Hello,
As there is no more feedback on this patch, should i suppose that I need to abandon it?
I can integrate it in my driver... but as, N and CTS calculation is not platform dependent, this would make sense to add it in a generic part. (Example of another platform that could use it: https://patchwork.kernel.org/patch/8887341)
Thanks and regards Arnaud
On 04/28/2016 02:13 PM, Arnaud Pouliquen wrote:
Add linux-fbdev diffusion list in loop for patch-set review.
On 04/21/2016 05:29 PM, Arnaud POULIQUEN wrote:
Add helper functions 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
drivers/video/hdmi.c | 208 +++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/hdmi.h | 24 ++++++ 2 files changed, 232 insertions(+)
diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c index 1626892..5d124ef 100644 --- a/drivers/video/hdmi.c +++ b/drivers/video/hdmi.c @@ -1242,3 +1242,211 @@ 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 hdmi_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][13] = {
- [HDMI_AUDIO_N_CTS_32KHZ] = {
/* N and CTS values for 32 kHz rate*/{ 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 (truncated)*/{ 296703297, { 5824, 421875, 0 } }, /* 297/1.001 MHz (rounded)*/{ 297000000, { 3072, 222750, 0 } }, /* 297 MHz */- },
- [HDMI_AUDIO_N_CTS_44_1KHZ] = {
/* N and CTS values for 44.1 kHz, 88.2 kHz and 176.4 kHz rates*/{ 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 (truncated) */{ 296703297, { 4459, 234375, 0 } }, /* 297/1.001 MHz (rounded) */{ 297000000, { 4704, 247500, 0 } }, /* 297 MHz */- },
- [HDMI_AUDIO_N_CTS_48KHZ] = {
/* N and CTS values for 48 kHz, 96 kHz and 192 kHz rates*/{ 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 (truncated) */{ 296703297, { 5824, 281250, 0 } }, /* 297/1.001 MHz (rounded) */{ 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;}- }
- /*
* Pre-defined 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 = ((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..088d09f8 100644 --- a/include/linux/hdmi.h +++ b/include/linux/hdmi.h @@ -333,4 +333,28 @@ 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 percent of the time
to generate accurate audio clock
- as exemple: if cts_1_ratio = 30: to have an accurate value, user
- should transfer CTS value 70% of the time and (CTS+1) value 30% of the time
- */
+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 */