> -----Original Message----- > From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > Sent: Friday, October 30, 2020 5:37 PM > To: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx> > Cc: alsa-devel@xxxxxxxxxxxxxxxx; vkoul@xxxxxxxxxx; vinod.koul@xxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; jank@xxxxxxxxxxx; > srinivas.kandagatla@xxxxxxxxxx; rander.wang@xxxxxxxxxxxxxxx; > ranjani.sridharan@xxxxxxxxxxxxxxx; hui.wang@xxxxxxxxxxxxx; pierre- > louis.bossart@xxxxxxxxxxxxxxx; Kale, Sanyog R <sanyog.r.kale@xxxxxxxxx>; Lin, > Mengdong <mengdong.lin@xxxxxxxxx>; Liao, Bard <bard.liao@xxxxxxxxx> > Subject: Re: [PATCH v3] soundwire: SDCA: add helper macro to access > controls > > On Fri, Oct 30, 2020 at 04:49:55AM +0800, Bard Liao wrote: > > From: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx> > > > > The upcoming SDCA (SoundWire Device Class Audio) specification defines > > a hierarchical encoding to interface with Class-defined capabilities. > > > > The specification is not yet accessible to the general public but this > > information is released with explicit permission from the MIPI Board > > to avoid delays with SDCA support on Linux platforms. > > > > A block of 64 MBytes of register addresses are allocated to SDCA > > controls, starting at address 0x40000000. The 26 LSBs which identify > > individual controls are set based on the following variables: > > > > - Function Number. An SCDA device can be split in up to 8 independent > > Functions. Each of these Functions is described in the SDCA > > specification, e.g. Smart Amplifier, Smart Microphone, Simple > > Microphone, Jack codec, HID, etc. > > > > - Entity Number. Within each Function, an Entity is an identifiable > > block. Up to 127 Entities are connected in a pre-defined > > graph (similar to USB), with Entity0 reserved for Function-level > > configurations. In contrast to USB, the SDCA spec pre-defines > > Function Types, topologies, and allowed options, i.e. the degree of > > freedom is not unlimited to limit the possibility of errors in > > descriptors leading to software quirks. > > > > - Control Selector. Within each Entity, the SDCA specification defines > > 48 controls such as Mute, Gain, AGC, etc, and 16 implementation > > defined ones. Some Control Selectors might be used for low-level > > platform setup, and other exposed to applications and users. Note > > that the same Control Selector capability, e.g. Latency control, > > might be located at different offsets in different entities, the > > Control Selector mapping is Entity-specific. > > > > - Control Number. Some Control Selectors allow channel-specific values > > to be set, with up to 64 channels allowed. This is mostly used for > > volume control. > > > > - Current/Next values. Some Control Selectors are > > 'Dual-Ranked'. Software may either update the Current value directly > > for immediate effect. Alternatively, software may write into the > > 'Next' values and update the SoundWire 1.2 'Commit Groups' register > > to copy 'Next' values into 'Current' ones in a synchronized > > manner. This is different from bank switching which is typically > > used to change the bus configuration only. > > > > - MBQ. the Multi-Byte Quantity bit is used to provide atomic updates > > when accessing more that one byte, for example a 16-bit volume > > control would be updated consistently, the intermediate values > > mixing old MSB with new LSB are not applied. > > > > These 6 parameters are used to build a 32-bit address to access the > > desired Controls. Because of address range, paging is required, but > > the most often used parameter values are placed in the lower 16 bits > > of the address. This helps to keep the paging registers constant while > > updating Controls for a specific Device/Function. > > > > Reviewed-by: Rander Wang <rander.wang@xxxxxxxxxxxxxxx> > > Reviewed-by: Guennadi Liakhovetski > > <guennadi.liakhovetski@xxxxxxxxxxxxxxx> > > Reviewed-by: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx> > > Signed-off-by: Pierre-Louis Bossart > > <pierre-louis.bossart@xxxxxxxxxxxxxxx> > > Signed-off-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx> > > --- > > Changelog: > > > > v2: > > - add SDW_SDCA_MBQ_CTL > > > > v3: > > - add SDW_SDCA_NEXT_CTL > > > > --- > > include/linux/soundwire/sdw_registers.h | 32 > > +++++++++++++++++++++++++ > > 1 file changed, 32 insertions(+) > > > > diff --git a/include/linux/soundwire/sdw_registers.h > > b/include/linux/soundwire/sdw_registers.h > > index f420e8059779..e14dff9a9c7f 100644 > > --- a/include/linux/soundwire/sdw_registers.h > > +++ b/include/linux/soundwire/sdw_registers.h > > @@ -298,4 +298,36 @@ > > #define SDW_CASC_PORT_MASK_INTSTAT3 1 > > #define SDW_CASC_PORT_REG_OFFSET_INTSTAT3 2 > > > > +/* > > + * v1.2 device - SDCA address mapping > > + * > > + * Spec definition > > + * Bits Contents > > + * 31 0 (required by addressing range) > > + * 30:26 0b10000 (Control Prefix) > > + * 25 0 (Reserved) > > + * 24:22 Function Number [2:0] > > + * 21 Entity[6] > > + * 20:19 Control Selector[5:4] > > + * 18 0 (Reserved) > > + * 17:15 Control Number[5:3] > > + * 14 Next > > + * 13 MBQ > > + * 12:7 Entity[5:0] > > + * 6:3 Control Selector[3:0] > > + * 2:0 Control Number[2:0] > > + */ > > + > > +#define SDW_SDCA_CTL(fun, ent, ctl, ch) (BIT(30) | > \ > > + (((fun) & 0x7) << 22) | \ > > + (((ent) & 0x40) << 15) | \ > > + (((ent) & 0x3f) << 7) | \ > > + (((ctl) & 0x30) << 15) | \ > > + (((ctl) & 0x0f) << 3) | \ > > + (((ch) & 0x38) << 12) | \ > > + ((ch) & 0x07)) > > + > > +#define SDW_SDCA_MBQ_CTL(reg) ((reg) | BIT(13)) > > +#define SDW_SDCA_NEXT_CTL(reg) ((reg) | BIT(14)) > > + > > #endif /* __SDW_REGISTERS_H */ > > > No users of these macros? SDW_SDCA_CTL is used in sdca codec drivers which are not upstream yet. SDW_SDCA_MBQ_CTL will be used in a new regmap method. SDW_SDCA_NEXT_CTL can be used in sdca codec drivers, too.
