On 9/26/20 9:18 PM, William Breathitt Gray wrote:
This is a reimplementation of the Generic Counter driver interface.
I'll follow up if I find any problems while testing but here are some
comments I had from looking over the patch.
diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
new file mode 100644
index 000000000000..987c6e8277eb
--- /dev/null
+++ b/drivers/counter/counter-core.c
+/**
+ * counter_register - register Counter to the system
+ * @counter: pointer to Counter to register
+ *
+ * This function registers a Counter to the system. A sysfs "counter" directory
+ * will be created and populated with sysfs attributes correlating with the
+ * Counter Signals, Synapses, and Counts respectively.
+ */
+int counter_register(struct counter_device *const counter)
+{
+ struct device *const dev = &counter->dev;
+ int err;
+
+ /* Acquire unique ID */
+ counter->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
+ if (counter->id < 0)
+ return counter->id;
+
+ /* Configure device structure for Counter */
+ dev->type = &counter_device_type;
+ dev->bus = &counter_bus_type;
+ if (counter->parent) {
+ dev->parent = counter->parent;
+ dev->of_node = counter->parent->of_node;
+ }
+ dev_set_name(dev, "counter%d", counter->id);
+ device_initialize(dev);> + dev_set_drvdata(dev, counter);
+
+ /* Add Counter sysfs attributes */
+ err = counter_sysfs_add(counter);
+ if (err)
+ goto err_free_id;
+
+ /* Add device to system */
+ err = device_add(dev);
+ if (err) {
+ put_device(dev);
+ goto err_free_id;
+ }
+
+ return 0;
+
+err_free_id:
+ /* get_device/put_device combo used to free managed resources */
+ get_device(dev);
+ put_device(dev);
I've never seen this in a driver before, so it makes me think this is
not the "right way" to do this. After device_initialize() is called, we
already should have a reference to dev, so only device_put() is needed.
+ ida_simple_remove(&counter_ida, counter->id);
In the case of error after device_initialize() is called, won't this
result in ida_simple_remove() being called twice, once here and once in
the release callback?
+ return err;
+}
+EXPORT_SYMBOL_GPL(counter_register);
+
+/**
+ * counter_unregister - unregister Counter from the system
+ * @counter: pointer to Counter to unregister
+ *
+ * The Counter is unregistered from the system; all allocated memory is freed.
+ */
+void counter_unregister(struct counter_device *const counter)
+{
+ if (!counter)
+ return;
+
+ device_unregister(&counter->dev);
+}
+EXPORT_SYMBOL_GPL(counter_unregister);
+
+static void devm_counter_unreg(struct device *dev, void *res)
To be consistent, it would be nice to spell out unregister.
+{
+ counter_unregister(*(struct counter_device **)res);
+}
+
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
new file mode 100644
index 000000000000..e66ed99dd5ea
--- /dev/null
+++ b/drivers/counter/counter-sysfs.c
+/**
+ * counter_sysfs_add - Adds Counter sysfs attributes to the device structure
+ * @counter: Pointer to the Counter device structure
+ *
+ * Counter sysfs attributes are created and added to the respective device
+ * structure for later registration to the system. Resource-managed memory
+ * allocation is performed by this function, and this memory should be freed
+ * when no longer needed (automatically by a device_unregister call, or
+ * manually by a devres_release_all call).
+ */
+int counter_sysfs_add(struct counter_device *const counter)
+{
+ struct device *const dev = &counter->dev;
+ const size_t num_groups = counter->num_signals + counter->num_counts +
+ 1;
It is OK to go past 80 columns, especially for just for a few characters.
+ struct counter_attribute_group *groups;
+ size_t i, j;
+ int err;
+ struct attribute_group *group;
+ struct counter_attribute *p;
+
+ /* Allocate space for attribute groups (signals, counts, and ext) */
+ groups = devm_kcalloc(dev, num_groups, sizeof(*groups), GFP_KERNEL);
+ if (!groups)
+ return -ENOMEM;
+
+ /* Initialize attribute lists */
+ for (i = 0; i < num_groups; i++)
+ INIT_LIST_HEAD(&groups[i].attr_list);
+
+ /* Register Counter device attributes */
+ err = counter_device_register(counter, groups);
This function name is a bit misleading. At first I though we were registering
a new counter device (struct device). Maybe counter_sysfs_create_attrs()
would be a better name? (I wouldn't mind having all functions in this
file having a "counter_sysfs_" prefix for that matter.)
diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
index 1ff07faef27f..938085dead80 100644
--- a/drivers/counter/ti-eqep.c
+++ b/drivers/counter/ti-eqep.c
@@ -406,7 +414,7 @@ static int ti_eqep_probe(struct platform_device *pdev)
priv->counter.name = dev_name(dev);
priv->counter.parent = dev;
- priv->counter.ops = &ti_eqep_counter_ops;
+ priv->counter.parent = &ti_eqep_counter_ops;
priv->counter.counts = ti_eqep_counts;
priv->counter.num_counts = ARRAY_SIZE(ti_eqep_counts);
priv->counter.signals = ti_eqep_signals;
This looks like an unintentional change and causes a compile error.
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 9dbd5df4cd34..132bfecca5c3 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -6,417 +6,195 @@
#ifndef _COUNTER_H_
#define _COUNTER_H_
-#include <linux/counter_enum.h>
#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
struct list_head is defined in linux/types.h. Is there something else
we are using from linux/list.h in this file?
#include <linux/types.h>
It would be helpful to have kernel doc comments on everything in this file.
