Quoting AngeloGioacchino Del Regno (2022-02-21 15:30:07)
> Il 18/02/22 15:54, Guillaume Ranquet ha scritto:
> > From: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
> >
> > Similar to HDMI, DP uses audio infoframes as well which are structured
> > very similar to the HDMI ones.
> >
> > This patch adds a helper function to pack the HDMI audio infoframe for
> > DP, called hdmi_audio_infoframe_pack_for_dp().
> > hdmi_audio_infoframe_pack_only() is split into two parts. One of them
> > packs the payload only and can be used for HDMI and DP.
> >
> > Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
> > Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx>
> > ---
> > drivers/video/hdmi.c | 83 ++++++++++++++++++++++++++++---------
> > include/drm/drm_dp_helper.h | 2 +
> > include/linux/hdmi.h | 7 +++-
> > 3 files changed, 72 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
> > index 947be761dfa40..63e74d9fd210e 100644
> > --- a/drivers/video/hdmi.c
> > +++ b/drivers/video/hdmi.c
> > @@ -21,6 +21,7 @@
> > * DEALINGS IN THE SOFTWARE.
> > */
> >
> > +#include <drm/drm_dp_helper.h>
> > #include <linux/bitops.h>
> > #include <linux/bug.h>
> > #include <linux/errno.h>
> > @@ -381,12 +382,34 @@ static int hdmi_audio_infoframe_check_only(const struct hdmi_audio_infoframe *fr
> > *
> > * Returns 0 on success or a negative error code on failure.
> > */
> > -int hdmi_audio_infoframe_check(struct hdmi_audio_infoframe *frame)
> > +int hdmi_audio_infoframe_check(const struct hdmi_audio_infoframe *frame)
> > {
> > return hdmi_audio_infoframe_check_only(frame);
> > }
> > EXPORT_SYMBOL(hdmi_audio_infoframe_check);
> >
> > +static void
> > +hdmi_audio_infoframe_pack_payload(const struct hdmi_audio_infoframe *frame,
> > + u8 *buffer)
> > +{
> > + u8 channels;
> > +
> > + if (frame->channels >= 2)
> > + channels = frame->channels - 1;
> > + else
> > + channels = 0;
> > +
> > + buffer[0] = ((frame->coding_type & 0xf) << 4) | (channels & 0x7);
> > + buffer[1] = ((frame->sample_frequency & 0x7) << 2) |
> > + (frame->sample_size & 0x3);
> > + buffer[2] = frame->coding_type_ext & 0x1f;
> > + buffer[3] = frame->channel_allocation;
> > + buffer[4] = (frame->level_shift_value & 0xf) << 3;
> > +
> > + if (frame->downmix_inhibit)
> > + buffer[4] |= BIT(7);
> > +}
> > +
> > /**
> > * hdmi_audio_infoframe_pack_only() - write HDMI audio infoframe to binary buffer
> > * @frame: HDMI audio infoframe
> > @@ -404,7 +427,6 @@ EXPORT_SYMBOL(hdmi_audio_infoframe_check);
> > ssize_t hdmi_audio_infoframe_pack_only(const struct hdmi_audio_infoframe *frame,
> > void *buffer, size_t size)
> > {
> > - unsigned char channels;
> > u8 *ptr = buffer;
> > size_t length;
> > int ret;
> > @@ -420,28 +442,13 @@ ssize_t hdmi_audio_infoframe_pack_only(const struct hdmi_audio_infoframe *frame,
> >
> > memset(buffer, 0, size);
> >
> > - if (frame->channels >= 2)
> > - channels = frame->channels - 1;
> > - else
> > - channels = 0;
> > -
> > ptr[0] = frame->type;
> > ptr[1] = frame->version;
> > ptr[2] = frame->length;
> > ptr[3] = 0; /* checksum */
> >
> > - /* start infoframe payload */
> > - ptr += HDMI_INFOFRAME_HEADER_SIZE;
> > -
> > - ptr[0] = ((frame->coding_type & 0xf) << 4) | (channels & 0x7);
> > - ptr[1] = ((frame->sample_frequency & 0x7) << 2) |
> > - (frame->sample_size & 0x3);
> > - ptr[2] = frame->coding_type_ext & 0x1f;
> > - ptr[3] = frame->channel_allocation;
> > - ptr[4] = (frame->level_shift_value & 0xf) << 3;
> > -
> > - if (frame->downmix_inhibit)
> > - ptr[4] |= BIT(7);
> > + hdmi_audio_infoframe_pack_payload(frame,
> > + ptr + HDMI_INFOFRAME_HEADER_SIZE);
> >
> > hdmi_infoframe_set_checksum(buffer, length);
> >
> > @@ -479,6 +486,44 @@ ssize_t hdmi_audio_infoframe_pack(struct hdmi_audio_infoframe *frame,
> > }
> > EXPORT_SYMBOL(hdmi_audio_infoframe_pack);
> >
> > +/**
> > + * hdmi_audio_infoframe_pack_for_dp - Pack a HDMI Audio infoframe for
> > + * displayport
>
> This fits in one line (82 cols is ok)... but, anyway, please capitalize D and P
> in the DisplayPort word.
>
Yeah, I ran clang-format and didn't want to contradict the tool :)
I'll fix that for v9
> > + *
> > + * @frame HDMI Audio infoframe
>
> You're almost there! You missed a colon after each description.
> Also, I personally like seeing indented descriptions as, in my opinion, this
> enhances human readability, as it's a bit more pleasing to the eye... but
> it's not a requirement, so you be the judge.
>
> * @frame: HDMI Audio infoframe
> * @sdp: Secondary data packet......
> * @dp_version: DisplayPort version......
>
> Please fix.
>
I completly forgot to generate and check the kerneldoc.
Sorry.
> > + * @sdp secondary data packet for display port. This is filled with the
> > + * appropriate data
> > + * @dp_version Display Port version to be encoded in the header
> > + *
> > + * Packs a HDMI Audio Infoframe to be sent over Display Port. This function
> > + * fills the secondary data packet to be used for Display Port.
> > + *
> > + * Return: Number of total written bytes or a negative errno on failure.
> > + */
> > +ssize_t
> > +hdmi_audio_infoframe_pack_for_dp(const struct hdmi_audio_infoframe *frame,
> > + struct dp_sdp *sdp, u8 dp_version)
> > +{
> > + int ret;
> > +
> > + ret = hdmi_audio_infoframe_check(frame);
> > + if (ret)
> > + return ret;
> > +
> > + memset(sdp->db, 0, sizeof(sdp->db));
> > +
> > + // Secondary-data packet header
>
> Please, C-style comments:
>
> /* Secondary-data packet header */
>
> Thanks,
> Angelo
I think this is not the only case of C++ comment that slipped past me...
I'll revise the whole series.
Thx,
Guillaume.
