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From:   Alan Tull <atull@kernel.org>
To:     Moritz Fischer <mdf@kernel.org>, Jonathan Corbet <corbet@lwn.net>
Cc:     Randy Dunlap <rdunlap@infradead.org>, linux-kernel@vger.kernel.org,
        linux-fpga@vger.kernel.org, linux-doc@vger.kernel.org,
        Alan Tull <atull@kernel.org>
Subject: [PATCH 3/8] fpga: bridge: add devm_fpga_bridge_create
Date:   Tue, 14 Aug 2018 14:15:21 -0500
Message-Id: <20180814191526.3247-4-atull@kernel.org>
In-Reply-To: <20180814191526.3247-1-atull@kernel.org>
References: <20180814191526.3247-1-atull@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Add devm_fpga_bridge_create() which is the managed
version of fpga_bridge_create().

Change current bridge drivers to use
devm_fpga_bridge_create().

Signed-off-by: Alan Tull <atull@kernel.org>
---
 Documentation/driver-api/fpga/fpga-bridge.rst |  3 ++
 drivers/fpga/altera-fpga2sdram.c              |  8 ++-
 drivers/fpga/altera-freeze-bridge.c           | 13 ++---
 drivers/fpga/altera-hps2fpga.c                |  7 ++-
 drivers/fpga/dfl-fme-br.c                     | 11 ++--
 drivers/fpga/fpga-bridge.c                    | 72 +++++++++++++++++++++++----
 drivers/fpga/xilinx-pr-decoupler.c            |  4 +-
 include/linux/fpga/fpga-bridge.h              |  4 ++
 8 files changed, 84 insertions(+), 38 deletions(-)

diff --git a/Documentation/driver-api/fpga/fpga-bridge.rst b/Documentation/driver-api/fpga/fpga-bridge.rst
index 2c2aaca..ebbcbde 100644
--- a/Documentation/driver-api/fpga/fpga-bridge.rst
+++ b/Documentation/driver-api/fpga/fpga-bridge.rst
@@ -11,6 +11,9 @@ API to implement a new FPGA bridge
    :functions: fpga_bridge_ops
 
 .. kernel-doc:: drivers/fpga/fpga-bridge.c
+   :functions: devm_fpga_bridge_create
+
+.. kernel-doc:: drivers/fpga/fpga-bridge.c
    :functions: fpga_bridge_create
 
 .. kernel-doc:: drivers/fpga/fpga-bridge.c
diff --git a/drivers/fpga/altera-fpga2sdram.c b/drivers/fpga/altera-fpga2sdram.c
index 23660cc..a78e49c 100644
--- a/drivers/fpga/altera-fpga2sdram.c
+++ b/drivers/fpga/altera-fpga2sdram.c
@@ -121,18 +121,16 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 	/* Get f2s bridge configuration saved in handoff register */
 	regmap_read(sysmgr, SYSMGR_ISWGRP_HANDOFF3, &priv->mask);
 
-	br = fpga_bridge_create(dev, F2S_BRIDGE_NAME,
-				&altera_fpga2sdram_br_ops, priv);
+	br = devm_fpga_bridge_create(dev, F2S_BRIDGE_NAME,
+				     &altera_fpga2sdram_br_ops, priv);
 	if (!br)
 		return -ENOMEM;
 
 	platform_set_drvdata(pdev, br);
 
 	ret = fpga_bridge_register(br);
-	if (ret) {
-		fpga_bridge_free(br);
+	if (ret)
 		return ret;
-	}
 
 	dev_info(dev, "driver initialized with handoff %08x\n", priv->mask);
 
diff --git a/drivers/fpga/altera-freeze-bridge.c b/drivers/fpga/altera-freeze-bridge.c
index ffd586c..dd58c4a 100644
--- a/drivers/fpga/altera-freeze-bridge.c
+++ b/drivers/fpga/altera-freeze-bridge.c
@@ -213,7 +213,6 @@ static int altera_freeze_br_probe(struct platform_device *pdev)
 	struct fpga_bridge *br;
 	struct resource *res;
 	u32 status, revision;
-	int ret;
 
 	if (!np)
 		return -ENODEV;
@@ -245,20 +244,14 @@ static int altera_freeze_br_probe(struct platform_device *pdev)
 
 	priv->base_addr = base_addr;
 
