On Thu, 31 Oct 2024, Imre Deak <imre.deak@xxxxxxxxx> 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@xxxxxxxxxx>
>> ---
>> 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
