[PATCH] mtd: nand: orion: fix clk handling

Simon Baatz
2017-03-12T21:34:06Z

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')
Cc: <stable@vger.kernel.org> # v4.5+
Signed-off-by: Simon Baatz <gmbnomis@gmail.com>
---
drivers/mtd/nand/orion_nand.c | 42 +++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
index 4a91c5d000be..b355aa738fae 100644
--- 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 mtd_info *mtd, uint8_t *buf, int len)

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(struct platform_device *pdev)
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);

ret = nand_scan(mtd, 1);
if (ret)
@@ -169,26 +173,22 @@ static int __init orion_nand_probe(struct platform_device *pdev)
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;
}
--
2.9.3