[media] af9033: estimate cnr from formula

Use formulas for cnr estimates and get rid of old lut-based estimate.

Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

diff --git a/drivers/media/dvb-frontends/af9033.c b/drivers/media/dvb-frontends/af9033.c
index 7e0d1cf74705badbedef6004d146bbcf663d735b..aaed7cfe5f6660d608084607c8d5d2afa5f1848e 100644 (file)
--- a/drivers/media/dvb-frontends/af9033.c
+++ b/drivers/media/dvb-frontends/af9033.c
@@ -622,9 +622,9 @@ static int af9033_read_status(struct dvb_frontend *fe, enum fe_status *status)
        struct af9033_dev *dev = fe->demodulator_priv;
        struct i2c_client *client = dev->client;
        struct dtv_frontend_properties *c = &fe->dtv_property_cache;
-       int ret, i, tmp = 0;
+       int ret, tmp = 0;
        u8 buf[7];
-       unsigned int utmp;
+       unsigned int utmp, utmp1;
 
        dev_dbg(&client->dev, "\n");
 
@@ -686,15 +686,12 @@ static int af9033_read_status(struct dvb_frontend *fe, enum fe_status *status)
 
        /* CNR */
        if (dev->fe_status & FE_HAS_VITERBI) {
-               u32 snr_val, snr_lut_size;
-               const struct val_snr *snr_lut = NULL;
-
                /* Read raw SNR value */
                ret = regmap_bulk_read(dev->regmap, 0x80002c, buf, 3);
                if (ret)
                        goto err;
 
-               snr_val = (buf[2] << 16) | (buf[1] << 8) | (buf[0] << 0);
+               utmp1 = buf[2] << 16 | buf[1] << 8 | buf[0] << 0;
 
                /* Read superframe number */
                ret = regmap_read(dev->regmap, 0x80f78b, &utmp);
@@ -702,7 +699,7 @@ static int af9033_read_status(struct dvb_frontend *fe, enum fe_status *status)
                        goto err;
 
                if (utmp)
-                       snr_val /= utmp;
+                       utmp1 /= utmp;
 
                /* Read current transmission mode */
                ret = regmap_read(dev->regmap, 0x80f900, &utmp);
@@ -711,16 +708,19 @@ static int af9033_read_status(struct dvb_frontend *fe, enum fe_status *status)
 
                switch ((utmp >> 0) & 3) {
                case 0:
-                       snr_val *= 4;
+                       /* 2k */
+                       utmp1 *= 4;
                        break;
                case 1:
-                       snr_val *= 1;
+                       /* 8k */
+                       utmp1 *= 1;
                        break;
                case 2:
-                       snr_val *= 2;
+                       /* 4k */
+                       utmp1 *= 2;
                        break;
                default:
-                       snr_val *= 0;
+                       utmp1 *= 0;
                        break;
                }
 
@@ -731,34 +731,48 @@ static int af9033_read_status(struct dvb_frontend *fe, enum fe_status *status)
 
                switch ((utmp >> 0) & 3) {
                case 0:
-                       snr_lut_size = ARRAY_SIZE(qpsk_snr_lut);
-                       snr_lut = qpsk_snr_lut;
+                       /*
+                        * QPSK
+                        * CNR[dB] 13 * -log10((1690000 - value) / value) + 2.6
+                        * value [653799, 1689999], 2.6 / 13 = 3355443
+                        */
+                       utmp1 = clamp(utmp1, 653799U, 1689999U);
+                       utmp1 = ((u64)(intlog10(utmp1)
+                                - intlog10(1690000 - utmp1)
+                                + 3355443) * 13 * 1000) >> 24;
                        break;
                case 1:
-                       snr_lut_size = ARRAY_SIZE(qam16_snr_lut);
-                       snr_lut = qam16_snr_lut;
+                       /*
+                        * QAM-16
+                        * CNR[dB] 6 * log10((value - 370000) / (828000 - value)) + 15.7
+                        * value [371105, 827999], 15.7 / 6 = 43900382
+                        */
+                       utmp1 = clamp(utmp1, 371105U, 827999U);
+                       utmp1 = ((u64)(intlog10(utmp1 - 370000)
+                                - intlog10(828000 - utmp1)
+                                + 43900382) * 6 * 1000) >> 24;
                        break;
                case 2:
-                       snr_lut_size = ARRAY_SIZE(qam64_snr_lut);
-                       snr_lut = qam64_snr_lut;
+                       /*
+                        * QAM-64
+                        * CNR[dB] 8 * log10((value - 193000) / (425000 - value)) + 23.8
+                        * value [193246, 424999], 23.8 / 8 = 49912218
+                        */
+                       utmp1 = clamp(utmp1, 193246U, 424999U);
+                       utmp1 = ((u64)(intlog10(utmp1 - 193000)
+                                - intlog10(425000 - utmp1)
+                                + 49912218) * 8 * 1000) >> 24;
                        break;
                default:
-                       snr_lut_size = 0;
-                       tmp = 0;
+                       utmp1 = 0;
                        break;
                }
 
