Re: [PATCH v4 3/7] usb: serial: implement read IIR/MSR ep for F81232

From: Johan Hovold
Date: Wed Feb 04 2015 - 07:41:33 EST

On Fri, Jan 30, 2015 at 02:13:37PM +0800, Peter Hung wrote:
> The F81232 interrupt ep will continuously report IIR register value.
> We had implement the interrupt callback to read IIR, If noticed with
> MSR change, we will call worker to read MSR later.
>
> Signed-off-by: Peter Hung <hpeter+linux_kernel@xxxxxxxxx>
> ---
> drivers/usb/serial/f81232.c | 114 +++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 107 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c
> index 9ef9775..274120d 100644
> --- a/drivers/usb/serial/f81232.c
> +++ b/drivers/usb/serial/f81232.c
> @@ -23,6 +23,7 @@
> #include <linux/uaccess.h>
> #include <linux/usb.h>
> #include <linux/usb/serial.h>
> +#include <linux/serial_reg.h>
>
> static const struct usb_device_id id_table[] = {
> { USB_DEVICE(0x1934, 0x0706) },
> @@ -44,23 +45,112 @@ MODULE_DEVICE_TABLE(usb, id_table);
> #define UART_OVERRUN_ERROR 0x40
> #define UART_CTS 0x80

Now that your including serial_req and using the standard register
masks, you should remove the old (incorrect ones) at some point. Most
are left unused after the whole series has been applied (except UART_DCD
and that looks like a bug).

>
> +#define REGISTER_REQUEST 0xA0
> +#define GET_REGISTER 0xc0
> +#define SET_REGISTER 0x40

Add a F81232-prefix to these (and other driver specific defines), and a
new line before the time out.

> +#define F81232_USB_TIMEOUT 3000
> +
> +#define SERIAL_BASE_ADDRESS (0x0120)

No parentheses.

> +#define MODEM_STATUS_REGISTER (0x06 + SERIAL_BASE_ADDRESS)

Missing newline.

> struct f81232_private {
> spinlock_t lock;
> u8 line_control;
> u8 line_status;

How about renaming this one modem_status?

> +
> + struct work_struct int_worker;

Call this one interrupt_work instead.

> + struct usb_serial_port *port;
> };
>
> +static inline int f81232_get_register(struct usb_device *dev,
> + u16 reg, u8 *data)

Let the compiler decide whether this should be inlined.

Should should probably also pass the usb-serial port rather than
usb_device and use &port->dev for the error message.

> +{
> + int status;
> +
> + status = usb_control_msg(dev,
> + usb_rcvctrlpipe(dev, 0),
> + REGISTER_REQUEST,
> + GET_REGISTER,
> + reg,
> + 0,
> + data,
> + sizeof(*data),
> + F81232_USB_TIMEOUT);
> +
> + if (status < 0) {
> + dev_dbg(&dev->dev,
> + "%s status: %d\n", __func__, status);

dev_err.

Is the line break needed still?

> + }
> +
> + return status;
> +}
> +
> +static void f81232_read_msr(struct f81232_private *priv)
> +{
> + int status;
> + unsigned long flags;
> + u8 current_msr, old_msr;
> + struct usb_device *dev = priv->port->serial->dev;
> + struct tty_struct *tty;
> +
> + status = f81232_get_register(dev, MODEM_STATUS_REGISTER, &current_msr);
> +

No newline before checking the return value. Comment applies to whole series.

> + if (status < 0) {
> + dev_dbg(&dev->dev, "%s fail, status: %d\n", __func__, status);
> + return;
> + }

You already logged the error in get_register, but use dev_err (and
&port->dev) if you want this here.

> +
> + spin_lock_irqsave(&priv->lock, flags);
> + old_msr = priv->line_status;
> + spin_unlock_irqrestore(&priv->lock, flags);

You never use old_msr so just drop this bit.

> +
> + if (current_msr & UART_MSR_ANY_DELTA) {

Just return unless there has been a change and reduce the indentation
below.

> + tty = tty_port_tty_get(&priv->port->port);
> +
> + if (tty) {
> + if (current_msr & UART_MSR_DDCD) {
> + usb_serial_handle_dcd_change(priv->port,
> + tty, current_msr & UART_MSR_DCD);
> + }
> +
> + tty_kref_put(tty);
> + }
> +
> + spin_lock_irqsave(&priv->lock, flags);
> + priv->line_status = current_msr;
> + spin_unlock_irqrestore(&priv->lock, flags);
> +
> + wake_up_interruptible(&priv->port->port.delta_msr_wait);
> + }
> +
> + dev_dbg(&dev->dev, "%s: %x\n", __func__, priv->line_status);
> +}

Missing newline.

> static void f81232_update_line_status(struct usb_serial_port *port,
> unsigned char *data,
> unsigned int actual_length)
> {
> - /*
> - * FIXME: Update port->icount, and call
> - *
> - * wake_up_interruptible(&port->port.delta_msr_wait);
> - *
> - * on MSR changes.
> - */
> + struct f81232_private *priv = usb_get_serial_port_data(port);
> + struct usb_device *dev = port->serial->dev;

Use &port->dev for debugging and drop this one.

> +
> + if (!actual_length)
> + return;
> +
> + switch (data[0] & 0x07) {
> + case 0x00: /* msr change */
> + dev_dbg(&dev->dev, "IIR: MSR Change: %x\n", data[0]);
> + schedule_work(&priv->int_worker);
> + break;
> +

I'd drop the newlines after break.

> + case 0x02: /* tx-empty */
> + break;
> +
> + case 0x04: /* rx data available */
> + break;
> +
> + case 0x06: /* lsr change */
> + /* we can forget it. the LSR will read from bulk-in */
> + dev_dbg(&dev->dev, "IIR: LSR Change: %x\n", data[0]);
> + break;
> + }
> }
>
> static void f81232_read_int_callback(struct urb *urb)
> @@ -270,6 +360,14 @@ static int f81232_ioctl(struct tty_struct *tty,
> return -ENOIOCTLCMD;
> }
>
> +static void f81232_int_work_wq(struct work_struct *work)

Rename this f81232_interrupt_work.

> +{
> + struct f81232_private *priv =
> + container_of(work, struct f81232_private, int_worker);
> +
> + f81232_read_msr(priv);
> +}
> +
> static int f81232_port_probe(struct usb_serial_port *port)
> {
> struct f81232_private *priv;
> @@ -279,10 +377,12 @@ static int f81232_port_probe(struct usb_serial_port *port)
> return -ENOMEM;
>
> spin_lock_init(&priv->lock);
> + INIT_WORK(&priv->int_worker, f81232_int_work_wq);
>
> usb_set_serial_port_data(port, priv);
>
> port->port.drain_delay = 256;
> + priv->port = port;
>
> return 0;
> }

This already looks much better, thanks for resending.

Johan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/