nvmem: core: add NVMEM_SYSFS Kconfig

Many nvmem providers are not very keen on having default sysfs
nvmem entry, as most of the usecases for them are inside kernel
itself. And in some cases read/writes to some areas in nvmem are
restricted and trapped at secure monitor level, so accessing them
from userspace would result in board reboots.

This patch adds new NVMEM_SYSFS Kconfig to make binary sysfs entry
an optional one. This provision will give more flexibility to users.
This patch also moves existing sysfs code to a new file so that its
not compiled in when its not really required.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Gaurav Kohli <gkohli@codeaurora.org>
Tested-by: Gaurav Kohli <gkohli@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 260 deletions

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 5abebf2128b8..c7892c3da91f 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -17,27 +17,7 @@
 #include <linux/nvmem-provider.h>
 #include <linux/of.h>
 #include <linux/slab.h>
-
-struct nvmem_device {
-	struct module		*owner;
-	struct device		dev;
-	int			stride;
-	int			word_size;
-	int			id;
-	struct kref		refcnt;
-	size_t			size;
-	bool			read_only;
-	int			flags;
-	enum nvmem_type		type;
-	struct bin_attribute	eeprom;
-	struct device		*base_dev;
-	struct list_head	cells;
-	nvmem_reg_read_t	reg_read;
-	nvmem_reg_write_t	reg_write;
-	void *priv;
-};
-
-#define FLAG_COMPAT		BIT(0)
+#include "nvmem.h"
 
 struct nvmem_cell {
 	const char		*name;
@@ -61,18 +41,7 @@ static LIST_HEAD(nvmem_lookup_list);
 
 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
 
-static const char * const nvmem_type_str[] = {
-	[NVMEM_TYPE_UNKNOWN] = "Unknown",
-	[NVMEM_TYPE_EEPROM] = "EEPROM",
-	[NVMEM_TYPE_OTP] = "OTP",
-	[NVMEM_TYPE_BATTERY_BACKED] = "Battery backed",
-};
-
-#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 int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
 			  void *val, size_t bytes)
 {
@@ -91,187 +60,6 @@ static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
 	return -EINVAL;
 }
 
