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/of.h>
   6 #include <linux/soundwire/sdw.h>
   7 #include <linux/soundwire/sdw_type.h>
   8 #include "bus.h"
   9
  10 static void sdw_slave_release(struct device *dev)
  11 {
  12         struct sdw_slave *slave = dev_to_sdw_dev(dev);
  13
  14         kfree(slave);
  15 }
  16
  17 static int sdw_slave_add(struct sdw_bus *bus,
  18                          struct sdw_slave_id *id, struct fwnode_handle *fwnode)
  19 {
  20         struct sdw_slave *slave;
  21         int ret;
  22
  23         slave = kzalloc(sizeof(*slave), GFP_KERNEL);
  24         if (!slave)
  25                 return -ENOMEM;
  26
  27         /* Initialize data structure */
  28         memcpy(&slave->id, id, sizeof(*id));
  29         slave->dev.parent = bus->dev;
  30         slave->dev.fwnode = fwnode;
  31
  32         /* name shall be sdw:link:mfg:part:class:unique */
  33         dev_set_name(&slave->dev, "sdw:%x:%x:%x:%x:%x",
  34                      bus->link_id, id->mfg_id, id->part_id,
  35                      id->class_id, id->unique_id);
  36
  37         slave->dev.release = sdw_slave_release;
  38         slave->dev.bus = &sdw_bus_type;
  39         slave->dev.of_node = of_node_get(to_of_node(fwnode));
  40         slave->bus = bus;
  41         slave->status = SDW_SLAVE_UNATTACHED;
  42         slave->dev_num = 0;
  43
  44         mutex_lock(&bus->bus_lock);
  45         list_add_tail(&slave->node, &bus->slaves);
  46         mutex_unlock(&bus->bus_lock);
  47
  48         ret = device_register(&slave->dev);
  49         if (ret) {
  50                 dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
  51
  52                 /*
  53                  * On err, don't free but drop ref as this will be freed
  54                  * when release method is invoked.
  55                  */
  56                 mutex_lock(&bus->bus_lock);
  57                 list_del(&slave->node);
  58                 mutex_unlock(&bus->bus_lock);
  59                 put_device(&slave->dev);
  60         }
  61         sdw_slave_debugfs_init(slave);
  62
  63         return ret;
  64 }
  65
  66 #if IS_ENABLED(CONFIG_ACPI)
  67 /*
  68  * sdw_acpi_find_slaves() - Find Slave devices in Master ACPI node
  69  * @bus: SDW bus instance
  70  *
  71  * Scans Master ACPI node for SDW child Slave devices and registers it.
  72  */
  73 int sdw_acpi_find_slaves(struct sdw_bus *bus)
  74 {
  75         struct acpi_device *adev, *parent;
  76
  77         parent = ACPI_COMPANION(bus->dev);
  78         if (!parent) {
  79                 dev_err(bus->dev, "Can't find parent for acpi bind\n");
  80                 return -ENODEV;
  81         }
  82
  83         list_for_each_entry(adev, &parent->children, node) {
  84                 unsigned long long addr;
  85                 struct sdw_slave_id id;
  86                 unsigned int link_id;
  87                 acpi_status status;
  88
  89                 status = acpi_evaluate_integer(adev->handle,
  90                                                METHOD_NAME__ADR, NULL, &addr);
  91
  92                 if (ACPI_FAILURE(status)) {
  93                         dev_err(bus->dev, "_ADR resolution failed: %x\n",
  94                                 status);
  95                         return status;
  96                 }
  97
  98                 /* Extract link id from ADR, Bit 51 to 48 (included) */
  99                 link_id = (addr >> 48) & GENMASK(3, 0);
 100
 101                 /* Check for link_id match */
 102                 if (link_id != bus->link_id)
 103                         continue;
 104
 105                 sdw_extract_slave_id(bus, addr, &id);
 106
 107                 /*
 108                  * don't error check for sdw_slave_add as we want to continue
 109                  * adding Slaves
 110                  */
 111                 sdw_slave_add(bus, &id, acpi_fwnode_handle(adev));
 112         }
 113
 114         return 0;
 115 }
 116
 117 #endif
 118
 119 /*
 120  * sdw_of_find_slaves() - Find Slave devices in master device tree node
 121  * @bus: SDW bus instance
 122  *
 123  * Scans Master DT node for SDW child Slave devices and registers it.
 124  */
 125 int sdw_of_find_slaves(struct sdw_bus *bus)
 126 {
 127         struct device *dev = bus->dev;
 128         struct device_node *node;
 129
 130         for_each_child_of_node(bus->dev->of_node, node) {
 131                 int link_id, sdw_version, ret, len;
 132                 const char *compat = NULL;
 133                 struct sdw_slave_id id;
 134                 const __be32 *addr;
 135
 136                 compat = of_get_property(node, "compatible", NULL);
 137                 if (!compat)
 138                         continue;
 139
 140                 ret = sscanf(compat, "sdw%01x%04hx%04hx%02hhx", &sdw_version,
 141                              &id.mfg_id, &id.part_id, &id.class_id);
 142
 143                 if (ret != 4) {
 144                         dev_err(dev, "Invalid compatible string found %s\n",
 145                                 compat);
 146                         continue;
 147                 }
 148
 149                 addr = of_get_property(node, "reg", &len);
 150                 if (!addr || (len < 2 * sizeof(u32))) {
 151                         dev_err(dev, "Invalid Link and Instance ID\n");
 152                         continue;
 153                 }
 154
 155                 link_id = be32_to_cpup(addr++);
 156                 id.unique_id = be32_to_cpup(addr);
 157                 id.sdw_version = sdw_version;
 158
 159                 /* Check for link_id match */
 160                 if (link_id != bus->link_id)
 161                         continue;
 162
 163                 sdw_slave_add(bus, &id, of_fwnode_handle(node));
 164         }
 165
 166         return 0;
 167 }