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Subject[PATCH 1/3] platform/surface: aggregator: Move device registry helper functions to core module
Date
Move helper functions for client device registration to the core module.
This simplifies addition of future DT/OF support and also allows us to
split out the device hub drivers into their own module.

At the same time, also improve device node validation a bit by not
silently skipping devices with invalid device UID specifiers. Further,
ensure proper lifetime management for the firmware/software nodes
associated with the added devices.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---
drivers/platform/surface/aggregator/bus.c | 149 ++++++++++++++++--
.../surface/surface_aggregator_registry.c | 75 +--------
include/linux/surface_aggregator/device.h | 52 ++++++
3 files changed, 187 insertions(+), 89 deletions(-)

diff --git a/drivers/platform/surface/aggregator/bus.c b/drivers/platform/surface/aggregator/bus.c
index abbbb5b08b07..e0b0381a2834 100644
--- a/drivers/platform/surface/aggregator/bus.c
+++ b/drivers/platform/surface/aggregator/bus.c
@@ -6,6 +6,7 @@
*/

#include <linux/device.h>
+#include <linux/property.h>
#include <linux/slab.h>

#include <linux/surface_aggregator/controller.h>
@@ -14,6 +15,9 @@
#include "bus.h"
#include "controller.h"

+
+/* -- Device and bus functions. --------------------------------------------- */
+
static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
@@ -46,6 +50,7 @@ static void ssam_device_release(struct device *dev)
struct ssam_device *sdev = to_ssam_device(dev);

ssam_controller_put(sdev->ctrl);
+ fwnode_handle_put(sdev->dev.fwnode);
kfree(sdev);
}

@@ -363,6 +368,134 @@ void ssam_device_driver_unregister(struct ssam_device_driver *sdrv)
}
EXPORT_SYMBOL_GPL(ssam_device_driver_unregister);

