[PATCH v2 00/12] Synopsys DisplayPort Controller improvements for Rockchip platforms

[PATCH v2 00/12] Synopsys DisplayPort Controller improvements for Rockchip platforms

[Sebastian Reichel]

This patch series updates the Synopsys Designware DisplayPort bridge
together with the only existing user: The Rockchip RK3576/RK3588:

 1. follow-up bridges (PHY, USB-C connector)
    this is needed to get USB-C DP AltMode working; I've followed the
    Qualcomm driver as reference

 2. runtime PM
    the initial driver has been upstreamed without RPM; add it to
    avoid wasting power when nothing is plugged

 3. audio
    the initial driver has been upstreamed without audio support;
    this adds all missing bits for audio with single stream transport

To properly make use of the bridge code the following USBDP PHY series
is also needed:

https://lore.kernel.org/linux-phy/20260428-rockchip-usbdp-cleanup-v4-0-7775671ece22@collabora.com/

There are two parts, which possibly need some discussion:

 1. I added a dedicated bridge callback for out-of-band hotplug events,
    which is separate from the hotplug_notify. I have a feeling, that
    there might be a better solution, but haven't found it.

 2. The DT binding for audio support - explicitly marked as RFC - works
    perfectly fine, but is not ready for MST. I don't intend to
    implement that right now, but the binding should obviously take it
    into consideration to avoid breaking it in the future. I've put
    some points for discussion into the relevant patch.

P.S.: I will be out of office in May, so please do not expect speedy
      response from me :)

Changes since PATCHv1:
 * https://lore.kernel.org/r/20260326-synopsys-dw-dp-improvements-v1-0-501849162290@collabora.com
 * rebased to latest drm-misc-next
 * prepended the Patches from Cristian's cleanup series, as they also
   needed a rebase and should be merged first
   https://lore.kernel.org/dri-devel/20260327-drm-rk-fixes-v3-0-fd2e6900c08c@collabora.com/
 * fix issue with the audio stream (un)prepare handling in last patch

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
Cristian Ciocaltea (2):
      drm/bridge: synopsys: dw-dp: Support unregistering the AUX channel
      drm/rockchip: dw_dp: Release core resources

Sebastian Reichel (10):
      drm/bridge: synopsys: dw-dp: Simplify driver data setting
      drm/bridge: synopsys: dw-dp: Support MEDIA_BUS_FMT_FIXED
      drm/bridge: synopsys: dw-dp: Add follow-up bridge support
      drm/bridge: Add out-of-band HPD notify handler
      drm/rockchip: dw_dp: Implement out-of-band HPD handling
      drm/bridge: synopsys: dw-dp: Support software triggered OOB HPD
      drm/bridge: synopsys: dw-dp: Add Runtime PM support
      drm/rockchip: dw_dp: Add runtime PM support
      [RFC] dt-bindings: display: rockchip: dw-dp: fix sound DAI cells
      drm/bridge: synopsys: dw-dp: Add audio support

 .../bindings/display/rockchip/rockchip,dw-dp.yaml  |   5 +-
 drivers/gpu/drm/bridge/synopsys/dw-dp.c            | 314 ++++++++++++++++++++-
 drivers/gpu/drm/display/drm_bridge_connector.c     |   6 +
 drivers/gpu/drm/rockchip/dw_dp-rockchip.c          | 180 +++++++++++-
 include/drm/bridge/dw_dp.h                         |   7 +
 include/drm/drm_bridge.h                           |  14 +
 6 files changed, 512 insertions(+), 14 deletions(-)
---
base-commit: 3221890f4e14f17ab46224798e89fbe099904edc
change-id: 20260325-synopsys-dw-dp-improvements-7da2e98df1dd

Best regards,
-- 
Sebastian Reichel <sebastian.reichel@collabora.com>

[PATCH v2 01/12] drm/bridge: synopsys: dw-dp: Support unregistering the AUX channel

[Sebastian Reichel]

From: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>

The DisplayPort AUX channel gets initialized and registered during
dw_dp_bind(), but it is never unregistered, which may lead to resource
leaks and/or use-after-free.

Add the missing dw_dp_unbind() function to allow the users of the
library to handle the required cleanup, i.e. unregister the AUX adapter.

Fixes: 86eecc3a9c2e ("drm/bridge: synopsys: Add DW DPTX Controller support library")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-dp.c | 6 ++++++
 include/drm/bridge/dw_dp.h              | 1 +
 2 files changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index 3f4530c117c7..6211ba6ba7bd 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -2093,6 +2093,12 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 }
 EXPORT_SYMBOL_GPL(dw_dp_bind);
 
+void dw_dp_unbind(struct dw_dp *dp)
+{
+	drm_dp_aux_unregister(&dp->aux);
+}
+EXPORT_SYMBOL_GPL(dw_dp_unbind);
+
 MODULE_AUTHOR("Andy Yan <andyshrk@163.com>");
 MODULE_DESCRIPTION("DW DP Core Library");
 MODULE_LICENSE("GPL");
diff --git a/include/drm/bridge/dw_dp.h b/include/drm/bridge/dw_dp.h
index 25363541e69d..22105c3e8e4d 100644
--- a/include/drm/bridge/dw_dp.h
+++ b/include/drm/bridge/dw_dp.h
@@ -24,4 +24,5 @@ struct dw_dp_plat_data {
 
 struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 			 const struct dw_dp_plat_data *plat_data);
+void dw_dp_unbind(struct dw_dp *dp);
 #endif /* __DW_DP__ */

-- 
2.53.0

[PATCH v2 02/12] drm/rockchip: dw_dp: Release core resources

[Sebastian Reichel]

From: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>

Core resources such as the DisplayPort AUX channel get initialized and
registered during dw_dp_bind(), but are never unregistered, which may
lead to memory leaks and/or use-after-free:

