linux-kernel - [RFC PATCH 07/10] drm/bridge: ps8640: require manual DSI power control

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Date:   Mon, 16 Oct 2023 19:53:52 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Douglas Anderson <dianders@...omium.org>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Jessica Zhang <quic_jesszhan@...cinc.com>
Cc:     Marek Vasut <marex@...x.de>, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org
Subject: [RFC PATCH 07/10] drm/bridge: ps8640: require manual DSI power control

The Parade PS8640 bridge will fail to start if the DSI link is enabled
when the bridge is being reset / powered up (even to the LP-11 state).
To ensure that the DSI link is powered down, require manual control over
the DSI link state.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
 drivers/gpu/drm/bridge/parade-ps8640.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
index 8161b1a1a4b1..6c5daaa70cb7 100644
--- a/drivers/gpu/drm/bridge/parade-ps8640.c
+++ b/drivers/gpu/drm/bridge/parade-ps8640.c
@@ -458,6 +458,10 @@ static void ps8640_atomic_pre_enable(struct drm_bridge *bridge,
 
 	ps8640_bridge_vdo_control(ps_bridge, ENABLE);
 
+	ret = mipi_dsi_host_power_up(ps_bridge->dsi->host);
+	if (ret < 0)
+		dev_warn(dev, "failed to power up DSI host: %d\n", ret);
+
 	ps_bridge->pre_enabled = true;
 }
 
@@ -468,6 +472,8 @@ static void ps8640_atomic_post_disable(struct drm_bridge *bridge,
 
 	ps_bridge->pre_enabled = false;
 
+	mipi_dsi_host_power_down(ps_bridge->dsi->host);
+
 	ps8640_bridge_vdo_control(ps_bridge, DISABLE);
 	pm_runtime_put_sync_suspend(&ps_bridge->page[PAGE0_DP_CNTL]->dev);
 }
@@ -562,6 +568,11 @@ static int ps8640_bridge_get_dsi_resources(struct device *dev, struct ps8640 *ps
 	if (!host)
 		return -EPROBE_DEFER;
 
+	if (!mipi_dsi_host_power_control_available(host)) {
+		dev_err(dev, "MIPI DSI host doesn't provide tight power control\n");
+		return -ENODEV;
+	}
+
 	dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
 	if (IS_ERR(dsi)) {
 		dev_err(dev, "failed to create dsi device\n");
@@ -572,7 +583,8 @@ static int ps8640_bridge_get_dsi_resources(struct device *dev, struct ps8640 *ps
 
 	dsi->host = host;
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO |
-			  MIPI_DSI_MODE_VIDEO_SYNC_PULSE;
+			  MIPI_DSI_MODE_VIDEO_SYNC_PULSE |
+			  MIPI_DSI_MANUAL_POWERUP;
 	dsi->format = MIPI_DSI_FMT_RGB888;
 	dsi->lanes = NUM_MIPI_LANES;
 
-- 
2.42.0