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Message-ID: <20150526150407.10241.89123.stgit@warthog.procyon.org.uk>
Date: Tue, 26 May 2015 16:04:07 +0100
From: David Howells <dhowells@...hat.com>
To: crope@....fi
Cc: dhowells@...hat.com, linux-kernel@...r.kernel.org,
linux-media@...r.kernel.org
Subject: [PATCH 2/2] ts2020: Provide DVBv5 API signal strength
Provide a DVBv5 API signal strength. This is in units of 0.001 dBm rather
than a percentage.
>>From Antti Palosaari's testing with a signal generator, it appears that the
gain calculated according to Montage's specification if negated is a
reasonable representation of the signal strength of the generator.
To this end:
(1) Polled statistic gathering needed to be implemented in the TS2020 driver.
This is done in the ts2020_stat_work() function.
(2) The calculated gain is placed as the signal strength in the
dtv_property_cache associated with the front end with the scale set to
FE_SCALE_DECIBEL.
(3) The DVBv3 format signal strength then needed to be calculated from the
signal strength stored in the dtv_property_cache rather than accessing
the value when ts2020_read_signal_strength() is called.
Signed-off-by: David Howells <dhowells@...hat.com>
---
drivers/media/dvb-frontends/ts2020.c | 62 +++++++++++++++++++++++++++++-----
1 file changed, 53 insertions(+), 9 deletions(-)
diff --git a/drivers/media/dvb-frontends/ts2020.c b/drivers/media/dvb-frontends/ts2020.c
index 277e1cf..80ae039 100644
--- a/drivers/media/dvb-frontends/ts2020.c
+++ b/drivers/media/dvb-frontends/ts2020.c
@@ -32,10 +32,11 @@ struct ts2020_priv {
struct regmap_config regmap_config;
struct regmap *regmap;
struct dvb_frontend *fe;
+ struct delayed_work stat_work;
int (*get_agc_pwm)(struct dvb_frontend *fe, u8 *_agc_pwm);
/* i2c details */
- int i2c_address;
struct i2c_adapter *i2c;
+ int i2c_address;
u8 clk_out:2;
u8 clk_out_div:5;
u32 frequency_div; /* LO output divider switch frequency */
@@ -65,6 +66,7 @@ static int ts2020_release(struct dvb_frontend *fe)
static int ts2020_sleep(struct dvb_frontend *fe)
{
struct ts2020_priv *priv = fe->tuner_priv;
+ int ret;
u8 u8tmp;
if (priv->tuner == TS2020_M88TS2020)
@@ -72,11 +74,18 @@ static int ts2020_sleep(struct dvb_frontend *fe)
else
u8tmp = 0x00;
- return regmap_write(priv->regmap, u8tmp, 0x00);
+ ret = regmap_write(priv->regmap, u8tmp, 0x00);
+ if (ret < 0)
+ return ret;
+
+ /* stop statistics polling */
+ cancel_delayed_work_sync(&priv->stat_work);
+ return 0;
}
static int ts2020_init(struct dvb_frontend *fe)
{
+ struct dtv_frontend_properties *c = &fe->dtv_property_cache;
struct ts2020_priv *priv = fe->tuner_priv;
int i;
u8 u8tmp;
@@ -138,6 +147,13 @@ static int ts2020_init(struct dvb_frontend *fe)
reg_vals[i].val);
}
+ /* Initialise v5 stats here */
+ c->strength.len = 1;
+ c->strength.stat[0].scale = FE_SCALE_DECIBEL;
+ c->strength.stat[0].uvalue = 0;
+
+ /* Start statistics polling */
+ schedule_delayed_work(&priv->stat_work, 0);
return 0;
}
@@ -411,19 +427,46 @@ static int ts2020_get_tuner_gain(struct dvb_frontend *fe, __s64 *_gain)
}
/*
+ * Gather statistics on a regular basis
+ */
+static void ts2020_stat_work(struct work_struct *work)
+{
+ struct ts2020_priv *priv = container_of(work, struct ts2020_priv,
+ stat_work.work);
+ struct i2c_client *client = priv->client;
+ struct dtv_frontend_properties *c = &priv->fe->dtv_property_cache;
+ int ret;
+
+ dev_dbg(&client->dev, "\n");
+
+ ret = ts2020_get_tuner_gain(priv->fe, &c->strength.stat[0].svalue);
+ if (ret < 0)
+ goto err;
+
+ c->strength.stat[0].scale = FE_SCALE_DECIBEL;
+
+ schedule_delayed_work(&priv->stat_work, msecs_to_jiffies(2000));
+ return;
+err:
+ dev_dbg(&client->dev, "failed=%d\n", ret);
+}
+
+/*
* Read TS2020 signal strength in v3 format.
*/
static int ts2020_read_signal_strength(struct dvb_frontend *fe,
- u16 *signal_strength)
+ u16 *_signal_strength)
{
+ struct dtv_frontend_properties *c = &fe->dtv_property_cache;
unsigned strength;
__s64 gain;
- int ret;
- /* Determine the total gain of the tuner */
- ret = ts2020_get_tuner_gain(fe, &gain);
- if (ret < 0)
- return ret;
+ if (c->strength.stat[0].scale == FE_SCALE_NOT_AVAILABLE) {
+ *_signal_strength = 0;
+ return 0;
+ }
+
+ gain = c->strength.stat[0].svalue;
/* Calculate the signal strength based on the total gain of the tuner */
if (gain < -85000)
@@ -439,7 +482,7 @@ static int ts2020_read_signal_strength(struct dvb_frontend *fe,
/* 90% - 99%: strong signal */
strength = 90 + (45000 + gain) / 5000;
- *signal_strength = strength * 65535 / 100;
+ *_signal_strength = strength * 65535 / 100;
return 0;
}
@@ -546,6 +589,7 @@ static int ts2020_probe(struct i2c_client *client,
dev->get_agc_pwm = pdata->get_agc_pwm;
fe->tuner_priv = dev;
dev->client = client;
+ INIT_DELAYED_WORK(&dev->stat_work, ts2020_stat_work);
/* check if the tuner is there */
ret = regmap_read(dev->regmap, 0x00, &utmp);
--
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