| Message ID | 1461226077-25273-2-git-send-email-arnaud.pouliquen@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Arnaud, Am Donnerstag, den 21.04.2016, 10:07 +0200 schrieb Arnaud Pouliquen: > Add helper function to compute HDMI CTS and N parameters > Implementation is based on HDMI 1.4b specification. > > Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com> > Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> > Acked-by: Vincent ABRIOU <vincent.abriou@st.com> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> > --- > drivers/video/hdmi.c | 202 +++++++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/hdmi.h | 22 ++++++ > 2 files changed, 224 insertions(+) > > diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c > index 1626892..6381ce0 100644 > --- a/drivers/video/hdmi.c > +++ b/drivers/video/hdmi.c > @@ -1242,3 +1242,205 @@ int hdmi_infoframe_unpack(union hdmi_infoframe *frame, void *buffer) > return ret; > } > EXPORT_SYMBOL(hdmi_infoframe_unpack); > + > +/** > + * audio clock regeneration (acr) parameters > + * N and CTS computation are based on HDMI specification 1.4b > + */ > +enum audio_rate { > + HDMI_AUDIO_N_CTS_32KHZ, > + HDMI_AUDIO_N_CTS_44_1KHZ, > + HDMI_AUDIO_N_CTS_48KHZ, > +}; > + > +struct hdmi_audio_acr { > + unsigned int tmds_clk; > + struct hdmi_audio_n_cts n_cts; > +}; > + > +static const struct hdmi_audio_acr hdmi_audio_standard_acr[3][12] = { > + { /*32 kHz*/ If you used [HDMI_AUDIO_N_CTS_32KHZ] = { instead, that would mirror how the array is indexed via audio_freq_id in hdmi_audio_get_coherent_n_cts below. > + { 25174825, { 4576, 28125, 0 } }, /* 25,20/1.001 MHz */ ^ s/,/./ > + { 25200000, { 4096, 25200, 0 } }, /* 25.20 MHz */ > + { 27000000, { 4096, 27000, 0 } }, /* 27.00 MHz */ > + { 27027000, { 4096, 27027, 0 } }, /* 27.00*1.001 MHz */ > + { 54000000, { 4096, 54000, 0 } }, /* 54.00 MHz */ > + { 54054000, { 4096, 54054, 0 } }, /* 54.00*1.001 MHz */ > + { 74175824, { 11648, 210937, 50 } }, /* 74.25/1.001 MHz */ > + { 74250000, { 4096, 74250, 0 } }, /* 74.25 MHz */ > + { 148351648, { 11648, 421875, 0 } }, /* 148.50/1.001 MHz */ > + { 148500000, { 4096, 148500, 0 } }, /* 148.50 MHz */ > + { 296703296, { 5824, 421875, 0 } }, /* 297/1.001 MHz */ ^ Maybe add a comment above that tmds_clk is rounded down? > + { 297000000, { 3072, 222750, 0 } }, /* 297 MHz */ > + }, > + { /*44.1 kHz, 88.2 kHz 176.4 kHz*/ > + { 25174825, { 7007, 31250, 0 } }, /* 25,20/1.001 MHz */ > + { 25200000, { 6272, 28000, 0 } }, /* 25.20 MHz */ > + { 27000000, { 6272, 30000, 0 } }, /* 27.00 MHz */ > + { 27027000, { 6272, 30030, 0 } }, /* 27.00*1.001 MHz */ > + { 54000000, { 6272, 60000, 0 } }, /* 54.00 MHz */ > + { 54054000, { 6272, 60060, 0 } }, /* 54.00*1.001 MHz */ > + { 74175824, { 17836, 234375, 0 } }, /* 74.25/1.001 MHz */ > + { 74250000, { 6272, 82500, 0 } }, /* 74.25 MHz */ > + { 148351648, { 8918, 234375, 0 } }, /* 148.50/1.001 MHz */ > + { 148500000, { 6272, 165000, 0 } }, /* 148.50 MHz */ > + { 296703296, { 4459, 234375, 0 } }, /* 297/1.001 MHz */ > + { 297000000, { 4704, 247500, 0 } }, /* 297 MHz */ > + }, > + { /*48 kHz, 96 kHz 192 kHz*/ > + { 