That stream format carries 504 x I+Q samples per 1024 USB frame.
Sample resolution is 8-bit signed. Default it when sampling rate
is 9Msps or over.
Signed-off-by: Antti Palosaari <crope@xxxxxx>
---
drivers/staging/media/msi3101/sdr-msi3101.c | 94 ++++++++++++++++++++++++++++-
1 file changed, 92 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/media/msi3101/sdr-msi3101.c b/drivers/staging/media/msi3101/sdr-msi3101.c
index a3cc4c6..bf735f9 100644
--- a/drivers/staging/media/msi3101/sdr-msi3101.c
+++ b/drivers/staging/media/msi3101/sdr-msi3101.c
@@ -448,7 +448,7 @@ leave:
/*
* +===========================================================================
- * | 00-1023 | USB packet
+ * | 00-1023 | USB packet type '384'
* +===========================================================================
* | 00- 03 | sequence number of first sample in that USB packet
* +---------------------------------------------------------------------------
@@ -502,6 +502,93 @@ leave:
#define I2F_MASK ((1 << I2F_FRAC_BITS) - 1)
/*
+ * Converts signed 8-bit integer into 32-bit IEEE floating point
+ * representation.
+ */
+static u32 msi3101_convert_sample_504(struct msi3101_state *s, u16 x)
+{
+ u32 msb, exponent, fraction, sign;
+
+ /* Zero is special */
+ if (!x)
+ return 0;
+
+ /* Negative / positive value */
+ if (x & (1 << 7)) {
+ x = -x;
+ x &= 0x7f; /* result is 7 bit ... + sign */
+ sign = 1 << 31;
+ } else {
+ sign = 0 << 31;
+ }
+
+ /* Get location of the most significant bit */
+ msb = __fls(x);
+
+ fraction = ror32(x, (msb - I2F_FRAC_BITS) & 0x1f) & I2F_MASK;
+ exponent = (127 + msb) << I2F_FRAC_BITS;
+
+ return (fraction + exponent) | sign;
+}
+
+static int msi3101_convert_stream_504(struct msi3101_state *s, u32 *dst,
+ u8 *src, unsigned int src_len)
+{
+ int i, j, i_max, dst_len = 0;
+ u16 sample[2];
+ u32 sample_num[3];
+
+ /* There could be 1-3 1024 bytes URB frames */
+ i_max = src_len / 1024;
+
+ for (i = 0; i < i_max; i++) {
+ sample_num[i] = src[3] << 24 | src[2] << 16 | src[1] << 8 | src[0] << 0;
+ if (i == 0 && s->next_sample != sample_num[0]) {
+ dev_dbg_ratelimited(&s->udev->dev,
+ "%d samples lost, %d %08x:%08x\n",
+ sample_num[0] - s->next_sample,
+ src_len, s->next_sample, sample_num[0]);
+ }
+
+ /*
+ * Dump all unknown 'garbage' data - maybe we will discover
+ * someday if there is something rational...
+ */
+ dev_dbg_ratelimited(&s->udev->dev, "%*ph\n", 12, &src[4]);
+
+ src += 16;
+ for (j = 0; j < 1008; j += 2) {
+ sample[0] = src[j + 0];
+ sample[1] = src[j + 1];
+
+ *dst++ = msi3101_convert_sample_504(s, sample[0]);
+ *dst++ = msi3101_convert_sample_504(s, sample[1]);
+ }
+ /* 504 x I+Q 32bit float samples */
+ dst_len += 504 * 2 * 4;
+ src += 1008;
+ }
+
+ /* calculate samping rate and output it in 10 seconds intervals */
+ if ((s->jiffies + msecs_to_jiffies(10000)) <= jiffies) {
+ unsigned long jiffies_now = jiffies;
+ unsigned long msecs = jiffies_to_msecs(jiffies_now) - jiffies_to_msecs(s->jiffies);
+ unsigned int samples = sample_num[i_max - 1] - s->sample;
+ s->jiffies = jiffies_now;
+ s->sample = sample_num[i_max - 1];
+ dev_dbg(&s->udev->dev,
+ "slen=%d samples=%u msecs=%lu sampling rate=%lu\n",
+ src_len, samples, msecs,
+ samples * 1000UL / msecs);
+ }
+
+ /* next sample (sample = sample + i * 504) */
+ s->next_sample = sample_num[i_max - 1] + 504;
+
+ return dst_len;
+}
+
+/*
* Converts signed ~10+3-bit integer into 32-bit IEEE floating point
* representation.
*/
@@ -1134,9 +1221,12 @@ static int msi3101_set_usb_adc(struct msi3101_state *s)
} else if (f_sr < 8000000) {
s->convert_stream = msi3101_convert_stream_336;
reg7 = 0x00008507;
- } else {
+ } else if (f_sr < 9000000) {
s->convert_stream = msi3101_convert_stream_384;
reg7 = 0x0000a507;
+ } else {
+ s->convert_stream = msi3101_convert_stream_504;
+ reg7 = 0x000c9407;
}
/*
--
1.7.11.7
--
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