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 --- drivers/gpu/drm/drm_edid.c | 57 ++++++++++++++++++++++++++++++++++++++ include/drm/drm_edid.h | 18 ++++++++++-- 2 files changed, 73 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 81d5f2524246..2389d34ce10e 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -4666,6 +4666,63 @@ 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(struct cea_sad *sad) +{ + switch (sad->freq) { + case CEA_SAD_FREQ_32KHZ: + return 32000; + case CEA_SAD_FREQ_44KHZ: + return 44100; + case CEA_SAD_FREQ_48KHZ: + return 48000; + case CEA_SAD_FREQ_88KHZ: + return 88200; + case CEA_SAD_FREQ_96KHZ: + return 96000; + case CEA_SAD_FREQ_176KHZ: + return 176400; + case CEA_SAD_FREQ_192KHZ: + return 192000; + default: + return -EINVAL; + } +} +EXPORT_SYMBOL(drm_cea_sad_get_sample_rate); + +/** + * 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(struct cea_sad *sad) +{ + switch (sad->byte2) { + case CEA_SAD_UNCOMPRESSED_WORD_16BIT: + return 16; + case CEA_SAD_UNCOMPRESSED_WORD_20BIT: + return 20; + case 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 759328a5eeb2..bed091a749ef 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -361,12 +361,24 @@ struct edid {
/* Short Audio Descriptor */ struct cea_sad { - u8 format; + u8 format; /* See HDMI_AUDIO_CODING_TYPE_* */ u8 channels; /* max number of channels - 1 */ - u8 freq; + u8 freq; /* See CEA_SAD_FREQ_* */ u8 byte2; /* meaning depends on format */ };
+#define CEA_SAD_FREQ_32KHZ BIT(0) +#define CEA_SAD_FREQ_44KHZ BIT(1) +#define CEA_SAD_FREQ_48KHZ BIT(2) +#define CEA_SAD_FREQ_88KHZ BIT(3) +#define CEA_SAD_FREQ_96KHZ BIT(4) +#define CEA_SAD_FREQ_176KHZ BIT(5) +#define CEA_SAD_FREQ_192KHZ BIT(6) + +#define CEA_SAD_UNCOMPRESSED_WORD_16BIT BIT(0) +#define CEA_SAD_UNCOMPRESSED_WORD_20BIT BIT(1) +#define CEA_SAD_UNCOMPRESSED_WORD_24BIT BIT(2) + struct drm_encoder; struct drm_connector; struct drm_connector_state; @@ -374,6 +386,8 @@ 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(struct cea_sad *sad); +int drm_cea_sad_get_uncompressed_word_length(struct cea_sad *sad); int drm_av_sync_delay(struct drm_connector *connector, const struct drm_display_mode *mode);