Imre Deak
2024-Oct-31 21:05 UTC
[PATCH RFC 1/4] drm/dp: Add helper to set LTTPRs in transparent mode
On Thu, Oct 31, 2024 at 05:12:45PM +0200, Abel Vesa wrote:> According to the DisplayPort standard, LTTPRs have two operating > modes: > - non-transparent - it replies to DPCD LTTPR field specific AUX > requests, while passes through all other AUX requests > - transparent - it passes through all AUX requests. > > Switching between this two modes is done by the DPTX by issuing > an AUX write to the DPCD PHY_REPEATER_MODE register. > > Add a generic helper that allows switching between these modes. > > Signed-off-by: Abel Vesa <abel.vesa at linaro.org> > --- > drivers/gpu/drm/display/drm_dp_helper.c | 17 +++++++++++++++++ > include/drm/display/drm_dp_helper.h | 1 + > 2 files changed, 18 insertions(+) > > diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c > index 6ee51003de3ce616c3a52653c2f1979ad7658e21..38d612345986ad54b42228902ea718a089d169c4 100644 > --- a/drivers/gpu/drm/display/drm_dp_helper.c > +++ b/drivers/gpu/drm/display/drm_dp_helper.c > @@ -2694,6 +2694,23 @@ int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]) > } > EXPORT_SYMBOL(drm_dp_lttpr_max_link_rate); > > +/** > + * drm_dp_lttpr_set_transparent_mode - set the LTTPR in transparent mode > + * @aux: DisplayPort AUX channel > + * @enable: Enable or disable transparent mode > + * > + * Returns 0 on success or a negative error code on failure.Should be "Returns 1 on success".> + */ > + > +int drm_dp_lttpr_set_transparent_mode(struct drm_dp_aux *aux, bool enable) > +{ > + u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT : > + DP_PHY_REPEATER_MODE_NON_TRANSPARENT; > + > + return drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE, val); > +} > +EXPORT_SYMBOL(drm_dp_lttpr_set_transparent_mode); > + > /** > * drm_dp_lttpr_max_lane_count - get the maximum lane count supported by all LTTPRs > * @caps: LTTPR common capabilities > diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h > index 279624833ea9259809428162f4e845654359f8c9..8821ab2d36b0e04d38ccbdddcb703b34de7ed680 100644 > --- a/include/drm/display/drm_dp_helper.h > +++ b/include/drm/display/drm_dp_helper.h > @@ -625,6 +625,7 @@ int drm_dp_read_lttpr_phy_caps(struct drm_dp_aux *aux, > u8 caps[DP_LTTPR_PHY_CAP_SIZE]); > int drm_dp_lttpr_count(const u8 cap[DP_LTTPR_COMMON_CAP_SIZE]); > int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]); > +int drm_dp_lttpr_set_transparent_mode(struct drm_dp_aux *aux, bool enable); > int drm_dp_lttpr_max_lane_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]); > bool drm_dp_lttpr_voltage_swing_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]); > bool drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]); > > -- > 2.34.1 >
Jani Nikula
2024-Nov-01 09:22 UTC
[PATCH RFC 1/4] drm/dp: Add helper to set LTTPRs in transparent mode
On Thu, 31 Oct 2024, Imre Deak <imre.deak at intel.com> wrote:> On Thu, Oct 31, 2024 at 05:12:45PM +0200, Abel Vesa wrote: >> According to the DisplayPort standard, LTTPRs have two operating >> modes: >> - non-transparent - it replies to DPCD LTTPR field specific AUX >> requests, while passes through all other AUX requests >> - transparent - it passes through all AUX requests. >> >> Switching between this two modes is done by the DPTX by issuing >> an AUX write to the DPCD PHY_REPEATER_MODE register. >> >> Add a generic helper that allows switching between these modes. >> >> Signed-off-by: Abel Vesa <abel.vesa at linaro.org> >> --- >> drivers/gpu/drm/display/drm_dp_helper.c | 17 +++++++++++++++++ >> include/drm/display/drm_dp_helper.h | 1 + >> 2 files changed, 18 insertions(+) >> >> diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c >> index 6ee51003de3ce616c3a52653c2f1979ad7658e21..38d612345986ad54b42228902ea718a089d169c4 100644 >> --- a/drivers/gpu/drm/display/drm_dp_helper.c >> +++ b/drivers/gpu/drm/display/drm_dp_helper.c >> @@ -2694,6 +2694,23 @@ int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]) >> } >> EXPORT_SYMBOL(drm_dp_lttpr_max_link_rate); >> >> +/** >> + * drm_dp_lttpr_set_transparent_mode - set the LTTPR in transparent mode >> + * @aux: DisplayPort AUX channel >> + * @enable: Enable or disable transparent mode >> + * >> + * Returns 0 on success or a negative error code on failure. > > Should be "Returns 1 on success".But is that a sensible return value?> >> + */ >> +Superfluous newline.>> +int drm_dp_lttpr_set_transparent_mode(struct drm_dp_aux *aux, bool enable) >> +{ >> + u8 val = enable ? DP_PHY_REPEATER_MODE_TRANSPARENT : >> + DP_PHY_REPEATER_MODE_NON_TRANSPARENT; >> + >> + return drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE, val); >> +} >> +EXPORT_SYMBOL(drm_dp_lttpr_set_transparent_mode); >> + >> /** >> * drm_dp_lttpr_max_lane_count - get the maximum lane count supported by all LTTPRs >> * @caps: LTTPR common capabilities >> diff --git a/include/drm/display/drm_dp_helper.h b/include/drm/display/drm_dp_helper.h >> index 279624833ea9259809428162f4e845654359f8c9..8821ab2d36b0e04d38ccbdddcb703b34de7ed680 100644 >> --- a/include/drm/display/drm_dp_helper.h >> +++ b/include/drm/display/drm_dp_helper.h >> @@ -625,6 +625,7 @@ int drm_dp_read_lttpr_phy_caps(struct drm_dp_aux *aux, >> u8 caps[DP_LTTPR_PHY_CAP_SIZE]); >> int drm_dp_lttpr_count(const u8 cap[DP_LTTPR_COMMON_CAP_SIZE]); >> int drm_dp_lttpr_max_link_rate(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]); >> +int drm_dp_lttpr_set_transparent_mode(struct drm_dp_aux *aux, bool enable); >> int drm_dp_lttpr_max_lane_count(const u8 caps[DP_LTTPR_COMMON_CAP_SIZE]); >> bool drm_dp_lttpr_voltage_swing_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]); >> bool drm_dp_lttpr_pre_emphasis_level_3_supported(const u8 caps[DP_LTTPR_PHY_CAP_SIZE]); >> >> -- >> 2.34.1 >>-- Jani Nikula, Intel