Multi Function Devices (MFDs) have multiple sub module whose driver is developed in different sub-system like GPIO, regulators, RTC, clock etc. The device tree of such device contains multiple sub-node which contains the properties of these sub-modules.
The sub module gets of_node handle either by the dev->of_node or by getting the child node handle from parent DT handle by finding child name on parent's of_node. To provide the of_node of sub-module directly, currently there is only one approach: - Add compatible value when defining the sub-module in mfd core and add this properties when adding DT. Introduce the of_node_name of each sub devices which is set when defining the mfd_cells of the sub devices and get the handle of these child node when adding the mfd_devices by getting the sub-node handle with matching the node name getting the sub-node handle with matching the node name. Signed-off-by: Laxman Dewangan <[email protected]> --- Creating this patch based on the discussion on patch [PATCH 1/4] mfd: add support for AMS AS3722 PMIC The discussion on above patch is not concluded and want to have further discussion on this patch. Documentation/devicetree/bindings/mfd/mfd-core.txt | 57 ++++++++++++++++++++ drivers/mfd/mfd-core.c | 10 +++- include/linux/mfd/core.h | 6 ++ 3 files changed, 71 insertions(+), 2 deletions(-) create mode 100644 Documentation/devicetree/bindings/mfd/mfd-core.txt diff --git a/Documentation/devicetree/bindings/mfd/mfd-core.txt b/Documentation/devicetree/bindings/mfd/mfd-core.txt new file mode 100644 index 0000000..d68c893 --- /dev/null +++ b/Documentation/devicetree/bindings/mfd/mfd-core.txt @@ -0,0 +1,57 @@ +MFD DT binding document +----------------------- + +Multi Function Devices (MFDs) have multiple sub module whose driver is developed +in different sub-system like GPIO, regulators, RTC, clock etc. The device +tree of such device contains multiple sub-node which contains the properties +of these sub-modules. +The sub modules get of_node handle either by the dev->of_node or by getting +the child node handle from parent DT handle by finding child name on parent's +of_node. +To provide the of_node of sub-module directly, there is two approach: +- Add compatible value when defining the sub-module in mfd core and + add this properties when adding DT. +- Add the of_node_name when defining the sub-module in mfd core and + add keep same name of child node when adding DT. + +If none of above matches then sub-module driver will not get their of_node +and they need to derive the method to get their node from parent node. + +Examples: +DT file: +-------- + mfd_device_dt { + .... + gpio_child { + /* Properties which need by gpio sub module */ + }; + + rtc_child { + /* Properties which need by rtc sub module */ + }; + + regulator_child { + /* Properties which need by regulator sub module */ + }; + }; + + +Driver code: +----------- +static struct mfd_cell mfd_abc_devs[] = { + { + .name = "mfd-abc-gpio", + .of_node_name = "gpio_child"; + }, + { + .name = "mfd-abc-regulator", + .of_node_name = "regulator_child"; + }, + { + .name = "mfd-abc-rtc", + .of_node_name = "rtc_child"; + }, +}; + +Here sub-node names are gpio_child, rtc_child, regulator_child and it is same +as of_node_name defined in the driver. diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c index f421586..88836c2 100644 --- a/drivers/mfd/mfd-core.c +++ b/drivers/mfd/mfd-core.c @@ -99,9 +99,15 @@ static int mfd_add_device(struct device *parent, int id, pdev->dev.dma_mask = parent->dma_mask; pdev->dev.dma_parms = parent->dma_parms; - if (parent->of_node && cell->of_compatible) { + if (parent->of_node && (cell->of_compatible || cell->of_node_name)) { for_each_child_of_node(parent->of_node, np) { - if (of_device_is_compatible(np, cell->of_compatible)) { + if (cell->of_compatible && + of_device_is_compatible(np, cell->of_compatible)) { + pdev->dev.of_node = np; + break; + } + if (cell->of_node_name && np->name && + !strcmp(cell->of_node_name, np->name)) { pdev->dev.of_node = np; break; } diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h index cebe97e..4cf891f 100644 --- a/include/linux/mfd/core.h +++ b/include/linux/mfd/core.h @@ -45,6 +45,12 @@ struct mfd_cell { const char *of_compatible; /* + * Device tree sub-node name. + * See: Documentation/devicetree/bindings/mfd/mfd-core.txt + */ + const char *of_node_name; + + /* * These resources can be specified relative to the parent device. * For accessing hardware you should use resources from the platform dev */ -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
