drivers/mfd/mfd-core.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * drivers/mfd/mfd-core.c
  *
  * core MFD support
  * Copyright (c) 2006 Ian Molton
  * Copyright (c) 2007,2008 Dmitry Baryshkov
  */

 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/acpi.h>
 #include <linux/property.h>
 #include <linux/mfd/core.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/irqdomain.h>
 #include <linux/of.h>
 #include <linux/regulator/consumer.h>

 static struct device_type mfd_dev_type = {
 	.name	= "mfd_device",
 };

 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;
 }
 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;
 }
 EXPORT_SYMBOL(mfd_cell_disable);

 static int mfd_platform_add_cell(struct platform_device *pdev,
 				 const struct mfd_cell *cell,
 				 atomic_t *usage_count)
 {
 	if (!cell)
 		return 0;

 	pdev->mfd_cell = kmemdup(cell, sizeof(*cell), GFP_KERNEL);
 	if (!pdev->mfd_cell)
 		return -ENOMEM;

 	pdev->mfd_cell->usage_count = usage_count;
 	return 0;
 }

 #if IS_ENABLED(CONFIG_ACPI)
 static void mfd_acpi_add_device(const struct mfd_cell *cell,
 				struct platform_device *pdev)
 {
 	const struct mfd_cell_acpi_match *match = cell->acpi_match;
 	struct acpi_device *parent, *child;
 	struct acpi_device *adev;

 	parent = ACPI_COMPANION(pdev->dev.parent);
 	if (!parent)
 		return;

 	/*
 	 * MFD child device gets its ACPI handle either from the ACPI device
 	 * directly under the parent that matches the either _HID or _CID, or
 	 * _ADR or it will use the parent handle if is no ID is given.
 	 *
 	 * Note that use of _ADR is a grey area in the ACPI specification,
 	 * though Intel Galileo Gen2 is using it to distinguish the children
 	 * devices.
 	 */
 	adev = parent;
 	if (match) {
 		if (match->pnpid) {
 			struct acpi_device_id ids[2] = {};

 			strlcpy(ids[0].id, match->pnpid, sizeof(ids[0].id));
 			list_for_each_entry(child, &parent->children, node) {
 				if (!acpi_match_device_ids(child, ids)) {
 					adev = child;
 					break;
 				}
 			}
 		} else {
 			unsigned long long adr;
 			acpi_status status;

 			list_for_each_entry(child, &parent->children, node) {
 				status = acpi_evaluate_integer(child->handle,
 							       "_ADR", NULL,
 							       &adr);
 				if (ACPI_SUCCESS(status) && match->adr == adr) {
 					adev = child;
 					break;
 				}
 			}
 		}
 	}

 	ACPI_COMPANION_SET(&pdev->dev, adev);
 }
 #else
 static inline void mfd_acpi_add_device(const struct mfd_cell *cell,
 				       struct platform_device *pdev)
 {
 }
 #endif

 static int mfd_add_device(struct device *parent, int id,
 			  const struct mfd_cell *cell, atomic_t *usage_count,
 			  struct resource *mem_base,
 			  int irq_base, struct irq_domain *domain)
 {
 	struct resource *res;
 	struct platform_device *pdev;
 	struct device_node *np = NULL;
 	int ret = -ENOMEM;
 	int platform_id;
 	int r;

 	if (id == PLATFORM_DEVID_AUTO)
 		platform_id = id;
 	else
 		platform_id = id + cell->id;

 	pdev = platform_device_alloc(cell->name, platform_id);
 	if (!pdev)
 		goto fail_alloc;

 	res = kcalloc(cell->num_resources, sizeof(*res), GFP_KERNEL);
 	if (!res)
 		goto fail_device;

 	pdev->dev.parent = parent;
 	pdev->dev.type = &mfd_dev_type;
 	pdev->dev.dma_mask = parent->dma_mask;
 	pdev->dev.dma_parms = parent->dma_parms;
 	pdev->dev.coherent_dma_mask = parent->coherent_dma_mask;

