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devres: Add devm_of_iomap()

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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.

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 useful) 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@kernel.crashing.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
This commit is contained in:
Benjamin Herrenschmidt 2018-06-05 13:21:26 +10:00
parent d5e748ff2b
commit d5e838275c
2 changed files with 40 additions and 0 deletions
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4
include/linux/device.h
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@ -696,6 +696,10 @@ extern void devm_free_pages(struct device *dev, unsigned long addr);
void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res);
void __iomem *devm_of_iomap(struct device *dev,
struct device_node *node, int index,
resource_size_t *size);
/* allows to add/remove a custom action to devres stack */
int devm_add_action(struct device *dev, void (*action)(void *), void *data);
void devm_remove_action(struct device *dev, void (*action)(void *), void *data);

36
lib/devres.c
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@ -4,6 +4,7 @@
#include <linux/io.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <linux/of_address.h>
enum devm_ioremap_type {
DEVM_IOREMAP = 0,
@ -162,6 +163,41 @@ void __iomem *devm_ioremap_resource(struct device *dev, struct resource *res)
}
EXPORT_SYMBOL(devm_ioremap_resource);
/*
* 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)
{
struct resource res;
if (of_address_to_resource(node, index, &res))
return IOMEM_ERR_PTR(-EINVAL);
if (size)
*size = resource_size(&res);
return devm_ioremap_resource(dev, &res);
}
EXPORT_SYMBOL(devm_of_iomap);
#ifdef CONFIG_HAS_IOPORT_MAP
/*
* Generic iomap devres