linux-kernel - [PATCH 4.9 154/164] mtd: nand: orion: fix clk handling

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Date:   Tue, 23 May 2017 22:09:31 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Simon Baatz <gmbnomis@...il.com>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>
Subject: [PATCH 4.9 154/164] mtd: nand: orion: fix clk handling

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Simon Baatz <gmbnomis@...il.com>

commit 675b11d94ce9baa5eb365a51b35d2793f77c8ab8 upstream.

The clk handling in orion_nand.c had two problems:

- In the probe function, clk_put() was called for an enabled clock,
  which violates the API (see documentation for clk_put() in
  include/linux/clk.h)

- In the error path of the probe function, clk_put() could be called
  twice for the same clock.

In order to clean this up, use the managed function devm_clk_get() and
store the pointer to the clk in the driver data.

Fixes: baffab28b13120694fa3ebab08d3e99667a851d2 ('ARM: Orion: fix driver probe error handling with respect to clk')
Signed-off-by: Simon Baatz <gmbnomis@...il.com>
Signed-off-by: Boris Brezillon <boris.brezillon@...e-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/mtd/nand/orion_nand.c |   42 +++++++++++++++++++++---------------------
 1 file changed, 21 insertions(+), 21 deletions(-)

--- a/drivers/mtd/nand/orion_nand.c
+++ b/drivers/mtd/nand/orion_nand.c
@@ -23,6 +23,11 @@
 #include <asm/sizes.h>
 #include <linux/platform_data/mtd-orion_nand.h>
 
+struct orion_nand_info {
+	struct nand_chip chip;
+	struct clk *clk;
+};
+
 static void orion_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 {
 	struct nand_chip *nc = mtd_to_nand(mtd);
@@ -75,20 +80,21 @@ static void orion_nand_read_buf(struct m
 
 static int __init orion_nand_probe(struct platform_device *pdev)
 {
+	struct orion_nand_info *info;
 	struct mtd_info *mtd;
 	struct nand_chip *nc;
 	struct orion_nand_data *board;
 	struct resource *res;
-	struct clk *clk;
 	void __iomem *io_base;
 	int ret = 0;
 	u32 val = 0;
 
-	nc = devm_kzalloc(&pdev->dev,
-			sizeof(struct nand_chip),
+	info = devm_kzalloc(&pdev->dev,
+			sizeof(struct orion_nand_info),
 			GFP_KERNEL);
-	if (!nc)
+	if (!info)
 		return -ENOMEM;
+	nc = &info->chip;
 	mtd = nand_to_mtd(nc);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -145,15 +151,13 @@ static int __init orion_nand_probe(struc
 	if (board->dev_ready)
 		nc->dev_ready = board->dev_ready;
 
-	platform_set_drvdata(pdev, mtd);
+	platform_set_drvdata(pdev, info);
 
 	/* Not all platforms can gate the clock, so it is not
 	   an error if the clock does not exists. */
-	clk = clk_get(&pdev->dev, NULL);
-	if (!IS_ERR(clk)) {
-		clk_prepare_enable(clk);
-		clk_put(clk);
-	}
+	info->clk = devm_clk_get(&pdev->dev, NULL);
+	if (!IS_ERR(info->clk))
+		clk_prepare_enable(info->clk);
 
 	if (nand_scan(mtd, 1)) {
 		ret = -ENXIO;
@@ -170,26 +174,22 @@ static int __init orion_nand_probe(struc
 	return 0;
 
 no_dev:
-	if (!IS_ERR(clk)) {
-		clk_disable_unprepare(clk);
-		clk_put(clk);
-	}
+	if (!IS_ERR(info->clk))
+		clk_disable_unprepare(info->clk);
 
 	return ret;
 }
 
 static int orion_nand_remove(struct platform_device *pdev)
 {
-	struct mtd_info *mtd = platform_get_drvdata(pdev);
-	struct clk *clk;
+	struct orion_nand_info *info = platform_get_drvdata(pdev);
+	struct nand_chip *chip = &info->chip;
+	struct mtd_info *mtd = nand_to_mtd(chip);
 
 	nand_release(mtd);
 
-	clk = clk_get(&pdev->dev, NULL);
-	if (!IS_ERR(clk)) {
-		clk_disable_unprepare(clk);
-		clk_put(clk);
-	}
+	if (!IS_ERR(info->clk))
+		clk_disable_unprepare(info->clk);
 
 	return 0;
 }