25174825, { 6864, 28125, 0 } }, /* 25,20/1.001 MHz */ > + { 25200000, { 6144, 25200, 0 } }, /* 25.20 MHz */ > + { 27000000, { 6144, 27000, 0 } }, /* 27.00 MHz */ > + { 27027000, { 6144, 27027, 0 } }, /* 27.00*1.001 MHz */ > + { 54000000, { 6144, 54000, 0 } }, /* 54.00 MHz */ > + { 54054000, { 6144, 54054, 0 } }, /* 54.00*1.001 MHz */ > + { 74175824, { 11648, 140625, 0 } }, /* 74.25/1.001 MHz */ > + { 74250000, { 6144, 74250, 0 } }, /* 74.25 MHz */ > + { 148351648, { 5824, 140625, 0 } }, /* 148.50/1.001 MHz */ > + { 148500000, { 6144, 148500, 0 } }, /* 148.50 MHz */ > + { 296703296, { 5824, 281250, 0 } }, /* 297/1.001 MHz */ > + { 297000000, { 5120, 247500, 0 } }, /* 297 MHz */ > + } > +}; > + > +/** > + * hdmi_audio_get_coherent_n_cts() - compute N and CTS parameters for coherent > + * clocks. Coherent clock means that audio and TMDS clocks have the same > + * source (no drifts between clocks). > + * > + * @audio_fs: audio frame clock frequency in Hz > + * @tmds_clk: HDMI TMDS clock frequency in Hz > + * @n_cts: N and CTS parameter returned to user > + * > + * Values computed are based on table described in HDMI specification 1.4b > + * > + * Returns 0 on success or a negative error code on failure. > + */ > +int hdmi_audio_get_coherent_n_cts(unsigned int audio_fs, > + unsigned int tmds_clk, > + struct hdmi_audio_n_cts *n_cts) > +{ > + int audio_freq_id, i; > + int rate_coeff = 1; > + u64 val, min; > + const struct hdmi_audio_acr *acr_table; > + const struct hdmi_audio_n_cts *predef_n_cts = NULL; > + > + switch (audio_fs) { > + case 32000: > + audio_freq_id = HDMI_AUDIO_N_CTS_32KHZ; > + n_cts->n = 4096; > + break; > + case 44100: > + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; > + n_cts->n = 6272; > + break; > + case 48000: > + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; > + n_cts->n = 6144; > + break; > + case 88200: > + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; > + rate_coeff = 2; > + n_cts->n = 6272 * 2; > + break; > + case 96000: > + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; > + rate_coeff = 2; > + n_cts->n = 6144 * 2; > + break; > + case 176400: > + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; > + rate_coeff = 4; > + n_cts->n = 6272 * 4; > + break; > + case 192000: > + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; > + rate_coeff = 4; > + n_cts->n = 6144 * 4; > + break; > + default: > + return -EINVAL; > + } > + > + acr_table = hdmi_audio_standard_acr[audio_freq_id]; > + for (i = 0; i < ARRAY_SIZE(hdmi_audio_standard_acr[0]); i++) { > + if (tmds_clk == acr_table[i].tmds_clk) { > + predef_n_cts = &acr_table[i].n_cts; > + n_cts->n = predef_n_cts->n * rate_coeff; > + n_cts->cts = predef_n_cts->cts; > + n_cts->cts_1_ratio = predef_n_cts->cts_1_ratio; > + return 0; > + } > + } > + > + /* > + * predefined frequency not found. Compute CTS using formula: ^ > + * CTS = (Ftdms_clk * N) / (128* audio_fs) ^ ^ > + */ ^ Missing spaces. > + val = (u64)tmds_clk * n_cts->n; > + n_cts->cts = div64_u64(val, 128UL * audio_fs); > + > + n_cts->cts_1_ratio = 0; > + min = (u64)n_cts->cts * 128UL * audio_fs; > + if (min < (val)) { ^ ^ These parentheses are not needed. > + /* > + * non-accurate value for CTS ^ > + * compute ratio, needed by user to alternate in ACR ^ > + * between CTS and CTS + 1 value. ^ > + */ ^ Missing spaces. > + n_cts->cts_1_ratio = 100 - ((u32)(val - min)) * 100 / > + (128 * audio_fs); I don't understand the purpose of the (100-x) above (and how cts_1_ratio is supposed to be used). When for example val == (min + 0.3 * 128 * audio_fs) then cts_1_ratio = 70. To achieve an average CTS of (val), shouldn't (min) be used 70% of the time and (min+1) be used 30% of the time? I would have expected (cts_1_ratio == 30) in that case. > + } > + > + return 0; > +} > +EXPORT_SYMBOL(hdmi_audio_get_coherent_n_cts); > + > +/** > + * hdmi_audio_get_non_coherent_n() - get N parameter for non-coherent > + * clocks. None-coherent clocks means that audio and TMDS clocks have not the > + * same source (drifts between clocks). In this case assumption is that CTS is > + * automatically calculated by hardware. > + * > + * @audio_fs: audio frame clock frequency in Hz > + * > + * Values computed are based on table described in HDMI specification 1.4b > + * > + * Returns n value. > + */ > +int hdmi_audio_get_non_coherent_n(unsigned int audio_fs) > +{ > + unsigned int n; > + > + switch (audio_fs) { > + case 32000: > + n = 4096; > + break; > + case 44100: > + n = 6272; > + break; > + case 48000: > + n = 6144; > + break; > + case 88200: > + n = 6272 * 2; > + break; > + case 96000: > + n = 6144 * 2; > + break; > + case 176400: > + n = 6272 * 4; > + break; > + case 192000: > + n = 6144 * 4; > + break; > + default: > + /* Not pre-defined, recommended value: 128 * fs / 1000 */ > + n = (audio_fs * 128) / 1000; > + } > + > + return n; > +} > +EXPORT_SYMBOL(hdmi_audio_get_non_coherent_n); > + > diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h > index e974420..28b6794 100644 > --- a/include/linux/hdmi.h > +++ b/include/linux/hdmi.h > @@ -333,4 +333,26 @@ int hdmi_infoframe_unpack(union hdmi_infoframe *frame, void *buffer); > void hdmi_infoframe_log(const char *level, struct device *dev, > union hdmi_infoframe *frame); > > +/** > + * struct hdmi_audio_n_cts - n and cts parameter for ACR packets > + * @n: N parameter > + * @cts: CTS parameter > + * @cts_1_ratio: ratio from 0 to 99 to alternate "CTS" and "CTS + 1" values > + * ratio = 0: CTS parameter is accurate, no need to alternate with "CTS + 1" > + * value > + * ratio = x: Need to alternate with ACR "CTS + 1" value x% of the time to > + * generate accurate audio clock Does this mean that at cts_1_ratio == 30, CTS should be used 70% of the time, and CTS+1 should be used 30% of the time, or the other way around? > + */ > +struct hdmi_audio_n_cts { > + unsigned int n; > + unsigned int cts; > + unsigned int cts_1_ratio; > +}; > + > +int hdmi_audio_get_coherent_n_cts(unsigned int audio_fs, > + unsigned int tmds_clk, > + struct hdmi_audio_n_cts *n_cts); > + > +int hdmi_audio_get_non_coherent_n(unsigned int audio_fs); > + > #endif /* _DRM_HDMI_H */ regards Philipp
