sound/hda/hda_bus_type.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * HD-audio bus
0004  */
0005 #include <linux/init.h>
0006 #include <linux/device.h>
0007 #include <linux/module.h>
0008 #include <linux/mod_devicetable.h>
0009 #include <linux/export.h>
0010 #include <sound/hdaudio.h>
0011
0012 MODULE_DESCRIPTION("HD-audio bus");
0013 MODULE_LICENSE("GPL");
0014
0015 /**
0016  * hdac_get_device_id - gets the hdac device id entry
0017  * @hdev: HD-audio core device
0018  * @drv: HD-audio codec driver
0019  *
0020  * Compares the hdac device vendor_id and revision_id to the hdac_device
0021  * driver id_table and returns the matching device id entry.
0022  */
0023 const struct hda_device_id *
0024 hdac_get_device_id(struct hdac_device *hdev, struct hdac_driver *drv)
0025 {
0026     if (drv->id_table) {
0027         const struct hda_device_id *id  = drv->id_table;
0028
0029         while (id->vendor_id) {
0030             if (hdev->vendor_id == id->vendor_id &&
0031                 (!id->rev_id || id->rev_id == hdev->revision_id))
0032                 return id;
0033             id++;
0034         }
0035     }
0036
0037     return NULL;
0038 }
0039 EXPORT_SYMBOL_GPL(hdac_get_device_id);
0040
0041 static int hdac_codec_match(struct hdac_device *dev, struct hdac_driver *drv)
0042 {
0043     if (hdac_get_device_id(dev, drv))
0044         return 1;
0045     else
0046         return 0;
0047 }
0048
0049 static int hda_bus_match(struct device *dev, struct device_driver *drv)
0050 {
0051     struct hdac_device *hdev = dev_to_hdac_dev(dev);
0052     struct hdac_driver *hdrv = drv_to_hdac_driver(drv);
0053
0054     if (hdev->type != hdrv->type)
0055         return 0;
0056
0057     /*
0058      * if driver provided a match function use that otherwise we will
0059      * use hdac_codec_match function
0060      */
0061     if (hdrv->match)
0062         return hdrv->match(hdev, hdrv);
0063     else
0064         return hdac_codec_match(hdev, hdrv);
0065     return 1;
0066 }
0067
0068 static int hda_uevent(struct device *dev, struct kobj_uevent_env *env)
0069 {
0070     char modalias[32];
0071
0072     snd_hdac_codec_modalias(dev_to_hdac_dev(dev), modalias,
0073                 sizeof(modalias));
0074     if (add_uevent_var(env, "MODALIAS=%s", modalias))
0075         return -ENOMEM;
0076     return 0;
0077 }
0078
0079 struct bus_type snd_hda_bus_type = {
0080     .name = "hdaudio",
0081     .match = hda_bus_match,
0082     .uevent = hda_uevent,
0083 };
0084 EXPORT_SYMBOL_GPL(snd_hda_bus_type);
0085
0086 static int __init hda_bus_init(void)
0087 {
0088     return bus_register(&snd_hda_bus_type);
0089 }
0090
0091 static void __exit hda_bus_exit(void)
0092 {
0093     bus_unregister(&snd_hda_bus_type);
0094 }
0095
0096 subsys_initcall(hda_bus_init);
0097 module_exit(hda_bus_exit);