media: si2157: Briefly wait for tuning operation to complete

To detect errors in the tuning operation, this waits up 40ms for operation
completion status. This allows for error detection and prevents issuing
additional commands to the tuner before it is finished.

Tuning typically completes in 20-30ms.
Signed-off-by: Brad Love <brad@nextdimension.cc>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/tuners/si2157.c

@@ -301,6 +301,54 @@ static int si2157_sleep(struct dvb_frontend *fe)
 	return ret;
 }
 
+static int si2157_tune_wait(struct i2c_client *client)
+{
+#define TUN_TIMEOUT 40
+	struct si2157_dev *dev = i2c_get_clientdata(client);
+	int ret;
+	unsigned long timeout;
+	unsigned long start_time;
+	u8 wait_status;
+
+	mutex_lock(&dev->i2c_mutex);
+
+	/* wait tuner command complete */
+	start_time = jiffies;
+	timeout = start_time + msecs_to_jiffies(TUN_TIMEOUT);
+	while (!time_after(jiffies, timeout)) {
+		ret = i2c_master_recv(client, &wait_status,
+				      sizeof(wait_status));
+		if (ret < 0) {
+			goto err_mutex_unlock;
+		} else if (ret != sizeof(wait_status)) {
+			ret = -EREMOTEIO;
+			goto err_mutex_unlock;
+		}
+
+		/* tuner done? */
+		if ((wait_status & 0x81) == 0x81)
+			break;
+		usleep_range(5000, 10000);
+	}
+
+	dev_dbg(&client->dev, "tuning took %d ms, status=0x%x\n",
+		jiffies_to_msecs(jiffies) - jiffies_to_msecs(start_time),
+		wait_status);
+
+	if ((wait_status & 0xc0) != 0x80) {
+		ret = -ETIMEDOUT;
+		goto err_mutex_unlock;
+	}
+
+	mutex_unlock(&dev->i2c_mutex);
+	return 0;
+
+err_mutex_unlock:
+	mutex_unlock(&dev->i2c_mutex);
+	dev_err(&client->dev, "failed=%d\n", ret);
+	return ret;
+}
+
 static int si2157_set_params(struct dvb_frontend *fe)
 {
 	struct i2c_client *client = fe->tuner_priv;
@@ -400,6 +448,8 @@ static int si2157_set_params(struct dvb_frontend *fe)
 	dev->bandwidth = bandwidth;
 	dev->frequency = c->frequency;
 
+	si2157_tune_wait(client); /* wait to complete, ignore any errors */
+
 	return 0;
 err:
 	dev->bandwidth = 0;
@@ -595,6 +645,8 @@ static int si2157_set_analog_params(struct dvb_frontend *fe,
 
 	dev->bandwidth = bandwidth;
 
+	si2157_tune_wait(client); /* wait to complete, ignore any errors */
+
 	return 0;
 err:
 	dev->bandwidth = 0;