[PATCH v2 1/9] sound: sdw: Add hw_params to SoundWire config helper function

[Charles Keepax]

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 at opensource.cirrus.com>
---

I  was a little bit two minds about whether to make this an inline or
not, so any thoughts on that would be super welcome. The function does
very little, especially given that SNDRV_PCM_STREAM_PLAYBACK ==
SDW_DATA_DIR_RX so the if is also really just an assignment.

Thanks,
Charles

Changes since v1:
 - Correct spelling error in commit message

 include/sound/sdw.h | 49 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 include/sound/sdw.h

diff --git a/include/sound/sdw.h b/include/sound/sdw.h
new file mode 100644
index 0000000000000..6dcdb3228dba6
--- /dev/null
+++ b/include/sound/sdw.h
@@ -0,0 +1,49 @@
+/* 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 at 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
-- 
2.30.2