Now that we have an eDP controller that lists aux-bus, we can safely add an example to the aux-bus bindings.

NOTE: this example is just a copy of the one in the 'ti-sn65dsi86' one. It feels useful to have the example in both places simply because it's important to document the interaction between the two bindings in both places.

Signed-off-by: Douglas Anderson dianders@chromium.org ---

Changes in v8: - Separate DP AUX bus binding is new for v8.

.../bindings/display/dp-aux-bus.yaml | 65 +++++++++++++++++++ 1 file changed, 65 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/dp-aux-bus.yaml b/Documentation/devicetree/bindings/display/dp-aux-bus.yaml index 5e4afe9f98fb..43494d2a32a1 100644 --- a/Documentation/devicetree/bindings/display/dp-aux-bus.yaml +++ b/Documentation/devicetree/bindings/display/dp-aux-bus.yaml @@ -35,3 +35,68 @@ additionalProperties: false

required: - panel + +examples: + - | + #include <dt-bindings/clock/qcom,rpmh.h> + #include <dt-bindings/gpio/gpio.h> + #include <dt-bindings/interrupt-controller/irq.h> + + i2c { + #address-cells = <1>; + #size-cells = <0>; + + bridge@2d { + compatible = "ti,sn65dsi86"; + reg = <0x2d>; + + interrupt-parent = <&tlmm>; + interrupts = <10 IRQ_TYPE_LEVEL_HIGH>; + + enable-gpios = <&tlmm 102 GPIO_ACTIVE_HIGH>; + + vpll-supply = <&src_pp1800_s4a>; + vccio-supply = <&src_pp1800_s4a>; + vcca-supply = <&src_pp1200_l2a>; + vcc-supply = <&src_pp1200_l2a>; + + clocks = <&rpmhcc RPMH_LN_BB_CLK2>; + clock-names = "refclk"; + + no-hpd; + + ports { + #address-cells = <1>; + #size-cells = <0>; + + port@0 { + reg = <0>; + endpoint { + remote-endpoint = <&dsi0_out>; + }; + }; + + port@1 { + reg = <1>; + sn65dsi86_out: endpoint { + remote-endpoint = <&panel_in_edp>; + }; + }; + }; + + aux-bus { + panel { + compatible = "boe,nv133fhm-n62"; + power-supply = <&pp3300_dx_edp>; + backlight = <&backlight>; + hpd-gpios = <&sn65dsi86_bridge 2 GPIO_ACTIVE_HIGH>; + + port { + panel_in_edp: endpoint { + remote-endpoint = <&sn65dsi86_out>; + }; + }; + }; + }; + }; + };

Historically "simple" eDP panels have been handled by panel-simple which is a basic platform_device. In the device tree, the panel node was at the top level and not connected to anything else.

Let's change it so that, instead, panels can be represented as being children of the "DP AUX bus". Essentially we're saying that the hierarchy that we're going to represent is the "control" connections between devices. The DP AUX bus is a control bus provided by an eDP controller (the parent) and consumed by a device like a panel (the child).

The primary incentive here is to cleanly provide the panel driver the ability to communicate over the AUX bus while handling lifetime issues properly. The panel driver may want the AUX bus for controlling the backlight or querying the panel's EDID.

The idea for this bus's design was hashed out over IRC [1].

[1] https://people.freedesktop.org/~cbrill/dri-log/?channel=dri-devel&date=2...

Cc: Laurent Pinchart laurent.pinchart@ideasonboard.com Cc: Lyude Paul lyude@redhat.com Cc: Rajeev Nandan rajeevny@codeaurora.org Suggested-by: Laurent Pinchart laurent.pinchart@ideasonboard.com Signed-off-by: Douglas Anderson dianders@chromium.org Acked-by: Linus Walleij linus.walleij@linaro.org --- There's a whole lot of boilerplate code here. I've tried my best to grok what all of it should be, drawing inspiration from other similar bus drivers (auxiliary, i2c, serdev, platform) and I've tried to test several of the corner cases, but I can't actually believe that I've touched every code path. Please yell if you see something dumb.

