drivers/soundwire/slave.c

   1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
   2 // Copyright(c) 2015-17 Intel Corporation.
   3
   4 #include <linux/acpi.h>
   5 #include <linux/soundwire/sdw.h>
   6 #include <linux/soundwire/sdw_type.h>
   7 #include "bus.h"
   8
   9 static void sdw_slave_release(struct device *dev)
  10 {
  11         struct sdw_slave *slave = dev_to_sdw_dev(dev);
  12
  13         kfree(slave);
  14 }
  15
  16 static int sdw_slave_add(struct sdw_bus *bus,
  17                 struct sdw_slave_id *id, struct fwnode_handle *fwnode)
  18 {
  19         struct sdw_slave *slave;
  20         int ret;
  21
  22         slave = kzalloc(sizeof(*slave), GFP_KERNEL);
  23         if (!slave)
  24                 return -ENOMEM;
  25
  26         /* Initialize data structure */
  27         memcpy(&slave->id, id, sizeof(*id));
  28         slave->dev.parent = bus->dev;
  29         slave->dev.fwnode = fwnode;
  30
  31         /* name shall be sdw:link:mfg:part:class:unique */
  32         dev_set_name(&slave->dev, "sdw:%x:%x:%x:%x:%x",
  33                         bus->link_id, id->mfg_id, id->part_id,
  34                         id->class_id, id->unique_id);
  35
  36         slave->dev.release = sdw_slave_release;
  37         slave->dev.bus = &sdw_bus_type;
  38         slave->bus = bus;
  39         slave->status = SDW_SLAVE_UNATTACHED;
  40         slave->dev_num = 0;
  41
  42         mutex_lock(&bus->bus_lock);
  43         list_add_tail(&slave->node, &bus->slaves);
  44         mutex_unlock(&bus->bus_lock);
  45
  46         ret = device_register(&slave->dev);
  47         if (ret) {
  48                 dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
  49
  50                 /*
  51                  * On err, don't free but drop ref as this will be freed
  52                  * when release method is invoked.
  53                  */
  54                 mutex_lock(&bus->bus_lock);
  55                 list_del(&slave->node);
  56                 mutex_unlock(&bus->bus_lock);
  57                 put_device(&slave->dev);
  58         }
  59
  60         return ret;
  61 }
  62
  63 #if IS_ENABLED(CONFIG_ACPI)
  64 /*
  65  * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
  66  * @bus: SDW bus instance
  67  *
  68  * Scans Master ACPI node for SDW child Slave devices and registers it.
  69  */
  70 int sdw_acpi_find_slaves(struct sdw_bus *bus)
  71 {
  72         struct acpi_device *adev, *parent;
  73
  74         parent = ACPI_COMPANION(bus->dev);
  75         if (!parent) {
  76                 dev_err(bus->dev, "Can't find parent for acpi bind\n");
  77                 return -ENODEV;
  78         }
  79
  80         list_for_each_entry(adev, &parent->children, node) {
  81                 unsigned long long addr;
  82                 struct sdw_slave_id id;
  83                 unsigned int link_id;
  84                 acpi_status status;
  85
  86                 status = acpi_evaluate_integer(adev->handle,
  87                                         METHOD_NAME__ADR, NULL, &addr);
  88
  89                 if (ACPI_FAILURE(status)) {
  90                         dev_err(bus->dev, "_ADR resolution failed: %x\n",
  91                                                         status);
  92                         return status;
  93                 }
  94
  95                 /* Extract link id from ADR, Bit 51 to 48 (included) */
  96                 link_id = (addr >> 48) & GENMASK(3, 0);
  97
  98                 /* Check for link_id match */
  99                 if (link_id != bus->link_id)
 100                         continue;
 101
 102                 sdw_extract_slave_id(bus, addr, &id);
 103
 104                 /*
 105                  * don't error check for sdw_slave_add as we want to continue
 106                  * adding Slaves
 107                  */
 108                 sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
 109         }
 110
 111         return 0;
 112 }
 113
 114 #endif