-               for (i = 0; i < snr_lut_size; i++) {
-                       tmp = snr_lut[i].snr * 1000;
-                       if (snr_val < snr_lut[i].val)
-                               break;
-               }
+               dev_dbg(&client->dev, "cnr=%u\n", utmp1);
 
-               c->cnr.len = 1;
                c->cnr.stat[0].scale = FE_SCALE_DECIBEL;
-               c->cnr.stat[0].svalue = tmp;
+               c->cnr.stat[0].svalue = utmp1;
        } else {
-               c->cnr.len = 1;
                c->cnr.stat[0].scale = FE_SCALE_NOT_AVAILABLE;
        }
 

diff --git a/drivers/media/dvb-frontends/af9033_priv.h b/drivers/media/dvb-frontends/af9033_priv.h
index ad2e7c9b3ca95970e7ae435eca976c11c070acfe..8799cda1ae143a8405c96fc0f87f7197a124bb41 100644 (file)
--- a/drivers/media/dvb-frontends/af9033_priv.h
+++ b/drivers/media/dvb-frontends/af9033_priv.h
@@ -23,6 +23,7 @@
 #include <linux/math64.h>
 #include <linux/regmap.h>
 #include <linux/kernel.h>
+#include "dvb_math.h"
 
 struct reg_val {
        u32 reg;
@@ -89,102 +90,6 @@ static const struct coeff coeff_lut[] = {
        },
 };
 
-/* QPSK SNR lookup table */
-static const struct val_snr qpsk_snr_lut[] = {
-       { 0x0b4771,  0 },
-       { 0x0c1aed,  1 },
-       { 0x0d0d27,  2 },
-       { 0x0e4d19,  3 },
-       { 0x0e5da8,  4 },
-       { 0x107097,  5 },
-       { 0x116975,  6 },
-       { 0x1252d9,  7 },
-       { 0x131fa4,  8 },
-       { 0x13d5e1,  9 },
-       { 0x148e53, 10 },
-       { 0x15358b, 11 },
-       { 0x15dd29, 12 },
-       { 0x168112, 13 },
-       { 0x170b61, 14 },
-       { 0x17a532, 15 },
-       { 0x180f94, 16 },
-       { 0x186ed2, 17 },
-       { 0x18b271, 18 },
-       { 0x18e118, 19 },
-       { 0x18ff4b, 20 },
-       { 0x190af1, 21 },
-       { 0x191451, 22 },
-       { 0xffffff, 23 },
-};
-
-/* QAM16 SNR lookup table */
-static const struct val_snr qam16_snr_lut[] = {
-       { 0x04f0d5,  0 },
-       { 0x05387a,  1 },
-       { 0x0573a4,  2 },
-       { 0x05a99e,  3 },
-       { 0x05cc80,  4 },
-       { 0x05eb62,  5 },
-       { 0x05fecf,  6 },
-       { 0x060b80,  7 },
-       { 0x062501,  8 },
-       { 0x064865,  9 },
-       { 0x069604, 10 },
-       { 0x06f356, 11 },
-       { 0x07706a, 12 },
-       { 0x0804d3, 13 },
-       { 0x089d1a, 14 },
-       { 0x093e3d, 15 },
-       { 0x09e35d, 16 },
-       { 0x0a7c3c, 17 },
-       { 0x0afaf8, 18 },
-       { 0x0b719d, 19 },
-       { 0x0bda6a, 20 },
-       { 0x0c0c75, 21 },
-       { 0x0c3f7d, 22 },
-       { 0x0c5e62, 23 },
-       { 0x0c6c31, 24 },
-       { 0x0c7925, 25 },
-       { 0xffffff, 26 },
-};
-
-/* QAM64 SNR lookup table */
-static const struct val_snr qam64_snr_lut[] = {
-       { 0x0256d0,  0 },
-       { 0x027a65,  1 },
-       { 0x029873,  2 },
-       { 0x02b7fe,  3 },
-       { 0x02cf1e,  4 },
-       { 0x02e234,  5 },
-       { 0x02f409,  6 },
-       { 0x030046,  7 },
-       { 0x030844,  8 },
-       { 0x030a02,  9 },
-       { 0x030cde, 10 },
-       { 0x031031, 11 },
-       { 0x03144c, 12 },
-       { 0x0315dd, 13 },
-       { 0x031920, 14 },
-       { 0x0322d0, 15 },
-       { 0x0339fc, 16 },
-       { 0x0364a1, 17 },
-       { 0x038bcc, 18 },
-       { 0x03c7d3, 19 },
-       { 0x0408cc, 20 },
-       { 0x043bed, 21 },
-       { 0x048061, 22 },
-       { 0x04be95, 23 },
-       { 0x04fa7d, 24 },
-       { 0x052405, 25 },
-       { 0x05570d, 26 },
-       { 0x059feb, 27 },
-       { 0x05bf38, 28 },
-       { 0x05f78f, 29 },
-       { 0x0612c3, 30 },
-       { 0x0626be, 31 },
-       { 0xffffff, 32 },
-};
-
 /*
  * Afatech AF9033 demod init
  */