| Message ID | 1465219753-3737-6-git-send-email-mika.kahola@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jun 06, 2016 at 04:29:07PM +0300, Mika Kahola wrote: > Helper routine to read out maximum supported bits per > component for DisplayPort legay converters. > > Signed-off-by: Mika Kahola <mika.kahola@intel.com> > --- > drivers/gpu/drm/drm_dp_helper.c | 31 +++++++++++++++++++++++++++++++ > include/drm/drm_dp_helper.h | 2 ++ > 2 files changed, 33 insertions(+) > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > index 18b72eb..bac0ccc 100644 > --- a/drivers/gpu/drm/drm_dp_helper.c > +++ b/drivers/gpu/drm/drm_dp_helper.c > @@ -507,6 +507,37 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > } > EXPORT_SYMBOL(drm_dp_downstream_max_clock); > > +/** > + * drm_dp_downstream_max_bpc() - extract branch device max > + * bits per component > + * @dpcd: DisplayPort configuration data > + * @port_cap: port capabilities > + * > + * Returns max bpc on success or negative error code on failure > + */ > +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > + const u8 port_cap[4]) > +{ > + int type = drm_dp_downstream_type(dpcd, port_cap); > + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & > + DP_DETAILED_CAP_INFO_AVAILABLE; > + > + if (detailed_cap_info) { Early return again. > + if (type != DP_DS_PORT_TYPE_WIRELESS) { switch() again. > + int tmp; > + tmp = port_cap[2] & DP_DS_VGA_MAX_BPC_MASK; Should drop the "VGA" from that stuff since it applies to more than that. > + > + if (tmp == 0) > + return 8; > + else > + return 8 + (1<<tmp); switch() with each case would be less magicy. > + } > + } > + > + return -EINVAL; Again I think I'd just use 0 here. > +} > +EXPORT_SYMBOL(drm_dp_downstream_max_bpc); > + > /* > * I2C-over-AUX implementation > */ > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > index c3324d3..d4abc38 100644 > --- a/include/drm/drm_dp_helper.h > +++ b/include/drm/drm_dp_helper.h > @@ -812,6 +812,8 @@ int drm_dp_downstream_port_cap(struct drm_dp_aux *aux, > int drm_dp_downstream_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]); > int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > const u8 port_cap[4]); > +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > + const u8 port_cap[4]); > > int drm_dp_aux_register(struct drm_dp_aux *aux); > void drm_dp_aux_unregister(struct drm_dp_aux *aux); > -- > 1.9.1
On Thu, 2016-06-09 at 11:02 +0300, Ville Syrjälä wrote: > On Mon, Jun 06, 2016 at 04:29:07PM +0300, Mika Kahola wrote: > > Helper routine to read out maximum supported bits per > > component for DisplayPort legay converters. > > > > Signed-off-by: Mika Kahola <mika.kahola@intel.com> > > --- > > drivers/gpu/drm/drm_dp_helper.c | 31 +++++++++++++++++++++++++++++++ > > include/drm/drm_dp_helper.h | 2 ++ > > 2 files changed, 33 insertions(+) > > > > diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c > > index 18b72eb..bac0ccc 100644 > > --- a/drivers/gpu/drm/drm_dp_helper.c > > +++ b/drivers/gpu/drm/drm_dp_helper.c > > @@ -507,6 +507,37 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > > } > > EXPORT_SYMBOL(drm_dp_downstream_max_clock); > > > > +/** > > + * drm_dp_downstream_max_bpc() - extract branch device max > > + * bits per component > > + * @dpcd: DisplayPort configuration data > > + * @port_cap: port capabilities > > + * > > + * Returns max bpc on success or negative error code on failure > > + */ > > +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > > + const u8 port_cap[4]) > > +{ > > + int type = drm_dp_downstream_type(dpcd, port_cap); > > + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & > > + DP_DETAILED_CAP_INFO_AVAILABLE; > > + > > + if (detailed_cap_info) { > > Early return again. > > > + if (type != DP_DS_PORT_TYPE_WIRELESS) { > > switch() again. > > > + int tmp; > > + tmp = port_cap[2] & DP_DS_VGA_MAX_BPC_MASK; > > Should drop the "VGA" from that stuff since it applies to more than > that. Agreed. Maybe we could rename it as DP_DS_MAX_BPC_MASK instead. > > > + > > + if (tmp == 0) > > + return 8; > > + else > > + return 8 + (1<<tmp); > > switch() with each case would be less magicy. > > > + } > > + } > > + > > + return -EINVAL; > > Again I think I'd just use 0 here. > > > +} > > +EXPORT_SYMBOL(drm_dp_downstream_max_bpc); > > + > > /* > > * I2C-over-AUX implementation > > */ > > diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h > > index c3324d3..d4abc38 100644 > > --- a/include/drm/drm_dp_helper.h > > +++ b/include/drm/drm_dp_helper.h > > @@ -812,6 +812,8 @@ int drm_dp_downstream_port_cap(struct drm_dp_aux *aux, > > int drm_dp_downstream_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]); > > int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > > const u8 port_cap[4]); > > +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], > > + const u8 port_cap[4]); > > > > int drm_dp_aux_register(struct drm_dp_aux *aux); > > void drm_dp_aux_unregister(struct drm_dp_aux *aux); > > -- > > 1.9.1 >
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 18b72eb..bac0ccc 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -507,6 +507,37 @@ int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], } EXPORT_SYMBOL(drm_dp_downstream_max_clock); +/** + * drm_dp_downstream_max_bpc() - extract branch device max + * bits per component + * @dpcd: DisplayPort configuration data + * @port_cap: port capabilities + * + * Returns max bpc on success or negative error code on failure + */ +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], + const u8 port_cap[4]) +{ + int type = drm_dp_downstream_type(dpcd, port_cap); + bool detailed_cap_info = dpcd[DP_DOWNSTREAMPORT_PRESENT] & + DP_DETAILED_CAP_INFO_AVAILABLE; + + if (detailed_cap_info) { + if (type != DP_DS_PORT_TYPE_WIRELESS) { + int tmp; + tmp = port_cap[2] & DP_DS_VGA_MAX_BPC_MASK; + + if (tmp == 0) + return 8; + else + return 8 + (1<<tmp); + } + } + + return -EINVAL; +} +EXPORT_SYMBOL(drm_dp_downstream_max_bpc); + /* * I2C-over-AUX implementation */ diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index c3324d3..d4abc38 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -812,6 +812,8 @@ int drm_dp_downstream_port_cap(struct drm_dp_aux *aux, int drm_dp_downstream_type(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]); int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]); +int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], + const u8 port_cap[4]); int drm_dp_aux_register(struct drm_dp_aux *aux); void drm_dp_aux_unregister(struct drm_dp_aux *aux);
Helper routine to read out maximum supported bits per component for DisplayPort legay converters. Signed-off-by: Mika Kahola <mika.kahola@intel.com> --- drivers/gpu/drm/drm_dp_helper.c | 31 +++++++++++++++++++++++++++++++ include/drm/drm_dp_helper.h | 2 ++ 2 files changed, 33 insertions(+)