-	br = fpga_bridge_create(dev, FREEZE_BRIDGE_NAME,
-				&altera_freeze_br_br_ops, priv);
+	br = devm_fpga_bridge_create(dev, FREEZE_BRIDGE_NAME,
+				     &altera_freeze_br_br_ops, priv);
 	if (!br)
 		return -ENOMEM;
 
 	platform_set_drvdata(pdev, br);
 
-	ret = fpga_bridge_register(br);
-	if (ret) {
-		fpga_bridge_free(br);
-		return ret;
-	}
-
-	return 0;
+	return fpga_bridge_register(br);
 }
 
 static int altera_freeze_br_remove(struct platform_device *pdev)
diff --git a/drivers/fpga/altera-hps2fpga.c b/drivers/fpga/altera-hps2fpga.c
index a974d3f..77b95f2 100644
--- a/drivers/fpga/altera-hps2fpga.c
+++ b/drivers/fpga/altera-hps2fpga.c
@@ -180,7 +180,8 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 		}
 	}
 
-	br = fpga_bridge_create(dev, priv->name, &altera_hps2fpga_br_ops, priv);
+	br = devm_fpga_bridge_create(dev, priv->name,
+				     &altera_hps2fpga_br_ops, priv);
 	if (!br) {
 		ret = -ENOMEM;
 		goto err;
@@ -190,12 +191,10 @@ static int alt_fpga_bridge_probe(struct platform_device *pdev)
 
 	ret = fpga_bridge_register(br);
 	if (ret)
-		goto err_free;
+		goto err;
 
 	return 0;
 
-err_free:
-	fpga_bridge_free(br);
 err:
 	clk_disable_unprepare(priv->clk);
 
diff --git a/drivers/fpga/dfl-fme-br.c b/drivers/fpga/dfl-fme-br.c
index 7cc041d..3ff9f3a 100644
--- a/drivers/fpga/dfl-fme-br.c
+++ b/drivers/fpga/dfl-fme-br.c
@@ -61,7 +61,6 @@ static int fme_br_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct fme_br_priv *priv;
 	struct fpga_bridge *br;
-	int ret;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
@@ -69,18 +68,14 @@ static int fme_br_probe(struct platform_device *pdev)
 
 	priv->pdata = dev_get_platdata(dev);
 
-	br = fpga_bridge_create(dev, "DFL FPGA FME Bridge",
-				&fme_bridge_ops, priv);
+	br = devm_fpga_bridge_create(dev, "DFL FPGA FME Bridge",
+				     &fme_bridge_ops, priv);
 	if (!br)
 		return -ENOMEM;
 
 	platform_set_drvdata(pdev, br);
 
-	ret = fpga_bridge_register(br);
-	if (ret)
-		fpga_bridge_free(br);
-
-	return ret;
+	return fpga_bridge_register(br);
 }
 
 static int fme_br_remove(struct platform_device *pdev)
diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
index 24b8f98..c39d35f 100644
--- a/drivers/fpga/fpga-bridge.c
+++ b/drivers/fpga/fpga-bridge.c
@@ -324,6 +324,9 @@ ATTRIBUTE_GROUPS(fpga_bridge);
  * @br_ops:	pointer to structure of fpga bridge ops
  * @priv:	FPGA bridge private data
  *
+ * The caller of this function is responsible for freeing the bridge with
+ * fpga_bridge_free().  Using devm_fpga_bridge_create() instead is recommended.
+ *
  * Return: struct fpga_bridge or NULL
  */
 struct fpga_bridge *fpga_bridge_create(struct device *dev, const char *name,
@@ -378,8 +381,8 @@ struct fpga_bridge *fpga_bridge_create(struct device *dev, const char *name,
 EXPORT_SYMBOL_GPL(fpga_bridge_create);
 
 /**
- * fpga_bridge_free - free a fpga bridge and its id
- * @bridge:	FPGA bridge struct created by fpga_bridge_create
+ * fpga_bridge_free - free a fpga bridge created by fpga_bridge_create()
+ * @bridge:	FPGA bridge struct
  */
 void fpga_bridge_free(struct fpga_bridge *bridge)
 {
@@ -388,9 +391,56 @@ void fpga_bridge_free(struct fpga_bridge *bridge)
 }
 EXPORT_SYMBOL_GPL(fpga_bridge_free);
 
