On Mon, Jun 11, 2018 at 6:01 PM, Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote: > There are still quite a few cases where a device might want to get to a > different node of the device-tree, obtain the resources and map them. > > Drivers doing that currently open code the whole thing, which is error > proe. > > We have of_iomap() and of_io_request_and_map() but they both have shortcomings, > such as not returning the size of the resource found (which can be necessary) > and not being "managed". > > This adds a devm_of_iomap() that provides all of these and should probably > replace uses of the above in most drivers. > > Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > --- > > I'm cooking a driver that uses this, if there's no objection I'd like > to carry it in my pull request for that driver (it can also exist in > the DT tree of course). Just let me know. We generally only use of_iomap when there is no struct device for any new driver. Why can't you use devm_ioremap_resource? Is this a non-platform bus device? > > drivers/of/address.c | 35 +++++++++++++++++++++++++++++++++++ > include/linux/of_address.h | 5 +++++ > 2 files changed, 40 insertions(+) > > diff --git a/drivers/of/address.c b/drivers/of/address.c > index cf83c05f5650..b7d49ee7b690 100644 > --- a/drivers/of/address.c > +++ b/drivers/of/address.c > @@ -807,6 +807,41 @@ void __iomem *of_io_request_and_map(struct device_node *np, int index, > } > EXPORT_SYMBOL(of_io_request_and_map); > > +/* > + * devm_of_iomap - Requests a resource and maps the memory mapped IO > + * for a given device_node managed by a given device > + * > + * Checks that a resource is a valid memory region, requests the memory > + * region and ioremaps it. All operations are managed and will be undone > + * on driver detach of the device. > + * > + * This is to be used when a device requests/maps resources described > + * by other device tree nodes (children or otherwise). > + * > + * @dev: The device "managing" the resource > + * @node: The device-tree node where the resource resides > + * @index: index of the MMIO range in the "reg" property > + * @size: Returns the size of the resource (pass NULL if not needed) > + * Returns a pointer to the requested and mapped memory or an ERR_PTR() encoded > + * error code on failure. Usage example: > + * > + * base = devm_of_iomap(&pdev->dev, node, 0, NULL); > + * if (IS_ERR(base)) > + * return PTR_ERR(base); > + */ > +void __iomem *devm_of_iomap(struct device *dev, struct device_node *node, int index, > + resource_size_t *size) of/address.c generally doesn't depend on struct device. I'd like to keep it that way. Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
