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

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Thanks Stephen for review,

On 20/07/15 22:11, Stephen Boyd wrote:
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?

Only reason for using kzalloc is to give the code more flexibility to free any pointer in the array in case of errors.


+    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?
Yep, fixed it now.


+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.

Oops, Fixed this one too.

+    }
+
+    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.
thanks, that should make this more simple.

+
+    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?

Yes we can set dev.groups directly before device_add, I did this change 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?
Ok, make sense. I moved this too.
I have v9 ready will send it.

--srini

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