Changes in v8: - Allow dp-aux-bus to be a module to fix allmodconfig builds

Changes in v7: - Patch introducing the DP AUX bus is new for v7.

drivers/gpu/drm/Kconfig | 5 + drivers/gpu/drm/Makefile | 2 + drivers/gpu/drm/drm_dp_aux_bus.c | 326 +++++++++++++++++++++++++++++++ include/drm/drm_dp_aux_bus.h | 57 ++++++ 4 files changed, 390 insertions(+) create mode 100644 drivers/gpu/drm/drm_dp_aux_bus.c create mode 100644 include/drm/drm_dp_aux_bus.h

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig index d3a9ca4b1cec..be5c82e55ef6 100644 --- a/drivers/gpu/drm/Kconfig +++ b/drivers/gpu/drm/Kconfig @@ -35,6 +35,11 @@ config DRM_MIPI_DSI bool depends on DRM

+config DRM_DP_AUX_BUS + tristate + depends on DRM + depends on OF + config DRM_DP_AUX_CHARDEV bool "DRM DP AUX Interface" depends on DRM diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index a91cc7684904..0cff2ad2973b 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -33,6 +33,8 @@ drm-$(CONFIG_PCI) += drm_pci.o drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o

+obj-$(CONFIG_DRM_DP_AUX_BUS) += drm_dp_aux_bus.o + drm_vram_helper-y := drm_gem_vram_helper.o obj-$(CONFIG_DRM_VRAM_HELPER) += drm_vram_helper.o

