Messages in this thread Patch in this message |  | | Date | Wed, 25 May 2022 14:26:57 +0200 | Subject | Re: [PATCH v10 04/21] drm/edid: Add cea_sad helpers for freq/length | From | AngeloGioacchino Del Regno <> |
| |
Il 23/05/22 12:47, Guillaume Ranquet ha scritto: > This patch adds two helper functions that extract the frequency and word > length from a struct cea_sad. > > For these helper functions new defines are added that help translate the > 'freq' and 'byte2' fields into real numbers. > > Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com> > Signed-off-by: Guillaume Ranquet <granquet@baylibre.com> > --- > drivers/gpu/drm/drm_edid.c | 74 ++++++++++++++++++++++++++++++++++++++ > include/drm/drm_edid.h | 14 ++++++++ > 2 files changed, 88 insertions(+) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 561f53831e29..61ef1b1c972c 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -4758,6 +4758,80 @@ int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb) > } > EXPORT_SYMBOL(drm_edid_to_speaker_allocation); > > +/** > + * drm_cea_sad_get_sample_rate - Extract the sample rate from cea_sad > + * @sad: Pointer to the cea_sad struct > + * > + * Extracts the cea_sad frequency field and returns the sample rate in Hz. > + * > + * Return: Sample rate in Hz or a negative errno if parsing failed. > + */ > +int drm_cea_sad_get_sample_rate(const struct cea_sad *sad) > +{ > + switch (sad->freq) { > + case DRM_CEA_SAD_FREQ_32KHZ: > + return 32000; > + case DRM_CEA_SAD_FREQ_44KHZ: > + return 44100; > + case DRM_CEA_SAD_FREQ_48KHZ: > + return 48000; > + case DRM_CEA_SAD_FREQ_88KHZ: > + return 88200; > + case DRM_CEA_SAD_FREQ_96KHZ: > + return 96000; > + case DRM_CEA_SAD_FREQ_176KHZ: > + return 176400; > + case DRM_CEA_SAD_FREQ_192KHZ: > + return 192000; > + default: > + return -EINVAL; > + } > +} > +EXPORT_SYMBOL(drm_cea_sad_get_sample_rate); > + > +static bool drm_cea_sad_is_uncompressed(const struct cea_sad *sad) > +{ > + switch (sad->format) { > + case HDMI_AUDIO_CODING_TYPE_STREAM:
As far as I know, bit 0 is reserved, so HDMI_AUDIO_CODING_TYPE_STREAM should never occur here?
> + case HDMI_AUDIO_CODING_TYPE_PCM: > + return true; > + default: > + return false; > + } > +} > +
Also, I think that implementing a drm_cea_sad_get_compressed_max_bitrate() function should be pretty straightforward... the spec says that this is 8 bits, byte 3 (your byte2) contains the max bitrate divided by 8kHz, so to extract it, you read byte2 and multiply it by 8000Hz.
/** * drm_cea_sad_get_compressed_max_bitrate - Extract maximum bitrate * @sad: Pointer to the cea_sad structure * * Extracts the cea_sad byte2 field and returns the maximum bit rate * of a compressed audio stream. * * Note: This function may only be called for compressed audio. * * Return: Maximum bitrate of compressed audio stream in bit/s or * negative number for error */ int drm_cea_sad_get_compressed_max_bitrate(const struct cea_sad *sad) { if (drm_cea_sad_is_uncompressed(sad)) { DRM_ERROR("Not supported: tried to get max bitrate for uncompressed format: %u\n", sad->format); return -EINVAL; }
return sad->byte2 * 8000; }
> +/** > + * drm_cea_sad_get_uncompressed_word_length - Extract word length > + * @sad: Pointer to the cea_sad struct > + * > + * Extracts the cea_sad byte2 field and returns the word length for an > + * uncompressed stream. > + * > + * Note: This function may only be called for uncompressed audio. > + * > + * Return: Word length in bits or a negative errno if parsing failed. > + */ > +int drm_cea_sad_get_uncompressed_word_length(const struct cea_sad *sad) > +{ > + if (!drm_cea_sad_is_uncompressed(sad)) { > + DRM_WARN("Unable to get the uncompressed word length for a compressed format: %u\n", > + sad->format); > + return -EINVAL; > + } > + > + switch (sad->byte2) { > + case DRM_CEA_SAD_UNCOMPRESSED_WORD_16BIT: > + return 16; > + case DRM_CEA_SAD_UNCOMPRESSED_WORD_20BIT: > + return 20; > + case DRM_CEA_SAD_UNCOMPRESSED_WORD_24BIT: > + return 24; > + default: > + return -EINVAL; > + } > +} > +EXPORT_SYMBOL(drm_cea_sad_get_uncompressed_word_length); > + > /** > * drm_av_sync_delay - compute the HDMI/DP sink audio-video sync delay > * @connector: connector associated with the HDMI/DP sink > diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h > index 37c420423625..7a939cb95b38 100644 > --- a/include/drm/drm_edid.h > +++ b/include/drm/drm_edid.h > @@ -373,6 +373,18 @@ struct cea_sad { > u8 byte2; > }; > > +#define DRM_CEA_SAD_FREQ_32KHZ BIT(0) > +#define DRM_CEA_SAD_FREQ_44KHZ BIT(1) > +#define DRM_CEA_SAD_FREQ_48KHZ BIT(2) > +#define DRM_CEA_SAD_FREQ_88KHZ BIT(3) > +#define DRM_CEA_SAD_FREQ_96KHZ BIT(4) > +#define DRM_CEA_SAD_FREQ_176KHZ BIT(5) > +#define DRM_CEA_SAD_FREQ_192KHZ BIT(6) > + > +#define DRM_CEA_SAD_UNCOMPRESSED_WORD_16BIT BIT(0) > +#define DRM_CEA_SAD_UNCOMPRESSED_WORD_20BIT BIT(1) > +#define DRM_CEA_SAD_UNCOMPRESSED_WORD_24BIT BIT(2) > + > struct drm_encoder; > struct drm_connector; > struct drm_connector_state; > @@ -380,6 +392,8 @@ struct drm_display_mode; > > int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads); > int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb); > +int drm_cea_sad_get_sample_rate(const struct cea_sad *sad); > +int drm_cea_sad_get_uncompressed_word_length(const struct cea_sad *sad); > int drm_av_sync_delay(struct drm_connector *connector, > const struct drm_display_mode *mode); >
|  |