diff mbox series

[v4,2/2] drm/bridge: parade-ps8640: Populate devices on aux-bus

Message ID 20211026145622.v4.2.I09899dea340f11feab97d719cb4b62bef3179e4b@changeid (mailing list archive)
State New, archived
Headers show
Series [v4,1/2] drm/bridge: parade-ps8640: Enable runtime power management | expand

Commit Message

Philip Chen Oct. 26, 2021, 9:56 p.m. UTC
Conventionally, panel is listed under the root of the device tree.
When userland asks for display mode, ps8640 bridge is responsible
for returning EDID when ps8640_bridge_get_edid() is called.

Now enable a new option of listing panel under "aux-bus" of ps8640
bridge node in the device tree. In this case, panel driver can retrieve
EDID by triggering AUX transactions, without ps8640_bridge_get_edid()
calls at all.

To prevent the "old" and "new" options from interfering with each
other's logic flow, disable DRM_BRIDGE_OP_EDID when the new option
is taken.

Signed-off-by: Philip Chen <philipchen@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
---

(no changes since v3)

Changes in v3:
- Fix when to call of_node_put() in ps8640_of_panel_on_aux_bus()

Changes in v2:
- Add of_node_put() calls in ps8640_of_panel_on_aux_bus()
- Select DRM_DP_AUX_BUS for PS8640 driver in Kconfig
- Replace _put_sync() with _put_sync_suspend() in ps8640_post_disable()

 drivers/gpu/drm/bridge/Kconfig         |  1 +
 drivers/gpu/drm/bridge/parade-ps8640.c | 51 ++++++++++++++++++++------
 2 files changed, 40 insertions(+), 12 deletions(-)

Comments

Doug Anderson Oct. 27, 2021, 10:12 p.m. UTC | #1
Hi,

On Tue, Oct 26, 2021 at 2:56 PM Philip Chen <philipchen@chromium.org> wrote:
>
> Conventionally, panel is listed under the root of the device tree.
> When userland asks for display mode, ps8640 bridge is responsible
> for returning EDID when ps8640_bridge_get_edid() is called.
>
> Now enable a new option of listing panel under "aux-bus" of ps8640
> bridge node in the device tree. In this case, panel driver can retrieve
> EDID by triggering AUX transactions, without ps8640_bridge_get_edid()
> calls at all.
>
> To prevent the "old" and "new" options from interfering with each
> other's logic flow, disable DRM_BRIDGE_OP_EDID when the new option
> is taken.
>
> Signed-off-by: Philip Chen <philipchen@chromium.org>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> ---
>
> (no changes since v3)
>
> Changes in v3:
> - Fix when to call of_node_put() in ps8640_of_panel_on_aux_bus()
>
> Changes in v2:
> - Add of_node_put() calls in ps8640_of_panel_on_aux_bus()
> - Select DRM_DP_AUX_BUS for PS8640 driver in Kconfig
> - Replace _put_sync() with _put_sync_suspend() in ps8640_post_disable()

Not that it terribly matters, but I don't think the "put_sync" vs.
"put_sync_suspend" was in patch #2/2. It was in #1/2.


>  drivers/gpu/drm/bridge/Kconfig         |  1 +
>  drivers/gpu/drm/bridge/parade-ps8640.c | 51 ++++++++++++++++++++------
>  2 files changed, 40 insertions(+), 12 deletions(-)

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Philip Chen Oct. 27, 2021, 10:25 p.m. UTC | #2
Hi Doug

On Wed, Oct 27, 2021 at 3:13 PM Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Tue, Oct 26, 2021 at 2:56 PM Philip Chen <philipchen@chromium.org> wrote:
> >
> > Conventionally, panel is listed under the root of the device tree.
> > When userland asks for display mode, ps8640 bridge is responsible
> > for returning EDID when ps8640_bridge_get_edid() is called.
> >
> > Now enable a new option of listing panel under "aux-bus" of ps8640
> > bridge node in the device tree. In this case, panel driver can retrieve
> > EDID by triggering AUX transactions, without ps8640_bridge_get_edid()
> > calls at all.
> >
> > To prevent the "old" and "new" options from interfering with each
> > other's logic flow, disable DRM_BRIDGE_OP_EDID when the new option
> > is taken.
> >
> > Signed-off-by: Philip Chen <philipchen@chromium.org>
> > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > ---
> >
> > (no changes since v3)
> >
> > Changes in v3:
> > - Fix when to call of_node_put() in ps8640_of_panel_on_aux_bus()
> >
> > Changes in v2:
> > - Add of_node_put() calls in ps8640_of_panel_on_aux_bus()
> > - Select DRM_DP_AUX_BUS for PS8640 driver in Kconfig
> > - Replace _put_sync() with _put_sync_suspend() in ps8640_post_disable()
>
> Not that it terribly matters, but I don't think the "put_sync" vs.
> "put_sync_suspend" was in patch #2/2. It was in #1/2.
Oops, sorry, I did a terrible job separating the changes between patch
#1/2 and #2/2.
Will retroactively fix v2 change log when I post v5.

