On 11/14/19 10:04 PM, Brad Love wrote:
Add get_rf_strength callback to get RSSI from the tuner. DVBv5
stat cache is updated. get_rf_strength is called by tuner_core
for analog tuners and is also used by some bridge drivers to
obtain RSSI directly from the tuner.
Driver is updating its signal strength already. Is there any reason you
don't use existing value but add this new I/O to read it?
Antti
Signed-off-by: Brad Love <brad@xxxxxxxxxxxxxxxx>
---
Changes since v1:
- simplify normalization of signal strength calculation
- use clamp and add description of operation
- remove __func__ from dev_dbg macro
drivers/media/tuners/si2157.c | 40 ++++++++++++++++++++++++++++++++++-
1 file changed, 39 insertions(+), 1 deletion(-)
diff --git a/drivers/media/tuners/si2157.c b/drivers/media/tuners/si2157.c
index 16d7169f46fb..aaf223b9b781 100644
--- a/drivers/media/tuners/si2157.c
+++ b/drivers/media/tuners/si2157.c
@@ -725,6 +725,42 @@ static int si2157_get_if_frequency(struct dvb_frontend *fe, u32 *frequency)
return 0;
}
+static int si2157_get_rf_strength(struct dvb_frontend *fe, u16 *rssi)
+{
+ struct i2c_client *client = fe->tuner_priv;
+ struct dtv_frontend_properties *c = &fe->dtv_property_cache;
+ struct si2157_cmd cmd;
+ int ret;
+ int strength;
+
+ dev_dbg(&client->dev, "\n");
+
+ memcpy(cmd.args, "\x42\x00", 2);
+ cmd.wlen = 2;
+ cmd.rlen = 12;
+ ret = si2157_cmd_execute(client, &cmd);
+ if (ret)
+ goto err;
+
+ c->strength.stat[0].scale = FE_SCALE_DECIBEL;
+ c->strength.stat[0].svalue = (s8)cmd.args[3] * 1000;
+
+ /* normalize values based on Silicon Labs reference
+ * add 100, then anything > 80 is 100% signal
+ */
+ strength = (s8)cmd.args[3] + 100;
+ strength = clamp_val(strength, 0, 80);
+ *rssi = (u16)(strength * 0xffff / 80);
+
+ dev_dbg(&client->dev, "strength=%d rssi=%u\n",
+ (s8)cmd.args[3], *rssi);
+
+ return 0;
+err:
+ dev_dbg(&client->dev, "failed=%d\n", ret);
+ return ret;
+}
+
static const struct dvb_tuner_ops si2157_ops = {
.info = {
.name = "Silicon Labs Si2141/Si2146/2147/2148/2157/2158",
@@ -738,7 +774,9 @@ static const struct dvb_tuner_ops si2157_ops = {
.set_analog_params = si2157_set_analog_params,
.get_frequency = si2157_get_frequency,
.get_bandwidth = si2157_get_bandwidth,
- .get_if_frequency = si2157_get_if_frequency,
+ .get_if_frequency = si2157_get_if_frequency,
+
+ .get_rf_strength = si2157_get_rf_strength,
};
static void si2157_stat_work(struct work_struct *work)
--
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