 	ret = regulator_bulk_register_supply_alias(
 			&pdev->dev, cell->parent_supplies,
 			parent, cell->parent_supplies,
 			cell->num_parent_supplies);
 	if (ret < 0)
 		goto fail_res;

 	if (parent->of_node && cell->of_compatible) {
 		for_each_child_of_node(parent->of_node, np) {
 			if (of_device_is_compatible(np, cell->of_compatible)) {
 				pdev->dev.of_node = np;
 				pdev->dev.fwnode = &np->fwnode;
 				break;
 			}
 		}
 	}

 	mfd_acpi_add_device(cell, pdev);

 	if (cell->pdata_size) {
 		ret = platform_device_add_data(pdev,
 					cell->platform_data, cell->pdata_size);
 		if (ret)
 			goto fail_alias;
 	}

 	if (cell->properties) {
 		ret = platform_device_add_properties(pdev, cell->properties);
 		if (ret)
 			goto fail_alias;
 	}

 	ret = mfd_platform_add_cell(pdev, cell, usage_count);
 	if (ret)
 		goto fail_alias;

 	for (r = 0; r < cell->num_resources; r++) {
 		res[r].name = cell->resources[r].name;
 		res[r].flags = cell->resources[r].flags;

 		/* Find out base to use */
 		if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) {
 			res[r].parent = mem_base;
 			res[r].start = mem_base->start +
 				cell->resources[r].start;
 			res[r].end = mem_base->start +
 				cell->resources[r].end;
 		} else if (cell->resources[r].flags & IORESOURCE_IRQ) {
 			if (domain) {
 				/* Unable to create mappings for IRQ ranges. */
 				WARN_ON(cell->resources[r].start !=
 					cell->resources[r].end);
 				res[r].start = res[r].end = irq_create_mapping(
 					domain, cell->resources[r].start);
 			} else {
 				res[r].start = irq_base +
 					cell->resources[r].start;
 				res[r].end   = irq_base +
 					cell->resources[r].end;
 			}
 		} else {
 			res[r].parent = cell->resources[r].parent;
 			res[r].start = cell->resources[r].start;
 			res[r].end   = cell->resources[r].end;
 		}

 		if (!cell->ignore_resource_conflicts) {
 			if (has_acpi_companion(&pdev->dev)) {
 				ret = acpi_check_resource_conflict(&res[r]);
 				if (ret)
 					goto fail_alias;
 			}
 		}
 	}

 	ret = platform_device_add_resources(pdev, res, cell->num_resources);
 	if (ret)
 		goto fail_alias;

 	ret = platform_device_add(pdev);
 	if (ret)
 		goto fail_alias;

 	if (cell->pm_runtime_no_callbacks)
 		pm_runtime_no_callbacks(&pdev->dev);

 	kfree(res);

 	return 0;

 fail_alias:
 	regulator_bulk_unregister_supply_alias(&pdev->dev,
 					       cell->parent_supplies,
 					       cell->num_parent_supplies);
 fail_res:
 	kfree(res);
 fail_device:
 	platform_device_put(pdev);
 fail_alloc:
 	return ret;
 }

 /**
  * mfd_add_devices - register child devices
  *
  * @parent:	Pointer to parent device.
  * @id:		Can be PLATFORM_DEVID_AUTO to let the Platform API take care
  *		of device numbering, or will be added to a device's cell_id.
  * @cells:	Array of (struct mfd_cell)s describing child devices.
  * @n_devs:	Number of child devices to register.
  * @mem_base:	Parent register range resource for child devices.
  * @irq_base:	Base of the range of virtual interrupt numbers allocated for
  *		this MFD device. Unused if @domain is specified.
  * @domain:	Interrupt domain to create mappings for hardware interrupts.
  */
 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 *domain)
 {
 	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,
 				     irq_base, domain);
 		if (ret)
 			goto fail;
 	}

 	return 0;

