drivers/soundwire/bus_type.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright(c) 2015-17 Intel Corporation.
   3
   4 #include <linux/module.h>
   5 #include <linux/mod_devicetable.h>
   6 #include <linux/pm_domain.h>
   7 #include <linux/soundwire/sdw.h>
   8 #include <linux/soundwire/sdw_type.h>
   9
  10 /**
  11  * sdw_get_device_id - find the matching SoundWire device id
  12  * @slave: SoundWire Slave Device
  13  * @drv: SoundWire Slave Driver
  14  *
  15  * The match is done by comparing the mfg_id and part_id from the
  16  * struct sdw_device_id.
  17  */
  18 static const struct sdw_device_id *
  19 sdw_get_device_id(struct sdw_slave *slave, struct sdw_driver *drv)
  20 {
  21         const struct sdw_device_id *id = drv->id_table;
  22
  23         while (id && id->mfg_id) {
  24                 if (slave->id.mfg_id == id->mfg_id &&
  25                     slave->id.part_id == id->part_id)
  26                         return id;
  27                 id++;
  28         }
  29
  30         return NULL;
  31 }
  32
  33 static int sdw_bus_match(struct device *dev, struct device_driver *ddrv)
  34 {
  35         struct sdw_slave *slave = dev_to_sdw_dev(dev);
  36         struct sdw_driver *drv = drv_to_sdw_driver(ddrv);
  37
  38         return !!sdw_get_device_id(slave, drv);
  39 }
  40
  41 int sdw_slave_modalias(const struct sdw_slave *slave, char *buf, size_t size)
  42 {
  43         /* modalias is sdw:m<mfg_id>p<part_id> */
  44
  45         return snprintf(buf, size, "sdw:m%04Xp%04X\n",
  46                         slave->id.mfg_id, slave->id.part_id);
  47 }
  48
  49 static int sdw_uevent(struct device *dev, struct kobj_uevent_env *env)
  50 {
  51         struct sdw_slave *slave = dev_to_sdw_dev(dev);
  52         char modalias[32];
  53
  54         sdw_slave_modalias(slave, modalias, sizeof(modalias));
  55
  56         if (add_uevent_var(env, "MODALIAS=%s", modalias))
  57                 return -ENOMEM;
  58
  59         return 0;
  60 }
  61
  62 struct bus_type sdw_bus_type = {
  63         .name = "soundwire",
  64         .match = sdw_bus_match,
  65         .uevent = sdw_uevent,
  66 };
  67 EXPORT_SYMBOL_GPL(sdw_bus_type);
  68
  69 static int sdw_drv_probe(struct device *dev)
  70 {
  71         struct sdw_slave *slave = dev_to_sdw_dev(dev);
  72         struct sdw_driver *drv = drv_to_sdw_driver(dev->driver);
  73         const struct sdw_device_id *id;
  74         int ret;
  75
  76         id = sdw_get_device_id(slave, drv);
  77         if (!id)
  78                 return -ENODEV;
  79
  80         slave->ops = drv->ops;
  81
  82         /*
  83          * attach to power domain but don't turn on (last arg)
  84          */
  85         ret = dev_pm_domain_attach(dev, false);
  86         if (ret != -EPROBE_DEFER) {
  87                 ret = drv->probe(slave, id);
  88                 if (ret) {
  89                         dev_err(dev, "Probe of %s failed: %d\n", drv->name, ret);
  90                         dev_pm_domain_detach(dev, false);
  91                 }
  92         }
  93
  94         if (ret)
  95                 return ret;
  96
  97         /* device is probed so let's read the properties now */
  98         if (slave->ops && slave->ops->read_prop)
  99                 slave->ops->read_prop(slave);
 100
 101         /*
 102          * Check for valid clk_stop_timeout, use DisCo worst case value of
 103          * 300ms
 104          *
 105          * TODO: check the timeouts and driver removal case
 106          */
 107         if (slave->prop.clk_stop_timeout == 0)
 108                 slave->prop.clk_stop_timeout = 300;
 109
 110         slave->bus->clk_stop_timeout = max_t(u32, slave->bus->clk_stop_timeout,
 111                                         slave->prop.clk_stop_timeout);
 112
 113         return 0;
 114 }
 115
 116 static int sdw_drv_remove(struct device *dev)
 117 {
 118         struct sdw_slave *slave = dev_to_sdw_dev(dev);
 119         struct sdw_driver *drv = drv_to_sdw_driver(dev->driver);
 120         int ret = 0;
 121
 122         if (drv->remove)
 123                 ret = drv->remove(slave);
 124
 125         dev_pm_domain_detach(dev, false);
 126
 127         return ret;
 128 }
 129
 130 static void sdw_drv_shutdown(struct device *dev)
 131 {
 132         struct sdw_slave *slave = dev_to_sdw_dev(dev);
 133         struct sdw_driver *drv = drv_to_sdw_driver(dev->driver);
 134
 135         if (drv->shutdown)
 136                 drv->shutdown(slave);
 137 }
 138
 139 /**
 140  * __sdw_register_driver() - register a SoundWire Slave driver
 141  * @drv: driver to register
 142  * @owner: owning module/driver
 143  *
 144  * Return: zero on success, else a negative error code.
 145  */
 146 int __sdw_register_driver(struct sdw_driver *drv, struct module *owner)
 147 {
 148         drv->driver.bus = &sdw_bus_type;
 149
 150         if (!drv->probe) {
 151                 pr_err("driver %s didn't provide SDW probe routine\n",
 152                                                         drv->name);
 153                 return -EINVAL;
 154         }
 155
 156         drv->driver.owner = owner;
 157         drv->driver.probe = sdw_drv_probe;
 158
 159         if (drv->remove)
 160                 drv->driver.remove = sdw_drv_remove;
 161
 162         if (drv->shutdown)
 163                 drv->driver.shutdown = sdw_drv_shutdown;
 164
 165         return driver_register(&drv->driver);
 166 }
 167 EXPORT_SYMBOL_GPL(__sdw_register_driver);
 168
 169 /**
 170  * sdw_unregister_driver() - unregisters the SoundWire Slave driver
 171  * @drv: driver to unregister
 172  */
 173 void sdw_unregister_driver(struct sdw_driver *drv)
 174 {
 175         driver_unregister(&drv->driver);
 176 }
 177 EXPORT_SYMBOL_GPL(sdw_unregister_driver);
 178
 179 static int __init sdw_bus_init(void)
 180 {
 181         return bus_register(&sdw_bus_type);
 182 }
 183
 184 static void __exit sdw_bus_exit(void)
 185 {
 186         bus_unregister(&sdw_bus_type);
 187 }
 188
 189 postcore_initcall(sdw_bus_init);
 190 module_exit(sdw_bus_exit);
 191
 192 MODULE_DESCRIPTION("SoundWire bus");
 193 MODULE_LICENSE("GPL v2");