On 04/21/2016 02:39 PM, Philipp Zabel wrote: > Hi Arnaud, > > Am Donnerstag, den 21.04.2016, 10:07 +0200 schrieb Arnaud Pouliquen: >> Add helper function to compute HDMI CTS and N parameters >> Implementation is based on HDMI 1.4b specification. >> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com> >> Acked-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> >> Acked-by: Vincent ABRIOU <vincent.abriou@st.com> > > Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> > >> --- >> drivers/video/hdmi.c | 202 +++++++++++++++++++++++++++++++++++++++++++++++++++ >> include/linux/hdmi.h | 22 ++++++ >> 2 files changed, 224 insertions(+) >> >> diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c >> index 1626892..6381ce0 100644 >> --- a/drivers/video/hdmi.c >> +++ b/drivers/video/hdmi.c >> @@ -1242,3 +1242,205 @@ int hdmi_infoframe_unpack(union hdmi_infoframe *frame, void *buffer) >> return ret; >> } >> EXPORT_SYMBOL(hdmi_infoframe_unpack); >> + >> +/** >> + * audio clock regeneration (acr) parameters >> + * N and CTS computation are based on HDMI specification 1.4b >> + */ >> +enum audio_rate { >> + HDMI_AUDIO_N_CTS_32KHZ, >> + HDMI_AUDIO_N_CTS_44_1KHZ, >> + HDMI_AUDIO_N_CTS_48KHZ, >> +}; >> + >> +struct hdmi_audio_acr { >> + unsigned int tmds_clk; >> + struct hdmi_audio_n_cts n_cts; >> +}; >> + >> +static const struct hdmi_audio_acr hdmi_audio_standard_acr[3][12] = { >> + { /*32 kHz*/ > > If you used > > [HDMI_AUDIO_N_CTS_32KHZ] = { > > instead, that would mirror how the array is indexed via audio_freq_id in > hdmi_audio_get_coherent_n_cts below. > >> + { 25174825, { 4576, 28125, 0 } }, /* 25,20/1.001 MHz */ > ^ > s/,/./ > >> + { 25200000, { 4096, 25200, 0 } }, /* 25.20 MHz */ >> + { 27000000, { 4096, 27000, 0 } }, /* 27.00 MHz */ >> + { 27027000, { 4096, 27027, 0 } }, /* 27.00*1.001 MHz */ >> + { 54000000, { 4096, 54000, 0 } }, /* 54.00 MHz */ >> + { 54054000, { 4096, 54054, 0 } }, /* 54.00*1.001 MHz */ >> + { 74175824, { 11648, 210937, 50 } }, /* 74.25/1.001 MHz */ >> + { 74250000, { 4096, 74250, 0 } }, /* 74.25 MHz */ >> + { 148351648, { 11648, 421875, 0 } }, /* 148.50/1.001 MHz */ >> + { 148500000, { 4096, 148500, 0 } }, /* 148.50 MHz */ >> + { 296703296, { 5824, 421875, 0 } }, /* 297/1.001 MHz */ > ^ > Maybe add a comment above that tmds_clk is rounded down? My apologize, I have forgotten to add 296703297 value to take into account truncated and rounded values as discussed in V2: { 296703296, { 5824, 421875, 0 } }, /* 297/1.001 MHz (truncated) */ { 296703297, { 5824, 421875, 0 } }, /* 297/1.001 MHz (rounded) */ > >> + { 297000000, { 3072, 222750, 0 } }, /* 297 MHz */ >> + }, >> + { /*44.1 kHz, 88.2 kHz 176.4 kHz*/ >> + { 25174825, { 7007, 31250, 0 } }, /* 25,20/1.001 MHz */ >> + { 25200000, { 6272, 28000, 0 } }, /* 25.20 MHz */ >> + { 27000000, { 6272, 30000, 0 } }, /* 27.00 MHz */ >> + { 27027000, { 6272, 30030, 0 } }, /* 27.00*1.001 MHz */ >> + { 54000000, { 6272, 60000, 0 } }, /* 54.00 MHz */ >> + { 54054000, { 6272, 60060, 0 } }, /* 54.00*1.001 MHz */ >> + { 74175824, { 17836, 234375, 0 } }, /* 74.25/1.001 MHz */ >> + { 74250000, { 6272, 82500, 0 } }, /* 74.25 MHz */ >> + { 148351648, { 8918, 234375, 0 } }, /* 148.50/1.001 MHz */ >> + { 148500000, { 