[alsa-devel] [RFC PATCH 4/5] drm: i915: add DisplayPort amp unmute for LPE audio mode

[Ville Syrjälä]

On Fri, Jan 27, 2017 at 03:17:34PM +0200, Ville Syrjälä wrote:
> On Fri, Jan 27, 2017 at 12:08:58PM +0200, Jani Nikula wrote:
> > On Thu, 26 Jan 2017, Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com> wrote:
> > > Enable chicken bit on LPE mode setup and unmute amp on
> > > notification
> > >
> > > FIXME: should these two phases done somewhere else?
> > >
> > > Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/i915_reg.h        | 12 ++++++++++++
> > >  drivers/gpu/drm/i915/intel_lpe_audio.c | 27 +++++++++++++++++++++++++++
> > >  2 files changed, 39 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > > index a9ffc8d..ee90f64 100644
> > > --- a/drivers/gpu/drm/i915/i915_reg.h
> > > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > > @@ -2061,6 +2061,18 @@ enum skl_disp_power_wells {
> > >  #define I915_HDMI_LPE_AUDIO_BASE	(VLV_DISPLAY_BASE + 0x65000)
> > >  #define I915_HDMI_LPE_AUDIO_SIZE	0x1000
> > >  
> > > +/* DisplayPort Audio w/ LPE */
> > > +#define CHICKEN_BIT_DBG_ENABLE		(1 << 0)
> > > +#define AMP_UNMUTE		        (1 << 1)
> 
> That should be called AMP_MUTE I think,
> 
> > 
> > The convention is to define registers first and the contents/bits for
> > each register immedialy below. For groups of registers (like
> > PORT_EN_B/C/D below) define all registers first and bits immediately
> > below. (But note that the chicken register is not part of the group.)
> > 
> > > +#define AUD_CHICKEN_BIT_REG		0x62F38
> 
> Spec calls this AUD_CHICKENBIT_REG. Might as well follow it to the
> letter.
> 
> > > +#define AUD_PORT_EN_B_DBG		0x62F20
> > > +#define AUD_PORT_EN_C_DBG		0x62F28
> > > +#define AUD_PORT_EN_D_DBG		0x62F2C
> 
> These match the spec. But to match the standard i915 convention they
> should be called _AUD_PORT_EN_B_DBG etc. Same forthe chicken bit
> register.

Actually they just match one version of the spec I had lying around.
Another versions says:

AUD_PORT_EN_B_DBG 0x62F20
AUD_PORT_EN_C_DBG 0x62F30
AUD_PORT_EN_D_DBG 0x62F34

-- 
Ville Syrjälä
Intel OTC