+
+/* -- Bus registration. ----------------------------------------------------- */
+
+/**
+ * ssam_bus_register() - Register and set-up the SSAM client device bus.
+ */
+int ssam_bus_register(void)
+{
+ return bus_register(&ssam_bus_type);
+}
+
+/**
+ * ssam_bus_unregister() - Unregister the SSAM client device bus.
+ */
+void ssam_bus_unregister(void)
+{
+ return bus_unregister(&ssam_bus_type);
+}
+
+
+/* -- Helpers for controller and hub devices. ------------------------------- */
+
+static int ssam_device_uid_from_string(const char *str, struct ssam_device_uid *uid)
+{
+ u8 d, tc, tid, iid, fn;
+ int n;
+
+ n = sscanf(str, "%hhx:%hhx:%hhx:%hhx:%hhx", &d, &tc, &tid, &iid, &fn);
+ if (n != 5)
+ return -EINVAL;
+
+ uid->domain = d;
+ uid->category = tc;
+ uid->target = tid;
+ uid->instance = iid;
+ uid->function = fn;
+
+ return 0;
+}
+
+static int ssam_get_uid_for_node(struct fwnode_handle *node, struct ssam_device_uid *uid)
+{
+ const char *str = fwnode_get_name(node);
+
+ /*
+ * To simplify definitions of firmware nodes, we set the device name
+ * based on the UID of the device, prefixed with "ssam:".
+ */
+ if (strncmp(str, "ssam:", strlen("ssam:")) != 0)
+ return -ENODEV;
+
+ str += strlen("ssam:");
+ return ssam_device_uid_from_string(str, uid);
+}
+
+static int ssam_add_client_device(struct device *parent, struct ssam_controller *ctrl,
+ struct fwnode_handle *node)
+{
+ struct ssam_device_uid uid;
+ struct ssam_device *sdev;
+ int status;
+
+ status = ssam_get_uid_for_node(node, &uid);
+ if (status)
+ return status;
+
+ sdev = ssam_device_alloc(ctrl, uid);
+ if (!sdev)
+ return -ENOMEM;
+
+ sdev->dev.parent = parent;
+ sdev->dev.fwnode = fwnode_handle_get(node);
+
+ status = ssam_device_add(sdev);
+ if (status)
+ ssam_device_put(sdev);
+
+ return status;
+}
+
+/**
+ * __ssam_register_clients() - Register client devices defined under the
+ * given firmware node as children of the given device.
+ * @parent: The parent device under which clients should be registered.
+ * @ctrl: The controller with which client should be registered.
+ * @node: The firmware node holding definitions of the devices to be added.
+ *
+ * Register all clients that have been defined as children of the given root
+ * firmware node as children of the given parent device. The respective child
+ * firmware nodes will be associated with the correspondingly created child
+ * devices.
+ *
+ * The given controller will be used to instantiate the new devices. See
+ * ssam_device_add() for details.
+ *
+ * Note that, generally, the use of either ssam_device_register_clients() or
+ * ssam_register_clients() should be preferred as they directly use the
+ * firmware node and/or controller associated with the given device. This
+ * function is only intended for use when different device specifications (e.g.
+ * ACPI and firmware nodes) need to be combined (as is done in the platform hub
+ * of the device registry).
+ *
+ * Return: Returns zero on success, nonzero on failure.
+ */
+int __ssam_register_clients(struct device *parent, struct ssam_controller *ctrl,
+ struct fwnode_handle *node)
+{
+ struct fwnode_handle *child;
+ int status;
+
+ fwnode_for_each_child_node(node, child) {
+ /*
+ * Try to add the device specified in the firmware node. If
+ * this fails with -ENODEV, the node does not specify any SSAM
+ * device, so ignore it and continue with the next one.
+ */
+ status = ssam_add_client_device(parent, ctrl, child);
+ if (status && status != -ENODEV)
+ goto err;
+ }
+
+ return 0;
+err:
+ ssam_remove_clients(parent);
+ return status;
+}
+EXPORT_SYMBOL_GPL(__ssam_register_clients);
+
static int ssam_remove_device(struct device *dev, void *_data)
{
struct ssam_device *sdev = to_ssam_device(dev);
@@ -387,19 +520,3 @@ void ssam_remove_clients(struct device *dev)
device_for_each_child_reverse(dev, NULL, ssam_remove_device);
}
EXPORT_SYMBOL_GPL(ssam_remove_clients);
-
-/**
- * ssam_bus_register() - Register and set-up the SSAM client device bus.
- */
-int ssam_bus_register(void)
-{
- return bus_register(&ssam_bus_type);
-}
-
-/**
- * ssam_bus_unregister() - Unregister the SSAM client device bus.
- */
-void ssam_bus_unregister(void)
-{
- return bus_unregister(&ssam_bus_type);
-}
diff --git a/drivers/platform/surface/surface_aggregator_registry.c b/drivers/platform/surface/surface_aggregator_registry.c
index f1c5905f1c16..c680792a037e 100644
--- a/drivers/platform/surface/surface_aggregator_registry.c
+++ b/drivers/platform/surface/surface_aggregator_registry.c
@@ -286,76 +286,6 @@ static const struct software_node *ssam_node_group_sp8[] = {
};


-/* -- Device registry helper functions. ------------------------------------- */
-
-static int ssam_uid_from_string(const char *str, struct ssam_device_uid *uid)
-{
- u8 d, tc, tid, iid, fn;
- int n;
-
- n = sscanf(str, "ssam:%hhx:%hhx:%hhx:%hhx:%hhx", &d, &tc, &tid, &iid, &fn);
- if (n != 5)
- return -EINVAL;
-
- uid->domain = d;
- uid->category = tc;
- uid->target = tid;
- uid->instance = iid;
- uid->function = fn;
-
- return 0;
-}
-
-static int ssam_hub_add_device(struct device *parent, struct ssam_controller *ctrl,
- struct fwnode_handle *node)
-{
- struct ssam_device_uid uid;
- struct ssam_device *sdev;
- int status;
-
- status = ssam_uid_from_string(fwnode_get_name(node), &uid);
- if (status)
- return status;
-
- sdev = ssam_device_alloc(ctrl, uid);
- if (!sdev)
- return -ENOMEM;
-
- sdev->dev.parent = parent;
- sdev->dev.fwnode = node;
-
- status = ssam_device_add(sdev);
- if (status)
- ssam_device_put(sdev);
-
- return status;
-}
-
-static int ssam_hub_register_clients(struct device *parent, struct ssam_controller *ctrl,
- struct fwnode_handle *node)
-{
- struct fwnode_handle *child;
- int status;
-
- fwnode_for_each_child_node(node, child) {
- /*
- * Try to add the device specified in the firmware node. If
- * this fails with -EINVAL, the node does not specify any SSAM
- * device, so ignore it and continue with the next one.
- */
-
- status = ssam_hub_add_device(parent, ctrl, child);
- if (status && status != -EINVAL)
- goto err;
- }
-
- return 0;
-err:
- ssam_remove_clients(parent);
- return status;
-}
-
-
/* -- SSAM generic subsystem hub driver framework. -------------------------- */