diff --git a/drivers/gpu/drm/drm_dp_aux_bus.c b/drivers/gpu/drm/drm_dp_aux_bus.c new file mode 100644 index 000000000000..d0e44de287d4 --- /dev/null +++ b/drivers/gpu/drm/drm_dp_aux_bus.c @@ -0,0 +1,326 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2021 Google Inc. + * + * The DP AUX bus is used for devices that are connected over a DisplayPort + * AUX bus. The devices on the far side of the bus are referred to as + * endpoints in this code. + * + * Commonly there is only one device connected to the DP AUX bus: a panel. + * Though historically panels (even DP panels) have been modeled as simple + * platform devices, putting them under the DP AUX bus allows the panel driver + * to perform transactions on that bus. + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/pm_domain.h> +#include <linux/pm_runtime.h> + +#include <drm/drm_dp_aux_bus.h> +#include <drm/drm_dp_helper.h> + + +/** + * dp_aux_ep_match() - The match function for the dp_aux_bus. + * @dev: The device to match. + * @drv: The driver to try to match against. + * + * At the moment, we just match on device tree. + * + * Return: True if this driver matches this device; false otherwise. + */ +static int dp_aux_ep_match(struct device *dev, struct device_driver *drv) +{ + return !!of_match_device(drv->of_match_table, dev); +} + +/** + * dp_aux_ep_probe() - The probe function for the dp_aux_bus. + * @dev: The device to probe. + * + * Calls through to the endpoint driver probe. + * + * Return: 0 if no error or negative error code. + */ +static int dp_aux_ep_probe(struct device *dev) +{ + struct dp_aux_ep_driver *aux_ep_drv = to_dp_aux_ep_drv(dev->driver); + struct dp_aux_ep_device *aux_ep = to_dp_aux_ep_dev(dev); + int ret; + + ret = dev_pm_domain_attach(dev, true); + if (ret) + return dev_err_probe(dev, ret, "Failed to attach to PM Domain\n"); + + ret = aux_ep_drv->probe(aux_ep); + if (ret) + dev_pm_domain_detach(dev, true); + + return ret; +} + +/** + * dp_aux_ep_remove() - The remove function for the dp_aux_bus. + * @dev: The device to remove. + * + * Calls through to the endpoint driver remove. + * + * Return: 0 if no error or negative error code. + */ +static int dp_aux_ep_remove(struct device *dev) +{ + struct dp_aux_ep_driver *aux_ep_drv = to_dp_aux_ep_drv(dev->driver); + struct dp_aux_ep_device *aux_ep = to_dp_aux_ep_dev(dev); + + if (aux_ep_drv->remove) + aux_ep_drv->remove(aux_ep); + dev_pm_domain_detach(dev, true); + + return 0; +} + +/** + * dp_aux_ep_shutdown() - The shutdown function for the dp_aux_bus. + * @dev: The device to shutdown. + * + * Calls through to the endpoint driver shutdown. + */ +static void dp_aux_ep_shutdown(struct device *dev) +{ + struct dp_aux_ep_driver *aux_ep_drv; + + if (!dev->driver) + return; + + aux_ep_drv = to_dp_aux_ep_drv(dev->driver); + if (aux_ep_drv->shutdown) + aux_ep_drv->shutdown(to_dp_aux_ep_dev(dev)); +} + +static struct bus_type dp_aux_bus_type = { + .name = "dp-aux", + .match = dp_aux_ep_match, + .probe = dp_aux_ep_probe, + .remove = dp_aux_ep_remove, + .shutdown = dp_aux_ep_shutdown, +}; + +static ssize_t modalias_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return of_device_modalias(dev, buf, PAGE_SIZE); +} +static DEVICE_ATTR_RO(modalias); + +static struct attribute *dp_aux_ep_dev_attrs[] = { + &dev_attr_modalias.attr, + NULL, +}; +ATTRIBUTE_GROUPS(dp_aux_ep_dev); + +/** + * dp_aux_ep_dev_release() - Free memory for the dp_aux_ep device + * @dev: The device to free. + * + * Return: 0 if no error or negative error code. + */ +static void dp_aux_ep_dev_release(struct device *dev) +{ + kfree(to_dp_aux_ep_dev(dev)); +} + +static struct device_type dp_aux_device_type_type = { + .groups = dp_aux_ep_dev_groups, + .uevent = of_device_uevent_modalias, + .release = dp_aux_ep_dev_release, +}; + +/** + * of_dp_aux_ep_destroy() - Destroy an DP AUX endpoint device + * @dev: The device to destroy. + * @data: Not used + * + * This is just used as a callback by of_dp_aux_depopulate_ep_devices() and + * is called for _all_ of the child devices of the device providing the AUX bus. + * We'll only act on those that are of type "dp_aux_bus_type". + * + * This function is effectively an inverse of what's in the loop + * in of_dp_aux_populate_ep_devices(). + * + * Return: 0 if no error or negative error code. + */ +static int of_dp_aux_ep_destroy(struct device *dev, void *data) +{ + struct device_node *np = dev->of_node; + + if (dev->bus != &dp_aux_bus_type) + return 0; + + if (!of_node_check_flag(np, OF_POPULATED)) + return 0; + + of_node_clear_flag(np, OF_POPULATED); + of_node_put(np); + + device_unregister(dev); + + return 0; +} + +/** + * of_dp_aux_depopulate_ep_devices() - Undo of_dp_aux_populate_ep_devices + * @aux: The AUX channel whose devices we want to depopulate + * + * This will destroy all devices that were created + * by of_dp_aux_populate_ep_devices(). + */ +void of_dp_aux_depopulate_ep_devices(struct drm_dp_aux *aux) +{ + device_for_each_child_reverse(aux->dev, NULL, of_dp_aux_ep_destroy); +} +EXPORT_SYMBOL_GPL(of_dp_aux_depopulate_ep_devices); + +/** + * of_dp_aux_populate_ep_devices() - Populate the endpoint devices on the DP AUX + * @aux: The AUX channel whose devices we want to populate. It is required that + * drm_dp_aux_init() has already been called for this AUX channel. + * + * This will populate all the devices under the "aux-bus" node of the device + * providing the AUX channel (AKA aux->dev). + * + * When this function finishes, it is _possible_ (but not