[  224.661371] BUG: KASAN: slab-use-after-free in device_is_dependent+0xe0/0x2b0
[  224.662015] Read of size 8 at addr ffff00011aee8550 by task modprobe/658
[  224.662612]
[  224.662752] CPU: 7 UID: 0 PID: 658 Comm: modprobe Not tainted 7.0.0-rc2-next-20260305 #14 PREEMPT
[  224.662759] Hardware name: Radxa ROCK 5B (DT)
[  224.662762] Call trace:
[  224.662764]  show_stack+0x20/0x38 (C)
[  224.662772]  dump_stack_lvl+0x6c/0x98
[  224.662777]  print_report+0x160/0x4b8
[  224.662783]  kasan_report+0xb4/0xe0
[  224.662790]  __asan_report_load8_noabort+0x20/0x30
[  224.662796]  device_is_dependent+0xe0/0x2b0
[  224.662802]  device_is_dependent+0x108/0x2b0
[  224.662808]  device_link_add+0x1f8/0x10b0
[  224.662813]  devm_of_phy_get_by_index+0x120/0x200
[  224.662819]  dw_dp_bind+0x34c/0xb10 [dw_dp]
[  224.662830]  dw_dp_rockchip_bind+0x194/0x250 [rockchipdrm]
[  224.662864]  component_bind_all+0x3a8/0x720
[  224.662869]  rockchip_drm_bind+0x120/0x390 [rockchipdrm]
[  224.662899]  try_to_bring_up_aggregate_device+0x76c/0x838
[  224.662904]  component_master_add_with_match+0x1f4/0x230
[  224.662909]  rockchip_drm_platform_probe+0x420/0x538 [rockchipdrm]
[  224.662939]  platform_probe+0xe8/0x168
[  224.662945]  really_probe+0x340/0x828
[  224.662950]  __driver_probe_device+0x2e0/0x350
[  224.662954]  driver_probe_device+0x80/0x140
[  224.662959]  __driver_attach+0x398/0x460
[  224.662964]  bus_for_each_dev+0xe0/0x198
[  224.662968]  driver_attach+0x50/0x68
[  224.662972]  bus_add_driver+0x2a0/0x4c0
[  224.662977]  driver_register+0x294/0x360
[  224.662982]  __platform_driver_register+0x7c/0x98
[  224.662987]  rockchip_drm_init+0xc4/0xff8 [rockchipdrm]

Since a previous commit exported dw_dp_unbind() function in DW DP core
library to take care of the necessary cleanup, use this in the
component's unbind() callback, as well as in its bind() error path.

Fixes: d68ba7bac955 ("drm/rockchip: Add RK3588 DPTX output support")
Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/rockchip/dw_dp-rockchip.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
index a9a8bf43aa1d..150c2da8fee5 100644
--- a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
@@ -107,15 +107,26 @@ static int dw_dp_rockchip_bind(struct device *dev, struct device *master, void *
 		return PTR_ERR(dp->base);
 
 	connector = drm_bridge_connector_init(drm_dev, encoder);
-	if (IS_ERR(connector))
+	if (IS_ERR(connector)) {
+		dw_dp_unbind(dp->base);
 		return dev_err_probe(dev, PTR_ERR(connector),
 				     "Failed to init bridge connector");
+	}
 
 	return 0;
 }
 
+static void dw_dp_rockchip_unbind(struct device *dev, struct device *master,
+				  void *data)
+{
+	struct rockchip_dw_dp *dp = dev_get_drvdata(dev);
+
+	dw_dp_unbind(dp->base);
+}
+
 static const struct component_ops dw_dp_rockchip_component_ops = {
 	.bind = dw_dp_rockchip_bind,
+	.unbind = dw_dp_rockchip_unbind,
 };
 
 static int dw_dp_probe(struct platform_device *pdev)

-- 
2.53.0

[PATCH v2 03/12] drm/bridge: synopsys: dw-dp: Simplify driver data setting

[Sebastian Reichel]

There is no need to get the platform device just for setting up
the driver data. Simplify the logic.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/rockchip/dw_dp-rockchip.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
index 150c2da8fee5..52e956bffb12 100644
--- a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
@@ -74,7 +74,6 @@ static const struct drm_encoder_helper_funcs dw_dp_encoder_helper_funcs = {
 
 static int dw_dp_rockchip_bind(struct device *dev, struct device *master, void *data)
 {
-	struct platform_device *pdev = to_platform_device(dev);
 	const struct dw_dp_plat_data *plat_data;
 	struct drm_device *drm_dev = data;
 	struct rockchip_dw_dp *dp;
@@ -87,7 +86,7 @@ static int dw_dp_rockchip_bind(struct device *dev, struct device *master, void *
 		return -ENOMEM;
 
 	dp->dev = dev;
-	platform_set_drvdata(pdev, dp);
+	dev_set_drvdata(dev, dp);
 
 	plat_data = of_device_get_match_data(dev);
 	if (!plat_data)

-- 
2.53.0

[PATCH v2 04/12] drm/bridge: synopsys: dw-dp: Support MEDIA_BUS_FMT_FIXED

[Sebastian Reichel]

Add support for MEDIA_BUS_FMT_FIXED, which is e.g. requested for USB-C
DP chains as the last bridge in the chain (aux-hpd-bridge) does not
implement atomic_get_output_bus_fmts(), which results in the generic
drm_atomic_bridge_chain_select_bus_fmts() code using MEDIA_BUS_FMT_FIXED
instead.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-dp.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index 6211ba6ba7bd..fc4ddb7792d7 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -1528,6 +1528,7 @@ static int dw_dp_bridge_atomic_check(struct drm_bridge *bridge,
 				     struct drm_connector_state *conn_state)
 {
 	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
+	unsigned int out_bus_format = bridge_state->output_bus_cfg.format;
 	struct dw_dp *dp = bridge_to_dp(bridge);
 	struct dw_dp_bridge_state *state;
 	const struct dw_dp_output_format *fmt;
@@ -1538,7 +1539,10 @@ static int dw_dp_bridge_atomic_check(struct drm_bridge *bridge,
 	state = to_dw_dp_bridge_state(bridge_state);
 	mode = &state->mode;
 
-	fmt = dw_dp_get_output_format(bridge_state->output_bus_cfg.format);
+	if (out_bus_format == MEDIA_BUS_FMT_FIXED)
+		out_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+
+	fmt = dw_dp_get_output_format(out_bus_format);
 	if (!fmt)
 		return -EINVAL;
 

-- 
2.53.0

[PATCH v2 05/12] drm/bridge: synopsys: dw-dp: Add follow-up bridge support

[Sebastian Reichel]

Add support to use USB-C connectors with the DP altmode helper code on
devicetree based platforms. To get this working there must be a DRM
bridge chain from the DisplayPort controller to the USB-C connector.
E.g. on Rockchip RK3576:

root@rk3576 # cat /sys/kernel/debug/dri/0/encoder-0/bridges
bridge[0]: dw_dp_bridge_funcs
        refcount: 7
        type: [10] DP
        OF: /soc/dp@27e40000:rockchip,rk3576-dp
        ops: [0x47] detect edid hpd
bridge[1]: drm_aux_bridge_funcs
        refcount: 4
        type: [0] Unknown
        OF: /soc/phy@2b010000:rockchip,rk3576-usbdp-phy
        ops: [0x0]
bridge[2]: drm_aux_hpd_bridge_funcs
        refcount: 5
        type: [10] DP
        OF: /soc/i2c@2ac50000/typec-portc@22/connector:usb-c-connector
        ops: [0x4] hpd