 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)
 {
 	struct platform_device *pdev;
 	const struct mfd_cell *cell;
 	atomic_t **usage_count = c;

 	if (dev->type != &mfd_dev_type)
 		return 0;

 	pdev = to_platform_device(dev);
 	cell = mfd_get_cell(pdev);

 	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);
 }
 EXPORT_SYMBOL(mfd_remove_devices);

 static void devm_mfd_dev_release(struct device *dev, void *res)
 {
 	mfd_remove_devices(dev);
 }

 /**
  * devm_mfd_add_devices - Resource managed version of mfd_add_devices()
  *
  * Returns 0 on success or an appropriate negative error number on failure.
  * All child-devices of the MFD will automatically be removed when it gets
  * unbinded.
  */
 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 *domain)
 {
 	struct device **ptr;
 	int ret;

 	ptr = devres_alloc(devm_mfd_dev_release, sizeof(*ptr), GFP_KERNEL);
 	if (!ptr)
 		return -ENOMEM;

 	ret = mfd_add_devices(dev, id, cells, n_devs, mem_base,
 			      irq_base, domain);
 	if (ret < 0) {
 		devres_free(ptr);
 		return ret;
 	}

 	*ptr = dev;
 	devres_add(dev, ptr);

 	return ret;
 }
 EXPORT_SYMBOL(devm_mfd_add_devices);

 int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
 {
 	struct mfd_cell cell_entry;
 	struct device *dev;
 	struct platform_device *pdev;
 	int i;

 	/* fetch the parent cell's device (should already be registered!) */
 	dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
 	if (!dev) {
 		printk(KERN_ERR "failed to find device for cell %s\n", cell);
 		return -ENODEV;
 	}
 	pdev = to_platform_device(dev);
 	memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));

 	WARN_ON(!cell_entry.enable);

 	for (i = 0; i < n_clones; i++) {
 		cell_entry.name = clones[i];
 		/* don't give up if a single call fails; just report error */
 		if (mfd_add_device(pdev->dev.parent, -1, &cell_entry,
 				   cell_entry.usage_count, NULL, 0, NULL))
 			dev_err(dev, "failed to create platform device '%s'\n",
 					clones[i]);
 	}

 	put_device(dev);

 	return 0;
 }
 EXPORT_SYMBOL(mfd_clone_cell);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* drivers/mfd/mfd-core.c
	*
	* core MFD support
	* Copyright (c) 2006 Ian Molton
	* Copyright (c) 2007,2008 Dmitry Baryshkov
	*/

	#include <linux/kernel.h>
	#include <linux/platform_device.h>
	#include <linux/acpi.h>
	#include <linux/property.h>
	#include <linux/mfd/core.h>
	#include <linux/pm_runtime.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/irqdomain.h>
	#include <linux/of.h>
	#include <linux/regulator/consumer.h>

	static struct device_type mfd_dev_type = {
	.name = "mfd_device",
	};

	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;
	}
	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;
	}
	EXPORT_SYMBOL(mfd_cell_disable);

	static int mfd_platform_add_cell(struct platform_device *pdev,
	const struct mfd_cell *cell,
	atomic_t *usage_count)
	{
	if (!cell)
	return 0;

	pdev->mfd_cell = kmemdup(cell, sizeof(*cell), GFP_KERNEL);
	if (!pdev->mfd_cell)
	return -ENOMEM;

	pdev->mfd_cell->usage_count = usage_count;
	return 0;
	}

	#if IS_ENABLED(CONFIG_ACPI)
	static void mfd_acpi_add_device(const struct mfd_cell *cell,
	struct platform_device *pdev)
	{
	const struct mfd_cell_acpi_match *match = cell->acpi_match;
	struct acpi_device parent, child;
	struct acpi_device *adev;

	parent = ACPI_COMPANION(pdev->dev.parent);
	if (!parent)
	return;

