[PATCH v3 2/4] USB: serial: cp210x: Switch to new 16-bit register access functions.

[PATCH v3 2/4] USB: serial: cp210x: Switch to new 16-bit register access functions.

[Konstantin Shkolnyy]

Change to use new 16-bit register access functions instead of
cp210x_get_config and cp210x_set_config.

Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@gmail.com>
---
change in v3: Presented new function addition as a separate patch #1,
to simplify code review.

 drivers/usb/serial/cp210x.c | 80 ++++++++++++++++++---------------------------
 1 file changed, 31 insertions(+), 49 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 324eb7e..7a91c6c 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -588,17 +588,6 @@ 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
- */
-static inline int cp210x_set_config_single(struct usb_serial_port *port,
-		u8 request, unsigned int data)
-{
-	return cp210x_set_config(port, request, &data, 2);
-}
-
-/*
  * Detect CP2108 GET_LINE_CTL bug and activate workaround.
  * Write a known good value 0x800, read it back.
  * If it comes back swapped the bug is detected.
@@ -607,48 +596,47 @@ 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;
 }
@@ -697,14 +685,11 @@ 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);
@@ -718,15 +703,12 @@ 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);
 }
 
 /*
@@ -806,7 +788,7 @@ 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);
 
@@ -839,14 +821,14 @@ 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;
 	}
 
@@ -877,7 +859,7 @@ 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;
 	}
 
@@ -889,7 +871,7 @@ 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__);
@@ -898,7 +880,7 @@ 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;
 	}
 
@@ -972,7 +954,7 @@ 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;
@@ -1011,7 +993,7 @@ 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");
 	}
 
@@ -1038,7 +1020,7 @@ 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");
 	}
 
@@ -1052,7 +1034,7 @@ 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");
 	}
 
@@ -1092,7 +1074,7 @@ 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;
@@ -1113,7 +1095,7 @@ 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)
@@ -1147,7 +1129,7 @@ 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;
@@ -1155,7 +1137,7 @@ 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 v3 2/4] USB: serial: cp210x: Switch to new 16-bit register access functions.

[Martyn Welch]

On 02/01/16 03:12, Konstantin Shkolnyy wrote:
> Change to use new 16-bit register access functions instead of
> cp210x_get_config and cp210x_set_config.
>
> Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@gmail.com>
> ---
> change in v3: Presented new function addition as a separate patch #1,
> to simplify code review.
>
>   drivers/usb/serial/cp210x.c | 80 ++++++++++++++++++---------------------------
>   1 file changed, 31 insertions(+), 49 deletions(-)
>
> diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> index 324eb7e..7a91c6c 100644
> --- a/drivers/usb/serial/cp210x.c
> +++ b/drivers/usb/serial/cp210x.c
> @@ -588,17 +588,6 @@ 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
> - */
> -static inline int cp210x_set_config_single(struct usb_serial_port *port,
> -		u8 request, unsigned int data)
> -{
> -	return cp210x_set_config(port, request, &data, 2);
> -}
> -
> -/*
>    * Detect CP2108 GET_LINE_CTL bug and activate workaround.
>    * Write a known good value 0x800, read it back.
>    * If it comes back swapped the bug is detected.
> @@ -607,48 +596,47 @@ 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);

As mentioned in the comments to the first patch.

>   	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;
>   }
> @@ -697,14 +685,11 @@ 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;

Any reason for dropping the error message?

>
>   	/* Configure the termios structure */
>   	cp210x_get_termios(tty, port);
> @@ -718,15 +703,12 @@ 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);
>   }
>
>   /*
> @@ -806,7 +788,7 @@ 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);
>
> @@ -839,14 +821,14 @@ 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;
>   	}
>
> @@ -877,7 +859,7 @@ 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;
>   	}
>
> @@ -889,7 +871,7 @@ 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__);
> @@ -898,7 +880,7 @@ 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;
>   	}
>
> @@ -972,7 +954,7 @@ 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;
> @@ -1011,7 +993,7 @@ 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");
>   	}
>
> @@ -1038,7 +1020,7 @@ 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");
>   	}
>
> @@ -1052,7 +1034,7 @@ 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");
>   	}
>
> @@ -1092,7 +1074,7 @@ 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;
> @@ -1113,7 +1095,7 @@ 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)
> @@ -1147,7 +1129,7 @@ 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;
> @@ -1155,7 +1137,7 @@ 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 v3 2/4] USB: serial: cp210x: Switch to 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 11:44
> To: Konstantin Shkolnyy; johan@kernel.org
> Cc: linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH v3 2/4] USB: serial: cp210x: Switch to new 16-bit register
> access functions.
...

> > @@ -697,14 +685,11 @@ 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;
> 
> Any reason for dropping the error message?

I already print a message if the underlying usb_control_msg fails, so it should be covered there.

Re: [PATCH v3 2/4] USB: serial: cp210x: Switch to new 16-bit register access functions.

[Martyn Welch]

On 14/01/16 18:22, 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 11:44
>> To: Konstantin Shkolnyy; johan@kernel.org
>> Cc: linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
>> Subject: Re: [PATCH v3 2/4] USB: serial: cp210x: Switch to new 16-bit register
>> access functions.
> ...
>
>>> @@ -697,14 +685,11 @@ 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;
>>
>> Any reason for dropping the error message?
>
> I already print a message if the underlying usb_control_msg fails, so it should be covered there.
>

Sounds like a very valid reason :-)

Martyn

Re: [PATCH v3 2/4] USB: serial: cp210x: Switch to new 16-bit register access functions.

[Johan Hovold]

On Thu, Jan 14, 2016 at 06:22:29PM +0000, 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 11:44
> > To: Konstantin Shkolnyy; johan@kernel.org
> > Cc: linux-usb@vger.kernel.org; linux-kernel@vger.kernel.org
> > Subject: Re: [PATCH v3 2/4] USB: serial: cp210x: Switch to new 16-bit register
> > access functions.
> ...
> 
> > > @@ -697,14 +685,11 @@ 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;

Why rename the return value? I prefer ret over err, but there's no need
to change such things for code that's already in place.

> > >
> > > -	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;
> > 
> > Any reason for dropping the error message?
> 
> I already print a message if the underlying usb_control_msg fails, so
> it should be covered there.

Yes, but it's an unrelated change. The previous error message was more
informative.

Thanks,
Johan