linux-pinenote/include/linux/mfd/core.h
Andres Salomon 1e29af62f2 mfd: Add refcounting support to mfd_cells
This provides convenience functions for sharing of cells across
multiple mfd clients.  Mfd drivers can provide enable/disable hooks
to actually tweak the hardware, and clients can call
mfd_shared_cell_{en,dis}able without having to worry about whether
or not another client happens to have enabled or disabled the
cell/hardware.

Note that this is purely optional; drivers can continue to use
the mfd_cell's enable/disable hooks for their own purposes, if
desired.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2011-03-23 10:41:58 +01:00

90 lines
2.4 KiB
C

/*
* drivers/mfd/mfd-core.h
*
* core MFD support
* Copyright (c) 2006 Ian Molton
* Copyright (c) 2007 Dmitry Baryshkov
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#ifndef MFD_CORE_H
#define MFD_CORE_H
#include <linux/platform_device.h>
/*
* 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;
/* refcounting for multiple drivers to use a single cell */
atomic_t *usage_count;
int (*enable)(struct platform_device *dev);
int (*disable)(struct platform_device *dev);
int (*suspend)(struct platform_device *dev);
int (*resume)(struct platform_device *dev);
/* mfd_data can be used to pass data to client drivers */
void *mfd_data;
/*
* 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;
};
/*
* 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_shared_cell_enable(struct platform_device *pdev);
extern int mfd_shared_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->dev.platform_data;
}
/*
* Given a platform device that's been created by mfd_add_devices(), fetch
* the .mfd_data entry from the mfd_cell that created it.
*/
static inline void *mfd_get_data(struct platform_device *pdev)
{
return mfd_get_cell(pdev)->mfd_data;
}
extern int mfd_add_devices(struct device *parent, int id,
struct mfd_cell *cells, int n_devs,
struct resource *mem_base,
int irq_base);
extern void mfd_remove_devices(struct device *parent);
#endif