aoa/soundbus/soundbus.h

0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  * soundbus generic definitions
0004  *
0005  * Copyright 2006 Johannes Berg <johannes@sipsolutions.net>
0006  */
0007 #ifndef __SOUNDBUS_H
0008 #define __SOUNDBUS_H
0009
0010 #include <linux/of_device.h>
0011 #include <sound/pcm.h>
0012 #include <linux/list.h>
0013
0014
0015 /* When switching from master to slave or the other way around,
0016  * you don't want to have the codec chip acting as clock source
0017  * while the bus still is.
0018  * More importantly, while switch from slave to master, you need
0019  * to turn off the chip's master function first, but then there's
0020  * no clock for a while and other chips might reset, so we notify
0021  * their drivers after having switched.
0022  * The constants here are codec-point of view, so when we switch
0023  * the soundbus to master we tell the codec we're going to switch
0024  * and give it CLOCK_SWITCH_PREPARE_SLAVE!
0025  */
0026 enum clock_switch {
0027     CLOCK_SWITCH_PREPARE_SLAVE,
0028     CLOCK_SWITCH_PREPARE_MASTER,
0029     CLOCK_SWITCH_SLAVE,
0030     CLOCK_SWITCH_MASTER,
0031     CLOCK_SWITCH_NOTIFY,
0032 };
0033
0034 /* information on a transfer the codec can take */
0035 struct transfer_info {
0036     u64 formats;        /* SNDRV_PCM_FMTBIT_* */
0037     unsigned int rates; /* SNDRV_PCM_RATE_* */
0038     /* flags */
0039     u32 transfer_in:1, /* input = 1, output = 0 */
0040         must_be_clock_source:1;
0041     /* for codecs to distinguish among their TIs */
0042     int tag;
0043 };
0044
0045 struct codec_info_item {
0046     struct codec_info *codec;
0047     void *codec_data;
0048     struct soundbus_dev *sdev;
0049     /* internal, to be used by the soundbus provider */
0050     struct list_head list;
0051 };
0052
0053 /* for prepare, where the codecs need to know
0054  * what we're going to drive the bus with */
0055 struct bus_info {
0056     /* see below */
0057     int sysclock_factor;
0058     int bus_factor;
0059 };
0060
0061 /* information on the codec itself, plus function pointers */
0062 struct codec_info {
0063     /* the module this lives in */
0064     struct module *owner;
0065
0066     /* supported transfer possibilities, array terminated by
0067      * formats or rates being 0. */
0068     struct transfer_info *transfers;
0069
0070     /* Master clock speed factor
0071      * to be used (master clock speed = sysclock_factor * sampling freq)
0072      * Unused if the soundbus provider has no such notion.
0073      */
0074     int sysclock_factor;
0075
0076     /* Bus factor, bus clock speed = bus_factor * sampling freq)
0077      * Unused if the soundbus provider has no such notion.
0078      */
0079     int bus_factor;
0080
0081     /* operations */
0082     /* clock switching, see above */
0083     int (*switch_clock)(struct codec_info_item *cii,
0084                 enum clock_switch clock);
0085
0086     /* called for each transfer_info when the user
0087      * opens the pcm device to determine what the
0088      * hardware can support at this point in time.
0089      * That can depend on other user-switchable controls.
0090      * Return 1 if usable, 0 if not.
0091      * out points to another instance of a transfer_info
0092      * which is initialised to the values in *ti, and
0093      * it's format and rate values can be modified by
0094      * the callback if it is necessary to further restrict
0095      * the formats that can be used at the moment, for
0096      * example when one codec has multiple logical codec
0097      * info structs for multiple inputs.
