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Date:   Wed,  1 Sep 2021 19:55:26 -0700
In-Reply-To: <20210902025528.1017391-1-saravanak@google.com>
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Subject: [PATCH v1 1/2] driver core: Add support for FWNODE_FLAG_NEVER_PROBES
From:   Saravana Kannan <saravanak@google.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Len Brown <lenb@kernel.org>
Cc:     Saravana Kannan <saravanak@google.com>,
        Ulf Hansson <ulf.hansson@linaro.org>, kernel-team@android.com,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        linux-acpi@vger.kernel.org
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Precedence: bulk

Add a fwnode flag to mark a device as one that will never be probed even
though it's added to a bus.

Signed-off-by: Saravana Kannan <saravanak@google.com>
---
 drivers/base/core.c    | 8 ++++++++
 include/linux/fwnode.h | 8 +++++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index f6360490a4a3..5d14897a53e6 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1719,6 +1719,14 @@ static int fw_devlink_create_devlink(struct device *con,
 	struct device *sup_dev;
 	int ret = 0;
 
+	/*
+	 * If the consumer or supplier is a device that'll never be probed,
+	 * don't create devices link for it.
+	 */
+	if (con->fwnode->flags & FWNODE_FLAG_NEVER_PROBES ||
+	    sup_handle->flags & FWNODE_FLAG_NEVER_PROBES)
+		return -EINVAL;
+
 	sup_dev = get_dev_from_fwnode(sup_handle);
 	if (sup_dev) {
 		/*
diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
index 59828516ebaf..3ad667ae97d8 100644
--- a/include/linux/fwnode.h
+++ b/include/linux/fwnode.h
@@ -19,13 +19,15 @@ struct device;
 /*
  * fwnode link flags
  *
- * LINKS_ADDED:	The fwnode has already be parsed to add fwnode links.
- * NOT_DEVICE:	The fwnode will never be populated as a struct device.
- * INITIALIZED: The hardware corresponding to fwnode has been initialized.
+ * LINKS_ADDED:	 The fwnode has already be parsed to add fwnode links.
+ * NOT_DEVICE:	 The fwnode will never be populated as a struct device.
+ * INITIALIZED:  The hardware corresponding to fwnode has been initialized.
+ * NEVER_PROBES: The device that corresponds to this fwnode will never probe.
  */
 #define FWNODE_FLAG_LINKS_ADDED		BIT(0)
 #define FWNODE_FLAG_NOT_DEVICE		BIT(1)
 #define FWNODE_FLAG_INITIALIZED		BIT(2)
+#define FWNODE_FLAG_NEVER_PROBES	BIT(3)
 
 struct fwnode_handle {
 	struct fwnode_handle *secondary;
-- 
2.33.0.259.gc128427fd7-goog