[PATCH v4 0/4] serial: RS485 kerneldoc/documentation improvements

[PATCH v4 0/4] serial: RS485 kerneldoc/documentation improvements

[Ilpo Järvinen]

RS485 documentation improvements. While doing the kerneldoc conversion,
a few other items came up so they're now included in this series.

v4:
- Remove wrong private: markers
- Fix grammar problems

v3:
- More fixes to kernel doc formatting (thanks to Jiri)
- Added a few other related improvements

v2:
- Include serial_rs485 into documentation
- Add * to multi-line flag descriptions

Ilpo Järvinen (4):
  serial: Convert serial_rs485 to kernel doc
  Documentation: rs485: Link reference properly
  Documentation: rs485: Mention uart_get_rs485_mode()
  Documentation: rs485: Fix struct referencing

 .../driver-api/serial/serial-rs485.rst        | 37 +++++++------
 include/uapi/linux/serial.h                   | 55 ++++++++++++-------
 2 files changed, 56 insertions(+), 36 deletions(-)

-- 
2.30.2

[PATCH v4 1/4] serial: Convert serial_rs485 to kernel doc

[Ilpo Järvinen]

Convert struct serial_rs485 comments to kernel doc format and include
it into documentation.

Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 .../driver-api/serial/serial-rs485.rst        | 13 +++--
 include/uapi/linux/serial.h                   | 55 ++++++++++++-------
 2 files changed, 43 insertions(+), 25 deletions(-)

diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index 6ebad75c74ed..264e4b753713 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -29,11 +29,11 @@ RS485 Serial Communications
 3. Data Structures Already Available in the Kernel
 ==================================================
 
-   The Linux kernel provides the serial_rs485 structure (see [1]) to handle
-   RS485 communications. This data structure is used to set and configure RS485
+   The Linux kernel provides the serial_rs485 structure to handle RS485
+   communications. This data structure is used to set and configure RS485
    parameters in the platform data and in ioctls.
 
-   The device tree can also provide RS485 boot time parameters (see [2]
+   The device tree can also provide RS485 boot time parameters (see [1]
    for bindings). The driver is in charge of filling this data structure from
    the values given by the device tree.
 
@@ -47,6 +47,9 @@ RS485 Serial Communications
    for the uart_port. TIOCGRS485 ioctl can be used to read back the
    serial_rs485 structure matching to the current configuration.
 
+.. kernel-doc:: include/uapi/linux/serial.h
+   :identifiers: serial_rs485
+
 4. Usage from user-level
 ========================
 
@@ -126,6 +129,4 @@ RS485 Serial Communications
 6. References
 =============
 
- [1]	include/uapi/linux/serial.h
-
- [2]	Documentation/devicetree/bindings/serial/rs485.txt
+ [1]	Documentation/devicetree/bindings/serial/rs485.txt
diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
index cea06924b295..4634c913f16a 100644
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -107,33 +107,50 @@ struct serial_icounter_struct {
 	int reserved[9];
 };
 
