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authorTzung-Bi Shih <tzungbi@kernel.org>2025-08-28 08:36:00 +0000
committerTzung-Bi Shih <tzungbi@kernel.org>2025-09-14 11:34:41 +0800
commit56cb557279d70397cefb497e0f06bdd6fd685f8e (patch)
treea863b7f72ea4e475ae1363a96da57e4cad1a9687
parent7a79b0bfd8b3995a39d25bffcf57273635c0e542 (diff)
platform/chrome: cros_ec: Add a flag to track registration state
Introduce a `registered` flag to the `struct cros_ec_device` to allow callers to determine if the device has been fully registered and is ready for use. This is a preparatory step to prevent race conditions where other drivers might try to access the device before it is fully registered or after it has been unregistered. Link: https://lore.kernel.org/r/20250828083601.856083-5-tzungbi@kernel.org Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
-rw-r--r--drivers/platform/chrome/cros_ec.c7
-rw-r--r--drivers/platform/chrome/cros_ec_proto.c15
-rw-r--r--include/linux/platform_data/cros_ec_proto.h4
3 files changed, 26 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec.c b/drivers/platform/chrome/cros_ec.c
index 61bcef8741db..1da79e3d215b 100644
--- a/drivers/platform/chrome/cros_ec.c
+++ b/drivers/platform/chrome/cros_ec.c
@@ -9,6 +9,7 @@
* battery charging and regulator control, firmware update.
*/
+#include <linux/cleanup.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_platform.h>
@@ -316,6 +317,9 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
goto exit;
}
+ scoped_guard(mutex, &ec_dev->lock)
+ ec_dev->registered = true;
+
dev_info(dev, "Chrome EC device registered\n");
/*
@@ -343,6 +347,9 @@ EXPORT_SYMBOL(cros_ec_register);
*/
void cros_ec_unregister(struct cros_ec_device *ec_dev)
{
+ scoped_guard(mutex, &ec_dev->lock)
+ ec_dev->registered = false;
+
if (ec_dev->mkbp_event_supported)
blocking_notifier_chain_unregister(&ec_dev->event_notifier,
&ec_dev->notifier_ready);
diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
index 3e94a0a82173..1d8d9168ec1a 100644
--- a/drivers/platform/chrome/cros_ec_proto.c
+++ b/drivers/platform/chrome/cros_ec_proto.c
@@ -3,6 +3,7 @@
//
// Copyright (C) 2015 Google, Inc
+#include <linux/cleanup.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/limits.h>
@@ -1153,5 +1154,19 @@ int cros_ec_get_cmd_versions(struct cros_ec_device *ec_dev, u16 cmd)
}
EXPORT_SYMBOL_GPL(cros_ec_get_cmd_versions);
+/**
+ * cros_ec_device_registered - Return if the ec_dev is registered.
+ *
+ * @ec_dev: EC device
+ *
+ * Return: true if registered. Otherwise, false.
+ */
+bool cros_ec_device_registered(struct cros_ec_device *ec_dev)
+{
+ guard(mutex)(&ec_dev->lock);
+ return ec_dev->registered;
+}
+EXPORT_SYMBOL_GPL(cros_ec_device_registered);
+
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC communication protocol helpers");
diff --git a/include/linux/platform_data/cros_ec_proto.h b/include/linux/platform_data/cros_ec_proto.h
index 4d96cffbb9e3..de14923720a5 100644
--- a/include/linux/platform_data/cros_ec_proto.h
+++ b/include/linux/platform_data/cros_ec_proto.h
@@ -128,6 +128,7 @@ struct cros_ec_command {
* @dout_size: Size of dout buffer to allocate (zero to use static dout).
* @wake_enabled: True if this device can wake the system from sleep.
* @suspended: True if this device had been suspended.
+ * @registered: True if this device had been registered.
* @cmd_xfer: Send command to EC and get response.
* Returns the number of bytes received if the communication
* succeeded, but that doesn't mean the EC was happy with the
@@ -186,6 +187,7 @@ struct cros_ec_device {
int dout_size;
bool wake_enabled;
bool suspended;
+ bool registered;
int (*cmd_xfer)(struct cros_ec_device *ec,
struct cros_ec_command *msg);
int (*pkt_xfer)(struct cros_ec_device *ec,
@@ -278,6 +280,8 @@ int cros_ec_cmd_readmem(struct cros_ec_device *ec_dev, u8 offset, u8 size, void
int cros_ec_get_cmd_versions(struct cros_ec_device *ec_dev, u16 cmd);
+bool cros_ec_device_registered(struct cros_ec_device *ec_dev);
+
/**
* cros_ec_get_time_ns() - Return time in ns.
*