Commit 5a47c0fb authored by Lee Jones's avatar Lee Jones
Browse files

mfd: mfd-core: Remove usage counting for .{en,dis}able() call-backs 



The MFD implementation for reference counting was complex and unnecessary.
There was only one bona fide user which has now been converted to handle
the process in a different way. Any future resource protection, shared
enablement functions should be handed by the parent device, rather than
through the MFD subsystem API.

Signed-off-by: default avatarLee Jones <lee.jones@linaro.org>
Reviewed-by: default avatarDaniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
parent 504c3fad

drivers/mfd/mfd-core.c

+9 −48
Original line number Diff line number Diff line
@@ -26,53 +26,31 @@ static struct device_type mfd_dev_type = { 
int mfd_cell_enable(struct platform_device *pdev)

{

	const struct mfd_cell *cell = mfd_get_cell(pdev);

	int err = 0;



	if (!cell->enable) {

		dev_dbg(&pdev->dev, "No .enable() call-back registered\n");

		return 0;

	}



	/* only call enable hook if the cell wasn't previously enabled */

	if (atomic_inc_return(cell->usage_count) == 1)

		err = cell->enable(pdev);



	/* if the enable hook failed, decrement counter to allow retries */

	if (err)

		atomic_dec(cell->usage_count);



	return err;

	return cell->enable(pdev);

}

EXPORT_SYMBOL(mfd_cell_enable);



int mfd_cell_disable(struct platform_device *pdev)

{

	const struct mfd_cell *cell = mfd_get_cell(pdev);

	int err = 0;



	if (!cell->disable) {

		dev_dbg(&pdev->dev, "No .disable() call-back registered\n");

		return 0;

	}



	/* only disable if no other clients are using it */

	if (atomic_dec_return(cell->usage_count) == 0)

		err = cell->disable(pdev);



	/* if the disable hook failed, increment to allow retries */

	if (err)

		atomic_inc(cell->usage_count);



	/* sanity check; did someone call disable too many times? */

	WARN_ON(atomic_read(cell->usage_count) < 0);



	return err;

	return cell->disable(pdev);

}

EXPORT_SYMBOL(mfd_cell_disable);



static int mfd_platform_add_cell(struct platform_device *pdev,

				 const struct mfd_cell *cell,

				 atomic_t *usage_count)

				 const struct mfd_cell *cell)

{

	if (!cell)

		return 0;
@@ -81,7 +59,6 @@ static int mfd_platform_add_cell(struct platform_device *pdev, 
	if (!pdev->mfd_cell)

		return -ENOMEM;



	pdev->mfd_cell->usage_count = usage_count;

	return 0;

}
@@ -144,7 +121,7 @@ static inline void mfd_acpi_add_device(const struct mfd_cell *cell, 
#endif



static int mfd_add_device(struct device *parent, int id,

			  const struct mfd_cell *cell, atomic_t *usage_count,

			  const struct mfd_cell *cell,

			  struct resource *mem_base,

			  int irq_base, struct irq_domain *domain)

{
@@ -206,7 +183,7 @@ static int mfd_add_device(struct device *parent, int id, 
			goto fail_alias;

	}



	ret = mfd_platform_add_cell(pdev, cell, usage_count);

	ret = mfd_platform_add_cell(pdev, cell);

	if (ret)

		goto fail_alias;
@@ -296,16 +273,9 @@ int mfd_add_devices(struct device *parent, int id, 
{

	int i;

	int ret;

	atomic_t *cnts;



	/* initialize reference counting for all cells */

	cnts = kcalloc(n_devs, sizeof(*cnts), GFP_KERNEL);

	if (!cnts)

		return -ENOMEM;



	for (i = 0; i < n_devs; i++) {

		atomic_set(&cnts[i], 0);

		ret = mfd_add_device(parent, id, cells + i, cnts + i, mem_base,

		ret = mfd_add_device(parent, id, cells + i, mem_base,

				     irq_base, domain);

		if (ret)

			goto fail;
@@ -316,17 +286,15 @@ int mfd_add_devices(struct device *parent, int id, 
fail:

	if (i)

		mfd_remove_devices(parent);

	else

		kfree(cnts);



	return ret;

}

EXPORT_SYMBOL(mfd_add_devices);



static int mfd_remove_devices_fn(struct device *dev, void *c)

static int mfd_remove_devices_fn(struct device *dev, void *data)

{

	struct platform_device *pdev;

	const struct mfd_cell *cell;

	atomic_t **usage_count = c;



	if (dev->type != &mfd_dev_type)

		return 0;
@@ -337,20 +305,13 @@ static int mfd_remove_devices_fn(struct device *dev, void *c) 
	regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies,

					       cell->num_parent_supplies);



	/* find the base address of usage_count pointers (for freeing) */

	if (!*usage_count || (cell->usage_count < *usage_count))

		*usage_count = cell->usage_count;



	platform_device_unregister(pdev);

	return 0;

}



void mfd_remove_devices(struct device *parent)

{

	atomic_t *cnts = NULL;



	device_for_each_child_reverse(parent, &cnts, mfd_remove_devices_fn);

	kfree(cnts);

	device_for_each_child_reverse(parent, NULL, mfd_remove_devices_fn);

}

EXPORT_SYMBOL(mfd_remove_devices);

include/linux/mfd/core.h

+0 −2
Original line number Diff line number Diff line
@@ -59,8 +59,6 @@ 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);

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