[PATCH v2 1/3 RESEND] USB: serial: cp210x: New 16-bit register access functions.

[PATCH v2 1/3 RESEND] USB: serial: cp210x: New 16-bit register access functions.

[Konstantin Shkolnyy]

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>
---
 drivers/usb/serial/cp210x.c | 155 +++++++++++++++++++++++++++++++-------------
 1 file changed, 111 insertions(+), 44 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index fd67958..fd7c4f4 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -422,14 +422,88 @@ 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;
 }
 
 /*
@@ -441,48 +515,47 @@ 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;
 
 	/* has_swapped_line_ctl is 0 here because port_priv was kzalloced */
 	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;
 }
@@ -531,14 +604,11 @@ static unsigned int cp210x_quantise_baudrate(unsigned int baud)
 
 static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
 {
-	int result;
+	int err;
 
-	result = cp210x_set_config_single(port, CP210X_IFC_ENABLE,
-								UART_ENABLE);
-	if (result) {
-		dev_err(&port->dev, "%s - Unable to enable UART\n", __func__);
-		return result;
-	}
+	err = cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_ENABLE);
+	if (err)
+		return err;
 
 	/* Configure the termios structure */
 	cp210x_get_termios(tty, port);
@@ -552,15 +622,12 @@ 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);
 }
 
 /*
@@ -640,7 +707,7 @@ 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);
 
@@ -673,14 +740,14 @@ 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;
 	}
 
@@ -711,7 +778,7 @@ 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;
 	}
 
@@ -723,7 +790,7 @@ 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__);
@@ -732,7 +799,7 @@ 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;
 	}
 
@@ -806,7 +873,7 @@ 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;
@@ -845,7 +912,7 @@ 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");
 	}
 
@@ -872,7 +939,7 @@ 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");
 	}
 
@@ -886,7 +953,7 @@ 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");
 	}
 
@@ -926,7 +993,7 @@ 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;
@@ -947,7 +1014,7 @@ 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)
@@ -981,7 +1048,7 @@ 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;
@@ -989,7 +1056,7 @@ static void cp210x_break_ctl(struct tty_struct *tty, int break_state)
 		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)
-- 
1.8.4.5

Re: [PATCH v2 1/3 RESEND] USB: serial: cp210x: New 16-bit register access functions.

[Martyn Welch]

On 23/12/15 02:14, Konstantin Shkolnyy wrote:
> 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>
> ---
>   drivers/usb/serial/cp210x.c | 155 +++++++++++++++++++++++++++++++-------------
>   1 file changed, 111 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> index fd67958..fd7c4f4 100644
> --- a/drivers/usb/serial/cp210x.c
> +++ b/drivers/usb/serial/cp210x.c
> @@ -422,14 +422,88 @@ 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;

I could be wrong, but isn't dmabuf a little-endian stream (hence the 
byte order swapping in the existing set and get functions). Won't this 
break on big endian systems due to the lack of byte swapping?

Martyn

> +	} 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;
>   }
>
>   /*
> @@ -441,48 +515,47 @@ 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;
>
>   	/* has_swapped_line_ctl is 0 here because port_priv was kzalloced */
>   	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;
>   }
> @@ -531,14 +604,11 @@ static unsigned int cp210x_quantise_baudrate(unsigned int baud)
>
>   static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
>   {
> -	int result;
> +	int err;
>
> -	result = cp210x_set_config_single(port, CP210X_IFC_ENABLE,
> -								UART_ENABLE);
> -	if (result) {
> -		dev_err(&port->dev, "%s - Unable to enable UART\n", __func__);
> -		return result;
> -	}
> +	err = cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_ENABLE);
> +	if (err)
> +		return err;
>
>   	/* Configure the termios structure */
>   	cp210x_get_termios(tty, port);
> @@ -552,15 +622,12 @@ 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);
>   }
>
>   /*
> @@ -640,7 +707,7 @@ 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);
>
> @@ -673,14 +740,14 @@ 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;
>   	}
>
> @@ -711,7 +778,7 @@ 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;
>   	}
>
> @@ -723,7 +790,7 @@ 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__);
> @@ -732,7 +799,7 @@ 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;
>   	}
>
> @@ -806,7 +873,7 @@ 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;
> @@ -845,7 +912,7 @@ 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");
>   	}
>
> @@ -872,7 +939,7 @@ 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");
>   	}
>
> @@ -886,7 +953,7 @@ 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");
>   	}
>
> @@ -926,7 +993,7 @@ 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;
> @@ -947,7 +1014,7 @@ 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)
> @@ -981,7 +1048,7 @@ 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;
> @@ -989,7 +1056,7 @@ static void cp210x_break_ctl(struct tty_struct *tty, int break_state)
>   		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)
>

RE: [PATCH v2 1/3 RESEND] USB: serial: cp210x: New 16-bit register access functions.

[Konstantin Shkolnyy]

> -----Original Message-----
> From: linux-usb-owner@vger.kernel.org [mailto:linux-usb-
> owner@vger.kernel.org] On Behalf Of Martyn Welch
> Sent: Thursday, January 14, 2016 10:31
> To: Konstantin Shkolnyy; johan@kernel.org
> Cc: linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v2 1/3 RESEND] USB: serial: cp210x: New 16-bit register
> access functions.
> 
> On 23/12/15 02:14, Konstantin Shkolnyy wrote:
> > 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>
> > ---
> >   drivers/usb/serial/cp210x.c | 155
> +++++++++++++++++++++++++++++++-------------
> >   1 file changed, 111 insertions(+), 44 deletions(-)
> >
> > diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> > index fd67958..fd7c4f4 100644
> > --- a/drivers/usb/serial/cp210x.c
> > +++ b/drivers/usb/serial/cp210x.c
> > @@ -422,14 +422,88 @@ 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;
> 
> I could be wrong, but isn't dmabuf a little-endian stream (hence the
> byte order swapping in the existing set and get functions). Won't this
> break on big endian systems due to the lack of byte swapping?

This function is intended to not convert, as I tried to say in the header comment.

Re: [PATCH v2 1/3 RESEND] USB: serial: cp210x: New 16-bit register access functions.

[Martyn Welch]

On 14/01/16 17:10, Konstantin Shkolnyy wrote:
>> -----Original Message-----
>> From: linux-usb-owner@vger.kernel.org [mailto:linux-usb-
>> owner@vger.kernel.org] On Behalf Of Martyn Welch
>> Sent: Thursday, January 14, 2016 10:31
>> To: Konstantin Shkolnyy; johan@kernel.org
>> Cc: linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
>> Subject: Re: [PATCH v2 1/3 RESEND] USB: serial: cp210x: New 16-bit register
>> access functions.
>>
>> On 23/12/15 02:14, Konstantin Shkolnyy wrote:
>>> 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>
>>> ---
>>>    drivers/usb/serial/cp210x.c | 155
>> +++++++++++++++++++++++++++++++-------------
>>>    1 file changed, 111 insertions(+), 44 deletions(-)
>>>
>>> diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
>>> index fd67958..fd7c4f4 100644
>>> --- a/drivers/usb/serial/cp210x.c
>>> +++ b/drivers/usb/serial/cp210x.c
>>> @@ -422,14 +422,88 @@ 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;
>>
>> I could be wrong, but isn't dmabuf a little-endian stream (hence the
>> byte order swapping in the existing set and get functions). Won't this
>> break on big endian systems due to the lack of byte swapping?
>
> This function is intended to not convert, as I tried to say in the header comment.
>

Ah, gotcha - conversion done in cp210x_read_u16_reg().

Martyn