-static ssize_t type_show(struct device *dev,
-			 struct device_attribute *attr, char *buf)
-{
-	struct nvmem_device *nvmem = to_nvmem_device(dev);
-
-	return sprintf(buf, "%s\n", nvmem_type_str[nvmem->type]);
-}
-
-static DEVICE_ATTR_RO(type);
-
-static struct attribute *nvmem_attrs[] = {
-	&dev_attr_type.attr,
-	NULL,
-};
-
-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;
-	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;
-
-	if (count < nvmem->word_size)
-		return -EINVAL;
-
-	if (pos + count > nvmem->size)
-		count = nvmem->size - pos;
-
-	count = round_down(count, nvmem->word_size);
-
-	rc = nvmem_reg_read(nvmem, pos, buf, count);
-
-	if (rc)
-		return rc;
-
-	return count;
-}
-
-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;
-	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 -EFBIG;
-
-	if (count < nvmem->word_size)
-		return -EINVAL;
-
-	if (pos + count > nvmem->size)
-		count = nvmem->size - pos;
-
-	count = round_down(count, nvmem->word_size);
-
-	rc = nvmem_reg_write(nvmem, pos, buf, count);
-
-	if (rc)
-		return rc;
-
-	return count;
-}
-
-/* default read/write permissions */
-static struct bin_attribute bin_attr_rw_nvmem = {
-	.attr	= {
-		.name	= "nvmem",
-		.mode	= 0644,
-	},
-	.read	= bin_attr_nvmem_read,
-	.write	= bin_attr_nvmem_write,
-};
-
-static struct bin_attribute *nvmem_bin_rw_attributes[] = {
-	&bin_attr_rw_nvmem,
-	NULL,
-};
-
-static const struct attribute_group nvmem_bin_rw_group = {
-	.bin_attrs	= nvmem_bin_rw_attributes,
-	.attrs		= nvmem_attrs,
-};
-
-static const struct attribute_group *nvmem_rw_dev_groups[] = {
-	&nvmem_bin_rw_group,
-	NULL,
-};
-
-/* read only permission */
-static struct bin_attribute bin_attr_ro_nvmem = {
-	.attr	= {
-		.name	= "nvmem",
-		.mode	= 0444,
-	},
-	.read	= bin_attr_nvmem_read,
-};
-
-static struct bin_attribute *nvmem_bin_ro_attributes[] = {
-	&bin_attr_ro_nvmem,
-	NULL,
-};
-
-static const struct attribute_group nvmem_bin_ro_group = {
-	.bin_attrs	= nvmem_bin_ro_attributes,
-	.attrs		= nvmem_attrs,
-};
-
-static const struct attribute_group *nvmem_ro_dev_groups[] = {
-	&nvmem_bin_ro_group,
-	NULL,
-};
-
-/* default read/write permissions, root only */
-static struct bin_attribute bin_attr_rw_root_nvmem = {
-	.attr	= {
-		.name	= "nvmem",
-		.mode	= 0600,
-	},
-	.read	= bin_attr_nvmem_read,
-	.write	= bin_attr_nvmem_write,
-};
-
-static struct bin_attribute *nvmem_bin_rw_root_attributes[] = {
-	&bin_attr_rw_root_nvmem,
-	NULL,
-};
-
-static const struct attribute_group nvmem_bin_rw_root_group = {
-	.bin_attrs	= nvmem_bin_rw_root_attributes,
-	.attrs		= nvmem_attrs,
-};
-
-static const struct attribute_group *nvmem_rw_root_dev_groups[] = {
-	&nvmem_bin_rw_root_group,
-	NULL,
-};
-
-/* read only permission, root only */
-static struct bin_attribute bin_attr_ro_root_nvmem = {
-	.attr	= {
-		.name	= "nvmem",
-		.mode	= 0400,
-	},
-	.read	= bin_attr_nvmem_read,
-};
-
-static struct bin_attribute *nvmem_bin_ro_root_attributes[] = {
-	&bin_attr_ro_root_nvmem,
-	NULL,
-};
-
-static const struct attribute_group nvmem_bin_ro_root_group = {
-	.bin_attrs	= nvmem_bin_ro_root_attributes,
-	.attrs		= nvmem_attrs,
-};
-
-static const struct attribute_group *nvmem_ro_root_dev_groups[] = {
-	&nvmem_bin_ro_root_group,
-	NULL,
-};
-
 static void nvmem_release(struct device *dev)
 {
 	struct nvmem_device *nvmem = to_nvmem_device(dev);
@@ -422,43 +210,6 @@ err:
 	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_notifier() - Register a notifier block for nvmem events.
  *
@@ -651,14 +402,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 	nvmem->read_only = device_property_present(config->dev, "read-only") ||
 			   config->read_only || !nvmem->reg_write;
 
-	if (config->root_only)
-		nvmem->dev.groups = nvmem->read_only ?
-			nvmem_ro_root_dev_groups :
-			nvmem_rw_root_dev_groups;
-	else
-		nvmem->dev.groups = nvmem->read_only ?
-			nvmem_ro_dev_groups :
-			nvmem_rw_dev_groups;
+	nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config);
 
 	device_initialize(&nvmem->dev);
 
@@ -669,7 +413,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 		goto err_put_device;
 
 	if (config->compat) {
-		rval = nvmem_setup_compat(nvmem, config);
+		rval = nvmem_sysfs_setup_compat(nvmem, config);
 		if (rval)
 			goto err_device_del;
 	}
@@ -696,7 +440,7 @@ err_remove_cells:
 	nvmem_device_remove_all_cells(nvmem);
 err_teardown_compat:
 	if (config->compat)
-		device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
+		nvmem_sysfs_remove_compat(nvmem, config);
 err_device_del:
 	device_del(&nvmem->dev);
 err_put_device: