diff options
| -rw-r--r-- | drivers/media/platform/vivid/vivid-sdr-cap.c | 31 |
1 files changed, 12 insertions, 19 deletions
diff --git a/drivers/media/platform/vivid/vivid-sdr-cap.c b/drivers/media/platform/vivid/vivid-sdr-cap.c index c36b3f58dab6..d0c26577c06e 100644 --- a/drivers/media/platform/vivid/vivid-sdr-cap.c +++ b/drivers/media/platform/vivid/vivid-sdr-cap.c @@ -41,7 +41,7 @@ struct vivid_format { }; /* format descriptions for capture and preview */ -static struct vivid_format formats[] = { +static const struct vivid_format formats[] = { { .pixelformat = V4L2_SDR_FMT_CU8, .buffersize = SDR_CAP_SAMPLES_PER_BUF * 2, @@ -502,16 +502,10 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) s32 fixp_i; s32 fixp_q; - /* - * TODO: Generated beep tone goes very crackly when sample rate is - * increased to ~1Msps or more. That is because of huge rounding error - * of phase angle caused by used cosine implementation. - */ - /* calculate phase step */ #define BEEP_FREQ 1000 /* 1kHz beep */ src_phase_step = DIV_ROUND_CLOSEST(FIXP_2PI * BEEP_FREQ, - dev->sdr_adc_freq); + dev->sdr_adc_freq); for (i = 0; i < plane_size; i += 2) { mod_phase_step = fixp_cos32_rad(dev->sdr_fixp_src_phase, @@ -522,17 +516,15 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) dev->sdr_fixp_mod_phase += div_s64(s64tmp, M_100000PI); /* - * Transfer phases to [0 / 2xPI] in order to avoid variable + * Transfer phase angle to [0, 2xPI] in order to avoid variable * overflow and make it suitable for cosine implementation * used, which does not support negative angles. */ - while (dev->sdr_fixp_mod_phase < FIXP_2PI) - dev->sdr_fixp_mod_phase += FIXP_2PI; - while (dev->sdr_fixp_mod_phase > FIXP_2PI) - dev->sdr_fixp_mod_phase -= FIXP_2PI; + dev->sdr_fixp_src_phase %= FIXP_2PI; + dev->sdr_fixp_mod_phase %= FIXP_2PI; - while (dev->sdr_fixp_src_phase > FIXP_2PI) - dev->sdr_fixp_src_phase -= FIXP_2PI; + if (dev->sdr_fixp_mod_phase < 0) + dev->sdr_fixp_mod_phase += FIXP_2PI; fixp_i = fixp_cos32_rad(dev->sdr_fixp_mod_phase, FIXP_2PI); fixp_q = fixp_sin32_rad(dev->sdr_fixp_mod_phase, FIXP_2PI); @@ -544,7 +536,7 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) switch (dev->sdr_pixelformat) { case V4L2_SDR_FMT_CU8: - /* convert 'fixp float' to u8 */ + /* convert 'fixp float' to u8 [0, +255] */ /* u8 = X * 127.5 + 127.5; X is float [-1.0, +1.0] */ fixp_i = fixp_i * 1275 + FIXP_FRAC * 1275; fixp_q = fixp_q * 1275 + FIXP_FRAC * 1275; @@ -552,9 +544,10 @@ void vivid_sdr_cap_process(struct vivid_dev *dev, struct vivid_buffer *buf) *vbuf++ = DIV_ROUND_CLOSEST(fixp_q, FIXP_FRAC * 10); break; case V4L2_SDR_FMT_CS8: - /* convert 'fixp float' to s8 */ - fixp_i = fixp_i * 1275; - fixp_q = fixp_q * 1275; + /* convert 'fixp float' to s8 [-128, +127] */ + /* s8 = X * 127.5 - 0.5; X is float [-1.0, +1.0] */ + fixp_i = fixp_i * 1275 - FIXP_FRAC * 5; + fixp_q = fixp_q * 1275 - FIXP_FRAC * 5; *vbuf++ = DIV_ROUND_CLOSEST(fixp_i, FIXP_FRAC * 10); *vbuf++ = DIV_ROUND_CLOSEST(fixp_q, FIXP_FRAC * 10); break; |