+static void devm_fpga_bridge_release(struct device *dev, void *res)
+{
+	struct fpga_bridge *bridge = *(struct fpga_bridge **)res;
+
+	fpga_bridge_free(bridge);
+}
+
 /**
- * fpga_bridge_register - register a fpga bridge
- * @bridge:	FPGA bridge struct created by fpga_bridge_create
+ * devm_fpga_bridge_create - create and init a managed struct fpga_bridge
+ * @dev:	FPGA bridge device from pdev
+ * @name:	FPGA bridge name
+ * @br_ops:	pointer to structure of fpga bridge ops
+ * @priv:	FPGA bridge private data
+ *
+ * This function is intended for use in a FPGA bridge driver's probe function.
+ * After the bridge driver creates the struct with devm_fpga_bridge_create(), it
+ * should register the bridge with fpga_bridge_register().  The bridge driver's
+ * remove function should call fpga_bridge_unregister().  The bridge struct
+ * allocated with this function will be freed automatically on driver detach.
+ * This includes the case of a probe function returning error before calling
+ * fpga_bridge_register(), the struct will still get cleaned up.
+ *
+ *  Return: struct fpga_bridge or NULL
+ */
+struct fpga_bridge
+*devm_fpga_bridge_create(struct device *dev, const char *name,
+			 const struct fpga_bridge_ops *br_ops, void *priv)
+{
+	struct fpga_bridge **ptr, *bridge;
+
+	ptr = devres_alloc(devm_fpga_bridge_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	bridge = fpga_bridge_create(dev, name, br_ops, priv);
+	if (!bridge) {
+		devres_free(ptr);
+	} else {
+		*ptr = bridge;
+		devres_add(dev, ptr);
+	}
+
+	return bridge;
+}
+EXPORT_SYMBOL_GPL(devm_fpga_bridge_create);
+
+/**
+ * fpga_bridge_register - register a FPGA bridge
+ *
+ * @bridge: FPGA bridge struct
  *
  * Return: 0 for success, error code otherwise.
  */
@@ -412,8 +462,15 @@ int fpga_bridge_register(struct fpga_bridge *bridge)
 EXPORT_SYMBOL_GPL(fpga_bridge_register);
 
 /**
- * fpga_bridge_unregister - unregister and free a fpga bridge
- * @bridge:	FPGA bridge struct created by fpga_bridge_create
+ * fpga_bridge_unregister - unregister a FPGA bridge
+ *
+ * @bridge: FPGA bridge struct
+ *
+ * This function is intended for use in a FPGA bridge driver's remove function.
+ * If the bridge was created with devm_fpga_bridge_create(), the bridge struct
+ * will be automatically freed.  If the bridge was created with
+ * fpga_bridge_create(), the caller is responsible for freeing the bridge with
+ * fpga_bridge_free().
  */
 void fpga_bridge_unregister(struct fpga_bridge *bridge)
 {
@@ -430,9 +487,6 @@ EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
 
 static void fpga_bridge_dev_release(struct device *dev)
 {
-	struct fpga_bridge *bridge = to_fpga_bridge(dev);
-
-	fpga_bridge_free(bridge);
 }
 
 static int __init fpga_bridge_dev_init(void)
diff --git a/drivers/fpga/xilinx-pr-decoupler.c b/drivers/fpga/xilinx-pr-decoupler.c
index 07ba153..6410361 100644
--- a/drivers/fpga/xilinx-pr-decoupler.c
+++ b/drivers/fpga/xilinx-pr-decoupler.c
@@ -121,8 +121,8 @@ static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 
 	clk_disable(priv->clk);
 
-	br = fpga_bridge_create(&pdev->dev, "Xilinx PR Decoupler",
-				&xlnx_pr_decoupler_br_ops, priv);
+	br = devm_fpga_bridge_create(&pdev->dev, "Xilinx PR Decoupler",
+				     &xlnx_pr_decoupler_br_ops, priv);
 	if (!br) {
 		err = -ENOMEM;
 		goto err_clk;
diff --git a/include/linux/fpga/fpga-bridge.h b/include/linux/fpga/fpga-bridge.h
index ce550fc..817600a 100644
--- a/include/linux/fpga/fpga-bridge.h
+++ b/include/linux/fpga/fpga-bridge.h
@@ -69,4 +69,8 @@ void fpga_bridge_free(struct fpga_bridge *br);
 int fpga_bridge_register(struct fpga_bridge *br);
 void fpga_bridge_unregister(struct fpga_bridge *br);
 
+struct fpga_bridge
+*devm_fpga_bridge_create(struct device *dev, const char *name,
+			 const struct fpga_bridge_ops *br_ops, void *priv);
+
 #endif /* _LINUX_FPGA_BRIDGE_H */
-- 
2.7.4