Messages in this thread | | | Subject | Re: [alsa-devel] [RFC PATCH 1/7] soundwire: Add sysfs support for master(s) | From | Pierre-Louis Bossart <> | Date | Wed, 8 May 2019 11:42:15 -0500 |
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On 5/8/19 4:16 AM, Greg KH wrote: > On Wed, May 08, 2019 at 01:16:06PM +0530, Vinod Koul wrote: >> On 07-05-19, 17:49, Pierre-Louis Bossart wrote: >>> >>>>> The model here is that Master device is PCI or Platform device and then >>>>> creates a bus instance which has soundwire slave devices. >>>>> >>>>> So for any attribute on Master device (which has properties as well and >>>>> representation in sysfs), device specfic struct (PCI/platfrom doesn't >>>>> help). For slave that is not a problem as sdw_slave structure takes care >>>>> if that. >>>>> >>>>> So, the solution was to create the psedo sdw_master device for the >>>>> representation and have device-specific structure. >>>> >>>> Ok, much like the "USB host controller" type device. That's fine, make >>>> such a device, add it to your bus, and set the type correctly. And keep >>>> a pointer to that structure in your device-specific structure if you >>>> really need to get to anything in it. >>> >>> humm, you lost me on the last sentence. Did you mean using >>> set_drv/platform_data during the init and retrieving the bus information >>> with get_drv/platform_data as needed later? Or something else I badly need >>> to learn? >> >> IIUC Greg meant we should represent a soundwire master device type and >> use that here. Just like we have soundwire slave device type. Something >> like: >> >> struct sdw_master { >> struct device dev; >> struct sdw_master_prop *prop; >> ... >> }; >> >> In show function you get master from dev (container of) and then use >> that to access the master properties. So int.sdw.0 can be of this type. > > Yes, you need to represent the master device type if you are going to be > having an internal representation of it.
Humm, confused...In the existing code bus and master are synonyms, see e.g. following code excerpts:
* sdw_add_bus_master() - add a bus Master instance * @bus: bus instance * * Initializes the bus instance, read properties and create child * devices.
struct sdw_bus { struct device *dev; <<< pointer here unsigned int link_id; struct list_head slaves; DECLARE_BITMAP(assigned, SDW_MAX_DEVICES); struct mutex bus_lock; struct mutex msg_lock; const struct sdw_master_ops *ops; const struct sdw_master_port_ops *port_ops; struct sdw_bus_params params; struct sdw_master_prop prop;
The existing code creates a platform_device in drivers/soundwire/intel_init.c, and it's assigned by the following code:
static int intel_probe(struct platform_device *pdev) { struct sdw_cdns_stream_config config; struct sdw_intel *sdw; int ret;
sdw = devm_kzalloc(&pdev->dev, sizeof(*sdw), GFP_KERNEL); [snip] sdw->cdns.dev = &pdev->dev; sdw->cdns.bus.dev = &pdev->dev;
I really don't see what you are hinting at, sorry, unless we are talking about major surgery in the code.
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