guaranteed) that + * our sub-devices will have finished probing. It should be noted that if our + * sub-devices return -EPROBE_DEFER that we will not return any error codes + * ourselves but our sub-devices will _not_ have actually probed successfully + * yet. There may be other cases (maybe added in the future?) where sub-devices + * won't have been probed yet when this function returns, so it's best not to + * rely on that. + * + * If this function succeeds you should later make sure you call + * of_dp_aux_depopulate_ep_devices() to undo it, or just use the devm version + * of this function. + * + * Return: 0 if no error or negative error code. + */ +int of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux) +{ + struct device_node *bus, *np; + struct dp_aux_ep_device *aux_ep; + int ret; + + /* drm_dp_aux_init() should have been called already; warn if not */ + WARN_ON_ONCE(!aux->ddc.algo); + + if (!aux->dev->of_node) + return 0; + + bus = of_get_child_by_name(aux->dev->of_node, "aux-bus"); + if (!bus) + return 0; + + for_each_available_child_of_node(bus, np) { + if (of_node_test_and_set_flag(np, OF_POPULATED)) + continue; + + aux_ep = kzalloc(sizeof(*aux_ep), GFP_KERNEL); + aux_ep->aux = aux; + + aux_ep->dev.parent = aux->dev; + aux_ep->dev.bus = &dp_aux_bus_type; + aux_ep->dev.type = &dp_aux_device_type_type; + aux_ep->dev.of_node = of_node_get(np); + dev_set_name(&aux_ep->dev, "aux-%s", dev_name(aux->dev)); + + ret = device_register(&aux_ep->dev); + if (ret) { + dev_err(aux->dev, "Failed to create AUX EP for %pOF: %d\n", np, ret); + of_node_clear_flag(np, OF_POPULATED); + of_node_put(np); + + /* + * As per docs of device_register(), call this instead + * of kfree() directly for error cases. + */ + put_device(&aux_ep->dev); + + /* + * Following in the footsteps of of_i2c_register_devices(), + * we won't fail the whole function here--we'll just + * continue registering any other devices we find. + */ + } + } + + of_node_put(bus); + + return 0; +} + +static void of_dp_aux_depopulate_ep_devices_void(void *data) +{ + of_dp_aux_depopulate_ep_devices(data); +} + +/** + * devm_of_dp_aux_populate_ep_devices() - devm wrapper for of_dp_aux_populate_ep_devices() + * @aux: The AUX channel whose devices we want to populate + * + * Handles freeing w/ devm on the device "aux->dev". + * + * Return: 0 if no error or negative error code. + */ +int devm_of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux) +{ + int ret; + + ret = of_dp_aux_populate_ep_devices(aux); + if (ret) + return ret; + + return devm_add_action_or_reset(aux->dev, + of_dp_aux_depopulate_ep_devices_void, + aux); +} +EXPORT_SYMBOL_GPL(devm_of_dp_aux_populate_ep_devices); + +int __dp_aux_dp_driver_register(struct dp_aux_ep_driver *drv, struct module *owner) +{ + drv->driver.owner = owner; + drv->driver.bus = &dp_aux_bus_type; + + return driver_register(&drv->driver); + +} +EXPORT_SYMBOL_GPL(__dp_aux_dp_driver_register); + +void dp_aux_dp_driver_unregister(struct dp_aux_ep_driver *drv) +{ + driver_unregister(&drv->driver); +} +EXPORT_SYMBOL_GPL(dp_aux_dp_driver_unregister); + +static int __init dp_aux_bus_init(void) +{ + int ret; + + ret = bus_register(&dp_aux_bus_type); + if (ret) + return ret; + + return 0; +} + +static void __exit dp_aux_bus_exit(void) +{ + bus_unregister(&dp_aux_bus_type); +} + +subsys_initcall(dp_aux_bus_init); +module_exit(dp_aux_bus_exit); + +MODULE_AUTHOR("Douglas Anderson dianders@chromium.org"); +MODULE_DESCRIPTION("DRM DisplayPort AUX bus"); +MODULE_LICENSE("GPL v2"); diff --git a/include/drm/drm_dp_aux_bus.h b/include/drm/drm_dp_aux_bus.h new file mode 100644 index 000000000000..4f19b20b1dd6 --- /dev/null +++ b/include/drm/drm_dp_aux_bus.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright 2021 Google Inc. + * + * The DP AUX bus is used for devices that are connected over a DisplayPort + * AUX bus. The devices on the far side of the bus are referred to as + * endpoints in this code. + */ + +#ifndef _DP_AUX_BUS_H_ +#define _DP_AUX_BUS_H_ + +#include <linux/device.h> +#include <linux/mod_devicetable.h> + +/** + * struct dp_aux_ep_device - Main dev structure for DP AUX endpoints + * + * This is used to instantiate devices that are connected via a DP AUX + * bus. Usually the device is a panel, but conceivable other devices could + * be hooked up there. + */ +struct dp_aux_ep_device { + /** @dev: The normal dev pointer */ + struct device dev; + /** @aux: Pointer to the aux bus */ + struct drm_dp_aux *aux; +}; + +struct dp_aux_ep_driver { + int (*probe)(struct dp_aux_ep_device *aux_ep); + void (*remove)(struct dp_aux_ep_device *aux_ep); + void (*shutdown)(struct dp_aux_ep_device *aux_ep); + struct device_driver driver; +}; + +static inline struct dp_aux_ep_device *to_dp_aux_ep_dev(struct device *dev) +{ + return container_of(dev, struct dp_aux_ep_device, dev); +} + +static inline struct dp_aux_ep_driver *to_dp_aux_ep_drv(struct device_driver *drv) +{ + return container_of(drv, struct dp_aux_ep_driver, driver); +} + +int of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux); +void of_dp_aux_depopulate_ep_devices(struct drm_dp_aux *aux); +int devm_of_dp_aux_populate_ep_devices(struct drm_dp_aux *aux); + +#define dp_aux_dp_driver_register(aux_ep_drv) \ + __dp_aux_dp_driver_register(aux_ep_drv, THIS_MODULE) +int __dp_aux_dp_driver_register(struct dp_aux_ep_driver *aux_ep_drv, + struct module *owner); +void dp_aux_dp_driver_unregister(struct dp_aux_ep_driver *aux_ep_drv); + +#endif /* _DP_AUX_BUS_H_ */

