[PATCH 1/2] dt-bindings: drm/bridge: anx7625: Add right justify property

[PATCH 1/2] dt-bindings: drm/bridge: anx7625: Add right justify property

[Xin Ji]

Add property "analogix,audio-right-justify-enable" to control
anx7625 to enable right justify.

Signed-off-by: Xin Ji <xji@analogixsemi.com>
---
 .../devicetree/bindings/display/bridge/analogix,anx7625.yaml  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/bridge/analogix,anx7625.yaml b/Documentation/devicetree/bindings/display/bridge/analogix,anx7625.yaml
index 6ad466952c02..f1b08c6b4877 100644
--- a/Documentation/devicetree/bindings/display/bridge/analogix,anx7625.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/analogix,anx7625.yaml
@@ -82,6 +82,10 @@ properties:
     type: boolean
     description: let the driver enable audio HDMI codec function or not.
 
+  analogix,audio-right-justify-enable:
+    type: boolean
+    description: enable audio data stream right justify.
+
   aux-bus:
     $ref: /schemas/display/dp-aux-bus.yaml#
 
-- 
2.25.1

[PATCH 2/2] drm: anx7625: add I2S input stream right justified control

[Xin Ji]

The default audio data stream is left justify. When the
property "analogix,audio-right-justify-enable" is detected,
the code enables right justify.

Signed-off-by: Xin Ji <xji@analogixsemi.com>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 9 +++++++++
 drivers/gpu/drm/bridge/analogix/anx7625.h | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index c3af88e14f8b..f4bce0000676 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1883,6 +1883,9 @@ static int anx7625_parse_dt(struct device *dev,
 	if (of_property_read_bool(np, "analogix,audio-enable"))
 		pdata->audio_en = 1;
 
+	if (of_property_read_bool(np, "analogix,audio-right-justify-enable"))
+		pdata->audio_right_justify = 1;
+
 	return 0;
 }
 
@@ -2083,6 +2086,12 @@ static int anx7625_audio_hw_params(struct device *dev, void *data,
 		ret |= anx7625_write_and(ctx, ctx->i2c.tx_p2_client,
 				AUDIO_CHANNEL_STATUS_6, ~AUDIO_LAYOUT);
 
+	/* Right justified */
+	if (ctx->pdata.audio_right_justify)
+		ret |= anx7625_write_or(ctx, ctx->i2c.tx_p2_client,
+					AUDIO_CONTROL_REGISTER,
+					RIGHT_JUSTIFY_CTRL);
+
 	/* FS */
 	switch (params->sample_rate) {
 	case 32000:
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
index 957d234ec07c..9dd9970d2172 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.h
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
@@ -154,6 +154,8 @@
 #define HPD_TIME               54000
 
 #define AUDIO_CONTROL_REGISTER 0xe6
+#define RIGHT_JUSTIFY_CTRL     BIT(0)
+
 #define TDM_TIMING_MODE 0x08
 
 #define I2C_ADDR_72_DPTX              0x72
@@ -444,6 +446,7 @@ struct anx7625_platform_data {
 	int is_dpi;
 	int mipi_lanes;
 	int audio_en;
+	int audio_right_justify;
 	int dp_lane0_swing_reg_cnt;
 	u8 lane0_reg_data[DP_TX_SWING_REG_CNT];
 	int dp_lane1_swing_reg_cnt;
-- 
2.25.1

Re: [PATCH 1/2] dt-bindings: drm/bridge: anx7625: Add right justify property

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Adding a vendor-specific DT property for audio interface format bypasses standard ASoC DAI format negotiation.
--

--- Patch [1]: [PATCH 1/2] dt-bindings: drm/bridge: anx7625: Add right justify property ---
Please note that due to recitation restrictions, I cannot quote the original
patch code directly. The review below is provided as a free-form summary of
the findings.

commit c7f75f4b785470ba45b421324266273f5142da0b
Author: Xin Ji <xji@analogixsemi.com>

dt-bindings: drm/bridge: anx7625: Add right justify property

This commit adds a new boolean property to the analogix,anx7625 device tree
bindings. The property controls whether the driver enables the audio right
justify function for the data stream.

[Severity: Medium]
Does adding a vendor-specific devicetree property for the audio interface
format bypass the standard ASoC DAI format negotiation?

The standard hdmi-codec framework already supports right justified formats
using the existing DAI format structures, which are normally passed dynamically
to the driver's hw_params callback based on standard sound card properties.

Creating a custom property like analogix,audio-right-justify-enable hardcodes
this configuration statically in the devicetree, which creates a permanent ABI.
Should this driver instead rely on the standard hdmi-codec API to handle the
DAI format negotiation rather than introducing a custom vendor property?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260818020559.961335-1-xji@analogixsemi.com?part=1

Re: [PATCH 2/2] drm: anx7625: add I2S input stream right justified control

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:

New issues:
- [Medium] Bypassing standard ALSA HDMI codec DAI format negotiation.
- [Medium] RIGHT_JUSTIFY_CTRL bit is conditionally set but never cleared.

Pre-existing issues:
- [High] Use-After-Free due to interrupt firing after workqueue destruction.
--

--- Patch [2]: [PATCH 2/2] drm: anx7625: add I2S input stream right justified control ---
commit e78186b015f668998903e293729ea71c5bebfbd8
Author: Xin Ji <xji@analogixsemi.com>

drm: anx7625: add I2S input stream right justified control

The default audio data stream is left justify. When the
property "analogix,audio-right-justify-enable" is detected,
the code enables right justify.

> diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> index fffcd6154c710..d00aa6ea7273d 100644
> --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c

[ ... ]

> @@ -2083,6 +2086,12 @@ static int anx7625_audio_hw_params(struct device *dev, void *data,
>  		ret |= anx7625_write_and(ctx, ctx->i2c.tx_p2_client,
>  				AUDIO_CHANNEL_STATUS_6, ~AUDIO_LAYOUT);
>  
> +	/* Right justified */
> +	if (ctx->pdata.audio_right_justify)

[Severity: Medium]
Instead of bypassing standard ALSA HDMI codec DAI format negotiation,
should this code check the standard fmt->fmt parameter for HDMI_RIGHT_J?

When the driver receives HDMI_RIGHT_J via hdmi_codec_daifmt->fmt at the
start of anx7625_audio_hw_params(), it rejects it with -EINVAL. Relying
on a custom static DT property breaks compatibility with generic ALSA
sound cards that dynamically negotiate the DAI format.

[Severity: Medium]
Is there a missing clear operation for this bit?

If a bootloader or previous kernel execution left the RIGHT_JUSTIFY_CTRL
bit set, and ctx->pdata.audio_right_justify is false, the hardware will
remain in right-justified mode even when standard I2S is expected. Should
there be an anx7625_write_and() to clear the bit on the false path?

> +		ret |= anx7625_write_or(ctx, ctx->i2c.tx_p2_client,
> +					AUDIO_CONTROL_REGISTER,
> +					RIGHT_JUSTIFY_CTRL);
> +
>  	/* FS */
>  	switch (params->sample_rate) {
>  	case 32000:

[ ... ]

[Severity: High]
This isn't a bug introduced by this patch, but does the driver have a
use-after-free vulnerability during unbind?

In anx7625_i2c_remove(), the workqueue is destroyed before the interrupt is
disabled:

	if (platform->pdata.intp_irq)
		destroy_workqueue(platform->workqueue);

Because the driver uses devm_request_threaded_irq(), the interrupt is
only freed after remove() returns. If an interrupt (like Hot Plug Detect)
fires after destroy_workqueue(), the ISR anx7625_intr_hpd_isr() will
attempt to use it:

	queue_work(ctx->workqueue, &ctx->work);

Should disable_irq() be called before destroying the workqueue to prevent
the ISR from dereferencing the freed workqueue pointer?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260818020559.961335-1-xji@analogixsemi.com?part=2