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-dp.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index fc4ddb7792d7..ccc55e40e81c 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -1970,7 +1970,7 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct dw_dp *dp;
-	struct drm_bridge *bridge;
+	struct drm_bridge *bridge, *next_bridge;
 	void __iomem *res;
 	int ret;
 
@@ -2064,6 +2064,20 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 		goto unregister_aux;
 	}
 
+	next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 1, 0);
+	if (IS_ERR(next_bridge)) {
+		ret = PTR_ERR(next_bridge);
+		dev_err_probe(dev, ret, "failed to get follow-up bridge.\n");
+		goto unregister_aux;
+	}
+
+	ret = drm_bridge_attach(encoder, next_bridge, bridge,
+				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+	if (ret) {
+		dev_err_probe(dev, ret, "Failed to attach next bridge\n");
+		goto unregister_aux;
+	}
+
 	dw_dp_init_hw(dp);
 
 	ret = phy_init(dp->phy);

-- 
2.53.0

[PATCH v2 06/12] drm/bridge: Add out-of-band HPD notify handler

[Sebastian Reichel]

For DP bridges, that can be used for DP AltMode, it might be necessary
to enforce HPD status. There is an existing ->oob_hotplug_event() on
the DRM connector, but it currently just calls into hpd_notify().

As DP bridge drivers usually also implement .detect and that also
generates calls into hpd_notify, this is a bad place to force the
HPD status as the follow-up detect call might force it off again
resulting in all follow-up calls to the detection routine also
failing.

Avoid this by having a dedicated function for OOB events.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/display/drm_bridge_connector.c |  6 ++++++
 include/drm/drm_bridge.h                       | 14 ++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/drivers/gpu/drm/display/drm_bridge_connector.c b/drivers/gpu/drm/display/drm_bridge_connector.c
index d85ceb80c137..e3c3c0bb0cf0 100644
--- a/drivers/gpu/drm/display/drm_bridge_connector.c
+++ b/drivers/gpu/drm/display/drm_bridge_connector.c
@@ -180,6 +180,12 @@ static void drm_bridge_connector_oob_hotplug_event(struct drm_connector *connect
 	struct drm_bridge_connector *bridge_connector =
 		to_drm_bridge_connector(connector);
 
+	/* Notify all bridges in the pipeline of hotplug events. */
+	drm_for_each_bridge_in_chain_scoped(bridge_connector->encoder, bridge) {
+		if (bridge->funcs->oob_notify)
+			bridge->funcs->oob_notify(bridge, connector, status);
+	}
+
 	drm_bridge_connector_handle_hpd(bridge_connector, status);
 }
 
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index d6cd0f5af045..bba355c1ce1a 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -646,6 +646,20 @@ struct drm_bridge_funcs {
 	 */
 	void (*hpd_disable)(struct drm_bridge *bridge);
 
+	/**
+	 * @oob_notify:
+	 *
+	 * Notify the bridge of out of band hot plug detection.
+	 *
+	 * This callback is optional, it may be implemented by bridges that
+	 * need to be notified of display connection or disconnection for
+	 * internal reasons. One use case is to force the DP controllers HPD
+	 * signal for USB-C DP AltMode.
+	 */
+	void (*oob_notify)(struct drm_bridge *bridge,
+			   struct drm_connector *connector,
+			   enum drm_connector_status status);
+
 	/**
 	 * @hdmi_tmds_char_rate_valid:
 	 *

-- 
2.53.0

[PATCH v2 07/12] drm/rockchip: dw_dp: Implement out-of-band HPD handling

[Sebastian Reichel]

Implement out-of-band hotplug handling, which will be used to receive
external hotplug information from the USB-C state machine. This is
currently handled by the USBDP PHY, which brings quite some trouble
as the register being accessed requires the power-domain from the DP
controller and also requires custom TypeC HPD info parsing in the
USBDP PHY driver.

In contrast to the USBDP PHY this does not just enable the hotplug
signal when a DP AltMode capable adapter is plugged in, but instead
properly detects if a cable is plugged in for things like USB-C to
HDMI adapters.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/rockchip/dw_dp-rockchip.c | 126 ++++++++++++++++++++++++++++--
 1 file changed, 120 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
index 52e956bffb12..5750cf887981 100644
--- a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
@@ -8,9 +8,12 @@
 
 #include <linux/component.h>
 #include <linux/media-bus-format.h>
+#include <linux/hw_bitfield.h>
+#include <linux/mfd/syscon.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/videodev2.h>
+#include <linux/regmap.h>
 
 #include <drm/bridge/dw_dp.h>
 #include <drm/drm_atomic_helper.h>
@@ -24,12 +27,54 @@
 
 #include "rockchip_drm_drv.h"
 
+#define ROCKCHIP_MAX_CTRLS 2
+
+#define ROCKCHIP_VO_GRF_DP_SINK_HPD_SEL BIT(10)
+#define ROCKCHIP_VO_GRF_DP_SINK_HPD_CFG BIT(11)
+
+struct rockchip_dw_dp_plat_data {
+	u8 num_ctrls;
+	u32 ctrl_ids[ROCKCHIP_MAX_CTRLS];
+	u32 max_link_rate;
+	u8 pixel_mode;
+	u32 hpd_reg[ROCKCHIP_MAX_CTRLS];
+};
+
 struct rockchip_dw_dp {
 	struct dw_dp *base;
 	struct device *dev;
+	const struct rockchip_dw_dp_plat_data *pdata;
+	struct regmap *vo_grf;
 	struct rockchip_encoder encoder;
+	int id;
+	bool hpd_sel;
+	bool hpd_cfg;
 };
 
+static void dw_dp_rockchip_hpd_sw_sel(void *data, bool force_hpd_from_sw)
+{
+	struct rockchip_dw_dp *dp = data;
+	u32 hpd_reg = dp->pdata->hpd_reg[dp->id];
+
+	dp->hpd_sel = force_hpd_from_sw;
+
+	regmap_write(dp->vo_grf, hpd_reg,
+		     FIELD_PREP_WM16_CONST(ROCKCHIP_VO_GRF_DP_SINK_HPD_SEL, dp->hpd_sel));
+}
+
+static void dw_dp_rockchip_hpd_sw_cfg(void *data, bool hpd)
+{
+	struct rockchip_dw_dp *dp = data;
+	u32 hpd_reg = dp->pdata->hpd_reg[dp->id];
+
+	dev_dbg(dp->dev, "Force HPD connected=%s\n", str_yes_no(hpd));
+
+	dp->hpd_cfg = hpd;
+
+	regmap_write(dp->vo_grf, hpd_reg,
+		     FIELD_PREP_WM16_CONST(ROCKCHIP_VO_GRF_DP_SINK_HPD_CFG, dp->hpd_cfg));
+}
+
 static int dw_dp_encoder_atomic_check(struct drm_encoder *encoder,
 				      struct drm_crtc_state *crtc_state,
 				      struct drm_connector_state *conn_state)
@@ -72,14 +117,49 @@ static const struct drm_encoder_helper_funcs dw_dp_encoder_helper_funcs = {
 	.atomic_check		= dw_dp_encoder_atomic_check,
 };
 