-/*
+/**
+ * struct serial_rs485 - serial interface for controlling RS485 settings.
+ * @flags:			RS485 feature flags.
+ * @delay_rts_before_send:	Delay before send (milliseconds).
+ * @delay_rts_after_send:	Delay after send (milliseconds).
+ * @addr_recv:			Receive filter for RS485 addressing mode
+ *				(used only when %SER_RS485_ADDR_RECV is set).
+ * @addr_dest:			Destination address for RS485 addressing mode
+ *				(used only when %SER_RS485_ADDR_DEST is set).
+ * @padding0:			Padding (set to zero).
+ * @padding1:			Padding (set to zero).
+ * @padding:			Deprecated, use @padding0 and @padding1 instead.
+ *				Do not use with @addr_recv and @addr_dest (due to
+ *				overlap).
+ *
  * Serial interface for controlling RS485 settings on chips with suitable
  * support. Set with TIOCSRS485 and get with TIOCGRS485 if supported by your
  * platform. The set function returns the new state, with any unsupported bits
  * reverted appropriately.
+ *
+ * serial_rs485::flags bits are:
+ *
+ * * %SER_RS485_ENABLED		- RS485 enabled.
+ * * %SER_RS485_RTS_ON_SEND	- Logical level for RTS pin when sending.
+ * * %SER_RS485_RTS_AFTER_SEND	- Logical level for RTS pin after sent.
+ * * %SER_RS485_RX_DURING_TX	- Full-duplex RS485 line.
+ * * %SER_RS485_TERMINATE_BUS	- Enable bus termination (if supported).
+ * * %SER_RS485_ADDRB		- Enable RS485 addressing mode.
+ * * %SER_RS485_ADDR_RECV - Receive address filter (enables @addr_recv). Requires %SER_RS485_ADDRB.
+ * * %SER_RS485_ADDR_DEST - Destination address (enables @addr_dest). Requires %SER_RS485_ADDRB.
  */
-
 struct serial_rs485 {
-	__u32	flags;			/* RS485 feature flags */
-#define SER_RS485_ENABLED		(1 << 0)	/* If enabled */
-#define SER_RS485_RTS_ON_SEND		(1 << 1)	/* Logical level for
-							   RTS pin when
-							   sending */
-#define SER_RS485_RTS_AFTER_SEND	(1 << 2)	/* Logical level for
-							   RTS pin after sent*/
+	__u32	flags;
+#define SER_RS485_ENABLED		(1 << 0)
+#define SER_RS485_RTS_ON_SEND		(1 << 1)
+#define SER_RS485_RTS_AFTER_SEND	(1 << 2)
 #define SER_RS485_RX_DURING_TX		(1 << 4)
-#define SER_RS485_TERMINATE_BUS		(1 << 5)	/* Enable bus
-							   termination
-							   (if supported) */
-
-/* RS-485 addressing mode */
-#define SER_RS485_ADDRB			(1 << 6)	/* Enable addressing mode */
-#define SER_RS485_ADDR_RECV		(1 << 7)	/* Receive address filter */
-#define SER_RS485_ADDR_DEST		(1 << 8)	/* Destination address */
+#define SER_RS485_TERMINATE_BUS		(1 << 5)
+#define SER_RS485_ADDRB			(1 << 6)
+#define SER_RS485_ADDR_RECV		(1 << 7)
+#define SER_RS485_ADDR_DEST		(1 << 8)
 
-	__u32	delay_rts_before_send;	/* Delay before send (milliseconds) */
-	__u32	delay_rts_after_send;	/* Delay after send (milliseconds) */
+	__u32	delay_rts_before_send;
+	__u32	delay_rts_after_send;
 
 	/* The fields below are defined by flags */
 	union {
-- 
2.30.2

Re: [PATCH v4 1/4] serial: Convert serial_rs485 to kernel doc

[Bagas Sanjaya]

[-- Attachment #1: Type: text/plain, Size: 8710 bytes --]

On Thu, Sep 29, 2022 at 12:31:45PM +0300, Ilpo Järvinen wrote:
> diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
> index 6ebad75c74ed..264e4b753713 100644
> --- a/Documentation/driver-api/serial/serial-rs485.rst
> +++ b/Documentation/driver-api/serial/serial-rs485.rst
> @@ -29,11 +29,11 @@ RS485 Serial Communications
>  3. Data Structures Already Available in the Kernel
>  ==================================================
>  
> -   The Linux kernel provides the serial_rs485 structure (see [1]) to handle
> -   RS485 communications. This data structure is used to set and configure RS485
> +   The Linux kernel provides the serial_rs485 structure to handle RS485
> +   communications. This data structure is used to set and configure RS485
>     parameters in the platform data and in ioctls.
>  
> -   The device tree can also provide RS485 boot time parameters (see [2]
> +   The device tree can also provide RS485 boot time parameters (see [1]
>     for bindings). The driver is in charge of filling this data structure from
>     the values given by the device tree.
>  
> @@ -47,6 +47,9 @@ RS485 Serial Communications
>     for the uart_port. TIOCGRS485 ioctl can be used to read back the
>     serial_rs485 structure matching to the current configuration.
>  
> +.. kernel-doc:: include/uapi/linux/serial.h
> +   :identifiers: serial_rs485
> +
>  4. Usage from user-level
>  ========================
>  
> @@ -126,6 +129,4 @@ RS485 Serial Communications
>  6. References
>  =============
>  
> - [1]	include/uapi/linux/serial.h
> -
> - [2]	Documentation/devicetree/bindings/serial/rs485.txt
> + [1]	Documentation/devicetree/bindings/serial/rs485.txt

For formatting consistency with kernel-doc comment of the struct below,
the code keywords should be in inline code samples:

---- >8 ----
diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index e53aa291bcd7df..3d48c8b5a3e6f8 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -39,15 +39,15 @@ RS485 Serial Communications
    uart_get_rs485_mode().
 
