V4L/DVB (7674): tda10048: Adding an SNR table

Trying to improve the SNR reporting.

Signed-off-by: Steven Toth <stoth@hauppauge.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

diff --git a/drivers/media/dvb/frontends/tda10048.c b/drivers/media/dvb/frontends/tda10048.c
index 701dd02..090fb7d 100644 (file)
--- a/drivers/media/dvb/frontends/tda10048.c
+++ b/drivers/media/dvb/frontends/tda10048.c
@@ -26,6 +26,7 @@
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include "dvb_frontend.h"
+#include "dvb_math.h"
 #include "tda10048.h"
 
 #define TDA10048_DEFAULT_FIRMWARE "dvb-fe-tda10048-1.0.fw"
@@ -563,31 +564,167 @@ static int tda10048_read_signal_strength(struct dvb_frontend *fe,
        u16 *signal_strength)
 {
        struct tda10048_state *state = fe->demodulator_priv;
-       u16 v;
+       u8 v;
 
        dprintk(1, "%s()\n", __func__);
 
+       *signal_strength = 65535;
+
        v = tda10048_readreg(state, TDA10048_NP_OUT);
-       if (v == 0)
-               *signal_strength = 100;
-       else {
-               /* TODO: Apply .db math for correct values */
-               *signal_strength = v;
-       }
+       if (v > 0)
+               *signal_strength -= (v << 8) | v;
 
        return 0;
 }
 
+/* SNR lookup table */
+static struct snr_tab {
+       u8 val;
+       u8 data;
+} snr_tab[] = {
+       {   0,   0 },
+       {   1, 246 },
+       {   2, 215 },
+       {   3, 198 },
+       {   4, 185 },
+       {   5, 176 },
+       {   6, 168 },
+       {   7, 161 },
+       {   8, 155 },
+       {   9, 150 },
+       {  10, 146 },
+       {  11, 141 },
+       {  12, 138 },
+       {  13, 134 },
+       {  14, 131 },
+       {  15, 128 },
+       {  16, 125 },
+       {  17, 122 },
+       {  18, 120 },
+       {  19, 118 },
+       {  20, 115 },
+       {  21, 113 },
+       {  22, 111 },
+       {  23, 109 },
+       {  24, 107 },
+       {  25, 106 },
+       {  26, 104 },
+       {  27, 102 },
+       {  28, 101 },
+       {  29,  99 },
+       {  30,  98 },
+       {  31,  96 },
+       {  32,  95 },
+       {  33,  94 },
+       {  34,  92 },
+       {  35,  91 },
+       {  36,  90 },
+       {  37,  89 },
+       {  38,  88 },
+       {  39,  86 },
+       {  40,  85 },
+       {  41,  84 },
+       {  42,  83 },
+       {  43,  82 },
+       {  44,  81 },
+       {  45,  80 },
+       {  46,  79 },
+       {  47,  78 },
+       {  48,  77 },
+       {  49,  76 },
+       {  50,  76 },
+       {  51,  75 },
+       {  52,  74 },
+       {  53,  73 },
+       {  54,  72 },
+       {  56,  71 },
+       {  57,  70 },
+       {  58,  69 },
+       {  60,  68 },
+       {  61,  67 },
+       {  63,  66 },
+       {  64,  65 },
+       {  66,  64 },
+       {  67,  63 },
+       {  68,  62 },
+       {  69,  62 },
+       {  70,  61 },
+       {  72,  60 },
+       {  74,  59 },
+       {  75,  58 },
+       {  77,  57 },
+       {  79,  56 },
+       {  81,  55 },
+       {  83,  54 },
+       {  85,  53 },
+       {  87,  52 },
+       {  89,  51 },
+       {  91,  50 },
+       {  93,  49 },
+       {  95,  48 },
+       {  97,  47 },
+       { 100,  46 },
+       { 102,  45 },
+       { 104,  44 },
+       { 107,  43 },
+       { 109,  42 },
+       { 112,  41 },
+       { 114,  40 },
+       { 117,  39 },
+       { 120,  38 },
+       { 123,  37 },
+       { 125,  36 },
+       { 128,  35 },
+       { 131,  34 },
+       { 134,  33 },
+       { 138,  32 },
+       { 141,  31 },
+       { 144,  30 },
+       { 147,  29 },
+       { 151,  28 },
+       { 154,  27 },
+       { 158,  26 },
+       { 162,  25 },
+       { 165,  24 },
+       { 169,  23 },
+       { 173,  22 },
+       { 177,  21 },
+       { 181,  20 },
+       { 186,  19 },
+       { 190,  18 },
+       { 194,  17 },
+       { 199,  16 },
+       { 204,  15 },
+       { 208,  14 },
+       { 213,  13 },
+       { 218,  12 },
+       { 223,  11 },
+       { 229,  10 },
+       { 234,   9 },
+       { 239,   8 },
+       { 245,   7 },
+       { 251,   6 },
+       { 255,   5 },
+};
+
 static int tda10048_read_snr(struct dvb_frontend *fe, u16 *snr)
 {
        struct tda10048_state *state = fe->demodulator_priv;
+       u8 v;
+       int i, ret = -EINVAL;
 
        dprintk(1, "%s()\n", __func__);
 
-       /* TODO: This result should be the same as signal strength */
-       *snr = tda10048_readreg(state, TDA10048_NP_OUT);
+       v = tda10048_readreg(state, TDA10048_NP_OUT);
+       for (i = 0; i < ARRAY_SIZE(snr_tab); i++) {
+               if (v <= snr_tab[i].val) {
+                       *snr = snr_tab[i].data;
+                       ret = 0;
+                       break;
+               }
+       }
 
-       return 0;
+       return ret;
 }
 
 static int tda10048_read_ucblocks(struct dvb_frontend *fe, u32 *ucblocks)