6272, 165000, 0 } }, /* 148.50 MHz */ >> + { 296703296, { 4459, 234375, 0 } }, /* 297/1.001 MHz */ >> + { 297000000, { 4704, 247500, 0 } }, /* 297 MHz */ >> + }, >> + { /*48 kHz, 96 kHz 192 kHz*/ >> + { 25174825, { 6864, 28125, 0 } }, /* 25,20/1.001 MHz */ >> + { 25200000, { 6144, 25200, 0 } }, /* 25.20 MHz */ >> + { 27000000, { 6144, 27000, 0 } }, /* 27.00 MHz */ >> + { 27027000, { 6144, 27027, 0 } }, /* 27.00*1.001 MHz */ >> + { 54000000, { 6144, 54000, 0 } }, /* 54.00 MHz */ >> + { 54054000, { 6144, 54054, 0 } }, /* 54.00*1.001 MHz */ >> + { 74175824, { 11648, 140625, 0 } }, /* 74.25/1.001 MHz */ >> + { 74250000, { 6144, 74250, 0 } }, /* 74.25 MHz */ >> + { 148351648, { 5824, 140625, 0 } }, /* 148.50/1.001 MHz */ >> + { 148500000, { 6144, 148500, 0 } }, /* 148.50 MHz */ >> + { 296703296, { 5824, 281250, 0 } }, /* 297/1.001 MHz */ >> + { 297000000, { 5120, 247500, 0 } }, /* 297 MHz */ >> + } >> +}; >> + >> +/** >> + * hdmi_audio_get_coherent_n_cts() - compute N and CTS parameters for coherent >> + * clocks. Coherent clock means that audio and TMDS clocks have the same >> + * source (no drifts between clocks). >> + * >> + * @audio_fs: audio frame clock frequency in Hz >> + * @tmds_clk: HDMI TMDS clock frequency in Hz >> + * @n_cts: N and CTS parameter returned to user >> + * >> + * Values computed are based on table described in HDMI specification 1.4b >> + * >> + * Returns 0 on success or a negative error code on failure. >> + */ >> +int hdmi_audio_get_coherent_n_cts(unsigned int audio_fs, >> + unsigned int tmds_clk, >> + struct hdmi_audio_n_cts *n_cts) >> +{ >> + int audio_freq_id, i; >> + int rate_coeff = 1; >> + u64 val, min; >> + const struct hdmi_audio_acr *acr_table; >> + const struct hdmi_audio_n_cts *predef_n_cts = NULL; >> + >> + switch (audio_fs) { >> + case 32000: >> + audio_freq_id = HDMI_AUDIO_N_CTS_32KHZ; >> + n_cts->n = 4096; >> + break; >> + case 44100: >> + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; >> + n_cts->n = 6272; >> + break; >> + case 48000: >> + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; >> + n_cts->n = 6144; >> + break; >> + case 88200: >> + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; >> + rate_coeff = 2; >> + n_cts->n = 6272 * 2; >> + break; >> + case 96000: >> + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; >> + rate_coeff = 2; >> + n_cts->n = 6144 * 2; >> + break; >> + case 176400: >> + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; >> + rate_coeff = 4; >> + n_cts->n = 6272 * 4; >> + break; >> + case 192000: >> + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; >> + rate_coeff = 4; >> + n_cts->n = 6144 * 4; >> + break; >> + default: >> + return -EINVAL; >> + } >> + >> + acr_table = hdmi_audio_standard_acr[audio_freq_id]; >> + for (i = 0; i < ARRAY_SIZE(hdmi_audio_standard_acr[0]); i++) { >> + if (tmds_clk == acr_table[i].tmds_clk) { >> + predef_n_cts = &acr_table[i].n_cts; >> + n_cts->n = predef_n_cts->n * rate_coeff; >> + n_cts->cts = predef_n_cts->cts; >> + n_cts->cts_1_ratio = predef_n_cts->cts_1_ratio; >> + return 0; >> + } >> + } >> + >> + /* >> + * predefined frequency not