i2c: core: Add function for finding the bus speed from ACPI, take 2

[cascardo/linux.git] / drivers / i2c / i2c-core.c

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index d4b2f66..0579442 100644 (file)
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -107,6 +107,9 @@ struct i2c_acpi_lookup {
        struct i2c_board_info *info;
        acpi_handle adapter_handle;
        acpi_handle device_handle;
        struct i2c_board_info *info;
        acpi_handle adapter_handle;
        acpi_handle device_handle;

+       acpi_handle search_handle;
+       u32 speed;
+       u32 min_speed;

 };
 
 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
 };
 
 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)


@@ -130,19 +133,18 @@ static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
                return 1;
 
        info->addr = sb->slave_address;
                return 1;
 
        info->addr = sb->slave_address;

+       lookup->speed = sb->connection_speed;

        if (sb->access_mode == ACPI_I2C_10BIT_MODE)
                info->flags |= I2C_CLIENT_TEN;
 
        return 1;
 }
 
        if (sb->access_mode == ACPI_I2C_10BIT_MODE)
                info->flags |= I2C_CLIENT_TEN;
 
        return 1;
 }
 

-static int i2c_acpi_get_info(struct acpi_device *adev,
-                            struct i2c_board_info *info,
-                            acpi_handle *adapter_handle)
+static int i2c_acpi_do_lookup(struct acpi_device *adev,
+                             struct i2c_acpi_lookup *lookup)

 {
 {

+       struct i2c_board_info *info = lookup->info;

        struct list_head resource_list;
        struct list_head resource_list;

-       struct resource_entry *entry;
-       struct i2c_acpi_lookup lookup;

        int ret;
 
        if (acpi_bus_get_status(adev) || !adev->status.present ||
        int ret;
 
        if (acpi_bus_get_status(adev) || !adev->status.present ||


@@ -150,24 +152,41 @@ static int i2c_acpi_get_info(struct acpi_device *adev,
                return -EINVAL;
 
        memset(info, 0, sizeof(*info));
                return -EINVAL;
 
        memset(info, 0, sizeof(*info));

-       info->fwnode = acpi_fwnode_handle(adev);
-
-       memset(&lookup, 0, sizeof(lookup));
-       lookup.device_handle = acpi_device_handle(adev);
-       lookup.info = info;
+       lookup->device_handle = acpi_device_handle(adev);

 
        /* Look up for I2cSerialBus resource */
        INIT_LIST_HEAD(&resource_list);
        ret = acpi_dev_get_resources(adev, &resource_list,
 
        /* Look up for I2cSerialBus resource */
        INIT_LIST_HEAD(&resource_list);
        ret = acpi_dev_get_resources(adev, &resource_list,

-                                    i2c_acpi_fill_info, &lookup);
+                                    i2c_acpi_fill_info, lookup);

        acpi_dev_free_resource_list(&resource_list);
 
        if (ret < 0 || !info->addr)
                return -EINVAL;
 
        acpi_dev_free_resource_list(&resource_list);
 
        if (ret < 0 || !info->addr)
                return -EINVAL;
 

+       return 0;
+}
+
+static int i2c_acpi_get_info(struct acpi_device *adev,
+                            struct i2c_board_info *info,
+                            acpi_handle *adapter_handle)
+{
+       struct list_head resource_list;
+       struct resource_entry *entry;
+       struct i2c_acpi_lookup lookup;
+       int ret;
+
+       memset(&lookup, 0, sizeof(lookup));
+       lookup.info = info;
+
+       ret = i2c_acpi_do_lookup(adev, &lookup);
+       if (ret)
+               return ret;
+
+       info->fwnode = acpi_fwnode_handle(adev);

        *adapter_handle = lookup.adapter_handle;
 
        /* Then fill IRQ number if any */
        *adapter_handle = lookup.adapter_handle;
 
        /* Then fill IRQ number if any */

+       INIT_LIST_HEAD(&resource_list);

        ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
        if (ret < 0)
                return -EINVAL;
        ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
        if (ret < 0)
                return -EINVAL;


@@ -248,6 +267,64 @@ static void i2c_acpi_register_devices(struct i2c_adapter *adap)
                dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 }
 
                dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 }
 

+static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
+                                          void *data, void **return_value)
+{
+       struct i2c_acpi_lookup *lookup = data;
+       struct acpi_device *adev;
+
+       if (acpi_bus_get_device(handle, &adev))
+               return AE_OK;
+
+       if (i2c_acpi_do_lookup(adev, lookup))
+               return AE_OK;
+
+       if (lookup->search_handle != lookup->adapter_handle)
+               return AE_OK;
+
+       if (lookup->speed <= lookup->min_speed)
+               lookup->min_speed = lookup->speed;
+
+       return AE_OK;
+}
+
+/**
+ * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
+ * @dev: The device owning the bus
+ *
+ * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
+ * devices connected to this bus and use the speed of slowest device.
+ *
+ * Returns the speed in Hz or zero
+ */
+u32 i2c_acpi_find_bus_speed(struct device *dev)
+{
+       struct i2c_acpi_lookup lookup;
+       struct i2c_board_info dummy;
+       acpi_status status;
+
+       if (!has_acpi_companion(dev))
+               return 0;
+
+       memset(&lookup, 0, sizeof(lookup));
+       lookup.search_handle = ACPI_HANDLE(dev);
+       lookup.min_speed = UINT_MAX;
+       lookup.info = &dummy;
+
+       status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+                                    I2C_ACPI_MAX_SCAN_DEPTH,
+                                    i2c_acpi_lookup_speed, NULL,
+                                    &lookup, NULL);
+
+       if (ACPI_FAILURE(status)) {
+               dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
+               return 0;
+       }
+
+       return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
+}
+EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
+

 static int i2c_acpi_match_adapter(struct device *dev, void *data)
 {
        struct i2c_adapter *adapter = i2c_verify_adapter(dev);
 static int i2c_acpi_match_adapter(struct device *dev, void *data)
 {
        struct i2c_adapter *adapter = i2c_verify_adapter(dev);