ASoC: rsnd: explain SRC bypass mode settings in comment

 *

 */

/*

 *	How to use SRC bypass mode for debugging

 *

 * SRC has bypass mode, and it is useful for debugging.

 * In Gen2 case,

 * SRCm_MODE controls whether SRC is used or not

 * SSI_MODE0 controls whether SSIU which receives SRC data

 * is used or not.

 * Both SRCm_MODE/SSI_MODE0 settings are needed if you use SRC,

 * but SRC bypass mode needs SSI_MODE0 only.

 *

 * This driver request

 * struct rsnd_scu_platform_info {

 *	u32 flags;

 *	u32 convert_rate;

 * }

 *

 * rsnd_scu_hpbif_is_enable() will be true

 * if flags had RSND_SCU_USE_HPBIF,

 * and it controls whether SSIU is used or not.

 *

 * rsnd_scu_convert_rate() indicates

 * above convert_rate, and it controls

 * whether SRC is used or not.

 *

 * ex) doesn't use SRC

 * struct rsnd_scu_platform_info info = {

 *	.flags = 0,

 *	.convert_rate = 0,

 * };

 *

 * ex) uses SRC

 * struct rsnd_scu_platform_info info = {

 *	.flags = RSND_SCU_USE_HPBIF,

 *	.convert_rate = 48000,

 * };

 *

 * ex) uses SRC bypass mode

 * struct rsnd_scu_platform_info info = {

 *	.flags = RSND_SCU_USE_HPBIF,

 *	.convert_rate = 0,

 * };

 *

 */

#define rsnd_mod_to_scu(_mod)	\

	container_of((_mod), struct rsnd_scu, mod)