found. Compute CTS using formula: > ^ >> + * CTS = (Ftdms_clk * N) / (128* audio_fs) > ^ ^ >> + */ > ^ > Missing spaces. > >> + val = (u64)tmds_clk * n_cts->n; >> + n_cts->cts = div64_u64(val, 128UL * audio_fs); >> + >> + n_cts->cts_1_ratio = 0; >> + min = (u64)n_cts->cts * 128UL * audio_fs; >> + if (min < (val)) { > ^ ^ > These parentheses are not needed. > >> + /* >> + * non-accurate value for CTS > ^ >> + * compute ratio, needed by user to alternate in ACR > ^ >> + * between CTS and CTS + 1 value. > ^ >> + */ > ^ > Missing spaces. > >> + n_cts->cts_1_ratio = 100 - ((u32)(val - min)) * 100 / >> + (128 * audio_fs); > > I don't understand the purpose of the (100-x) above (and how cts_1_ratio > is supposed to be used). > > When for example val == (min + 0.3 * 128 * audio_fs) then > cts_1_ratio = 70. > To achieve an average CTS of (val), shouldn't (min) be used 70% of the > time and (min+1) be used 30% of the time? > I would have expected (cts_1_ratio == 30) in that case. you are right! my reasoning is foolish... Thank for pointing this error! >> >> +/** >> + * struct hdmi_audio_n_cts - n and cts parameter for ACR packets >> + * @n: N parameter >> + * @cts: CTS parameter >> + * @cts_1_ratio: ratio from 0 to 99 to alternate "CTS" and "CTS + 1" values >> + * ratio = 0: CTS parameter is accurate, no need to alternate with "CTS + 1" >> + * value >> + * ratio = x: Need to alternate with ACR "CTS + 1" value x% of the time to >> + * generate accurate audio clock > > Does this mean that at cts_1_ratio == 30, CTS should be used 70% of the > time, and CTS+1 should be used 30% of the time, or the other way around? yes CTS should be used 70% of the time, i will add example in comment > >> + */ >> +struct hdmi_audio_n_cts { >> + unsigned int n; >> + unsigned int cts; >> + unsigned int cts_1_ratio; >> +}; >> + >> +int hdmi_audio_get_coherent_n_cts(unsigned int audio_fs, >> + unsigned int tmds_clk, >> + struct hdmi_audio_n_cts *n_cts); >> + >> +int hdmi_audio_get_non_coherent_n(unsigned int audio_fs); >> + >> #endif /* _DRM_HDMI_H */ > > regards > Philipp > thanks and Regards Arnaud
diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c index 1626892..6381ce0 100644 --- a/drivers/video/hdmi.c +++ b/drivers/video/hdmi.c @@ -1242,3 +1242,205 @@ int hdmi_infoframe_unpack(union hdmi_infoframe *frame, void *buffer) return ret; } EXPORT_SYMBOL(hdmi_infoframe_unpack); + +/** + * audio clock regeneration (acr) parameters + * N and CTS computation are based on HDMI specification 1.4b + */ +enum audio_rate { + HDMI_AUDIO_N_CTS_32KHZ, + HDMI_AUDIO_N_CTS_44_1KHZ, + HDMI_AUDIO_N_CTS_48KHZ, +}; + +struct hdmi_audio_acr { + unsigned int tmds_clk; + struct hdmi_audio_n_cts n_cts; +}; + +static const struct hdmi_audio_acr hdmi_audio_standard_acr[3][12] = { + { /*32 kHz*/ + { 25174825, { 4576, 28125, 0 } }, /* 25,20/1.001 MHz */ + { 25200000, { 4096, 25200, 0 } }, /* 25.20 MHz */ + { 27000000, { 4096, 27000, 0 } }, /* 27.00 MHz */ + { 27027000, { 4096, 27027, 0 } }, /* 27.00*1.001 MHz */ + { 54000000, { 4096, 54000, 0 } }, /* 54.00 MHz */ + { 54054000, { 4096, 54054, 0 } }, /* 54.00*1.001 MHz */ + { 