+static struct regmap *dp_dp_rockchip_get_vo_grf(struct rockchip_dw_dp *dp)
+{
+	struct device_node *np = dev_of_node(dp->dev);
+	struct of_phandle_args args;
+	struct regmap *regmap;
+	int ret;
+
+	ret = of_parse_phandle_with_args(np, "phys", "#phy-cells", 0, &args);
+	if (ret)
+		return ERR_PTR(-ENODEV);
+
+	/*
+	 * Limit this workaround to RK3576 and RK3588, new platforms should
+	 * add a VO GRF phandle in the DisplayPort DT node.
+	 */
+	if (!of_device_is_compatible(args.np, "rockchip,rk3576-usbdp-phy") &&
+	    !of_device_is_compatible(args.np, "rockchip,rk3588-usbdp-phy")) {
+		regmap = ERR_PTR(-ENODEV);
+		goto out_put_node;
+	}
+
+	regmap = syscon_regmap_lookup_by_phandle(args.np, "rockchip,vo-grf");
+
+out_put_node:
+	of_node_put(args.np);
+	return regmap;
+}
+
 static int dw_dp_rockchip_bind(struct device *dev, struct device *master, void *data)
 {
-	const struct dw_dp_plat_data *plat_data;
+	const struct rockchip_dw_dp_plat_data *plat_data_const;
+	struct platform_device *pdev = to_platform_device(dev);
+	struct dw_dp_plat_data *plat_data;
 	struct drm_device *drm_dev = data;
 	struct rockchip_dw_dp *dp;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;
-	int ret;
+	struct resource *res;
+	int ret, id;
+
+	plat_data = drmm_kzalloc(drm_dev, sizeof(*plat_data), GFP_KERNEL);
+	if (!plat_data)
+		return -ENOMEM;
 
 	dp = drmm_kzalloc(drm_dev, sizeof(*dp), GFP_KERNEL);
 	if (!dp)
@@ -88,10 +168,38 @@ static int dw_dp_rockchip_bind(struct device *dev, struct device *master, void *
 	dp->dev = dev;
 	dev_set_drvdata(dev, dp);
 
-	plat_data = of_device_get_match_data(dev);
-	if (!plat_data)
+	plat_data_const = device_get_match_data(dev);
+	if (!plat_data_const)
 		return -ENODEV;
 
+	dp->pdata = plat_data_const;
+
+	res = platform_get_mem_or_io(pdev, 0);
+	if (IS_ERR(res))
+		return PTR_ERR(res);
+
+	/* find the DisplayPort ID from the io address */
+	dp->id = -ENODEV;
+	for (id = 0; id < plat_data_const->num_ctrls; id++) {
+		if (res->start == plat_data_const->ctrl_ids[id]) {
+			dp->id = id;
+			break;
+		}
+	}
+
+	if (dp->id < 0)
+		return dp->id;
+
+	dp->vo_grf = dp_dp_rockchip_get_vo_grf(dp);
+	if (IS_ERR(dp->vo_grf))
+		return PTR_ERR(dp->vo_grf);
+
+	plat_data->max_link_rate = plat_data_const->max_link_rate;
+	plat_data->pixel_mode = plat_data_const->pixel_mode;
+	plat_data->hpd_sw_sel = dw_dp_rockchip_hpd_sw_sel;
+	plat_data->hpd_sw_cfg = dw_dp_rockchip_hpd_sw_cfg;
+	plat_data->data = dp;
+
 	encoder = &dp->encoder.encoder;
 	encoder->possible_crtcs = drm_of_find_possible_crtcs(drm_dev, dev->of_node);
 	rockchip_drm_encoder_set_crtc_endpoint_id(&dp->encoder, dev->of_node, 0, 0);
@@ -138,14 +246,20 @@ static void dw_dp_remove(struct platform_device *pdev)
 	component_del(&pdev->dev, &dw_dp_rockchip_component_ops);
 }
 
-static const struct dw_dp_plat_data rk3588_dp_plat_data = {
+static const struct rockchip_dw_dp_plat_data rk3588_dp_plat_data = {
+	.num_ctrls = 2,
+	.ctrl_ids = {0xfde50000, 0xfde60000},
 	.max_link_rate = 810000,
 	.pixel_mode = DW_DP_MP_QUAD_PIXEL,
+	.hpd_reg = {0x0000, 0x0008},
 };
 
-static const struct dw_dp_plat_data rk3576_dp_plat_data = {
+static const struct rockchip_dw_dp_plat_data rk3576_dp_plat_data = {
+	.num_ctrls = 1,
+	.ctrl_ids = {0x27e40000},
 	.max_link_rate = 810000,
 	.pixel_mode = DW_DP_MP_DUAL_PIXEL,
+	.hpd_reg = {0x0000},
 };
 
 static const struct of_device_id dw_dp_of_match[] = {

-- 
2.53.0

[PATCH v2 08/12] drm/bridge: synopsys: dw-dp: Support software triggered OOB HPD

[Sebastian Reichel]

Add support for USB-C DP AltMode out-of-band hotplug handling. The
handling itself is implemented in the platform specific driver as the
registers to force HPD state are not part of the Designware DisplayPort
IP itself. Instead the platform integration might provide the necessary
functionality to mux the HPD signal.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-dp.c | 38 ++++++++++++++++++++++++++++++++-
 include/drm/bridge/dw_dp.h              |  3 +++
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index ccc55e40e81c..7ade88f74466 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -1817,6 +1817,19 @@ static struct drm_bridge_state *dw_dp_bridge_atomic_duplicate_state(struct drm_b
 	return &state->base;
 }
 
