Re: [PATCH v6 06/10] drm: Read DP branch device HW revision

[Mika Kahola <mika.kahola@intel.com>]

On Tue, 2016-07-12 at 15:54 +0200, Daniel Vetter wrote:
> On Wed, Jul 06, 2016 at 02:04:50PM +0300, Mika Kahola wrote:
> > HW revision is mandatory field for DisplayPort branch
> > devices. This is defined in DPCD register field 0x509.
> > 
> > Signed-off-by: Mika Kahola <mika.kahola@intel.com>
> > ---
> >  drivers/gpu/drm/drm_dp_helper.c | 21 +++++++++++++++++++++
> >  include/drm/drm_dp_helper.h     |  7 +++++++
> >  2 files changed, 28 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
> > index 4003464..cfd75df 100644
> > --- a/drivers/gpu/drm/drm_dp_helper.c
> > +++ b/drivers/gpu/drm/drm_dp_helper.c
> > @@ -514,6 +514,27 @@ int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> >  EXPORT_SYMBOL(drm_dp_downstream_max_bpc);
> >  
> >  /**
> > + * drm_dp_downstream_hw_rev() - read DP branch device HW revision
> > + * @aux: DisplayPort AUX channel
> > + *
> > + * Returns HW revision on succes or negative error code on failure
> > + */
> > +struct drm_dp_revision drm_dp_downstream_hw_rev(struct drm_dp_aux *aux)
> > +{
> > +	uint8_t tmp;
> > +	struct drm_dp_revision rev = { .major = -EINVAL, .minor = -EINVAL };
> > +
> > +	if (drm_dp_dpcd_read(aux, DP_BRANCH_HW_REV, &tmp, 1) != 1)
> > +		return rev;
> > +
> > +	rev.major = (tmp & 0xf0) >> 4;
> > +	rev.minor = tmp & 0xf;
> > +
> > +	return rev;
> > +}
> > +EXPORT_SYMBOL(drm_dp_downstream_hw_rev);
> > +
> > +/**
> >   * drm_dp_downstream_id() - identify branch device
> >   * @aux: DisplayPort AUX channel
> >   *
> > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
> > index 8264d54..5f577e4 100644
> > --- a/include/drm/drm_dp_helper.h
> > +++ b/include/drm/drm_dp_helper.h
> > @@ -446,6 +446,7 @@
> >  #define DP_SINK_OUI			    0x400
> >  #define DP_BRANCH_OUI			    0x500
> >  #define DP_BRANCH_ID                        0x503
> > +#define DP_BRANCH_HW_REV                    0x509
> >  
> >  #define DP_SET_POWER                        0x600
> >  # define DP_SET_POWER_D0                    0x1
> > @@ -803,6 +804,11 @@ struct drm_dp_link {
> >  	unsigned long capabilities;
> >  };
> >  
> > +struct drm_dp_revision {
> > +       int major;
> > +       int minor;
> > +};
> 
> Atm we have two styles of helpers:
> - The ones that put decoded values into struct drm_dp_link
> - A pile of functions that return individual values.
> 
> This seems to add a third one. I guess it'd be better to just move
> everything over to putting parsed values into drm_dp_link and fill that
> out for everything ...
> -Daniel

Ok. Let's move all this information to drm_dp_link. I'll revise the
patch.

Cheers,
Mika
> 
> > +
> >  int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link);
> >  int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link);
> >  int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link);
> > @@ -812,6 +818,7 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> >  int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> >  			      const u8 port_cap[4]);
> >  int drm_dp_downstream_id(struct drm_dp_aux *aux, char id[6]);
> > +struct drm_dp_revision drm_dp_downstream_hw_rev(struct drm_dp_aux *aux);
> >  
> >  void drm_dp_aux_init(struct drm_dp_aux *aux);
> >  int drm_dp_aux_register(struct drm_dp_aux *aux);
> > -- 
> > 1.9.1
> > 
> 

-- 
Mika Kahola - Intel OTC

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