On Thursday, October 01, 2015 02:20:23 PM Andy Shevchenko wrote: > From: Mika Westerberg <[email protected]> > > The way we currently scan I2C devices behind an I2C host controller does not > work in cases where the I2C device in question is not declared directly below > the host controller ACPI node. > > This is perfectly legal according the ACPI 6.0 specification and some existing > systems are doing this. > > To be able to enumerate all devices which are connected to a certain I2C host > controller we need to rework the current I2C scanning routine a bit. Instead > of > scanning directly below the host controller we scan the whole ACPI namespace > for present devices with valid I2cSerialBus() connection pointing to the host > controller in question. > > Signed-off-by: Mika Westerberg <[email protected]> > Signed-off-by: Andy Shevchenko <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]> > --- > drivers/i2c/i2c-core.c | 82 > ++++++++++++++++++++++++++++++++++++-------------- > 1 file changed, 59 insertions(+), 23 deletions(-) > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index a732107..24e516e 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -99,27 +99,40 @@ struct gsb_buffer { > }; > } __packed; > > -static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data) > +struct acpi_i2c_lookup { > + struct i2c_board_info *info; > + acpi_handle adapter_handle; > + acpi_handle device_handle; > +}; > + > +static int acpi_i2c_find_address(struct acpi_resource *ares, void *data) > { > - struct i2c_board_info *info = data; > + struct acpi_i2c_lookup *lookup = data; > + struct i2c_board_info *info = lookup->info; > + struct acpi_resource_i2c_serialbus *sb; > + acpi_handle adapter_handle; > + acpi_status status; > > - if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) { > - struct acpi_resource_i2c_serialbus *sb; > + if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) > + return 1; > > - sb = &ares->data.i2c_serial_bus; > - if (!info->addr && sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) { > - info->addr = sb->slave_address; > - if (sb->access_mode == ACPI_I2C_10BIT_MODE) > - info->flags |= I2C_CLIENT_TEN; > - } > - } else if (!info->irq) { > - struct resource r; > + sb = &ares->data.i2c_serial_bus; > + if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) > + return 1; > > - if (acpi_dev_resource_interrupt(ares, 0, &r)) > - info->irq = r.start; > + /* > + * Extract the ResourceSource and make sure that the handle matches > + * with the I2C adapter handle. > + */ > + status = acpi_get_handle(lookup->device_handle, > + sb->resource_source.string_ptr, > + &adapter_handle); > + if (ACPI_SUCCESS(status) && adapter_handle == lookup->adapter_handle) { > + info->addr = sb->slave_address; > + if (sb->access_mode == ACPI_I2C_10BIT_MODE) > + info->flags |= I2C_CLIENT_TEN; > } > > - /* Tell the ACPI core to skip this resource */ > return 1; > } > > @@ -128,6 +141,8 @@ static acpi_status acpi_i2c_add_device(acpi_handle > handle, u32 level, > { > struct i2c_adapter *adapter = data; > struct list_head resource_list; > + struct acpi_i2c_lookup lookup; > + struct resource_entry *entry; > struct i2c_board_info info; > struct acpi_device *adev; > int ret; > @@ -140,14 +155,37 @@ static acpi_status acpi_i2c_add_device(acpi_handle > handle, u32 level, > memset(&info, 0, sizeof(info)); > info.fwnode = acpi_fwnode_handle(adev); > > + memset(&lookup, 0, sizeof(lookup)); > + lookup.adapter_handle = ACPI_HANDLE(adapter->dev.parent); > + lookup.device_handle = handle; > + lookup.info = &info; > + > + /* > + * Look up for I2cSerialBus resource with ResourceSource that > + * matches with this adapter. > + */ > INIT_LIST_HEAD(&resource_list); > ret = acpi_dev_get_resources(adev, &resource_list, > - acpi_i2c_add_resource, &info); > + acpi_i2c_find_address, &lookup); > acpi_dev_free_resource_list(&resource_list); > > if (ret < 0 || !info.addr) > return AE_OK; > > + /* Then fill IRQ number if any */ > + ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL); > + if (ret < 0) > + return AE_OK; > + > + resource_list_for_each_entry(entry, &resource_list) { > + if (resource_type(entry->res) == IORESOURCE_IRQ) { > + info.irq = entry->res->start; > + break; > + } > + } > + > + acpi_dev_free_resource_list(&resource_list); > + > adev->power.flags.ignore_parent = true; > strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type)); > if (!i2c_new_device(adapter, &info)) { > @@ -160,6 +198,8 @@ static acpi_status acpi_i2c_add_device(acpi_handle > handle, u32 level, > return AE_OK; > } > > +#define ACPI_I2C_MAX_SCAN_DEPTH 32 > + > /** > * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter > * @adap: pointer to adapter > @@ -170,17 +210,13 @@ static acpi_status acpi_i2c_add_device(acpi_handle > handle, u32 level, > */ > static void acpi_i2c_register_devices(struct i2c_adapter *adap) > { > - acpi_handle handle; > acpi_status status; > > - if (!adap->dev.parent) > - return; > - > - handle = ACPI_HANDLE(adap->dev.parent); > - if (!handle) > + if (!adap->dev.parent || !has_acpi_companion(adap->dev.parent)) > return; > > - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1, > + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, > + ACPI_I2C_MAX_SCAN_DEPTH, > acpi_i2c_add_device, NULL, > adap, NULL); > if (ACPI_FAILURE(status)) > -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