+static void dw_dp_bridge_oob_notify(struct drm_bridge *bridge,
+				    struct drm_connector *connector,
+				    enum drm_connector_status status)
+{
+	bool hpd_high = status != connector_status_disconnected;
+	struct dw_dp *dp = bridge_to_dp(bridge);
+
+	if (dp->plat_data.hpd_sw_cfg)
+		dp->plat_data.hpd_sw_cfg(dp->plat_data.data, hpd_high);
+	else
+		dev_err_once(dp->dev, "Missing platform handler for OOB HPD handling\n");
+}
+
 static const struct drm_bridge_funcs dw_dp_bridge_funcs = {
 	.atomic_duplicate_state = dw_dp_bridge_atomic_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
@@ -1829,6 +1842,7 @@ static const struct drm_bridge_funcs dw_dp_bridge_funcs = {
 	.atomic_disable = dw_dp_bridge_atomic_disable,
 	.detect = dw_dp_bridge_detect,
 	.edid_read = dw_dp_bridge_edid_read,
+	.oob_notify = dw_dp_bridge_oob_notify,
 };
 
 static int dw_dp_link_retrain(struct dw_dp *dp)
@@ -1965,6 +1979,19 @@ static void dw_dp_phy_exit(void *data)
 	phy_exit(dp->phy);
 }
 
+static bool dw_dp_is_routed_to_usb_c(struct drm_encoder *encoder)
+{
+	struct drm_bridge *last_bridge __free(drm_bridge_put) = NULL;
+	struct fwnode_handle *fwnode;
+
+	last_bridge = drm_bridge_chain_get_last_bridge(encoder);
+	if (!last_bridge)
+		return false;
+
+	fwnode = of_fwnode_handle(last_bridge->of_node);
+	return fwnode_device_is_compatible(fwnode, "usb-c-connector");
+}
+
 struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 			 const struct dw_dp_plat_data *plat_data)
 {
@@ -1980,7 +2007,9 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 
 	dp->dev = dev;
 	dp->pixel_mode = plat_data->pixel_mode;
-
+	dp->plat_data.hpd_sw_sel = plat_data->hpd_sw_sel;
+	dp->plat_data.hpd_sw_cfg = plat_data->hpd_sw_cfg;
+	dp->plat_data.data = plat_data->data;
 	dp->plat_data.max_link_rate = plat_data->max_link_rate;
 	bridge = &dp->bridge;
 	mutex_init(&dp->irq_lock);
@@ -2078,6 +2107,13 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 		goto unregister_aux;
 	}
 
+	if (dw_dp_is_routed_to_usb_c(encoder)) {
+		dev_dbg(dev, "USB-C mode\n");
+
+		if (dp->plat_data.hpd_sw_sel)
+			dp->plat_data.hpd_sw_sel(dp->plat_data.data, 1);
+	}
+
 	dw_dp_init_hw(dp);
 
 	ret = phy_init(dp->phy);
diff --git a/include/drm/bridge/dw_dp.h b/include/drm/bridge/dw_dp.h
index 22105c3e8e4d..2127afa26b2c 100644
--- a/include/drm/bridge/dw_dp.h
+++ b/include/drm/bridge/dw_dp.h
@@ -20,6 +20,9 @@ enum {
 struct dw_dp_plat_data {
 	u32 max_link_rate;
 	u8 pixel_mode;
+	void *data;
+	void (*hpd_sw_sel)(void *data, bool hpd);
+	void (*hpd_sw_cfg)(void *data, bool hpd);
 };
 
 struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,

-- 
2.53.0

[PATCH v2 09/12] drm/bridge: synopsys: dw-dp: Add Runtime PM support

[Sebastian Reichel]

Add runtime PM stubs to the Synopsys DesignWare DisplayPort bridge
driver. Support is not enabled automatically and must be hooked up
in the vendor specific glue code.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-dp.c | 27 +++++++++++++++++++++++++++
 include/drm/bridge/dw_dp.h              |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index 7ade88f74466..b0ab2b3d478d 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -1465,6 +1465,8 @@ static ssize_t dw_dp_aux_transfer(struct drm_dp_aux *aux,
 	if (WARN_ON(msg->size > 16))
 		return -E2BIG;
 
+	ACQUIRE(pm_runtime_active_auto, pm)(dp->dev);
+
 	switch (msg->request & ~DP_AUX_I2C_MOT) {
 	case DP_AUX_NATIVE_WRITE:
 	case DP_AUX_I2C_WRITE:
@@ -1655,6 +1657,8 @@ static void dw_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 	struct drm_connector_state *conn_state;
 	int ret;
 
+	pm_runtime_get_sync(dp->dev);
+
 	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
 	if (!connector) {
 		dev_err(dp->dev, "failed to get connector\n");
@@ -1709,6 +1713,7 @@ static void dw_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 	dw_dp_link_disable(dp);
 	bitmap_zero(dp->sdp_reg_bank, SDP_REG_BANK_SIZE);
 	dw_dp_reset(dp);
+	pm_runtime_put_autosuspend(dp->dev);
 }
 
 static bool dw_dp_hpd_detect_link(struct dw_dp *dp, struct drm_connector *connector)
@@ -1729,6 +1734,8 @@ static enum drm_connector_status dw_dp_bridge_detect(struct drm_bridge *bridge,
 {
 	struct dw_dp *dp = bridge_to_dp(bridge);
 
+	ACQUIRE(pm_runtime_active_auto, pm)(dp->dev);
+
 	if (!dw_dp_hpd_detect(dp))
 		return connector_status_disconnected;
 
@@ -2153,6 +2160,26 @@ void dw_dp_unbind(struct dw_dp *dp)
 }
 EXPORT_SYMBOL_GPL(dw_dp_unbind);
 
+int dw_dp_runtime_suspend(struct dw_dp *dp)
+{
+	clk_disable_unprepare(dp->aux_clk);
+	clk_disable_unprepare(dp->apb_clk);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dp_runtime_suspend);
+
+int dw_dp_runtime_resume(struct dw_dp *dp)
+{
+	clk_prepare_enable(dp->apb_clk);
+	clk_prepare_enable(dp->aux_clk);
+
+	dw_dp_init_hw(dp);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dp_runtime_resume);
+
 MODULE_AUTHOR("Andy Yan <andyshrk@163.com>");
 MODULE_DESCRIPTION("DW DP Core Library");
 MODULE_LICENSE("GPL");
diff --git a/include/drm/bridge/dw_dp.h b/include/drm/bridge/dw_dp.h
index 2127afa26b2c..3037e0290861 100644
--- a/include/drm/bridge/dw_dp.h
+++ b/include/drm/bridge/dw_dp.h
@@ -28,4 +28,7 @@ struct dw_dp_plat_data {
 struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 			 const struct dw_dp_plat_data *plat_data);
 void dw_dp_unbind(struct dw_dp *dp);
+
+int dw_dp_runtime_suspend(struct dw_dp *dp);
+int dw_dp_runtime_resume(struct dw_dp *dp);
 #endif /* __DW_DP__ */