	/*
	* MFD child device gets its ACPI handle either from the ACPI device
	* directly under the parent that matches the either _HID or _CID, or
	* _ADR or it will use the parent handle if is no ID is given.
	*
	* Note that use of _ADR is a grey area in the ACPI specification,
	* though Intel Galileo Gen2 is using it to distinguish the children
	* devices.
	*/
	adev = parent;
	if (match) {
	if (match->pnpid) {
	struct acpi_device_id ids[2] = {};

	strlcpy(ids[0].id, match->pnpid, sizeof(ids[0].id));
	list_for_each_entry(child, &parent->children, node) {
	if (!acpi_match_device_ids(child, ids)) {
	adev = child;
	break;
	}
	}
	} else {
	unsigned long long adr;
	acpi_status status;

	list_for_each_entry(child, &parent->children, node) {
	status = acpi_evaluate_integer(child->handle,
	"_ADR", NULL,
	&adr);
	if (ACPI_SUCCESS(status) && match->adr == adr) {
	adev = child;
	break;
	}
	}
	}
	}

	ACPI_COMPANION_SET(&pdev->dev, adev);
	}
	#else
	static inline void mfd_acpi_add_device(const struct mfd_cell *cell,
	struct platform_device *pdev)
	{
	}
	#endif

	static int mfd_add_device(struct device *parent, int id,
	const struct mfd_cell cell, atomic_t usage_count,
	struct resource *mem_base,
	int irq_base, struct irq_domain *domain)
	{
	struct resource *res;
	struct platform_device *pdev;
	struct device_node *np = NULL;
	int ret = -ENOMEM;
	int platform_id;
	int r;

	if (id == PLATFORM_DEVID_AUTO)
	platform_id = id;
	else
	platform_id = id + cell->id;

	pdev = platform_device_alloc(cell->name, platform_id);
	if (!pdev)
	goto fail_alloc;

	res = kcalloc(cell->num_resources, sizeof(*res), GFP_KERNEL);
	if (!res)
	goto fail_device;

	pdev->dev.parent = parent;
	pdev->dev.type = &mfd_dev_type;
	pdev->dev.dma_mask = parent->dma_mask;
	pdev->dev.dma_parms = parent->dma_parms;
	pdev->dev.coherent_dma_mask = parent->coherent_dma_mask;

	ret = regulator_bulk_register_supply_alias(
	&pdev->dev, cell->parent_supplies,
	parent, cell->parent_supplies,
	cell->num_parent_supplies);
	if (ret < 0)
	goto fail_res;

	if (parent->of_node && cell->of_compatible) {
	for_each_child_of_node(parent->of_node, np) {
	if (of_device_is_compatible(np, cell->of_compatible)) {
	pdev->dev.of_node = np;
	pdev->dev.fwnode = &np->fwnode;
	break;
	}
	}
	}

	mfd_acpi_add_device(cell, pdev);

	if (cell->pdata_size) {
	ret = platform_device_add_data(pdev,
	cell->platform_data, cell->pdata_size);
	if (ret)
	goto fail_alias;
	}

	if (cell->properties) {
	ret = platform_device_add_properties(pdev, cell->properties);
	if (ret)
	goto fail_alias;
	}

	ret = mfd_platform_add_cell(pdev, cell, usage_count);
	if (ret)
	goto fail_alias;

	for (r = 0; r < cell->num_resources; r++) {
	res[r].name = cell->resources[r].name;
	res[r].flags = cell->resources[r].flags;

	/* Find out base to use */
	if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) {
	res[r].parent = mem_base;
	res[r].start = mem_base->start +
	cell->resources[r].start;
	res[r].end = mem_base->start +
	cell->resources[r].end;
	} else if (cell->resources[r].flags & IORESOURCE_IRQ) {
	if (domain) {
	/* Unable to create mappings for IRQ ranges. */
	WARN_ON(cell->resources[r].start !=
	cell->resources[r].end);
	res[r].start = res[r].end = irq_create_mapping(
	domain, cell->resources[r].start);
	} else {
	res[r].start = irq_base +
	cell->resources[r].start;
	res[r].end = irq_base +
	cell->resources[r].end;
	}
	} else {
	res[r].parent = cell->resources[r].parent;
	res[r].start = cell->resources[r].start;
	res[r].end = cell->resources[r].end;
	}

