterns"
Previous message: Joe Perches: "Re: [PATCH v5] checkpatch: extend attributes check to handle more patterns"
In reply to: Johan Hovold: "[PATCH 03/14] USB: serial: keyspan_pda: fix stalled writes"
Next in thread: Sebastian Andrzej Siewior: "Re: [PATCH 00/14] USB: serial: keyspan_pda: fix up write implementation"
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