If panel-simple is instantiated as a DP AUX bus endpoint then we have access to the DP AUX bus. Let's stash it in the panel-simple structure, leaving it NULL for the cases where the panel is instantiated in other ways.

If we happen to have access to the DP AUX bus and we weren't provided the ddc-i2c-bus in some other manner, let's use the DP AUX bus for it.

Signed-off-by: Douglas Anderson dianders@chromium.org Reviewed-by: Lyude Paul lyude@redhat.com ---

(no changes since v7)

Changes in v7: - Patch using the DP AUX for DDC new for v7.

drivers/gpu/drm/panel/panel-simple.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c index d3b5ae22d939..b09be6e5e147 100644 --- a/drivers/gpu/drm/panel/panel-simple.c +++ b/drivers/gpu/drm/panel/panel-simple.c @@ -37,6 +37,7 @@ #include <drm/drm_crtc.h> #include <drm/drm_device.h> #include <drm/drm_dp_aux_bus.h> +#include <drm/drm_dp_helper.h> #include <drm/drm_mipi_dsi.h> #include <drm/drm_panel.h>

@@ -186,6 +187,7 @@ struct panel_simple {

struct regulator *supply; struct i2c_adapter *ddc; + struct drm_dp_aux *aux;

struct gpio_desc *enable_gpio; struct gpio_desc *hpd_gpio; @@ -658,7 +660,8 @@ static void panel_simple_parse_panel_timing_node(struct device *dev, dev_err(dev, "Reject override mode: No display_timing found\n"); }

-static int panel_simple_probe(struct device *dev, const struct panel_desc *desc) +static int panel_simple_probe(struct device *dev, const struct panel_desc *desc, + struct drm_dp_aux *aux) { struct panel_simple *panel; struct display_timing dt; @@ -674,6 +677,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc) panel->enabled = false; panel->prepared_time = 0; panel->desc = desc; + panel->aux = aux;

panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd"); if (!panel->no_hpd) { @@ -708,6 +712,8 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)

if (!panel->ddc) return -EPROBE_DEFER; + } else if (aux) { + panel->ddc = &aux->ddc; }

if (desc == &panel_dpi) { @@ -4633,7 +4639,7 @@ static int panel_simple_platform_probe(struct platform_device *pdev) if (!id) return -ENODEV;

- return panel_simple_probe(&pdev->dev, id->data); + return panel_simple_probe(&pdev->dev, id->data, NULL); }

static int panel_simple_platform_remove(struct platform_device *pdev) @@ -4913,7 +4919,7 @@ static int panel_simple_dsi_probe(struct mipi_dsi_device *dsi)

desc = id->data;

- err = panel_simple_probe(&dsi->dev, &desc->desc); + err = panel_simple_probe(&dsi->dev, &desc->desc, NULL); if (err < 0) return err;

@@ -4966,7 +4972,7 @@ static int panel_simple_dp_aux_ep_probe(struct dp_aux_ep_device *aux_ep) if (!id) return -ENODEV;

- return panel_simple_probe(&aux_ep->dev, id->data); + return panel_simple_probe(&aux_ep->dev, id->data, aux_ep->aux); }

static void panel_simple_dp_aux_ep_remove(struct dp_aux_ep_device *aux_ep)

We want to provide our panel with access to the DP AUX channel. The way to do this is to let our panel be a child of ours using the fancy new DP AUX bus support.

