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USB: serial: cp210x: add 16-bit register access functions
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cp210x_get_config and cp210x_set_config are cumbersome to use. This change
introduces new register access functions for 16-bit values, instead of
the above functions.

Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
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Konstantin Shkolnyy authored and Johan Hovold committed Feb 29, 2016
1 parent 6424839 commit 19165b2
Showing 1 changed file with 108 additions and 39 deletions.
147 changes: 108 additions & 39 deletions drivers/usb/serial/cp210x.c
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Original file line number Diff line number Diff line change
Expand Up @@ -423,14 +423,88 @@ static int cp210x_set_config(struct usb_serial_port *port, u8 request,
}

/*
* cp210x_set_config_single
* Convenience function for calling cp210x_set_config on single data values
* without requiring an integer pointer
* Reads a variable-sized block of CP210X_ registers, identified by req.
* Returns data into buf in native USB byte order.
*/
static inline int cp210x_set_config_single(struct usb_serial_port *port,
u8 request, unsigned int data)
static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req,
void *buf, int bufsize)
{
return cp210x_set_config(port, request, &data, 2);
struct usb_serial *serial = port->serial;
struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
void *dmabuf;
int result;

dmabuf = kmalloc(bufsize, GFP_KERNEL);
if (!dmabuf) {
/*
* FIXME Some callers don't bother to check for error,
* at least give them consistent junk until they are fixed
*/
memset(buf, 0, bufsize);
return -ENOMEM;
}

result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
req, REQTYPE_INTERFACE_TO_HOST, 0,
port_priv->bInterfaceNumber, dmabuf, bufsize,
USB_CTRL_SET_TIMEOUT);
if (result == bufsize) {
memcpy(buf, dmabuf, bufsize);
result = 0;
} else {
dev_err(&port->dev, "failed get req 0x%x size %d status: %d\n",
req, bufsize, result);
if (result >= 0)
result = -EPROTO;

/*
* FIXME Some callers don't bother to check for error,
* at least give them consistent junk until they are fixed
*/
memset(buf, 0, bufsize);
}

kfree(dmabuf);

return result;
}

/*
* Reads any 16-bit CP210X_ register identified by req.
*/
static int cp210x_read_u16_reg(struct usb_serial_port *port, u8 req, u16 *val)
{
__le16 le16_val;
int err;

err = cp210x_read_reg_block(port, req, &le16_val, sizeof(le16_val));
if (err)
return err;

*val = le16_to_cpu(le16_val);
return 0;
}

/*
* Writes any 16-bit CP210X_ register (req) whose value is passed
* entirely in the wValue field of the USB request.
*/
static int cp210x_write_u16_reg(struct usb_serial_port *port, u8 req, u16 val)
{
struct usb_serial *serial = port->serial;
struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
int result;

result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
req, REQTYPE_HOST_TO_INTERFACE, val,
port_priv->bInterfaceNumber, NULL, 0,
USB_CTRL_SET_TIMEOUT);
if (result < 0) {
dev_err(&port->dev, "failed set request 0x%x status: %d\n",
req, result);
}

return result;
}

/*
Expand All @@ -442,47 +516,46 @@ static inline int cp210x_set_config_single(struct usb_serial_port *port,
static int cp210x_detect_swapped_line_ctl(struct usb_serial_port *port)
{
struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
unsigned int line_ctl_save;
unsigned int line_ctl_test;
u16 line_ctl_save;
u16 line_ctl_test;
int err;

err = cp210x_get_config(port, CP210X_GET_LINE_CTL, &line_ctl_save, 2);
err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, &line_ctl_save);
if (err)
return err;

line_ctl_test = 0x800;
err = cp210x_set_config(port, CP210X_SET_LINE_CTL, &line_ctl_test, 2);
err = cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, 0x800);
if (err)
return err;

err = cp210x_get_config(port, CP210X_GET_LINE_CTL, &line_ctl_test, 2);
err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, &line_ctl_test);
if (err)
return err;

if (line_ctl_test == 8) {
port_priv->has_swapped_line_ctl = true;
line_ctl_save = swab16((u16)line_ctl_save);
line_ctl_save = swab16(line_ctl_save);
}

return cp210x_set_config(port, CP210X_SET_LINE_CTL, &line_ctl_save, 2);
return cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, line_ctl_save);
}

/*
* Must always be called instead of cp210x_get_config(CP210X_GET_LINE_CTL)
* Must always be called instead of cp210x_read_u16_reg(CP210X_GET_LINE_CTL)
* to workaround cp2108 bug and get correct value.
*/
static int cp210x_get_line_ctl(struct usb_serial_port *port, unsigned int *ctl)
static int cp210x_get_line_ctl(struct usb_serial_port *port, u16 *ctl)
{
struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
int err;

err = cp210x_get_config(port, CP210X_GET_LINE_CTL, ctl, 2);
err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, ctl);
if (err)
return err;