-- 
2.53.0

[PATCH v2 10/12] drm/rockchip: dw_dp: Add runtime PM support

[Sebastian Reichel]

Add support for runtime PM to the Rockchip RK3576/3588 Synopsys
DesignWare DisplayPort driver.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/rockchip/dw_dp-rockchip.c | 40 +++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
index 5750cf887981..015d39d48648 100644
--- a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c
@@ -12,6 +12,7 @@
 #include <linux/mfd/syscon.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/videodev2.h>
 #include <linux/regmap.h>
 
@@ -58,6 +59,8 @@ static void dw_dp_rockchip_hpd_sw_sel(void *data, bool force_hpd_from_sw)
 
 	dp->hpd_sel = force_hpd_from_sw;
 
+	ACQUIRE(pm_runtime_active_auto, pm)(dp->dev);
+
 	regmap_write(dp->vo_grf, hpd_reg,
 		     FIELD_PREP_WM16_CONST(ROCKCHIP_VO_GRF_DP_SINK_HPD_SEL, dp->hpd_sel));
 }
@@ -71,6 +74,8 @@ static void dw_dp_rockchip_hpd_sw_cfg(void *data, bool hpd)
 
 	dp->hpd_cfg = hpd;
 
+	ACQUIRE(pm_runtime_active_auto, pm)(dp->dev);
+
 	regmap_write(dp->vo_grf, hpd_reg,
 		     FIELD_PREP_WM16_CONST(ROCKCHIP_VO_GRF_DP_SINK_HPD_CFG, dp->hpd_cfg));
 }
@@ -213,6 +218,12 @@ static int dw_dp_rockchip_bind(struct device *dev, struct device *master, void *
 	if (IS_ERR(dp->base))
 		return PTR_ERR(dp->base);
 
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_autosuspend_delay(dev, 500);
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to enable runtime PM\n");
+
 	connector = drm_bridge_connector_init(drm_dev, encoder);
 	if (IS_ERR(connector)) {
 		dw_dp_unbind(dp->base);
@@ -246,6 +257,34 @@ static void dw_dp_remove(struct platform_device *pdev)
 	component_del(&pdev->dev, &dw_dp_rockchip_component_ops);
 }
 
+static int dw_dp_rockchip_runtime_suspend(struct device *dev)
+{
+	struct rockchip_dw_dp *dp = dev_get_drvdata(dev);
+
+	return dw_dp_runtime_suspend(dp->base);
+}
+
+static int dw_dp_rockchip_runtime_resume(struct device *dev)
+{
+	struct rockchip_dw_dp *dp = dev_get_drvdata(dev);
+	u32 hpd_reg = dp->pdata->hpd_reg[dp->id];
+	int ret;
+
+	ret = dw_dp_runtime_resume(dp->base);
+	if (ret)
+		return ret;
+
+	regmap_write(dp->vo_grf, hpd_reg,
+		     FIELD_PREP_WM16_CONST(ROCKCHIP_VO_GRF_DP_SINK_HPD_SEL, dp->hpd_sel) |
+		     FIELD_PREP_WM16_CONST(ROCKCHIP_VO_GRF_DP_SINK_HPD_CFG, dp->hpd_cfg));
+
+	return 0;
+}
+
+static const struct dev_pm_ops dw_dp_pm_ops = {
+	RUNTIME_PM_OPS(dw_dp_rockchip_runtime_suspend, dw_dp_rockchip_runtime_resume, NULL)
+};
+
 static const struct rockchip_dw_dp_plat_data rk3588_dp_plat_data = {
 	.num_ctrls = 2,
 	.ctrl_ids = {0xfde50000, 0xfde60000},
@@ -280,5 +319,6 @@ struct platform_driver dw_dp_driver = {
 	.driver = {
 		.name = "dw-dp",
 		.of_match_table = dw_dp_of_match,
+		.pm = pm_ptr(&dw_dp_pm_ops),
 	},
 };

-- 
2.53.0

[PATCH RFC v2 11/12] dt-bindings: display: rockchip: dw-dp: fix sound DAI cells

[Sebastian Reichel]

The RK3588 and RK3576 DesignWare DisplayPort controllers both have two
possible DAI interfaces: I2S and S/PDIF. Thus it is needed to have an
argument to select the right interface.

In case of RK3576 this is not enough though. The RK3576 has the same IP
as RK3588, but configured with Multi Stream Transport (MST) enabled for
up to 3 displays and thus has a total of 6 DAI interfaces (I2S and
S/PDIF for each possible stream. Meanwhile the RK3588 does not support
MST and thus has only 2 DAI interfaces.

The binding update right now only supports the simple single stream
transport (SST) setup. To avoid further DT ABI breakage (or complicated
bindings supporting different number of arguments), it's probably a good
idea to take MST into account now even though the upstream Linux driver
does not yet support it.

I see two options:

1. Adding yet another cell, so that we have the following:
   <&dp_ctrl [display_stream] [i2s_or_spdif]>; potentially append
   extra input ports for MST video data to existing ports node
   (e.g. port@2). I would only handle the sound DAI part in my
   patch and basically use '0' for the display stream and just
   leave the option of using '1' or '2' once MST support is added.

2. The vendor kernel creates a sub-node for each supported display
   stream and puts the ports mapping as well as the DAI reference
   into that. This bundles all information for one display stream
   together, which creates a clean look but the subnode does not
   really describe any real thing in the hardware.

As upstream MST support seems to be quite limited, I wish for some
feedback about the preferred way to handle this.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 .../devicetree/bindings/display/rockchip/rockchip,dw-dp.yaml         | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-dp.yaml b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-dp.yaml
index 2b0d9e23e943..1303d0e2145a 100644
--- a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-dp.yaml
+++ b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-dp.yaml
@@ -83,7 +83,8 @@ properties:
     maxItems: 1
 
   "#sound-dai-cells":
-    const: 0
+    const: 1
+    description: 0 for I2S, 1 for SPDIF
 
 required:
   - compatible
@@ -144,7 +145,7 @@ examples:
         resets = <&cru SRST_DP0>;
         phys = <&usbdp_phy0 PHY_TYPE_DP>;
         power-domains = <&power RK3588_PD_VO0>;
-        #sound-dai-cells = <0>;
+        #sound-dai-cells = <1>;
 
         ports {
           #address-cells = <1>;

-- 
2.53.0

[PATCH v2 12/12] drm/bridge: synopsys: dw-dp: Add audio support

[Sebastian Reichel]

