@@ -1122,6 +1122,113 @@ static void of_i2c_register_devices(struct i2c_adapter *adap) { }
/* ACPI support code */
#if IS_ENABLED(CONFIG_ACPI)
+struct acpi_i2c_lookup {
+ struct i2c_board_info *info;
+ struct i2c_adapter *adapter;
+ bool found;
+ int index;
+ int n;
+};
+
+static int acpi_i2c_match_adapter(struct device *dev, void *data)
+{
+ return !!i2c_verify_adapter(dev);
+}
+
+static int acpi_i2c_find(struct acpi_resource *ares, void *data)
+{
+ struct acpi_i2c_lookup *lookup = data;
+ struct acpi_resource_i2c_serialbus *sb;
+ struct acpi_device_physical_node *phys;
+ struct acpi_device *adev;
+ acpi_status status;
+ acpi_handle handle;
+ char *path;
+
+ if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
+ return 1;
+
+ sb = &ares->data.i2c_serial_bus;
+ if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
+ return 1;
+
+ if (lookup->n++ != lookup->index)
+ return 1;
+
+ /*
+ * Need to look up the adapter from ACPI namespace and translate it
+ * to a physical device. That device should be existing I2C
+ * adapter.
+ */
+ path = sb->resource_source.string_ptr;
+ status = acpi_get_handle(ACPI_ROOT_OBJECT, path, &handle);
+ if (ACPI_FAILURE(status) || acpi_bus_get_device(handle, &adev))
+ return 1;
+
+ mutex_lock(&adev->physical_node_lock);
+ list_for_each_entry(phys, &adev->physical_node_list, node) {
+ struct device *dev;
+
+ dev = device_find_child(phys->dev, NULL,
+ acpi_i2c_match_adapter);
+ if (dev) {
+ lookup->adapter = to_i2c_adapter(dev);
+ break;
+ }
+ }
+ mutex_unlock(&adev->physical_node_lock);
+
+ if (!lookup->adapter)
+ return 1;
+
+ if (lookup->info) {
+ lookup->info->addr = sb->slave_address;
+ if (sb->access_mode == ACPI_I2C_10BIT_MODE)
+ lookup->info->flags |= I2C_CLIENT_TEN;
+ }
+
+ lookup->found = true;
+ return 1;
+}
+
+static int acpi_i2c_address_by_index(struct i2c_client *client, int index,
+ struct i2c_board_info *info,
+ struct i2c_adapter **adapter)
+{
+ struct acpi_i2c_lookup lookup;
+ struct acpi_device *adev;
+ LIST_HEAD(resources);
+ int ret;
+
+ adev = ACPI_COMPANION(&client->dev);
+ if (!adev)
+ return -ENODEV;
+
+ memset(&lookup, 0, sizeof(lookup));
+ lookup.index = index;
+ lookup.info = info;
+
+ ret = acpi_dev_get_resources(adev, &resources, acpi_i2c_find, &lookup);
+ acpi_dev_free_resource_list(&resources);
+ if (ret < 0)
+ return ret;
+
+ if (lookup.found) {
+ if (!adapter) {
+ /*
+ * Caller is not interested in the adapter so we
+ * will release it now. Otherwise it is up to the
+ * caller to call put_device() for it.
+ */
+ put_device(&lookup.adapter->dev);
+ } else {
+ *adapter = lookup.adapter;
+ }
+ }
+
+ return lookup.found ? 0 : -EADDRNOTAVAIL;
+}
+
static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
{
struct i2c_board_info *info = data;
@@ -1230,6 +1337,67 @@ static void acpi_i2c_register_devices(struct i2c_adapter *adap)
static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
#endif /* CONFIG_ACPI */
+/**
+ * i2c_address_by_index - Return an I2C address for a device
+ * @client: the client with multiple addresses
+ * @index: index of the additional address
+ * @info: pointer to board info which is filled in
+ * @adapter: adapter on which bus the address is is stored here
+ *
+ * In case of an I2C device with multiple addresses this function can be
+ * used to look up those additional addresses. Returns %0 if the address
+ * with given @index is found or %-EADDRNOTAVAIL if no such address is
+ * found. Note that the function returns address of the current @client as
+ * well so callers need to check against that if necessary.
+ *
+ * Note that the caller must do put_device() to the @adapter->dev once it
+ * is not used anymore.
+ */
+int i2c_address_by_index(struct i2c_client *client, int index,
+ struct i2c_board_info *info,
+ struct i2c_adapter **adapter)
+{
+ if (IS_ENABLED(CONFIG_ACPI))
+ return acpi_i2c_address_by_index(client, index, info, adapter);
+
+ /*
+ * Normal case means that the address at index zero is the address
+ * of the current client device.
+ */
+ if (!index) {
+ if (info) {
+ info->addr = client->addr;
+ info->flags = client->flags;
+ info->irq = client->irq;
+ }
+ if (adapter)
+ *adapter = client->adapter;
+
+ return 0;
+ }
+
+ return -EADDRNOTAVAIL;
+}
+EXPORT_SYMBOL_GPL(i2c_address_by_index);
+
+/**
+ * i2c_num_addresses - Returns number of addresses given device has
+ * @client: the client with multiple addresses
+ *
+ * An I2C device that has multiple addresses can use this function to find
+ * out how many of them it has. For single address devices the function
+ * always returns %1.
+ */
+size_t i2c_num_addresses(struct i2c_client *client)
+{
+ size_t n = 0;
+
+ while (!i2c_address_by_index(client, n, NULL, NULL))
+ n++;
+ return n;
+}
+EXPORT_SYMBOL_GPL(i2c_num_addresses);
+
static int i2c_do_add_adapter(struct i2c_driver *driver,
struct i2c_adapter *adap)
{
@@ -322,6 +322,11 @@ extern int i2c_probe_func_quick_read(struct i2c_adapter *, unsigned short addr);
extern struct i2c_client *
i2c_new_dummy(struct i2c_adapter *adap, u16 address);
+extern int i2c_address_by_index(struct i2c_client *client, int index,
+ struct i2c_board_info *info,
+ struct i2c_adapter **adapter);
+extern size_t i2c_num_addresses(struct i2c_client *client);
+
extern void i2c_unregister_device(struct i2c_client *);
#endif /* I2C */