/* Workaround swapped bytes in 16-bit value from CP210X_GET_LINE_CTL */
if (port_priv->has_swapped_line_ctl)
*ctl = swab16((u16)(*ctl));
*ctl = swab16(*ctl);

return 0;
}
Expand Down Expand Up @@ -533,8 +606,7 @@ static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
{
int result;

result = cp210x_set_config_single(port, CP210X_IFC_ENABLE,
UART_ENABLE);
result = cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_ENABLE);
if (result) {
dev_err(&port->dev, "%s - Unable to enable UART\n", __func__);
return result;
Expand All @@ -552,15 +624,12 @@ static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)

static void cp210x_close(struct usb_serial_port *port)
{
unsigned int purge_ctl;

usb_serial_generic_close(port);

/* Clear both queues; cp2108 needs this to avoid an occasional hang */
purge_ctl = PURGE_ALL;
cp210x_set_config(port, CP210X_PURGE, &purge_ctl, 2);
cp210x_write_u16_reg(port, CP210X_PURGE, PURGE_ALL);

cp210x_set_config_single(port, CP210X_IFC_ENABLE, UART_DISABLE);
cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_DISABLE);
}

/*
Expand Down Expand Up @@ -640,7 +709,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
struct device *dev = &port->dev;
unsigned int cflag, modem_ctl[4];
unsigned int baud;
unsigned int bits;
u16 bits;

cp210x_get_config(port, CP210X_GET_BAUDRATE, &baud, 4);

Expand Down Expand Up @@ -673,14 +742,14 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
cflag |= CS8;
bits &= ~BITS_DATA_MASK;
bits |= BITS_DATA_8;
cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
break;
default:
dev_dbg(dev, "%s - Unknown number of data bits, using 8\n", __func__);
cflag |= CS8;
bits &= ~BITS_DATA_MASK;
bits |= BITS_DATA_8;
cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
break;
}

Expand Down Expand Up @@ -711,7 +780,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
dev_dbg(dev, "%s - Unknown parity mode, disabling parity\n", __func__);
cflag &= ~PARENB;
bits &= ~BITS_PARITY_MASK;
cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
break;
}

Expand All @@ -723,7 +792,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
case BITS_STOP_1_5:
dev_dbg(dev, "%s - stop bits = 1.5 (not supported, using 1 stop bit)\n", __func__);
bits &= ~BITS_STOP_MASK;
cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
break;
case BITS_STOP_2:
dev_dbg(dev, "%s - stop bits = 2\n", __func__);
Expand All @@ -732,7 +801,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
default:
dev_dbg(dev, "%s - Unknown number of stop bits, using 1 stop bit\n", __func__);
bits &= ~BITS_STOP_MASK;
cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
break;
}

Expand Down Expand Up @@ -806,7 +875,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
{
struct device *dev = &port->dev;
unsigned int cflag, old_cflag;
unsigned int bits;
u16 bits;
unsigned int modem_ctl[4];

cflag = tty->termios.c_cflag;
Expand Down Expand Up @@ -845,7 +914,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
bits |= BITS_DATA_8;
break;
}
if (cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
dev_dbg(dev, "Number of data bits requested not supported by device\n");
}

Expand All @@ -872,7 +941,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
}
}
}
if (cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
dev_dbg(dev, "Parity mode not supported by device\n");
}

Expand All @@ -886,7 +955,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
bits |= BITS_STOP_1;
dev_dbg(dev, "%s - stop bits = 1\n", __func__);
}
if (cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
dev_dbg(dev, "Number of stop bits requested not supported by device\n");
}

Expand Down Expand Up @@ -926,7 +995,7 @@ static int cp210x_tiocmset(struct tty_struct *tty,
static int cp210x_tiocmset_port(struct usb_serial_port *port,
unsigned int set, unsigned int clear)
{
unsigned int control = 0;
u16 control = 0;

if (set & TIOCM_RTS) {
control |= CONTROL_RTS;
Expand All @@ -947,7 +1016,7 @@ static int cp210x_tiocmset_port(struct usb_serial_port *port,

dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control);

return cp210x_set_config(port, CP210X_SET_MHS, &control, 2);
return cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
}

static void cp210x_dtr_rts(struct usb_serial_port *p, int on)
Expand Down Expand Up @@ -981,15 +1050,15 @@ static int cp210x_tiocmget(struct tty_struct *tty)
static void cp210x_break_ctl(struct tty_struct *tty, int break_state)
{
struct usb_serial_port *port = tty->driver_data;
unsigned int state;
u16 state;

if (break_state == 0)
state = BREAK_OFF;
else
state = BREAK_ON;
dev_dbg(&port->dev, "%s - turning break %s\n", __func__,
state == BREAK_OFF ? "off" : "on");
cp210x_set_config(port, CP210X_SET_BREAK, &state, 2);
cp210x_write_u16_reg(port, CP210X_SET_BREAK, state);
}

static int cp210x_port_probe(struct usb_serial_port *port)
Expand Down

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