	if (!cell->ignore_resource_conflicts) {
	if (has_acpi_companion(&pdev->dev)) {
	ret = acpi_check_resource_conflict(&res[r]);
	if (ret)
	goto fail_alias;
	}
	}
	}

	ret = platform_device_add_resources(pdev, res, cell->num_resources);
	if (ret)
	goto fail_alias;

	ret = platform_device_add(pdev);
	if (ret)
	goto fail_alias;

	if (cell->pm_runtime_no_callbacks)
	pm_runtime_no_callbacks(&pdev->dev);

	kfree(res);

	return 0;

	fail_alias:
	regulator_bulk_unregister_supply_alias(&pdev->dev,
	cell->parent_supplies,
	cell->num_parent_supplies);
	fail_res:
	kfree(res);
	fail_device:
	platform_device_put(pdev);
	fail_alloc:
	return ret;
	}

	/**
	* mfd_add_devices - register child devices
	*
	* @parent: Pointer to parent device.
	* @id: Can be PLATFORM_DEVID_AUTO to let the Platform API take care
	* of device numbering, or will be added to a device's cell_id.
	* @cells: Array of (struct mfd_cell)s describing child devices.
	* @n_devs: Number of child devices to register.
	* @mem_base: Parent register range resource for child devices.
	* @irq_base: Base of the range of virtual interrupt numbers allocated for
	* this MFD device. Unused if @domain is specified.
	* @domain: Interrupt domain to create mappings for hardware interrupts.
	*/
	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 *domain)
	{
	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,
	irq_base, domain);
	if (ret)
	goto fail;
	}

	return 0;

	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)
	{
	struct platform_device *pdev;
	const struct mfd_cell *cell;
	atomic_t **usage_count = c;

	if (dev->type != &mfd_dev_type)
	return 0;

	pdev = to_platform_device(dev);
	cell = mfd_get_cell(pdev);

	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);
	}
	EXPORT_SYMBOL(mfd_remove_devices);

	static void devm_mfd_dev_release(struct device dev, void res)
	{
	mfd_remove_devices(dev);
	}

	/**
	* devm_mfd_add_devices - Resource managed version of mfd_add_devices()
	*
	* Returns 0 on success or an appropriate negative error number on failure.
	* All child-devices of the MFD will automatically be removed when it gets
	* unbinded.
	*/
	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 *domain)
	{
	struct device **ptr;
	int ret;

	ptr = devres_alloc(devm_mfd_dev_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
	return -ENOMEM;

	ret = mfd_add_devices(dev, id, cells, n_devs, mem_base,
	irq_base, domain);
	if (ret < 0) {
	devres_free(ptr);
	return ret;
	}

	*ptr = dev;
	devres_add(dev, ptr);

	return ret;
	}
	EXPORT_SYMBOL(devm_mfd_add_devices);

	int mfd_clone_cell(const char cell, const char *clones, size_t n_clones)
	{
	struct mfd_cell cell_entry;
	struct device *dev;
	struct platform_device *pdev;
	int i;

	/* fetch the parent cell's device (should already be registered!) */
	dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
	if (!dev) {
	printk(KERN_ERR "failed to find device for cell %s\n", cell);
	return -ENODEV;
	}
	pdev = to_platform_device(dev);
	memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));

	WARN_ON(!cell_entry.enable);

	for (i = 0; i < n_clones; i++) {
	cell_entry.name = clones[i];
	/* don't give up if a single call fails; just report error */
	if (mfd_add_device(pdev->dev.parent, -1, &cell_entry,
	cell_entry.usage_count, NULL, 0, NULL))
	dev_err(dev, "failed to create platform device '%s'\n",
	clones[i]);
	}

	put_device(dev);

	return 0;
	}
	EXPORT_SYMBOL(mfd_clone_cell);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");