[PATCH v1 1/2] drm/bridge: synopsys: Add audio support for dw-hdmi-qp

Dmitry Baryshkov dmitry.baryshkov at linaro.org
Sat Jan 18 03:31:59 UTC 2025


On Fri, Jan 17, 2025 at 11:46:57AM -0500, Detlev Casanova wrote:
> From: Sugar Zhang <sugar.zhang at rock-chips.com>
> 
> Register the dw-hdmi-qp bridge driver as an HDMI audio codec.
> 
> The register values computation functions (for n) are based on the
> downstream driver, as well as the register writing functions.
> 
> The driver uses the generic HDMI Codec framework in order to implement
> the HDMI audio support.
> 
> Signed-off-by: Sugar Zhang <sugar.zhang at rock-chips.com>
> Signed-off-by: Detlev Casanova <detlev.casanova at collabora.com>
> ---
>  drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 472 +++++++++++++++++++
>  1 file changed, 472 insertions(+)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> index b281cabfe992..55ceeb180bc6 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
> @@ -36,6 +36,66 @@
>  
>  #define SCRAMB_POLL_DELAY_MS	3000
>  
> +/*
> + * Unless otherwise noted, entries in this table are 100% optimization.
> + * Values can be obtained from hdmi_compute_n() but that function is
> + * slow so we pre-compute values we expect to see.
> + *
> + * All 32k and 48k values are expected to be the same (due to the way
> + * the math works) for any rate that's an exact kHz.
> + */
> +static const struct dw_hdmi_audio_tmds_n {
> +	unsigned long tmds;
> +	unsigned int n_32k;
> +	unsigned int n_44k1;
> +	unsigned int n_48k;
> +} common_tmds_n_table[] = {
> +	{ .tmds = 25175000, .n_32k = 4096, .n_44k1 = 12854, .n_48k = 6144, },
> +	{ .tmds = 25200000, .n_32k = 4096, .n_44k1 = 5656, .n_48k = 6144, },
> +	{ .tmds = 27000000, .n_32k = 4096, .n_44k1 = 5488, .n_48k = 6144, },
> +	{ .tmds = 28320000, .n_32k = 4096, .n_44k1 = 5586, .n_48k = 6144, },
> +	{ .tmds = 30240000, .n_32k = 4096, .n_44k1 = 5642, .n_48k = 6144, },
> +	{ .tmds = 31500000, .n_32k = 4096, .n_44k1 = 5600, .n_48k = 6144, },
> +	{ .tmds = 32000000, .n_32k = 4096, .n_44k1 = 5733, .n_48k = 6144, },
> +	{ .tmds = 33750000, .n_32k = 4096, .n_44k1 = 6272, .n_48k = 6144, },
> +	{ .tmds = 36000000, .n_32k = 4096, .n_44k1 = 5684, .n_48k = 6144, },
> +	{ .tmds = 40000000, .n_32k = 4096, .n_44k1 = 5733, .n_48k = 6144, },
> +	{ .tmds = 49500000, .n_32k = 4096, .n_44k1 = 5488, .n_48k = 6144, },
