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Message-ID: <DM6PR11MB40748AD8D57C73E4D79D4676FF150@DM6PR11MB4074.namprd11.prod.outlook.com>
Date: Fri, 30 Oct 2020 11:24:35 +0000
From: "Liao, Bard" <bard.liao@...el.com>
To: Greg KH <gregkh@...uxfoundation.org>,
Bard Liao <yung-chuan.liao@...ux.intel.com>
CC: "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
"vkoul@...nel.org" <vkoul@...nel.org>,
"vinod.koul@...aro.org" <vinod.koul@...aro.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"jank@...ence.com" <jank@...ence.com>,
"srinivas.kandagatla@...aro.org" <srinivas.kandagatla@...aro.org>,
"rander.wang@...ux.intel.com" <rander.wang@...ux.intel.com>,
"ranjani.sridharan@...ux.intel.com"
<ranjani.sridharan@...ux.intel.com>,
"hui.wang@...onical.com" <hui.wang@...onical.com>,
"pierre-louis.bossart@...ux.intel.com"
<pierre-louis.bossart@...ux.intel.com>,
"Kale, Sanyog R" <sanyog.r.kale@...el.com>,
"Lin, Mengdong" <mengdong.lin@...el.com>
Subject: RE: [PATCH v3] soundwire: SDCA: add helper macro to access controls
> -----Original Message-----
> From: Greg KH <gregkh@...uxfoundation.org>
> Sent: Friday, October 30, 2020 5:37 PM
> To: Bard Liao <yung-chuan.liao@...ux.intel.com>
> Cc: alsa-devel@...a-project.org; vkoul@...nel.org; vinod.koul@...aro.org;
> linux-kernel@...r.kernel.org; jank@...ence.com;
> srinivas.kandagatla@...aro.org; rander.wang@...ux.intel.com;
> ranjani.sridharan@...ux.intel.com; hui.wang@...onical.com; pierre-
> louis.bossart@...ux.intel.com; Kale, Sanyog R <sanyog.r.kale@...el.com>; Lin,
> Mengdong <mengdong.lin@...el.com>; Liao, Bard <bard.liao@...el.com>
> 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@...ux.intel.com>
> >
> > 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@...ux.intel.com>
> > Reviewed-by: Guennadi Liakhovetski
> > <guennadi.liakhovetski@...ux.intel.com>
> > Reviewed-by: Kai Vehmanen <kai.vehmanen@...ux.intel.com>
> > Signed-off-by: Pierre-Louis Bossart
> > <pierre-louis.bossart@...ux.intel.com>
> > Signed-off-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
> > ---
> > 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.
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