From 1e29af62f2b285bd18685da93c3ce8c33ca2d1db Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Thu, 17 Feb 2011 19:07:34 -0800 Subject: 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 Signed-off-by: Samuel Ortiz --- include/linux/mfd/core.h | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h index 71cd1f983cce..22a2f5ebd9db 100644 --- a/include/linux/mfd/core.h +++ b/include/linux/mfd/core.h @@ -25,8 +25,11 @@ 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); @@ -50,6 +53,15 @@ struct mfd_cell { 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. @@ -69,7 +81,7 @@ static inline void *mfd_get_data(struct platform_device *pdev) } extern int mfd_add_devices(struct device *parent, int id, - const struct mfd_cell *cells, int n_devs, + struct mfd_cell *cells, int n_devs, struct resource *mem_base, int irq_base); -- cgit v1.2.2