linux-stable/include/linux/mfd/core.h

164 lines
4.7 KiB
C
Raw Normal View History

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* drivers/mfd/mfd-core.h
*
* core MFD support
* Copyright (c) 2006 Ian Molton
* Copyright (c) 2007 Dmitry Baryshkov
*/
#ifndef MFD_CORE_H
#define MFD_CORE_H
#include <linux/platform_device.h>
#define MFD_RES_SIZE(arr) (sizeof(arr) / sizeof(struct resource))
#define MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, _of_reg, _use_of_reg, _match) \
{ \
.name = (_name), \
.resources = (_res), \
.num_resources = MFD_RES_SIZE((_res)), \
.platform_data = (_pdata), \
.pdata_size = (_pdsize), \
.of_compatible = (_compat), \
.of_reg = (_of_reg), \
.use_of_reg = (_use_of_reg), \
.acpi_match = (_match), \
.id = (_id), \
}
#define MFD_CELL_OF_REG(_name, _res, _pdata, _pdsize, _id, _compat, _of_reg) \
MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, _of_reg, true, NULL)
#define MFD_CELL_OF(_name, _res, _pdata, _pdsize, _id, _compat) \
MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, 0, false, NULL)
#define MFD_CELL_ACPI(_name, _res, _pdata, _pdsize, _id, _match) \
MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, NULL, 0, false, _match)
#define MFD_CELL_BASIC(_name, _res, _pdata, _pdsize, _id) \
MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, NULL, 0, false, NULL)
#define MFD_CELL_RES(_name, _res) \
MFD_CELL_ALL(_name, _res, NULL, 0, 0, NULL, 0, false, NULL)
#define MFD_CELL_NAME(_name) \
MFD_CELL_ALL(_name, NULL, NULL, 0, 0, NULL, 0, false, NULL)
#define MFD_DEP_LEVEL_NORMAL 0
#define MFD_DEP_LEVEL_HIGH 1
struct irq_domain;
struct software_node;
/* Matches ACPI PNP id, either _HID or _CID, or ACPI _ADR */
struct mfd_cell_acpi_match {
const char *pnpid;
const unsigned long long adr;
};
/*
* This struct describes the MFD part ("cell").
* After registration the copy of this structure will become the platform data
* of the resulting platform_device
*/
struct mfd_cell {
const char *name;
int id;
int level;
int (*enable)(struct platform_device *dev);
int (*disable)(struct platform_device *dev);
int (*suspend)(struct platform_device *dev);
int (*resume)(struct platform_device *dev);
/* platform data passed to the sub devices drivers */
void *platform_data;
size_t pdata_size;
/* Software node for the device. */
const struct software_node *swnode;
/*
* Device Tree compatible string
* See: Documentation/devicetree/usage-model.rst Chapter 2.2 for details
*/
const char *of_compatible;
mfd: core: Make a best effort attempt to match devices with the correct of_nodes Currently, when a child platform device (sometimes referred to as a sub-device) is registered via the Multi-Functional Device (MFD) API, the framework attempts to match the newly registered platform device with its associated Device Tree (OF) node. Until now, the device has been allocated the first node found with an identical OF compatible string. Unfortunately, if there are, say for example '3' devices which are to be handled by the same driver and therefore have the same compatible string, each of them will be allocated a pointer to the *first* node. An example Device Tree entry might look like this: mfd_of_test { compatible = "mfd,of-test-parent"; #address-cells = <0x02>; #size-cells = <0x02>; child@aaaaaaaaaaaaaaaa { compatible = "mfd,of-test-child"; reg = <0xaaaaaaaa 0xaaaaaaaa 0 0x11>, <0xbbbbbbbb 0xbbbbbbbb 0 0x22>; }; child@cccccccc { compatible = "mfd,of-test-child"; reg = <0x00000000 0xcccccccc 0 0x33>; }; child@dddddddd00000000 { compatible = "mfd,of-test-child"; reg = <0xdddddddd 0x00000000 0 