[PATCH v4 2/2] drivers: serial: probe all uart devices

[Sean Anderson]

On 11/17/20 10:00 AM, Vabhav Sharma wrote:
> From: Vabhav Sharma <vabhav.sharma at nxp.com>
> 
> U-Boot DM model probe only single device at a time
> which is enabled and configured using device tree
> or platform data method.
> 
> PL011 UART IP is SBSA compliant and firmware does the
> serial port set-up, initialization and let the kernel use
> UART port for sending and receiving characters.
> 
> Normally software talk to one serial port time but some
> LayerScape platform require all the UART devices enabled
> in Linux for various use case.
> 
> Adding support to probe all enabled serial devices like SBSA
> compliant PL011 UART ports probe and initialization by firmware.
> 
> Signed-off-by: Vabhav Sharma <vabhav.sharma at nxp.com>
> Reviewed-by: Stefan Roese <sr at denx.de>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> --
> v3:
>   Incorporated Simon and Stephan review comment
>   - Define generic function uclass_probe_all(enum uclass_id)
>     in drivers/core/uclass.c
>   - Added the function in caller of serial_find_console_or_panic()
>   - Removed repeated sequence with generic function call uclass_probe_all()
>   - Dependent on other patch [PATCH] dm: core: add function uclass_probe_all()
>     to probe all devices
> 
> v2:
>   Incorporated Stefan review comment, Update #ifdef with macro
>   if (IS_ENABLED)..
> ---
>  drivers/serial/Kconfig         | 17 +++++++++++++++++
>  drivers/serial/serial-uclass.c |  4 ++++
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index b4805a2..af8779b 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -134,6 +134,23 @@ config SERIAL_SEARCH_ALL
>  
>  	  If unsure, say N.
>  
> +config SERIAL_PROBE_ALL
> +	bool "Probe all available serial devices"
> +	depends on DM_SERIAL
> +	default n
> +	help
> +	  The serial subsystem only probe for single serial device,

nit: probes for a

> +	  but does not probe for other remaining serial devices.
> +	  With this option set,we make probing and searching for

nit: set, we

> +	  all available devices optional.
> +	  Normally, U-Boot talk to one serial port at a time but SBSA

nit: talks
nit: time, but

> +	  compliant UART devices like PL011 require initialization
> +	  by firmware and let the kernel use serial port for sending

nit: to let the kernel use the

> +	  and receiving the characters.
> +
> +	  If probing is not required for all remaining available
> +	  devices other than default current console device, say N.

Perhaps use the "If unsure, say N." wording like other Kconfigs.

> +
>  config SPL_DM_SERIAL
>  	bool "Enable Driver Model for serial drivers in SPL"
>  	depends on DM_SERIAL && SPL_DM
> diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
> index f3c25d4..417d3af 100644
> --- a/drivers/serial/serial-uclass.c
> +++ b/drivers/serial/serial-uclass.c
> @@ -172,6 +172,10 @@ int serial_init(void)
>  /* Called after relocation */
>  int serial_initialize(void)
>  {
> +	/* Scanning uclass to probe devices */
> +	if (IS_ENABLED(CONFIG_SERIAL_PROBE_ALL))
> +		uclass_probe_all(UCLASS_SERIAL);
> +
>  	return serial_init();
>  }
>  
>