74175824, { 11648, 210937, 50 } }, /* 74.25/1.001 MHz */ + { 74250000, { 4096, 74250, 0 } }, /* 74.25 MHz */ + { 148351648, { 11648, 421875, 0 } }, /* 148.50/1.001 MHz */ + { 148500000, { 4096, 148500, 0 } }, /* 148.50 MHz */ + { 296703296, { 5824, 421875, 0 } }, /* 297/1.001 MHz */ + { 297000000, { 3072, 222750, 0 } }, /* 297 MHz */ + }, + { /*44.1 kHz, 88.2 kHz 176.4 kHz*/ + { 25174825, { 7007, 31250, 0 } }, /* 25,20/1.001 MHz */ + { 25200000, { 6272, 28000, 0 } }, /* 25.20 MHz */ + { 27000000, { 6272, 30000, 0 } }, /* 27.00 MHz */ + { 27027000, { 6272, 30030, 0 } }, /* 27.00*1.001 MHz */ + { 54000000, { 6272, 60000, 0 } }, /* 54.00 MHz */ + { 54054000, { 6272, 60060, 0 } }, /* 54.00*1.001 MHz */ + { 74175824, { 17836, 234375, 0 } }, /* 74.25/1.001 MHz */ + { 74250000, { 6272, 82500, 0 } }, /* 74.25 MHz */ + { 148351648, { 8918, 234375, 0 } }, /* 148.50/1.001 MHz */ + { 148500000, { 6272, 165000, 0 } }, /* 148.50 MHz */ + { 296703296, { 4459, 234375, 0 } }, /* 297/1.001 MHz */ + { 297000000, { 4704, 247500, 0 } }, /* 297 MHz */ + }, + { /*48 kHz, 96 kHz 192 kHz*/ + { 25174825, { 6864, 28125, 0 } }, /* 25,20/1.001 MHz */ + { 25200000, { 6144, 25200, 0 } }, /* 25.20 MHz */ + { 27000000, { 6144, 27000, 0 } }, /* 27.00 MHz */ + { 27027000, { 6144, 27027, 0 } }, /* 27.00*1.001 MHz */ + { 54000000, { 6144, 54000, 0 } }, /* 54.00 MHz */ + { 54054000, { 6144, 54054, 0 } }, /* 54.00*1.001 MHz */ + { 74175824, { 11648, 140625, 0 } }, /* 74.25/1.001 MHz */ + { 74250000, { 6144, 74250, 0 } }, /* 74.25 MHz */ + { 148351648, { 5824, 140625, 0 } }, /* 148.50/1.001 MHz */ + { 148500000, { 6144, 148500, 0 } }, /* 148.50 MHz */ + { 296703296, { 5824, 281250, 0 } }, /* 297/1.001 MHz */ + { 297000000, { 5120, 247500, 0 } }, /* 297 MHz */ + } +}; + +/** + * hdmi_audio_get_coherent_n_cts() - compute N and CTS parameters for coherent + * clocks. Coherent clock means that audio and TMDS clocks have the same + * source (no drifts between clocks). + * + * @audio_fs: audio frame clock frequency in Hz + * @tmds_clk: HDMI TMDS clock frequency in Hz + * @n_cts: N and CTS parameter returned to user + * + * Values computed are based on table described in HDMI specification 1.4b + * + * Returns 0 on success or a negative error code on failure. + */ +int hdmi_audio_get_coherent_n_cts(unsigned int audio_fs, + unsigned int tmds_clk, + struct hdmi_audio_n_cts *n_cts) +{ + int audio_freq_id, i; + int rate_coeff = 1; + u64 val, min; + const struct hdmi_audio_acr *acr_table; + const struct hdmi_audio_n_cts *predef_n_cts = NULL; + + switch (audio_fs) { + case 32000: + audio_freq_id = HDMI_AUDIO_N_CTS_32KHZ; + n_cts->n = 4096; + break; + case 44100: + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; + n_cts->n = 6272; + break; + case 48000: + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; + n_cts->n = 6144; + break; + case 88200: + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; + rate_coeff = 2; + n_cts->n = 6272 * 2; + break; + case 96000: + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; + rate_coeff = 2; + n_cts->n = 6144 * 2; + break; + case 176400: + audio_freq_id = HDMI_AUDIO_N_CTS_44_1KHZ; + rate_coeff = 4; + n_cts->n = 6272 * 4; + break; + case 192000: + audio_freq_id = HDMI_AUDIO_N_CTS_48KHZ; + rate_coeff = 4; + n_cts->n = 6144 * 4; + break; + default: + return -EINVAL; + } + + acr_table = hdmi_audio_standard_acr[audio_freq_id]; + for (i = 0; i < ARRAY_SIZE(hdmi_audio_standard_acr[0]); i++) { + if (tmds_clk == acr_table[i].tmds_clk) { + predef_n_cts = &acr_table[i].n_cts; + n_cts->n = predef_n_cts->n * rate_coeff; + n_cts->cts = predef_n_cts->cts; + n_cts->cts_1_ratio = predef_n_cts->cts_1_ratio; + return 0; + } + } + + /* + * predefined frequency not found. Compute CTS using formula: + * CTS = (Ftdms_clk * N) / (128* audio_fs) + */ + val = (u64)tmds_clk * n_cts->n; + n_cts->cts = div64_u64(val, 128UL * audio_fs); + + n_cts->cts_1_ratio = 0; + min = (u64)n_cts->cts * 128UL * audio_fs; + if (min < (val)) { + /* + * non-accurate value for CTS + * compute ratio, needed by user to alternate in ACR + * between CTS and CTS + 1 value. + */ + n_cts->cts_1_ratio = 100 - ((u32)(val - min)) * 100 / + (128 * audio_fs); + } + + return 0; +} +EXPORT_SYMBOL(hdmi_audio_get_coherent_n_cts); + +/** + * hdmi_audio_get_non_coherent_n() - get N parameter for non-coherent + * clocks. None-coherent clocks means that audio and TMDS clocks have not the + * same source (drifts between clocks). In this case assumption is that CTS is + * automatically calculated by hardware. + * + * @audio_fs: audio frame clock frequency in Hz + * + * Values computed are based on table described in HDMI specification 1.4b + * + * Returns n value. + */ +int hdmi_audio_get_non_coherent_n(unsigned int audio_fs) +{ + unsigned int n; + + switch (audio_fs) { + case 32000: + n = 4096; + break; + case 44100: + n = 6272; + break; + case 48000: + n = 6144; + break; + case 88200: + n = 6272 * 2; + break; + case 96000: + n = 6144 * 2; + break; + case 176400: + n = 6272 * 4; + break; + case 192000: + n = 6144 * 4; + break; + default: + /* Not pre-defined, recommended value: 128 * fs / 1000 */ + n = (audio_fs * 128) / 1000; + } + + return n; +} +EXPORT_SYMBOL(hdmi_audio_get_non_coherent_n); + diff --git a/include/linux/hdmi.h b/include/linux/hdmi.h index e974420..28b6794 100644 --- a/include/linux/hdmi.h +++ b/include/linux/hdmi.h @@ -333,4 +333,26 @@ int hdmi_infoframe_unpack(union hdmi_infoframe *frame, void *buffer); void hdmi_infoframe_log(const char *level, struct device *dev, union hdmi_infoframe *frame); +/** + * struct hdmi_audio_n_cts - n and cts parameter for ACR packets + * @n: N parameter + * @cts: CTS parameter + * @cts_1_ratio: ratio from 0 to 99 to alternate "CTS" and "CTS + 1" values + * ratio = 0: CTS parameter is accurate, no need to alternate with "CTS + 1" + * value + * ratio = x: Need to alternate with ACR "CTS + 1" value x% of the time to + * generate accurate audio clock + */ +struct hdmi_audio_n_cts { + unsigned int n; + unsigned int cts; + unsigned int cts_1_ratio; +}; + +int hdmi_audio_get_coherent_n_cts(unsigned int audio_fs, + unsigned int tmds_clk, + struct hdmi_audio_n_cts *n_cts); + +int hdmi_audio_get_non_coherent_n(unsigned int audio_fs); + #endif /* _DRM_HDMI_H */