    Any driver for devices capable of working both as RS232 and RS485 should
-   implement the rs485_config callback and provide rs485_supported in the
-   struct uart_port. The serial core calls rs485_config to do the device
-   specific part in response to TIOCSRS485 ioctl (see below). The
-   rs485_config callback receives a pointer to a sanitizated struct
+   implement the ``rs485_config`` callback and provide ``rs485_supported`` in
+   the ``struct uart_port``. The serial core calls ``rs485_config`` to do the
+   device specific part in response to TIOCSRS485 ioctl (see below). The
+   ``rs485_config`` callback receives a pointer to a sanitizated struct
    serial_rs485. The struct serial_rs485 userspace provides is sanitized
-   before calling rs485_config using rs485_supported that indicates what
-   RS485 features the driver supports for the struct uart_port. TIOCGRS485
-   ioctl can be used to read back the struct serial_rs485 matching to the
-   current configuration.
+   before calling ``rs485_config`` using ``rs485_supported`` that indicates
+   what RS485 features the driver supports for the struct uart_port.
+   TIOCGRS485 ioctl can be used to read back the struct serial_rs485 matching
+   to the current configuration.
 
 .. kernel-doc:: include/uapi/linux/serial.h
    :identifiers: serial_rs485 uart_get_rs485_mode
@@ -108,23 +108,26 @@ RS485 Serial Communications
 ========================
 
    The Linux kernel provides addressing mode for multipoint RS-485 serial
-   communications line. The addressing mode is enabled with SER_RS485_ADDRB
+   communications line. The addressing mode is enabled with ``SER_RS485_ADDRB``
    flag in struct serial_rs485. The struct serial_rs485 has two additional
    flags and fields for enabling receive and destination addresses.
 
    Address mode flags:
-	- SER_RS485_ADDRB: Enabled addressing mode (sets also ADDRB in termios).
-	- SER_RS485_ADDR_RECV: Receive (filter) address enabled.
-	- SER_RS485_ADDR_DEST: Set destination address.
 
-   Address fields (enabled with corresponding SER_RS485_ADDR_* flag):
-	- addr_recv: Receive address.
-	- addr_dest: Destination address.
+	- ``SER_RS485_ADDRB``: Enabled addressing mode (sets also ADDRB in
+          termios).
+	- ``SER_RS485_ADDR_RECV``: Receive (filter) address enabled.
+	- ``SER_RS485_ADDR_DEST``: Set destination address.
+
+   Address fields (enabled with corresponding ``SER_RS485_ADDR_*`` flag):
+
+	- ``addr_recv``: Receive address.
+	- ``addr_dest``: Destination address.
 
    Once a receive address is set, the communication can occur only with the
    particular device and other peers are filtered out. It is left up to the
    receiver side to enforce the filtering. Receive address will be cleared
-   if SER_RS485_ADDR_RECV is not set.
+   if ``SER_RS485_ADDR_RECV`` is not set.
 
    Note: not all devices supporting RS485 support multipoint addressing.
 

> diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
> index cea06924b295..4634c913f16a 100644
> --- a/include/uapi/linux/serial.h
> +++ b/include/uapi/linux/serial.h
> @@ -107,33 +107,50 @@ struct serial_icounter_struct {
>  	int reserved[9];
>  };
>  
> -/*
> +/**
> + * struct serial_rs485 - serial interface for controlling RS485 settings.
> + * @flags:			RS485 feature flags.
> + * @delay_rts_before_send:	Delay before send (milliseconds).
> + * @delay_rts_after_send:	Delay after send (milliseconds).
> + * @addr_recv:			Receive filter for RS485 addressing mode
> + *				(used only when %SER_RS485_ADDR_RECV is set).
> + * @addr_dest:			Destination address for RS485 addressing mode
> + *				(used only when %SER_RS485_ADDR_DEST is set).
> + * @padding0:			Padding (set to zero).
> + * @padding1:			Padding (set to zero).
> + * @padding:			Deprecated, use @padding0 and @padding1 instead.
> + *				Do not use with @addr_recv and @addr_dest (due to
> + *				overlap).
> + *
>   * Serial interface for controlling RS485 settings on chips with suitable
>   * support. Set with TIOCSRS485 and get with TIOCGRS485 if supported by your
>   * platform. The set function returns the new state, with any unsupported bits
>   * reverted appropriately.
> + *
> + * serial_rs485::flags bits are:
> + *

Maybe better say "The flag bits are:"?

