sound: sdw: Add hw_params to SoundWire config helper function

The vast majority of the current users of the SoundWire framework
have almost identical code for converting from hw_params to SoundWire
configuration. Whilst complex devices might require more, it is very
likely that most new devices will follow the same pattern. Save a
little code by factoring this out into a helper function.
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20221123165432.594972-1-ckeepax@opensource.cirrus.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/sound/sdw.h

+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * linux/sound/sdw.h -- SoundWire helpers for ALSA/ASoC
+ *
+ * Copyright (c) 2022 Cirrus Logic Inc.
+ *
+ * Author: Charles Keepax <ckeepax@opensource.cirrus.com>
+ */
+
+#include <linux/soundwire/sdw.h>
+#include <sound/asound.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#ifndef __INCLUDE_SOUND_SDW_H
+#define __INCLUDE_SOUND_SDW_H
+
+/**
+ * snd_sdw_params_to_config() - Conversion from hw_params to SoundWire config
+ *
+ * @substream: Pointer to the PCM substream structure
+ * @params: Pointer to the hardware params structure
+ * @stream_config: Stream configuration for the SoundWire audio stream
+ * @port_config: Port configuration for the SoundWire audio stream
+ *
+ * This function provides a basic conversion from the hw_params structure to
+ * SoundWire configuration structures. The user will at a minimum need to also
+ * set the port number in the port config, but may also override more of the
+ * setup, or in the case of a complex user, not use this helper at all and
+ * open-code everything.
+ */
+static inline void snd_sdw_params_to_config(struct snd_pcm_substream *substream,
+					    struct snd_pcm_hw_params *params,
+					    struct sdw_stream_config *stream_config,
+					    struct sdw_port_config *port_config)
+{
+	stream_config->frame_rate = params_rate(params);
+	stream_config->ch_count = params_channels(params);
+	stream_config->bps = snd_pcm_format_width(params_format(params));
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		stream_config->direction = SDW_DATA_DIR_RX;
+	else
+		stream_config->direction = SDW_DATA_DIR_TX;
+
+	port_config->ch_mask = GENMASK(stream_config->ch_count - 1, 0);
+}
+
+#endif