>
>
> >  drivers/gpu/drm/bridge/Kconfig         |  1 +
> >  drivers/gpu/drm/bridge/parade-ps8640.c | 51 ++++++++++++++++++++------
> >  2 files changed, 40 insertions(+), 12 deletions(-)
>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index 431b6e12a81f..61db5a66b493 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -182,6 +182,7 @@  config DRM_PARADE_PS8622
 config DRM_PARADE_PS8640
 	tristate "Parade PS8640 MIPI DSI to eDP Converter"
 	depends on OF
+	select DRM_DP_AUX_BUS
 	select DRM_KMS_HELPER
 	select DRM_MIPI_DSI
 	select DRM_PANEL
diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
index cf1f630a3958..e737f1a27f30 100644
--- a/drivers/gpu/drm/bridge/parade-ps8640.c
+++ b/drivers/gpu/drm/bridge/parade-ps8640.c
@@ -14,6 +14,7 @@ 
 #include <linux/regulator/consumer.h>
 
 #include <drm/drm_bridge.h>
+#include <drm/drm_dp_aux_bus.h>
 #include <drm/drm_dp_helper.h>
 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_of.h>
@@ -149,6 +150,23 @@  static inline struct ps8640 *aux_to_ps8640(struct drm_dp_aux *aux)
 	return container_of(aux, struct ps8640, aux);
 }
 
+static bool ps8640_of_panel_on_aux_bus(struct device *dev)
+{
+	struct device_node *bus, *panel;
+
+	bus = of_get_child_by_name(dev->of_node, "aux-bus");
+	if (!bus)
+		return false;
+
+	panel = of_get_child_by_name(bus, "panel");
+	of_node_put(bus);
+	if (!panel)
+		return false;
+	of_node_put(panel);
+
+	return true;
+}
+
 static int ps8640_ensure_hpd(struct ps8640 *ps_bridge)
 {
 	struct regmap *map = ps_bridge->regmap[PAGE2_TOP_CNTL];
@@ -556,17 +574,6 @@  static int ps8640_probe(struct i2c_client *client)
 	if (!ps_bridge)
 		return -ENOMEM;
 
-	/* port@1 is ps8640 output port */
-	ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
-	if (ret < 0)
-		return ret;
-	if (!panel)
-		return -ENODEV;
-
-	ps_bridge->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
-	if (IS_ERR(ps_bridge->panel_bridge))
-		return PTR_ERR(ps_bridge->panel_bridge);
-
 	ps_bridge->supplies[0].supply = "vdd33";
 	ps_bridge->supplies[1].supply = "vdd12";
 	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ps_bridge->supplies),
@@ -589,9 +596,16 @@  static int ps8640_probe(struct i2c_client *client)
 
 	ps_bridge->bridge.funcs = &ps8640_bridge_funcs;
 	ps_bridge->bridge.of_node = dev->of_node;
-	ps_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
 	ps_bridge->bridge.type = DRM_MODE_CONNECTOR_eDP;
 
+	/*
+	 * In the device tree, if panel is listed under aux-bus of the bridge
+	 * node, panel driver should be able to retrieve EDID by itself using
+	 * aux-bus. So let's not set DRM_BRIDGE_OP_EDID here.
+	 */
+	if (!ps8640_of_panel_on_aux_bus(&client->dev))
+		ps_bridge->bridge.ops = DRM_BRIDGE_OP_EDID;
+
 	ps_bridge->page[PAGE0_DP_CNTL] = client;
 
 	ps_bridge->regmap[PAGE0_DP_CNTL] = devm_regmap_init_i2c(client, ps8640_regmap_config);
@@ -630,6 +644,19 @@  static int ps8640_probe(struct i2c_client *client)
 	if (ret)
 		return ret;
 
+	devm_of_dp_aux_populate_ep_devices(&ps_bridge->aux);
+
+	/* port@1 is ps8640 output port */
+	ret = drm_of_find_panel_or_bridge(np, 1, 0, &panel, NULL);
+	if (ret < 0)
+		return ret;
+	if (!panel)
+		return -ENODEV;
+
+	ps_bridge->panel_bridge = devm_drm_panel_bridge_add(dev, panel);
+	if (IS_ERR(ps_bridge->panel_bridge))
+		return PTR_ERR(ps_bridge->panel_bridge);
+
 	drm_bridge_add(&ps_bridge->bridge);
 
 	return 0;