0x44>; }; }; When used with example sub-device registration like this: static const struct mfd_cell mfd_of_test_cell[] = { OF_MFD_CELL("mfd-of-test-child", NULL, NULL, 0, 0, "mfd,of-test-child"), OF_MFD_CELL("mfd-of-test-child", NULL, NULL, 0, 1, "mfd,of-test-child"), OF_MFD_CELL("mfd-of-test-child", NULL, NULL, 0, 2, "mfd,of-test-child") }; ... the current implementation will result in all devices being allocated the first OF node found containing a matching compatible string: [0.712511] mfd-of-test-child mfd-of-test-child.0: Probing platform device: 0 [0.712710] mfd-of-test-child mfd-of-test-child.0: Using OF node: child@aaaaaaaaaaaaaaaa [0.713033] mfd-of-test-child mfd-of-test-child.1: Probing platform device: 1 [0.713381] mfd-of-test-child mfd-of-test-child.1: Using OF node: child@aaaaaaaaaaaaaaaa [0.713691] mfd-of-test-child mfd-of-test-child.2: Probing platform device: 2 [0.713889] mfd-of-test-child mfd-of-test-child.2: Using OF node: child@aaaaaaaaaaaaaaaa After this patch each device will be allocated a unique OF node: [0.712511] mfd-of-test-child mfd-of-test-child.0: Probing platform device: 0 [0.712710] mfd-of-test-child mfd-of-test-child.0: Using OF node: child@aaaaaaaaaaaaaaaa [0.713033] mfd-of-test-child mfd-of-test-child.1: Probing platform device: 1 [0.713381] mfd-of-test-child mfd-of-test-child.1: Using OF node: child@cccccccc [0.713691] mfd-of-test-child mfd-of-test-child.2: Probing platform device: 2 [0.713889] mfd-of-test-child mfd-of-test-child.2: Using OF node: child@dddddddd00000000 Which is fine if all OF nodes are identical. However if we wish to apply an attribute to particular device, we really need to ensure the correct OF node will be associated with the device containing the correct address. We accomplish this by matching the device's address expressed in DT with one provided during sub-device registration. Like this: static const struct mfd_cell mfd_of_test_cell[] = { OF_MFD_CELL_REG("mfd-of-test-child", NULL, NULL, 0, 1, "mfd,of-test-child", 0xdddddddd00000000), OF_MFD_CELL_REG("mfd-of-test-child", NULL, NULL, 0, 2, "mfd,of-test-child", 0xaaaaaaaaaaaaaaaa), OF_MFD_CELL_REG("mfd-of-test-child", NULL, NULL, 0, 3, "mfd,of-test-child", 0x00000000cccccccc) }; This will ensure a specific device (designated here using the platform_ids; 1, 2 and 3) is matched with a particular OF node: [0.712511] mfd-of-test-child mfd-of-test-child.0: Probing platform device: 0 [0.712710] mfd-of-test-child mfd-of-test-child.0: Using OF node: child@dddddddd00000000 [0.713033] mfd-of-test-child mfd-of-test-child.1: Probing platform device: 1 [0.713381] mfd-of-test-child mfd-of-test-child.1: Using OF node: child@aaaaaaaaaaaaaaaa [0.713691] mfd-of-test-child mfd-of-test-child.2: Probing platform device: 2 [0.713889] mfd-of-test-child mfd-of-test-child.2: Using OF node: child@cccccccc This implementation is still not infallible, hence the mention of "best effort" in the commit subject. Since we have not *insisted* on the existence of 'reg' properties (in some scenarios they just do not make sense) and no device currently uses the new 'of_reg' attribute, we have to make an on-the-fly judgement call whether to associate the OF node anyway. Which we do in cases where parent drivers haven't specified a particular OF node to match to. So there is a *slight* possibility of the following result (note: the implementation here is convoluted, but it shows you one means by which this process can still break): /* * First entry will match to the first OF node with matching compatible * Second will fail, since the first took its OF