Implement audio support for the Synopsys DesignWare DisplayPort
controller.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-dp.c | 221 +++++++++++++++++++++++++++++++-
 1 file changed, 220 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index b0ab2b3d478d..9553bad690d9 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -23,17 +23,21 @@
 #include <drm/drm_bridge.h>
 #include <drm/drm_bridge_connector.h>
 #include <drm/display/drm_dp_helper.h>
+#include <drm/display/drm_hdmi_audio_helper.h>
 #include <drm/drm_edid.h>
 #include <drm/drm_of.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_simple_kms_helper.h>
 
+#include <sound/hdmi-codec.h>
+
 #define DW_DP_VERSION_NUMBER			0x0000
 #define DW_DP_VERSION_TYPE			0x0004
 #define DW_DP_ID				0x0008
 
 #define DW_DP_CONFIG_REG1			0x0100
+#define AUDIO_SELECT				GENMASK(2, 1)
 #define DW_DP_CONFIG_REG2			0x0104
 #define DW_DP_CONFIG_REG3			0x0108
 
@@ -110,6 +114,10 @@
 #define HBR_MODE_ENABLE				BIT(10)
 #define AUDIO_DATA_WIDTH			GENMASK(9, 5)
 #define AUDIO_DATA_IN_EN			GENMASK(4, 1)
+#define AUDIO_DATA_IN_EN_CHANNEL12		BIT(0)
+#define AUDIO_DATA_IN_EN_CHANNEL34		BIT(1)
+#define AUDIO_DATA_IN_EN_CHANNEL56		BIT(2)
+#define AUDIO_DATA_IN_EN_CHANNEL78		BIT(3)
 #define AUDIO_INF_SELECT			BIT(0)
 
 #define DW_DP_SDP_VERTICAL_CTRL			0x0500
@@ -253,6 +261,8 @@
 
 #define SDP_REG_BANK_SIZE			16
 
+#define DW_DP_SDP_VERSION			0x12
+
 struct dw_dp_link_caps {
 	bool enhanced_framing;
 	bool tps3_supported;
@@ -305,6 +315,19 @@ struct dw_dp_hotplug {
 	bool long_hpd;
 };
 
+enum dw_dp_audio_interface_support {
+	DW_DP_AUDIO_I2S_ONLY = 0,
+	DW_DP_AUDIO_SPDIF_ONLY = 1,
+	DW_DP_AUDIO_I2S_AND_SPDIF = 2,
+	DW_DP_AUDIO_NONE = 3,
+};
+
+enum dw_dp_audio_interface {
+	DW_DP_AUDIO_I2S = 0,
+	DW_DP_AUDIO_SPDIF = 1,
+	DW_DP_AUDIO_UNUSED,
+};
+
 struct dw_dp {
 	struct drm_bridge bridge;
 	struct device *dev;
@@ -320,6 +343,8 @@ struct dw_dp {
 	int irq;
 	struct work_struct hpd_work;
 	struct dw_dp_hotplug hotplug;
+	enum dw_dp_audio_interface audio_interface;
+	int audio_channels;
 	/* Serialize hpd status access */
 	struct mutex irq_lock;
 
@@ -1837,6 +1862,186 @@ static void dw_dp_bridge_oob_notify(struct drm_bridge *bridge,
 		dev_err_once(dp->dev, "Missing platform handler for OOB HPD handling\n");
 }
 
