Re: [PATCH] watchdog: Add a device managed API for watchdog_register_device()

From: Guenter Roeck
Date: Thu May 26 2016 - 09:24:26 EST


On 05/26/2016 01:31 AM, Neil Armstrong wrote:
This helps in reducing code in .remove callbacks and sometimes
dropping .remove callbacks entirely.

Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
Documentation/driver-model/devres.txt | 3 +++
drivers/watchdog/watchdog_core.c | 36 +++++++++++++++++++++++++++++++++++
include/linux/watchdog.h | 3 +++
3 files changed, 42 insertions(+)

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index c63eea0..589296b 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -357,3 +357,6 @@ SLAVE DMA ENGINE

SPI
devm_spi_register_master()
+
+WATCHDOG
+ devm_watchdog_register_device()
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 981a668..a664d80 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -329,6 +329,42 @@ void watchdog_unregister_device(struct watchdog_device *wdd)

EXPORT_SYMBOL_GPL(watchdog_unregister_device);

+static void devm_watchdog_unregister_device(struct device *dev, void *res)
+{
+ watchdog_unregister_device(*(struct watchdog_device **)res);
+}
+
+/**
+ * devm_watchdog_register_device() - resource managed watchdog_register_device()
+ * @dev: device that is registering this watchdog device
+ * @wdd: watchdog device
+ *
+ * Managed watchdog_register_device(). For watchdog device registered by this
+ * function, watchdog_unregister_device() is automatically called on driver
+ * detach. See watchdog_register_device() for more information.
+ */
+int devm_watchdog_register_device(struct device *dev,
+ struct watchdog_device *wdd)
+{
+ struct watchdog_device **rcwdd;
+ int ret;
+
+ rcwdd = devres_alloc(devm_watchdog_unregister_device, sizeof(*wdd),
+ GFP_KERNEL);
+ if (!rcwdd)
+ return -ENOMEM;
+
+ ret = watchdog_register_device(wdd);
+ if (!ret) {
+ *rcwdd = wdd;
+ devres_add(dev, rcwdd);
+ } else
+ devres_free(rcwdd);
+

Please use { } in the else path as well.

Thanks,
Guenter

+ return ret;
+}
+EXPORT_SYMBOL_GPL(devm_watchdog_register_device);
+
static int __init watchdog_deferred_registration(void)
{
mutex_lock(&wtd_deferred_reg_mutex);
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 51732d6c..6b75e38 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -180,4 +180,7 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd,
extern int watchdog_register_device(struct watchdog_device *);
extern void watchdog_unregister_device(struct watchdog_device *);

+/* devres register variant */
+int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
+
#endif /* ifndef _LINUX_WATCHDOG_H */