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[media] r820t: Give a better estimation of the signal strength 

Instead of a binary signal strength measure, use the tuner gain
to obtain a better estimation of the signal strength.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Tested-by: Antti Palosaari <crope@iki.fi>
hifive-unleashed-5.1
Mauro Carvalho Chehab 2013-04-07 18:12:56 -03:00
parent 6889ab2a25
commit f8fde0e045
1 changed files with 27 additions and 3 deletions
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30
drivers/media/tuners/r820t.c
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@ -1082,6 +1082,18 @@ static int r820t_set_tv_standard(struct r820t_priv *priv,
return 0;
}
static int r820t_read_gain(struct r820t_priv *priv)
{
u8 data[4];
int rc;
rc = r820_read(priv, 0x00, data, sizeof(data));
if (rc < 0)
return rc;
return ((data[3] & 0x0f) << 1) + ((data[3] & 0xf0) >> 4);
}
static int generic_set_freq(struct dvb_frontend *fe,
u32 freq /* in HZ */,
unsigned bw,
@ -1353,11 +1365,23 @@ static int r820t_set_params(struct dvb_frontend *fe)
static int r820t_signal(struct dvb_frontend *fe, u16 *strength)
{
struct r820t_priv *priv = fe->tuner_priv;
int rc = 0;
if (priv->has_lock)
*strength = 0xffff;
else
if (priv->has_lock) {
rc = r820t_read_gain(priv);
if (rc < 0)
return rc;
/* A higher gain at LNA means a lower signal strength */
*strength = (45 - rc) << 4 | 0xff;
} else {
*strength = 0;
}
tuner_dbg("%s: %s, gain=%d strength=%d\n",
__func__,
priv->has_lock ? "PLL locked" : "no signal",
rc, *strength);
return 0;
}