> + * * %SER_RS485_ENABLED		- RS485 enabled.
> + * * %SER_RS485_RTS_ON_SEND	- Logical level for RTS pin when sending.
> + * * %SER_RS485_RTS_AFTER_SEND	- Logical level for RTS pin after sent.
> + * * %SER_RS485_RX_DURING_TX	- Full-duplex RS485 line.
> + * * %SER_RS485_TERMINATE_BUS	- Enable bus termination (if supported).
> + * * %SER_RS485_ADDRB		- Enable RS485 addressing mode.
> + * * %SER_RS485_ADDR_RECV - Receive address filter (enables @addr_recv). Requires %SER_RS485_ADDRB.
> + * * %SER_RS485_ADDR_DEST - Destination address (enables @addr_dest). Requires %SER_RS485_ADDRB.
>   */
> -
>  struct serial_rs485 {
> -	__u32	flags;			/* RS485 feature flags */
> -#define SER_RS485_ENABLED		(1 << 0)	/* If enabled */
> -#define SER_RS485_RTS_ON_SEND		(1 << 1)	/* Logical level for
> -							   RTS pin when
> -							   sending */
> -#define SER_RS485_RTS_AFTER_SEND	(1 << 2)	/* Logical level for
> -							   RTS pin after sent*/
> +	__u32	flags;
> +#define SER_RS485_ENABLED		(1 << 0)
> +#define SER_RS485_RTS_ON_SEND		(1 << 1)
> +#define SER_RS485_RTS_AFTER_SEND	(1 << 2)
>  #define SER_RS485_RX_DURING_TX		(1 << 4)
> -#define SER_RS485_TERMINATE_BUS		(1 << 5)	/* Enable bus
> -							   termination
> -							   (if supported) */
> -
> -/* RS-485 addressing mode */
> -#define SER_RS485_ADDRB			(1 << 6)	/* Enable addressing mode */
> -#define SER_RS485_ADDR_RECV		(1 << 7)	/* Receive address filter */
> -#define SER_RS485_ADDR_DEST		(1 << 8)	/* Destination address */
> +#define SER_RS485_TERMINATE_BUS		(1 << 5)
> +#define SER_RS485_ADDRB			(1 << 6)
> +#define SER_RS485_ADDR_RECV		(1 << 7)
> +#define SER_RS485_ADDR_DEST		(1 << 8)
>  
> -	__u32	delay_rts_before_send;	/* Delay before send (milliseconds) */
> -	__u32	delay_rts_after_send;	/* Delay after send (milliseconds) */
> +	__u32	delay_rts_before_send;
> +	__u32	delay_rts_after_send;
>  
>  	/* The fields below are defined by flags */
>  	union {

All struct members are described in htmldocs output, thanks. 

-- 
An old man doll... just what I always wanted! - Clara

[-- Attachment #2: signature.asc --]
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[PATCH v4 2/4] Documentation: rs485: Link reference properly

[Ilpo Järvinen]

Link DT bindings reference properly.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 Documentation/driver-api/serial/serial-rs485.rst | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index 264e4b753713..513758a702a6 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -33,9 +33,9 @@ RS485 Serial Communications
    communications. This data structure is used to set and configure RS485
    parameters in the platform data and in ioctls.
 
-   The device tree can also provide RS485 boot time parameters (see [1]
-   for bindings). The driver is in charge of filling this data structure from
-   the values given by the device tree.
+   The device tree can also provide RS485 boot time parameters
+   [#DT-bindings]_. The driver is in charge of filling this data structure
+   from the values given by the device tree.
 