+static int dw_dp_audio_infoframe_send(struct dw_dp *dp)
+{
+	struct hdmi_audio_infoframe frame;
+	struct dw_dp_sdp sdp;
+	int ret;
+
+	ret = hdmi_audio_infoframe_init(&frame);
+	if (ret < 0)
+		return ret;
+
+	frame.coding_type = HDMI_AUDIO_CODING_TYPE_STREAM;
+	frame.sample_frequency = HDMI_AUDIO_SAMPLE_FREQUENCY_STREAM;
+	frame.sample_size = HDMI_AUDIO_SAMPLE_SIZE_STREAM;
+	frame.channels = dp->audio_channels;
+
+	ret = hdmi_audio_infoframe_pack_for_dp(&frame, &sdp.base, DW_DP_SDP_VERSION);
+	if (ret < 0)
+		return ret;
+
+	sdp.flags = DW_DP_SDP_VERTICAL_INTERVAL;
+
+	return dw_dp_send_sdp(dp, &sdp);
+}
+
+static int dw_dp_audio_startup(struct drm_bridge *bridge,
+			       struct drm_connector *connector)
+{
+	struct dw_dp *dp = bridge_to_dp(bridge);
+
+	dev_dbg(dp->dev, "audio startup\n");
+	pm_runtime_get_sync(dp->dev);
+
+	return 0;
+}
+
+static void dw_dp_audio_unprepare(struct drm_bridge *bridge,
+				  struct drm_connector *connector)
+{
+	struct dw_dp *dp = bridge_to_dp(bridge);
+
+	/* Disable all audio streams */
+	regmap_update_bits(dp->regmap, DW_DP_AUD_CONFIG1, AUDIO_DATA_IN_EN,
+			   FIELD_PREP(AUDIO_DATA_IN_EN, 0));
+
+	if (dp->audio_interface == DW_DP_AUDIO_SPDIF)
+		clk_disable_unprepare(dp->spdif_clk);
+	else if (dp->audio_interface == DW_DP_AUDIO_I2S)
+		clk_disable_unprepare(dp->i2s_clk);
+
+	dp->audio_interface = DW_DP_AUDIO_UNUSED;
+}
+
+static int dw_dp_audio_prepare(struct drm_bridge *bridge,
+			       struct drm_connector *connector,
+			       struct hdmi_codec_daifmt *daifmt,
+			       struct hdmi_codec_params *params)
+{
+	struct dw_dp *dp = bridge_to_dp(bridge);
+	u8 audio_data_in_en, supported_audio_interfaces;
+	u32 cfg1;
+	int ret;
+
+	/*
+	 * prepare might be called multiple times, so release the clocks
+	 * from previous calls to keep the calls in balance.
+	 */
+	if (dp->audio_interface != DW_DP_AUDIO_UNUSED)
+		dw_dp_audio_unprepare(bridge, connector);
+
+	dp->audio_channels = params->cea.channels;
+	switch (params->cea.channels) {
+	case 1:
+	case 2:
+		audio_data_in_en = AUDIO_DATA_IN_EN_CHANNEL12;
+		break;
+	case 8:
+		audio_data_in_en = AUDIO_DATA_IN_EN_CHANNEL12 |
+				   AUDIO_DATA_IN_EN_CHANNEL34 |
+				   AUDIO_DATA_IN_EN_CHANNEL56 |
+				   AUDIO_DATA_IN_EN_CHANNEL78;
+		break;
+	default:
+		dev_err(dp->dev, "invalid audio channels %d\n", dp->audio_channels);
+		return -EINVAL;
+	}
+
+	switch (daifmt->fmt) {
+	case HDMI_SPDIF:
+		dp->audio_interface = DW_DP_AUDIO_SPDIF;
+		break;
+	case HDMI_I2S:
+		/*
+		 * It is recommended to use SPDIF instead of I2S, since I2S mode requires
+		 * manually inserting PCUV control bits from userspace and this is done
+		 * automatically in hardware for SPDIF mode.
+		 */
+		dp->audio_interface = DW_DP_AUDIO_I2S;
+		break;
+	default:
+		dev_err(dp->dev, "invalid DAI format %d\n", daifmt->fmt);
+		return -EINVAL;
+	}
+
+	regmap_read(dp->regmap, DW_DP_CONFIG_REG1, &cfg1);
+	supported_audio_interfaces = FIELD_GET(AUDIO_SELECT, cfg1);
+
+	if (supported_audio_interfaces != DW_DP_AUDIO_I2S_AND_SPDIF &&
+	    supported_audio_interfaces != dp->audio_interface) {
+		dev_err(dp->dev, "unsupported DAI %d\n", daifmt->fmt);
+		return -EINVAL;
+	}
+
+	clk_prepare_enable(dp->spdif_clk);
+	clk_prepare_enable(dp->i2s_clk);
+
+	regmap_update_bits(dp->regmap, DW_DP_AUD_CONFIG1,
+			   AUDIO_DATA_IN_EN | NUM_CHANNELS | AUDIO_DATA_WIDTH |
+			   AUDIO_INF_SELECT | HBR_MODE_ENABLE,
+			   FIELD_PREP(AUDIO_DATA_IN_EN, audio_data_in_en) |
+			   FIELD_PREP(NUM_CHANNELS, dp->audio_channels - 1) |
+			   FIELD_PREP(AUDIO_DATA_WIDTH, params->sample_width) |
+			   FIELD_PREP(AUDIO_INF_SELECT, dp->audio_interface) |
+			   FIELD_PREP(HBR_MODE_ENABLE, 0));
+
+	/* Wait for inf switch */
+	usleep_range(20, 40);
+
+	if (dp->audio_interface == DW_DP_AUDIO_I2S)
+		clk_disable_unprepare(dp->spdif_clk);
+	else if (dp->audio_interface == DW_DP_AUDIO_SPDIF)
+		clk_disable_unprepare(dp->i2s_clk);
+
+	/*
+	 * Send audio stream during vertical and horizontal blanking periods.
+	 * Send out audio timestamp SDP once per video frame during the vertical
+	 * blanking period
+	 */
+	regmap_update_bits(dp->regmap, DW_DP_SDP_VERTICAL_CTRL,
+			   EN_AUDIO_STREAM_SDP | EN_AUDIO_TIMESTAMP_SDP,
+			   FIELD_PREP(EN_AUDIO_STREAM_SDP, 1) |
+			   FIELD_PREP(EN_AUDIO_TIMESTAMP_SDP, 1));
+	regmap_update_bits(dp->regmap, DW_DP_SDP_HORIZONTAL_CTRL,
+			   EN_AUDIO_STREAM_SDP,
+			   FIELD_PREP(EN_AUDIO_STREAM_SDP, 1));
+
+	ret = dw_dp_audio_infoframe_send(dp);
+	if (ret < 0)
+		dev_err(dp->dev, "failed to send audio infoframe\n");
+
+	dev_dbg(dp->dev, "audio prepare with %d channels using DAI=%d\n",
+		dp->audio_channels, dp->audio_interface);
+
+	return 0;
+}
+
+static void dw_dp_audio_shutdown(struct drm_bridge *bridge,
+				 struct drm_connector *connector)
+{
+	struct dw_dp *dp = bridge_to_dp(bridge);
+
+	dev_dbg(dp->dev, "audio shutdown\n");
+
+	dw_dp_audio_unprepare(bridge, connector);
+	pm_runtime_put_autosuspend(dp->dev);
+}
+
+static int dw_dp_audio_mute_stream(struct drm_bridge *bridge,
+				   struct drm_connector *connector,
+				   bool enable, int direction)
+{
+	struct dw_dp *dp = bridge_to_dp(bridge);
+
+	dev_dbg(dp->dev, "audio %smute\n", enable ? "" : "un");
+
+	regmap_update_bits(dp->regmap, DW_DP_AUD_CONFIG1, AUDIO_MUTE,
+			   FIELD_PREP(AUDIO_MUTE, enable));
+
+	return 0;
+}
+
 static const struct drm_bridge_funcs dw_dp_bridge_funcs = {
 	.atomic_duplicate_state = dw_dp_bridge_atomic_duplicate_state,
 	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
@@ -1850,6 +2055,11 @@ static const struct drm_bridge_funcs dw_dp_bridge_funcs = {
 	.detect = dw_dp_bridge_detect,
 	.edid_read = dw_dp_bridge_edid_read,
 	.oob_notify = dw_dp_bridge_oob_notify,
+
+	.dp_audio_startup = dw_dp_audio_startup,
+	.dp_audio_prepare = dw_dp_audio_prepare,
+	.dp_audio_shutdown = dw_dp_audio_shutdown,
+	.dp_audio_mute_stream = dw_dp_audio_mute_stream,
 };
 
 static int dw_dp_link_retrain(struct dw_dp *dp)
@@ -2076,10 +2286,19 @@ struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
 	}
 
 	bridge->of_node = dev->of_node;
-	bridge->ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_HPD;
+	bridge->ops = DRM_BRIDGE_OP_DP_AUDIO |
+		      DRM_BRIDGE_OP_DETECT |
+		      DRM_BRIDGE_OP_EDID |
+		      DRM_BRIDGE_OP_HPD;
 	bridge->type = DRM_MODE_CONNECTOR_DisplayPort;
 	bridge->ycbcr_420_allowed = true;
 
+	dp->audio_interface = DW_DP_AUDIO_UNUSED;
+	bridge->hdmi_audio_dev = dev;
+	bridge->hdmi_audio_max_i2s_playback_channels = 8;
+	bridge->hdmi_audio_dai_port = 1;
+	bridge->hdmi_audio_spdif_playback = true;
+
 	ret = devm_drm_bridge_add(dev, bridge);
 	if (ret)
 		return ERR_PTR(ret);

-- 
2.53.0