drivers/media/dvb-frontends/mn88472.c

Source file repositories/reference/linux-study-clean/drivers/media/dvb-frontends/mn88472.c

File Facts

System
Linux kernel
Corpus path
drivers/media/dvb-frontends/mn88472.c
Extension
.c
Size
17791 bytes
Lines
732
Domain
Driver Families
Bucket
drivers/media
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (utmp) {
			/* CNR[dB]: 10 * log10(65536 / value) + 2 */
			/* log10(65536) = 80807124, 0.2 = 3355443 */
			stmp = ((u64)80807124 - intlog10(utmp) + 3355443)
			       * 10000 >> 24;

			dev_dbg(&client->dev, "cnr=%d value=%u\n", stmp, utmp);
		} else {
			stmp = 0;
		}

		c->cnr.stat[0].svalue = stmp;
		c->cnr.stat[0].scale = FE_SCALE_DECIBEL;
	} else if (*status & FE_HAS_VITERBI &&
		   c->delivery_system == SYS_DVBT2) {
		/* DVB-T2 CNR */
		for (i = 0; i < 3; i++) {
			ret = regmap_bulk_read(dev->regmap[2], 0xbc + i,
					       &buf[i], 1);
			if (ret)
				goto err;
		}

		utmp = buf[1] << 8 | buf[2] << 0;
		utmp1 = (buf[0] >> 2) & 0x01; /* 0=SISO, 1=MISO */
		if (utmp) {
			if (utmp1) {
				/* CNR[dB]: 10 * log10(16384 / value) - 6 */
				/* log10(16384) = 70706234, 0.6 = 10066330 */
				stmp = ((u64)70706234 - intlog10(utmp)
				       - 10066330) * 10000 >> 24;
				dev_dbg(&client->dev, "cnr=%d value=%u MISO\n",
					stmp, utmp);
			} else {
				/* CNR[dB]: 10 * log10(65536 / value) + 2 */
				/* log10(65536) = 80807124, 0.2 = 3355443 */
				stmp = ((u64)80807124 - intlog10(utmp)
				       + 3355443) * 10000 >> 24;

				dev_dbg(&client->dev, "cnr=%d value=%u SISO\n",
					stmp, utmp);
			}
		} else {
			stmp = 0;
		}

		c->cnr.stat[0].svalue = stmp;
		c->cnr.stat[0].scale = FE_SCALE_DECIBEL;
	} else if (*status & FE_HAS_VITERBI &&
		   c->delivery_system == SYS_DVBC_ANNEX_A) {
		/* DVB-C CNR */
		ret = regmap_bulk_read(dev->regmap[1], 0xa1, buf, 4);
		if (ret)
			goto err;

		utmp1 = buf[0] << 8 | buf[1] << 0; /* signal */
		utmp2 = buf[2] << 8 | buf[3] << 0; /* noise */
		if (utmp1 && utmp2) {
			/* CNR[dB]: 10 * log10(8 * (signal / noise)) */
			/* log10(8) = 15151336 */
			stmp = ((u64)15151336 + intlog10(utmp1)
			       - intlog10(utmp2)) * 10000 >> 24;

			dev_dbg(&client->dev, "cnr=%d signal=%u noise=%u\n",
				stmp, utmp1, utmp2);
		} else {
			stmp = 0;
		}

		c->cnr.stat[0].svalue = stmp;
		c->cnr.stat[0].scale = FE_SCALE_DECIBEL;
	} else {
		c->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
	}

	/* PER */
	if (*status & FE_HAS_SYNC) {
		ret = regmap_bulk_read(dev->regmap[0], 0xe1, buf, 4);
		if (ret)
			goto err;

		utmp1 = buf[0] << 8 | buf[1] << 0;
		utmp2 = buf[2] << 8 | buf[3] << 0;
		dev_dbg(&client->dev, "block_error=%u block_count=%u\n",
			utmp1, utmp2);

		c->block_error.stat[0].scale = FE_SCALE_COUNTER;
		c->block_error.stat[0].uvalue += utmp1;
		c->block_count.stat[0].scale = FE_SCALE_COUNTER;
		c->block_count.stat[0].uvalue += utmp2;

Annotation

Implementation Notes