enum ssam_hub_state {
@@ -385,7 +315,6 @@ struct ssam_hub {
static void ssam_hub_update_workfn(struct work_struct *work)
{
struct ssam_hub *hub = container_of(work, struct ssam_hub, update_work.work);
- struct fwnode_handle *node = dev_fwnode(&hub->sdev->dev);
enum ssam_hub_state state;
int status = 0;

@@ -425,7 +354,7 @@ static void ssam_hub_update_workfn(struct work_struct *work)
hub->state = state;

if (hub->state == SSAM_HUB_CONNECTED)
- status = ssam_hub_register_clients(&hub->sdev->dev, hub->sdev->ctrl, node);
+ status = ssam_device_register_clients(hub->sdev);
else
ssam_remove_clients(&hub->sdev->dev);

@@ -769,7 +698,7 @@ static int ssam_platform_hub_probe(struct platform_device *pdev)

set_secondary_fwnode(&pdev->dev, root);

- status = ssam_hub_register_clients(&pdev->dev, ctrl, root);
+ status = __ssam_register_clients(&pdev->dev, ctrl, root);
if (status) {
set_secondary_fwnode(&pdev->dev, NULL);
software_node_unregister_node_group(nodes);
diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
index 6cf7e80312d5..46c45d1b6368 100644
--- a/include/linux/surface_aggregator/device.h
+++ b/include/linux/surface_aggregator/device.h
@@ -15,6 +15,7 @@

#include <linux/device.h>
#include <linux/mod_devicetable.h>
+#include <linux/property.h>
#include <linux/types.h>

#include <linux/surface_aggregator/controller.h>
@@ -375,11 +376,62 @@ void ssam_device_driver_unregister(struct ssam_device_driver *d);
/* -- Helpers for controller and hub devices. ------------------------------- */

#ifdef CONFIG_SURFACE_AGGREGATOR_BUS
+
+int __ssam_register_clients(struct device *parent, struct ssam_controller *ctrl,
+ struct fwnode_handle *node);
void ssam_remove_clients(struct device *dev);
+
#else /* CONFIG_SURFACE_AGGREGATOR_BUS */
+
+static inline int __ssam_register_clients(struct device *parent, struct ssam_controller *ctrl,
+ struct fwnode_handle *node)
+{
+ return 0;
+}
+
static inline void ssam_remove_clients(struct device *dev) {}
+
#endif /* CONFIG_SURFACE_AGGREGATOR_BUS */

+/**
+ * ssam_register_clients() - Register all client devices defined under the
+ * given parent device.
+ * @dev: The parent device under which clients should be registered.
+ * @ctrl: The controller with which client should be registered.
+ *
+ * Register all clients that have via firmware nodes been defined as children
+ * of the given (parent) device. The respective child firmware nodes will be
+ * associated with the correspondingly created child devices.
+ *
+ * The given controller will be used to instantiate the new devices. See
+ * ssam_device_add() for details.
+ *
+ * Return: Returns zero on success, nonzero on failure.
+ */
+static inline int ssam_register_clients(struct device *dev, struct ssam_controller *ctrl)
+{
+ return __ssam_register_clients(dev, ctrl, dev_fwnode(dev));
+}
+
+/**
+ * ssam_device_register_clients() - Register all client devices defined under
+ * the given SSAM parent device.
+ * @sdev: The parent device under which clients should be registered.
+ *
+ * Register all clients that have via firmware nodes been defined as children
+ * of the given (parent) device. The respective child firmware nodes will be
+ * associated with the correspondingly created child devices.
+ *
+ * The controller used by the parent device will be used to instantiate the new
+ * devices. See ssam_device_add() for details.
+ *
+ * Return: Returns zero on success, nonzero on failure.
+ */
+static inline int ssam_device_register_clients(struct ssam_device *sdev)
+{
+ return ssam_register_clients(&sdev->dev, sdev->ctrl);
+}
+

/* -- Helpers for client-device requests. ----------------------------------- */

--
2.36.1
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