> +	{ .tmds = 50000000, .n_32k = 4096, .n_44k1 = 5292, .n_48k = 6144, },
> +	{ .tmds = 54000000, .n_32k = 4096, .n_44k1 = 5684, .n_48k = 6144, },
> +	{ .tmds = 65000000, .n_32k = 4096, .n_44k1 = 7056, .n_48k = 6144, },
> +	{ .tmds = 68250000, .n_32k = 4096, .n_44k1 = 5376, .n_48k = 6144, },
> +	{ .tmds = 71000000, .n_32k = 4096, .n_44k1 = 7056, .n_48k = 6144, },
> +	{ .tmds = 72000000, .n_32k = 4096, .n_44k1 = 5635, .n_48k = 6144, },
> +	{ .tmds = 73250000, .n_32k = 4096, .n_44k1 = 14112, .n_48k = 6144, },
> +	{ .tmds = 74250000, .n_32k = 4096, .n_44k1 = 6272, .n_48k = 6144, },
> +	{ .tmds = 75000000, .n_32k = 4096, .n_44k1 = 5880, .n_48k = 6144, },
> +	{ .tmds = 78750000, .n_32k = 4096, .n_44k1 = 5600, .n_48k = 6144, },
> +	{ .tmds = 78800000, .n_32k = 4096, .n_44k1 = 5292, .n_48k = 6144, },
> +	{ .tmds = 79500000, .n_32k = 4096, .n_44k1 = 4704, .n_48k = 6144, },
> +	{ .tmds = 83500000, .n_32k = 4096, .n_44k1 = 7056, .n_48k = 6144, },
> +	{ .tmds = 85500000, .n_32k = 4096, .n_44k1 = 5488, .n_48k = 6144, },
> +	{ .tmds = 88750000, .n_32k = 4096, .n_44k1 = 14112, .n_48k = 6144, },
> +	{ .tmds = 97750000, .n_32k = 4096, .n_44k1 = 14112, .n_48k = 6144, },
> +	{ .tmds = 101000000, .n_32k = 4096, .n_44k1 = 7056, .n_48k = 6144, },
> +	{ .tmds = 106500000, .n_32k = 4096, .n_44k1 = 4704, .n_48k = 6144, },
> +	{ .tmds = 108000000, .n_32k = 4096, .n_44k1 = 5684, .n_48k = 6144, },
> +	{ .tmds = 115500000, .n_32k = 4096, .n_44k1 = 5712, .n_48k = 6144, },
> +	{ .tmds = 119000000, .n_32k = 4096, .n_44k1 = 5544, .n_48k = 6144, },
> +	{ .tmds = 135000000, .n_32k = 4096, .n_44k1 = 5488, .n_48k = 6144, },
> +	{ .tmds = 146250000, .n_32k = 4096, .n_44k1 = 6272, .n_48k = 6144, },
> +	{ .tmds = 148500000, .n_32k = 4096, .n_44k1 = 5488, .n_48k = 6144, },
> +	{ .tmds = 154000000, .n_32k = 4096, .n_44k1 = 5544, .n_48k = 6144, },
> +	{ .tmds = 162000000, .n_32k = 4096, .n_44k1 = 5684, .n_48k = 6144, },
> +
> +	/* For 297 MHz+ HDMI spec have some other rule for setting N */
> +	{ .tmds = 297000000, .n_32k = 3073, .n_44k1 = 4704, .n_48k = 5120, },
> +	{ .tmds = 594000000, .n_32k = 3073, .n_44k1 = 9408, .n_48k = 10240, },
> +
> +	/* End of table */
> +	{ .tmds = 0,         .n_32k = 0,    .n_44k1 = 0,    .n_48k = 0, },
> +};
> +
>  struct dw_hdmi_qp_i2c {
>  	struct i2c_adapter	adap;
>  
> @@ -59,6 +119,8 @@ struct dw_hdmi_qp {
>  		void *data;
>  	} phy;
>  
> +	struct mutex audio_mutex;