node and is no longer available * Third will succeed */ static const struct mfd_cell mfd_of_test_cell[] = { OF_MFD_CELL("mfd-of-test-child", NULL, NULL, 0, 1, "mfd,of-test-child"), OF_MFD_CELL_REG("mfd-of-test-child", NULL, NULL, 0, 2, "mfd,of-test-child", 0xaaaaaaaaaaaaaaaa), OF_MFD_CELL_REG("mfd-of-test-child", NULL, NULL, 0, 3, "mfd,of-test-child", 0x00000000cccccccc) }; The result: [0.753869] mfd-of-test-parent mfd_of_test: Registering 3 devices [0.756597] mfd-of-test-child: Failed to locate of_node [id: 2] [0.759999] mfd-of-test-child mfd-of-test-child.1: Probing platform device: 1 [0.760314] mfd-of-test-child mfd-of-test-child.1: Using OF node: child@aaaaaaaaaaaaaaaa [0.760908] mfd-of-test-child mfd-of-test-child.2: Probing platform device: 2 [0.761183] mfd-of-test-child mfd-of-test-child.2: No OF node associated with this device [0.761621] mfd-of-test-child mfd-of-test-child.3: Probing platform device: 3 [0.761899] mfd-of-test-child mfd-of-test-child.3: Using OF node: child@cccccccc We could code around this with some pre-parsing semantics, but the added complexity required to cover each and every corner-case is not justified. Merely patching the current failing (via this patch) is already working with some pretty small corner-cases. Other issues should be patched in the parent drivers which can be achieved simply by implementing OF_MFD_CELL_REG(). Signed-off-by: Lee Jones <lee.jones@linaro.org>
2020-06-11 06:35:33 +00:00
/*
* Address as defined in Device Tree. Used to compement 'of_compatible'
* (above) when matching OF nodes with devices that have identical
* compatible strings
*/
const u64 of_reg;
/* Set to 'true' to use 'of_reg' (above) - allows for of_reg=0 */
bool use_of_reg;
/* Matches ACPI */
const struct mfd_cell_acpi_match *acpi_match;
/*
* These resources can be specified relative to the parent device.
* For accessing hardware you should use resources from the platform dev
*/
int num_resources;
const struct resource *resources;
/* don't check for resource conflicts */
bool ignore_resource_conflicts;
/*
* Disable runtime PM callbacks for this subdevice - see
* pm_runtime_no_callbacks().
*/
bool pm_runtime_no_callbacks;
/* A list of regulator supplies that should be mapped to the MFD
* device rather than the child device when requested
*/
const char * const *parent_supplies;
int num_parent_supplies;
};
/*
* Convenience functions for clients using shared cells. Refcounting
* happens automatically, with the cell's enable/disable callbacks
* being called only when a device is first being enabled or no other
* clients are making use of it.
*/
extern int mfd_cell_enable(struct platform_device *pdev);
extern int mfd_cell_disable(struct platform_device *pdev);
/*
* Given a platform device that's been created by mfd_add_devices(), fetch
* the mfd_cell that created it.
*/
static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev)
{
return pdev->mfd_cell;
}
extern int mfd_add_devices(struct device *parent, int id,
const struct mfd_cell *cells, int n_devs,
struct resource *mem_base,
int irq_base, struct irq_domain *irq_domain);
static inline int mfd_add_hotplug_devices(struct device *parent,
const struct mfd_cell *cells, int n_devs)
{
return mfd_add_devices(parent, PLATFORM_DEVID_AUTO, cells, n_devs,
NULL, 0, NULL);
}
extern void mfd_remove_devices(struct device *parent);
extern void mfd_remove_devices_late(struct device *parent);
extern int devm_mfd_add_devices(struct device *dev, int id,
const struct mfd_cell *cells, int n_devs,
struct resource *mem_base,
int irq_base, struct irq_domain *irq_domain);
#endif