Signed-off-by: Douglas Anderson dianders@chromium.org Acked-by: Linus Walleij linus.walleij@linaro.org Reviewed-by: Lyude Paul lyude@redhat.com ---

(no changes since v7)

Changes in v7: - Patch to support for DP AUX bus on ti-sn65dsi86 new for v7.

drivers/gpu/drm/bridge/Kconfig | 1 + drivers/gpu/drm/bridge/ti-sn65dsi86.c | 13 +++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index 7e7f28eb9546..a82952a85db4 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -292,6 +292,7 @@ config DRM_TI_SN65DSI86 select DRM_PANEL select DRM_MIPI_DSI select AUXILIARY_BUS + select DRM_DP_AUX_BUS help Texas Instruments SN65DSI86 DSI to eDP Bridge driver

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c index 1ea07d704705..5263206792f6 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c @@ -23,6 +23,7 @@ #include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.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> @@ -1448,19 +1449,27 @@ static int ti_sn_aux_probe(struct auxiliary_device *adev, pdata->aux.transfer = ti_sn_aux_transfer; drm_dp_aux_init(&pdata->aux);

+ ret = devm_of_dp_aux_populate_ep_devices(&pdata->aux); + if (ret) + goto err; + /* * The eDP to MIPI bridge parts don't work until the AUX channel is * setup so we don't add it in the main driver probe, we add it now. */ ret = ti_sn65dsi86_add_aux_device(pdata, &pdata->bridge_aux, "bridge");

+ if (ret) + goto err; + + return 0; +err: /* * Clear of_node on any errors. Really this only matters if the error * is -EPROBE_DEFER to avoid (again) keep pinctrl from claiming when * it tries the probe again, but it shouldn't hurt on any error. */ - if (ret) - adev->dev.of_node = NULL; + adev->dev.of_node = NULL;

return ret; }

Putting the panel under the bridge chip (under the aux-bus node) allows the panel driver to get access to the DP AUX bus, enabling all sorts of fabulous new features.

While we're at this, get rid of a level of hierarchy for the panel node. It doesn't need "ports / port" and can just have a "port" child.

For Linux, this patch has a hard requirement on the patches adding DP AUX bus support to the ti-sn65dsi86 bridge chip driver. See the patch ("drm/bridge: ti-sn65dsi86: Add support for the DP AUX bus").

Signed-off-by: Douglas Anderson dianders@chromium.org Acked-by: Linus Walleij linus.walleij@linaro.org ---

(no changes since v7)

Changes in v7: - Panel now under bridge chip instead of getting a link to ddc-i2c

arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 30 ++++++++++---------- 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi index 24d293ef56d7..c76afd857b54 100644 --- a/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi +++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi @@ -260,21 +260,6 @@ max98357a: audio-codec-0 { #sound-dai-cells = <0>; };

- panel: panel { - /* Compatible will be filled in per-board */ - power-supply = <&pp3300_dx_edp>; - backlight = <&backlight>; - hpd-gpios = <&sn65dsi86_bridge 2 GPIO_ACTIVE_HIGH>; - - ports { - port { - panel_in_edp: endpoint { - remote-endpoint = <&sn65dsi86_out>; - }; - }; - }; - }; - pwmleds { compatible = "pwm-leds"; keyboard_backlight: keyboard-backlight { @@ -674,6 +659,21 @@ sn65dsi86_out: endpoint { }; }; }; + + aux-bus { + panel: panel { + /* Compatible will be filled in per-board */ + power-supply = <&pp3300_dx_edp>; + backlight = <&backlight>; + hpd-gpios = <&sn65dsi86_bridge 2 GPIO_ACTIVE_HIGH>; + + port { + panel_in_edp: endpoint { + remote-endpoint = <&sn65dsi86_out>; + }; + }; + }; + }; }; };