There should be a comment, what is being protected by this mutex.

> +
>  	struct regmap *regm;
>  };
>  

[...]

> +static int dw_hdmi_qp_init_audio_infoframe(struct dw_hdmi_qp *hdmi)
> +{
> +	struct hdmi_audio_infoframe frame;
> +	u8 infoframe_buf[HDMI_INFOFRAME_SIZE(AUDIO)];
> +	int ret = 0;
> +
> +	hdmi_audio_infoframe_init(&frame);
> +
> +	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 = 2;
> +
> +	ret = hdmi_audio_infoframe_pack(&frame, infoframe_buf,
> +					sizeof(infoframe_buf));
> +	if (ret < 0) {
> +		dev_err(hdmi->dev, "%s: Failed to pack audio infoframe: %d\n",
> +			__func__, ret);
> +		return ret;
> +	}
> +
> +	regmap_bulk_write(hdmi->regm, PKT_AUDI_CONTENTS1, &infoframe_buf[3], 2);
> +	dw_hdmi_qp_mod(hdmi,
> +		  PKTSCHED_ACR_TX_EN | PKTSCHED_AUDI_TX_EN,
> +		  PKTSCHED_ACR_TX_EN | PKTSCHED_AUDI_TX_EN,
> +		  PKTSCHED_PKT_EN);
> +
> +	return 0;
> +}
> +
> +static void dw_hdmi_qp_set_audio_infoframe(struct dw_hdmi_qp *hdmi,
> +				    struct hdmi_codec_params *hparms)
> +{
> +	u8 infoframe_buf[HDMI_INFOFRAME_SIZE(AUDIO)];
> +	int ret = 0;
> +
> +	ret = hdmi_audio_infoframe_pack(&hparms->cea, infoframe_buf,
> +					sizeof(infoframe_buf));

Please use existing functions,
drm_atomic_helper_connector_hdmi_update_audio_infoframe() and
drm_atomic_helper_connector_hdmi_clear_audio_infoframe() to manage the
infoframe. The drm_atomic_helper_connector_hdmi_update_infoframes()
function will take care of updating the audio infoframe.

> +	if (!ret) {
> +		dev_err(hdmi->dev, "%s: Failed to pack audio infoframe: %d\n",
> +			__func__, ret);
> +		return;
> +	}
> +
> +	/*
> +	 * AUDI_CONTENTS0: { RSV, HB2, HB1, RSV }
> +	 * AUDI_CONTENTS1: { PB3, PB2, PB1, PB0 }
> +	 * AUDI_CONTENTS2: { PB7, PB6, PB5, PB4 }
> +	 *
> +	 * PB0: CheckSum
> +	 * PB1: | CT3    | CT2  | CT1  | CT0  | F13  | CC2 | CC1 | CC0 |
> +	 * PB2: | F27    | F26  | F25  | SF2  | SF1  | SF0 | SS1 | SS0 |
> +	 * PB3: | F37    | F36  | F35  | F34  | F33  | F32 | F31 | F30 |
> +	 * PB4: | CA7    | CA6  | CA5  | CA4  | CA3  | CA2 | CA1 | CA0 |
> +	 * PB5: | DM_INH | LSV3 | LSV2 | LSV1 | LSV0 | F52 | F51 | F50 |
> +	 * PB6~PB10: Reserved
> +	 *
> +	 * AUDI_CONTENTS0 default value defined by HDMI specification,
> +	 * and shall only be changed for debug purposes.
> +	 * So, we only configure payload byte from PB0~PB7(2 word total).
> +	 */
> +	regmap_bulk_write(hdmi->regm, PKT_AUDI_CONTENTS1, &infoframe_buf[3], 2);

This should go to your dw_hdmi_qp_bridge_write_infoframe().

> +
> +	/* Enable ACR, AUDI, AMD */
> +	dw_hdmi_qp_mod(hdmi,
> +		  PKTSCHED_ACR_TX_EN | PKTSCHED_AUDI_TX_EN | PKTSCHED_AMD_TX_EN,
> +		  PKTSCHED_ACR_TX_EN | PKTSCHED_AUDI_TX_EN | PKTSCHED_AMD_TX_EN,
> +		  PKTSCHED_PKT_EN);
> +
> +	/* Enable AUDS */
> +	dw_hdmi_qp_mod(hdmi, PKTSCHED_AUDS_TX_EN, PKTSCHED_AUDS_TX_EN, PKTSCHED_PKT_EN);
> +	mutex_unlock(&hdmi->audio_mutex);
> +}
> +

-- 
With best wishes
Dmitry


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