From 34c1aeb579ddd36392e18e2fc354db441556811e Mon Sep 17 00:00:00 2001 From: Nikita Travkin Date: Sat, 8 Apr 2023 13:20:14 +0500 Subject: drm/bridge: ti-sn65dsi86: Implement wait_hpd_asserted This bridge doesn't actually implement HPD due to it being way too slow but instead expects the panel driver to wait enough to assume HPD is asserted. However some panels (such as the generic 'edp-panel') expect the bridge to deal with the delay and pass maximum delay to the aux instead. In order to support such panels, add a dummy implementation of wait that would just sleep the maximum delay and assume no failure has happened. Signed-off-by: Nikita Travkin Reviewed-by: Douglas Anderson Signed-off-by: Douglas Anderson Link: https://patchwork.freedesktop.org/patch/msgid/20230408082014.235425-1-nikita@trvn.ru --- drivers/gpu/drm/bridge/ti-sn65dsi86.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'drivers') diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 7a748785c545..260cad1fd1da 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -618,6 +618,24 @@ exit: return len; } +static int ti_sn_aux_wait_hpd_asserted(struct drm_dp_aux *aux, unsigned long wait_us) +{ + /* + * The HPD in this chip is a bit useless (See comment in + * ti_sn65dsi86_enable_comms) so if our driver is expected to wait + * for HPD, we just assume it's asserted after the wait_us delay. + * + * In case we are asked to wait forever (wait_us=0) take conservative + * 500ms delay. + */ + if (wait_us == 0) + wait_us = 500000; + + usleep_range(wait_us, wait_us + 1000); + + return 0; +} + static int ti_sn_aux_probe(struct auxiliary_device *adev, const struct auxiliary_device_id *id) { @@ -627,6 +645,7 @@ static int ti_sn_aux_probe(struct auxiliary_device *adev, pdata->aux.name = "ti-sn65dsi86-aux"; pdata->aux.dev = &adev->dev; pdata->aux.transfer = ti_sn_aux_transfer; + pdata->aux.wait_hpd_asserted = ti_sn_aux_wait_hpd_asserted; drm_dp_aux_init(&pdata->aux); ret = devm_of_dp_aux_populate_ep_devices(&pdata->aux); -- cgit v1.2.3