soundwire: Add compute_params callback

This callback allows masters to compute the bus parameters required.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20190813083550.5877-2-srinivas.kandagatla@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/stream.c

@@ -1485,6 +1485,16 @@ static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
 		bus->params.bandwidth += m_rt->stream->params.rate *
 			m_rt->ch_count * m_rt->stream->params.bps;
 
+		/* Compute params */
+		if (bus->compute_params) {
+			ret = bus->compute_params(bus);
+			if (ret < 0) {
+				dev_err(bus->dev, "Compute params failed: %d",
+					ret);
+				return ret;
+			}
+		}
+
 		/* Program params */
 		ret = sdw_program_params(bus);
 		if (ret < 0) {

include/linux/soundwire/sdw.h

@@ -728,6 +728,7 @@ struct sdw_master_ops {
  * Bit set implies used number, bit clear implies unused number.
  * @bus_lock: bus lock
  * @msg_lock: message lock
+ * @compute_params: points to Bus resource management implementation
  * @ops: Master callback ops
  * @port_ops: Master port callback ops
  * @params: Current bus parameters
@@ -750,6 +751,7 @@ struct sdw_bus {
 	DECLARE_BITMAP(assigned, SDW_MAX_DEVICES);
 	struct mutex bus_lock;
 	struct mutex msg_lock;
+	int (*compute_params)(struct sdw_bus *bus);
 	const struct sdw_master_ops *ops;
 	const struct sdw_master_port_ops *port_ops;
 	struct sdw_bus_params params;