On 2022-03-08 8:25 PM, Pierre-Louis Bossart wrote:
The NHLT information can be used to figure out which SSPs are enabled in a platform.
The 'SSP' link type is too broad for machine drivers, since it can cover the Bluetooth sideband and the analog audio codec connections, so this helper exposes a parameter to filter with the device type (DEVICE_I2S refers to analog audio codec in NHLT parlance).
The helper returns a mask, since more than one SSP may be used for analog audio, e.g. the NHLT spec describes the use of SSP0 for amplifiers and SSP1 for headset codec. Note that if more than one bit is set, it's impossible to determine which SSP is connected to what external component. Additional platform-specific information based on e.g. DMI quirks would still be required in the machine driver to configure the relevant dailinks.
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diff --git a/sound/hda/intel-nhlt.c b/sound/hda/intel-nhlt.c index 128476aa7c61..4063da378283 100644 --- a/sound/hda/intel-nhlt.c +++ b/sound/hda/intel-nhlt.c @@ -130,6 +130,28 @@ bool intel_nhlt_has_endpoint_type(struct nhlt_acpi_table *nhlt, u8 link_type) } EXPORT_SYMBOL(intel_nhlt_has_endpoint_type);
+int intel_nhlt_ssp_endpoint_mask(struct nhlt_acpi_table *nhlt, u8 device_type) +{
- struct nhlt_endpoint *epnt;
- int ssp_mask = 0;
- int i;
- if (!nhlt || (device_type != NHLT_DEVICE_BT && device_type != NHLT_DEVICE_I2S))
The '!nhlt' safety is superfluous in my opinion. Kernel core API e.g.: device one assumes caller is sane in basically all cases.
return 0;- epnt = (struct nhlt_endpoint *)nhlt->desc;
- for (i = 0; i < nhlt->endpoint_count; i++) {
if (epnt->linktype == NHLT_LINK_SSP && epnt->device_type == device_type) {/* for SSP the virtual bus id is the SSP port */ssp_mask |= BIT(epnt->virtual_bus_id);}epnt = (struct nhlt_endpoint *)((u8 *)epnt + epnt->length);- }
- return ssp_mask;
+} +EXPORT_SYMBOL(intel_nhlt_ssp_endpoint_mask);
Since this is a *public* API - not direct part of any driver, really - providing kernel-doc is recommended.
Regards, Czarek