    Any driver for devices capable of working both as RS232 and RS485 should
    implement the rs485_config callback and provide rs485_supported in the
@@ -129,4 +129,4 @@ RS485 Serial Communications
 6. References
 =============
 
- [1]	Documentation/devicetree/bindings/serial/rs485.txt
+.. [#DT-bindings]	Documentation/devicetree/bindings/serial/rs485.txt
-- 
2.30.2

[PATCH v4 3/4] Documentation: rs485: Mention uart_get_rs485_mode()

[Ilpo Järvinen]

Add to rs485 documentation that serial core prepares the struct
serial_rs485 when uart_get_rs485_mode() is called. Remove the wrong
claim that the driver must fill it by itself.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 Documentation/driver-api/serial/serial-rs485.rst | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index 513758a702a6..ee34c8e1e56e 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -34,8 +34,9 @@ RS485 Serial Communications
    parameters in the platform data and in ioctls.
 
    The device tree can also provide RS485 boot time parameters
-   [#DT-bindings]_. The driver is in charge of filling this data structure
-   from the values given by the device tree.
+   [#DT-bindings]_. The serial core fills the struct serial_rs485 from the
+   values given by the device tree when the driver calls
+   uart_get_rs485_mode().
 
    Any driver for devices capable of working both as RS232 and RS485 should
    implement the rs485_config callback and provide rs485_supported in the
@@ -48,7 +49,7 @@ RS485 Serial Communications
    serial_rs485 structure matching to the current configuration.
 
 .. kernel-doc:: include/uapi/linux/serial.h
-   :identifiers: serial_rs485
+   :identifiers: serial_rs485 uart_get_rs485_mode
 
 4. Usage from user-level
 ========================
-- 
2.30.2

[PATCH v4 4/4] Documentation: rs485: Fix struct referencing

[Ilpo Järvinen]

Use "struct serial_rs485" to get the references properly recognized.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 .../driver-api/serial/serial-rs485.rst        | 21 ++++++++++---------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index ee34c8e1e56e..e53aa291bcd7 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -29,7 +29,7 @@ RS485 Serial Communications
 3. Data Structures Already Available in the Kernel
 ==================================================
 
-   The Linux kernel provides the serial_rs485 structure to handle RS485
+   The Linux kernel provides the struct serial_rs485 to handle RS485
    communications. This data structure is used to set and configure RS485
    parameters in the platform data and in ioctls.
 
@@ -40,13 +40,14 @@ RS485 Serial Communications
 
    Any driver for devices capable of working both as RS232 and RS485 should
    implement the rs485_config callback and provide rs485_supported in the
-   uart_port structure. The serial core calls rs485_config to do the device
-   specific part in response to TIOCSRS485 ioctl (see below). The rs485_config
-   callback receives a pointer to a sanitizated serial_rs485 structure. The
-   serial_rs485 userspace provides is sanitized before calling rs485_config
-   using rs485_supported that indicates what RS485 features the driver supports
-   for the uart_port. TIOCGRS485 ioctl can be used to read back the
-   serial_rs485 structure matching to the current configuration.
+   struct uart_port. The serial core calls rs485_config to do the device
+   specific part in response to TIOCSRS485 ioctl (see below). The
+   rs485_config callback receives a pointer to a sanitizated struct
+   serial_rs485. The struct serial_rs485 userspace provides is sanitized
+   before calling rs485_config using rs485_supported that indicates what
+   RS485 features the driver supports for the struct uart_port. TIOCGRS485
+   ioctl can be used to read back the struct serial_rs485 matching to the
+   current configuration.
 
 .. kernel-doc:: include/uapi/linux/serial.h
    :identifiers: serial_rs485 uart_get_rs485_mode
@@ -108,8 +109,8 @@ RS485 Serial Communications
 
    The Linux kernel provides addressing mode for multipoint RS-485 serial
    communications line. The addressing mode is enabled with SER_RS485_ADDRB
-   flag in serial_rs485. Struct serial_rs485 has two additional flags and
-   fields for enabling receive and destination addresses.
+   flag in struct serial_rs485. The struct serial_rs485 has two additional
+   flags and fields for enabling receive and destination addresses.
 
    Address mode flags:
 	- SER_RS485_ADDRB: Enabled addressing mode (sets also ADDRB in termios).
-- 
2.30.2