0098      */
0099     int (*usable)(struct codec_info_item *cii,
0100               struct transfer_info *ti,
0101               struct transfer_info *out);
0102
0103     /* called when pcm stream is opened, probably not implemented
0104      * most of the time since it isn't too useful */
0105     int (*open)(struct codec_info_item *cii,
0106             struct snd_pcm_substream *substream);
0107
0108     /* called when the pcm stream is closed, at this point
0109      * the user choices can all be unlocked (see below) */
0110     int (*close)(struct codec_info_item *cii,
0111              struct snd_pcm_substream *substream);
0112
0113     /* if the codec must forbid some user choices because
0114      * they are not valid with the substream/transfer info,
0115      * it must do so here. Example: no digital output for
0116      * incompatible framerate, say 8KHz, on Onyx.
0117      * If the selected stuff in the substream is NOT
0118      * compatible, you have to reject this call! */
0119     int (*prepare)(struct codec_info_item *cii,
0120                struct bus_info *bi,
0121                struct snd_pcm_substream *substream);
0122
0123     /* start() is called before data is pushed to the codec.
0124      * Note that start() must be atomic! */
0125     int (*start)(struct codec_info_item *cii,
0126              struct snd_pcm_substream *substream);
0127
0128     /* stop() is called after data is no longer pushed to the codec.
0129      * Note that stop() must be atomic! */
0130     int (*stop)(struct codec_info_item *cii,
0131             struct snd_pcm_substream *substream);
0132
0133     int (*suspend)(struct codec_info_item *cii, pm_message_t state);
0134     int (*resume)(struct codec_info_item *cii);
0135 };
0136
0137 /* information on a soundbus device */
0138 struct soundbus_dev {
0139     /* the bus it belongs to */
0140     struct list_head onbuslist;
0141
0142     /* the of device it represents */
0143     struct platform_device ofdev;
0144
0145     /* what modules go by */
0146     char modalias[32];
0147
0148     /* These fields must be before attach_codec can be called.
0149      * They should be set by the owner of the alsa card object
0150      * that is needed, and whoever sets them must make sure
0151      * that they are unique within that alsa card object. */
0152     char *pcmname;
0153     int pcmid;
0154
0155     /* this is assigned by the soundbus provider in attach_codec */
0156     struct snd_pcm *pcm;
0157
0158     /* operations */
0159     /* attach a codec to this soundbus, give the alsa
0160      * card object the PCMs for this soundbus should be in.
0161      * The 'data' pointer must be unique, it is used as the
0162      * key for detach_codec(). */
0163     int (*attach_codec)(struct soundbus_dev *dev, struct snd_card *card,
0164                 struct codec_info *ci, void *data);
0165     void (*detach_codec)(struct soundbus_dev *dev, void *data);
0166     /* TODO: suspend/resume */
0167
0168     /* private for the soundbus provider */
0169     struct list_head codec_list;
0170     u32 have_out:1, have_in:1;
0171 };
0172 #define to_soundbus_device(d) container_of(d, struct soundbus_dev, ofdev.dev)
0173 #define of_to_soundbus_device(d) container_of(d, struct soundbus_dev, ofdev)
0174
0175 extern int soundbus_add_one(struct soundbus_dev *dev);
0176 extern void soundbus_remove_one(struct soundbus_dev *dev);
0177
0178 extern struct soundbus_dev *soundbus_dev_get(struct soundbus_dev *dev);
0179 extern void soundbus_dev_put(struct soundbus_dev *dev);
0180
0181 struct soundbus_driver {
0182     char *name;
0183     struct module *owner;
0184
0185     /* we don't implement any matching at all */
0186
0187     int (*probe)(struct soundbus_dev* dev);
0188     int (*remove)(struct soundbus_dev* dev);
0189
0190     int (*shutdown)(struct soundbus_dev* dev);
0191
0192     struct device_driver driver;
0193 };
0194 #define to_soundbus_driver(drv) container_of(drv,struct soundbus_driver, driver)
0195
0196 extern int soundbus_register_driver(struct soundbus_driver *drv);
0197 extern void soundbus_unregister_driver(struct soundbus_driver *drv);
0198
0199 extern struct attribute *soundbus_dev_attrs[];
0200
0201 #endif /* __SOUNDBUS_H */