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Commit b6c217ab authored by Andrew Lunn's avatar Andrew Lunn Committed by Greg Kroah-Hartman
Browse files

nvmem: Add backwards compatibility support for older EEPROM drivers. 



Older drivers made an 'eeprom' file available in the /sys device
directory. Have the NVMEM core provide this to retain backwards
compatibility.

Signed-off-by: default avatarAndrew Lunn <andrew@lunn.ch>
Acked-by: default avatarSrinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 811b0d65

drivers/nvmem/core.c

+76 −8
Original line number Diff line number Diff line
@@ -38,8 +38,13 @@ struct nvmem_device { 
	int			users;

	size_t			size;

	bool			read_only;

	int			flags;

	struct bin_attribute	eeprom;

	struct device		*base_dev;

};



#define FLAG_COMPAT		BIT(0)



struct nvmem_cell {

	const char		*name;

	int			offset;
@@ -56,16 +61,26 @@ static DEFINE_IDA(nvmem_ida); 
static LIST_HEAD(nvmem_cells);

static DEFINE_MUTEX(nvmem_cells_mutex);



#ifdef CONFIG_DEBUG_LOCK_ALLOC

static struct lock_class_key eeprom_lock_key;

#endif



#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev)



static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,

				    struct bin_attribute *attr,

				    char *buf, loff_t pos, size_t count)

{

	struct device *dev = container_of(kobj, struct device, kobj);

	struct nvmem_device *nvmem = to_nvmem_device(dev);

	struct device *dev;

	struct nvmem_device *nvmem;

	int rc;



	if (attr->private)

		dev = attr->private;

	else

		dev = container_of(kobj, struct device, kobj);

	nvmem = to_nvmem_device(dev);



	/* Stop the user from reading */

	if (pos >= nvmem->size)

		return 0;
@@ -90,10 +105,16 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, 
				     struct bin_attribute *attr,

				     char *buf, loff_t pos, size_t count)

{

	struct device *dev = container_of(kobj, struct device, kobj);

	struct nvmem_device *nvmem = to_nvmem_device(dev);

	struct device *dev;

	struct nvmem_device *nvmem;

	int rc;



	if (attr->private)

		dev = attr->private;

	else

		dev = container_of(kobj, struct device, kobj);

	nvmem = to_nvmem_device(dev);



	/* Stop the user from writing */

	if (pos >= nvmem->size)

		return 0;
@@ -349,6 +370,43 @@ static int nvmem_add_cells(struct nvmem_device *nvmem, 
	return rval;

}



/*

 * nvmem_setup_compat() - Create an additional binary entry in

 * drivers sys directory, to be backwards compatible with the older

 * drivers/misc/eeprom drivers.

 */

static int nvmem_setup_compat(struct nvmem_device *nvmem,

			      const struct nvmem_config *config)

{

	int rval;



	if (!config->base_dev)

		return -EINVAL;



	if (nvmem->read_only)

		nvmem->eeprom = bin_attr_ro_root_nvmem;

	else

		nvmem->eeprom = bin_attr_rw_root_nvmem;

	nvmem->eeprom.attr.name = "eeprom";

	nvmem->eeprom.size = nvmem->size;

#ifdef CONFIG_DEBUG_LOCK_ALLOC

	nvmem->eeprom.attr.key = &eeprom_lock_key;

#endif

	nvmem->eeprom.private = &nvmem->dev;

	nvmem->base_dev = config->base_dev;



	rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom);

	if (rval) {

		dev_err(&nvmem->dev,

			"Failed to create eeprom binary file %d\n", rval);

		return rval;

	}



	nvmem->flags |= FLAG_COMPAT;



	return 0;

}



/**

 * nvmem_register() - Register a nvmem device for given nvmem_config.

 * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
@@ -416,16 +474,23 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) 
	dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);



	rval = device_add(&nvmem->dev);

	if (rval) {

		ida_simple_remove(&nvmem_ida, nvmem->id);

		kfree(nvmem);

		return ERR_PTR(rval);

	if (rval)

		goto out;



	if (config->compat) {

		rval = nvmem_setup_compat(nvmem, config);

		if (rval)

			goto out;

	}



	if (config->cells)

		nvmem_add_cells(nvmem, config);



	return nvmem;

out:

	ida_simple_remove(&nvmem_ida, nvmem->id);

	kfree(nvmem);

	return ERR_PTR(rval);

}

EXPORT_SYMBOL_GPL(nvmem_register);
@@ -445,6 +510,9 @@ int nvmem_unregister(struct nvmem_device *nvmem) 
	}

	mutex_unlock(&nvmem_mutex);



	if (nvmem->flags & FLAG_COMPAT)

		device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);



	nvmem_device_remove_all_cells(nvmem);

	device_del(&nvmem->dev);

include/linux/nvmem-provider.h

+3 −1
Original line number Diff line number Diff line
@@ -24,6 +24,9 @@ struct nvmem_config { 
	int			ncells;

	bool			read_only;

	bool			root_only;

	/* To be only used by old driver/misc/eeprom drivers */

	bool			compat;

	struct device		*base_dev;

};



#if IS_ENABLED(CONFIG_NVMEM)
@@ -44,5 +47,4 @@ static inline int nvmem_unregister(struct nvmem_device *nvmem) 
}



#endif /* CONFIG_NVMEM */



#endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */