[PATCH] soundwire: bus: add enumerated slave to device list

[Pierre-Louis Bossart]

On 9/9/20 3:27 AM, Srinivas Kandagatla wrote:
> Currently slave devices are only added either from device tree or acpi
> entries. However lets say, there is wrong or no entry of a slave device
> in DT that is enumerated, then there is no way for user to know all
> the enumerated devices on the bus.

Sorry Srinivas, I don't understand your point.

The sysfs entries will include all devices that are described in 
platform firmware (be it DT or ACPI).

If you add to sysfs entries unknown devices which happen to be present 
on the bus, then what? How would you identify them from the devices that 
are described in firmware?

Also the sysfs entries describe properties, but if you haven't bound a 
driver then how would this work?

I really feel this deserves more explanations on the problem statement 
and what you are hoping to achieve in this case.

Thanks!

> 
> To fix this add slave device by default if there is no matching dt or
> acpi entry, so that we can see this in sysfs entry.
> 
> In my case I had a wrong address entry in DT, However I had no way to
> know what devices are actually enumerated on the bus!
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
> ---
>   drivers/soundwire/bus.c      | 1 +
>   drivers/soundwire/bus.h      | 2 ++
>   drivers/soundwire/bus_type.c | 6 ++++++
>   drivers/soundwire/slave.c    | 4 ++--
>   4 files changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
> index e6e0fb9a81b4..55d9c22c4ec5 100644
> --- a/drivers/soundwire/bus.c
> +++ b/drivers/soundwire/bus.c
> @@ -699,6 +699,7 @@ static int sdw_program_device_num(struct sdw_bus *bus)
>   
>   		if (!found) {
>   			/* TODO: Park this device in Group 13 */
> +			sdw_slave_add(bus, &id, NULL);
>   			dev_err(bus->dev, "Slave Entry not found\n");
>   		}
>   
> diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
> index 82484f741168..1517d6789dff 100644
> --- a/drivers/soundwire/bus.h
> +++ b/drivers/soundwire/bus.h
> @@ -19,6 +19,8 @@ static inline int sdw_acpi_find_slaves(struct sdw_bus *bus)
>   int sdw_of_find_slaves(struct sdw_bus *bus);
>   void sdw_extract_slave_id(struct sdw_bus *bus,
>   			  u64 addr, struct sdw_slave_id *id);
> +int sdw_slave_add(struct sdw_bus *bus, struct sdw_slave_id *id,
> +		  struct fwnode_handle *fwnode);
>   int sdw_master_device_add(struct sdw_bus *bus, struct device *parent,
>   			  struct fwnode_handle *fwnode);
>   int sdw_master_device_del(struct sdw_bus *bus);
> diff --git a/drivers/soundwire/bus_type.c b/drivers/soundwire/bus_type.c
> index 6fba55898cf0..ac036223046f 100644
> --- a/drivers/soundwire/bus_type.c
> +++ b/drivers/soundwire/bus_type.c
> @@ -84,6 +84,12 @@ static int sdw_drv_probe(struct device *dev)
>   	const struct sdw_device_id *id;
>   	int ret;
>   
> +	/*
> +	 * fw description is mandatory to bind
> +	 */
> +	if (!dev->fwnode || !dev->of_node)
> +		return -ENODEV;
> +
>   	id = sdw_get_device_id(slave, drv);
>   	if (!id)
>   		return -ENODEV;
> diff --git a/drivers/soundwire/slave.c b/drivers/soundwire/slave.c
> index 0839445ee07b..24a16ebf9ae2 100644
> --- a/drivers/soundwire/slave.c
> +++ b/drivers/soundwire/slave.c
> @@ -20,8 +20,8 @@ struct device_type sdw_slave_type = {
>   	.uevent =	sdw_slave_uevent,
>   };
>   
> -static int sdw_slave_add(struct sdw_bus *bus,
> -			 struct sdw_slave_id *id, struct fwnode_handle *fwnode)
> +int sdw_slave_add(struct sdw_bus *bus,
> +		  struct sdw_slave_id *id, struct fwnode_handle *fwnode)
>   {
>   	struct sdw_slave *slave;
>   	int ret;
>