| Message ID | 20211016095644.2.I44ee57ef73528243acf8f29af8d2416b810e1a9d@changeid (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/2] drm/bridge: parade-ps8640: Enable runtime power management | expand |
Hi, On Sat, Oct 16, 2021 at 9:57 AM Philip Chen <philipchen@chromium.org> wrote: > > Conventionally, panel is listed under the root in 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 the 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> > --- > > drivers/gpu/drm/bridge/parade-ps8640.c | 52 ++++++++++++++++++++------ > 1 file changed, 40 insertions(+), 12 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c > index acfe1bf0f936..98884f799ea8 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> You need a `select DRM_DP_AUX_BUS` in the Kconfig to avoid the errors that the build robot found for you. > #include <drm/drm_dp_helper.h> > #include <drm/drm_mipi_dsi.h> > #include <drm/drm_of.h> > @@ -149,6 +150,24 @@ 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; > + > + if (!dev->of_node) > + return false; You probably don't need the above check. I think things would be pretty broken if we didn't have an "of_node". > + 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); Other than the above, this looks reasonable to me. -Doug
Hi Doug, On Mon, Oct 18, 2021 at 1:43 PM Doug Anderson <dianders@chromium.org> wrote: > > Hi, > > On Sat, Oct 16, 2021 at 9:57 AM Philip Chen <philipchen@chromium.org> wrote: > > > > Conventionally, panel is listed under the root in 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 the 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> > > --- > > > > drivers/gpu/drm/bridge/parade-ps8640.c | 52 ++++++++++++++++++++------ > > 1 file changed, 40 insertions(+), 12 deletions(-) > > > > diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c > > index acfe1bf0f936..98884f799ea8 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> > > You need a `select DRM_DP_AUX_BUS` in the Kconfig to avoid the errors > that the build robot found for you. Thanks for the tip! I also found "select REGMAP_I2C" seems to be missing for ps8640. although the build robot didn't complain. Should I post a fix-up? > > > > #include <drm/drm_dp_helper.h> > > #include <drm/drm_mipi_dsi.h> > > #include <drm/drm_of.h> > > @@ -149,6 +150,24 @@ 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; > > + > > + if (!dev->of_node) > > + return false; > > You probably don't need the above check. I think things would be > pretty broken if we didn't have an "of_node". Removed in v2. PTAL. > > > > + 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); Added in v2. PTAL. > > > > + if (!panel) > > + return false; > > of_node_put(panel); Added in v2. PTAL. > > > Other than the above, this looks reasonable to me. > > -Doug
diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c index acfe1bf0f936..98884f799ea8 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 +150,24 @@ 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; + + if (!dev->of_node) + return false; + + bus = of_get_child_by_name(dev->of_node, "aux-bus"); + if (!bus) + return false; + + panel = of_get_child_by_name(bus, "panel"); + if (!panel) + return false; + + return true; +} + static void ps8640_ensure_hpd(struct ps8640 *ps_bridge) { struct regmap *map = ps_bridge->regmap[PAGE2_TOP_CNTL]; @@ -546,17 +565,6 @@ 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), @@ -579,9 +587,16 @@ 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); @@ -615,6 +630,19 @@ 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;
Conventionally, panel is listed under the root in 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 the 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> --- drivers/gpu/drm/bridge/parade-ps8640.c | 52 ++++++++++++++++++++------ 1 file changed, 40 insertions(+), 12 deletions(-)