Re: [PATCH v8 1/9] nvmem: Add a simple NVMEM framework for nvmem providers

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On 07/20/2015 07:43 AM, Srinivas Kandagatla wrote:
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
new file mode 100644
index 0000000..bde5528
--- /dev/null
+++ b/drivers/nvmem/core.c
@@ -0,0 +1,384 @@

+
+static int nvmem_add_cells(struct nvmem_device *nvmem,
+			   const struct nvmem_config *cfg)
+{
+	struct nvmem_cell **cells;
+	const struct nvmem_cell_info *info = cfg->cells;
+	int i, rval;
+
+	cells = kzalloc(sizeof(*cells) * cfg->ncells, GFP_KERNEL);

kcalloc?

+	if (!cells)
+		return -ENOMEM;
+
+	for (i = 0; i < cfg->ncells; i++) {
+		cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
+		if (!cells[i]) {
+			rval = -ENOMEM;
+			goto err;
+		}
+
+		rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]);
+		if (IS_ERR_VALUE(rval)) {
+			kfree(cells[i]);
+			goto err;
+		}
+
+		nvmem_cell_add(cells[i]);
+	}
+
+	nvmem->ncells = cfg->ncells;
+	/* remove tmp array */
+	kfree(cells);
+
+	return 0;
+err:
+	while (--i)
+		nvmem_cell_drop(cells[i]);
+
+	return rval;
+}
+
+/**
+ * nvmem_register() - Register a nvmem device for given nvmem_config.
+ * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
+ *
+ * @config: nvmem device configuration with which nvmem device is created.
+ *
+ * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device
+ * on success.
+ */
+

Why the newline?

+struct nvmem_device *nvmem_register(const struct nvmem_config *config)
+{
+	struct nvmem_device *nvmem;
+	struct device_node *np;
+	struct regmap *rm;
+	int rval;
+
+	if (!config->dev)
+		return ERR_PTR(-EINVAL);
+
+	rm = dev_get_regmap(config->dev, NULL);
+	if (!rm) {
+		dev_err(config->dev, "Regmap not found\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
+	if (!nvmem)
+		return ERR_PTR(-ENOMEM);
+
+	nvmem->id = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL);
+	if (nvmem->id < 0) {
+		kfree(nvmem);
+		return ERR_PTR(nvmem->id);

Oops, we already freed nvmem.

+	}
+
+	nvmem->regmap = rm;
+	nvmem->owner = config->owner;
+	nvmem->stride = regmap_get_reg_stride(rm);
+	nvmem->word_size = regmap_get_val_bytes(rm);
+	nvmem->size = regmap_get_max_register(rm) + nvmem->stride;
+	nvmem->dev.type = &nvmem_provider_type;
+	nvmem->dev.bus = &nvmem_bus_type;
+	nvmem->dev.parent = config->dev;
+	np = config->dev->of_node;
+	nvmem->dev.of_node = np;
+	dev_set_name(&nvmem->dev, "%s%d",
+		     config->name ? : "nvmem", config->id);
+
+	nvmem->read_only = np ? of_property_read_bool(np, "read-only") : 0;

of_property_read_bool(NULL, ..) "does the right thing" and returns false already.

+
+	nvmem->read_only |= config->read_only;
+
+	device_initialize(&nvmem->dev);
+
+	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 (device_create_bin_file(&nvmem->dev,
+				nvmem->read_only ? &bin_attr_ro_nvmem :
+				&bin_attr_rw_nvmem))
+		dev_warn(&nvmem->dev, "Failed to create sysfs binary file\n");

Why can't we have device_add() add the binary file attribute too?

+
+	if (config->cells)
+		nvmem_add_cells(nvmem, config);
+
+	return nvmem;
+}
+EXPORT_SYMBOL_GPL(nvmem_register);
+
+/**
+ * nvmem_unregister() - Unregister previously registered nvmem device
+ *
+ * @nvmem: Pointer to previously registered nvmem device.
+ *
+ * Return: Will be an negative on error or a zero on success.
+ */
+int nvmem_unregister(struct nvmem_device *nvmem)
+{
+	mutex_lock(&nvmem_mutex);
+	if (nvmem->users) {
+		mutex_unlock(&nvmem_mutex);
+		return -EBUSY;
+	}
+	mutex_unlock(&nvmem_mutex);

This lock doesn't seem to be doing anything in this patch? Perhaps it should be added in the second patch where consumers start making it useful?

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