diff options
| -rw-r--r-- | drivers/i2c/i2c-core.c | 99 | ||||
| -rw-r--r-- | include/linux/i2c.h | 9 |
2 files changed, 97 insertions, 11 deletions
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index d4b2f66..0579442 100644 --- 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; + acpi_handle search_handle; + u32 speed; + u32 min_speed; }; 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; + lookup->speed = sb->connection_speed; 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 resource_entry *entry; - struct i2c_acpi_lookup lookup; 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)); - 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, - i2c_acpi_fill_info, &lookup); + i2c_acpi_fill_info, lookup); 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 */ + INIT_LIST_HEAD(&resource_list); 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"); } +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); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index c1f60a3..5b4a3cb 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -780,4 +780,13 @@ static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node } #endif /* CONFIG_OF */ +#if IS_ENABLED(CONFIG_ACPI) +u32 i2c_acpi_find_bus_speed(struct device *dev); +#else +static inline u32 i2c_acpi_find_bus_speed(struct device *dev) +{ + return 0; +} +#endif /* CONFIG_ACPI */ + #endif /* _LINUX_I2C_H */ |