On Fri, Mar 15, 2019 at 02:32:55PM +0100, Paul Kocialkowski wrote:

Hi,

On Fri, 2019-03-15 at 18:38 +0530, Jagan Teki wrote:

Some display panels would come up with a non-DSI output which
can have an option to connect DSI interface by means of bridge
convertor.

This DSI to non-DSI bridge convertor would require a bridge
driver that would communicate the DSI controller for bridge
functionalities.

So, add support for bridge functionalities in Allwinner DSI
controller.

See a few comments below.


Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 65 +++++++++++++++++++-------
 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h |  1 +
 2 files changed, 49 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 0960b96b62cc..64d74313b842 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -781,6 +781,9 @@ static void sun6i_dsi_encoder_enable(struct drm_encoder *encoder)
 	if (!IS_ERR(dsi->panel))
 		drm_panel_prepare(dsi->panel);
 
+	if (!IS_ERR(dsi->bridge))
+		drm_bridge_pre_enable(dsi->bridge);
+
 	/*
 	 * FIXME: This should be moved after the switch to HS mode.
 	 *
@@ -796,6 +799,9 @@ static void sun6i_dsi_encoder_enable(struct drm_encoder *encoder)
 	if (!IS_ERR(dsi->panel))
 		drm_panel_enable(dsi->panel);
 
+	if (!IS_ERR(dsi->bridge))
+		drm_bridge_enable(dsi->bridge);
+
 	sun6i_dsi_start(dsi, DSI_START_HSC);
 
 	udelay(1000);
@@ -812,6 +818,9 @@ static void sun6i_dsi_encoder_disable(struct drm_encoder *encoder)
 	if (!IS_ERR(dsi->panel)) {
 		drm_panel_disable(dsi->panel);
 		drm_panel_unprepare(dsi->panel);
+	} else if (!IS_ERR(dsi->bridge)) {
+		drm_bridge_disable(dsi->bridge);
+		drm_bridge_post_disable(dsi->bridge);
 	}
 
 	phy_power_off(dsi->dphy);
@@ -973,11 +982,16 @@ static int sun6i_dsi_attach(struct mipi_dsi_host *host,
 	struct sun6i_dsi *dsi = host_to_sun6i_dsi(host);
 
 	dsi->device = device;
-	dsi->panel = of_drm_find_panel(device->dev.of_node);
-	if (IS_ERR(dsi->panel))
-		return PTR_ERR(dsi->panel);
 
-	dev_info(host->dev, "Attached device %s\n", device->name);
+	dsi->bridge = of_drm_find_bridge(device->dev.of_node);
+	if (!dsi->bridge) {

You are using IS_ERR to check that the bridge is alive in the changes
above, but switch to checking that it's non-NULL at this point.

Are both guaranteed to be interchangeable?

They aren't. Any ERR_PTR will be !NULL


+		dsi->panel = of_drm_find_panel(device->dev.of_node);
+		if (IS_ERR(dsi->panel))
+			return PTR_ERR(dsi->panel);
+	}

You should probably use drm_of_find_panel_or_bridge instead of
duplicating the logic here.

Or we can even use the drm_panel_bridge_add to simplify things.

Maxime


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