[media] cxd2820r: do not allow get_frontend() when demod is not initialized

This fixes bug introduced by multi-frontend to single-frontend change.

Finally HAS_LOCK is got back!
We are not allowed to access hardware in sleep mode...
Chip did not like when .get_frontend() reads some registers while
chip was sleeping and due to that HAS_LOCK bit was never gained.

TODO: We should add logic for dvb-core to drop out illegal calls like that.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/media/dvb/frontends/cxd2820r_core.c b/drivers/media/dvb/frontends/cxd2820r_core.c
index 372a4e700254..caae7f79c837 100644
--- a/drivers/media/dvb/frontends/cxd2820r_core.c
+++ b/drivers/media/dvb/frontends/cxd2820r_core.c
@@ -309,9 +309,14 @@ static int cxd2820r_read_status(struct dvb_frontend *fe, fe_status_t *status)
 
 static int cxd2820r_get_frontend(struct dvb_frontend *fe)
 {
+        struct cxd2820r_priv *priv = fe->demodulator_priv;
         int ret;
 
         dbg("%s: delsys=%d", __func__, fe->dtv_property_cache.delivery_system);
+
+        if (priv->delivery_system == SYS_UNDEFINED)
+                return 0;
+
         switch (fe->dtv_property_cache.delivery_system) {
         case SYS_DVBT:
                 ret = cxd2820r_get_frontend_t(fe);