[PATCH v2] w1: mxc_w1: Enable clock before calling clk_get_rate() on it

From: Stefan Potyra
Date: Wed May 02 2018 - 04:55:54 EST


According to the API, you may only call clk_get_rate() after actually
enabling it.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: a5fd9139f74c ("w1: add 1-wire master driver for i.MX27 / i.MX31")
Signed-off-by: Stefan Potyra <Stefan.Potyra@xxxxxxxxxxxxxx>
---
drivers/w1/masters/mxc_w1.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/w1/masters/mxc_w1.c b/drivers/w1/masters/mxc_w1.c
index 74f2e6e6202a..8851d441e5fd 100644
--- a/drivers/w1/masters/mxc_w1.c
+++ b/drivers/w1/masters/mxc_w1.c
@@ -112,6 +112,10 @@ static int mxc_w1_probe(struct platform_device *pdev)
if (IS_ERR(mdev->clk))
return PTR_ERR(mdev->clk);

+ err = clk_prepare_enable(mdev->clk);
+ if (err)
+ return err;
+
clkrate = clk_get_rate(mdev->clk);
if (clkrate < 10000000)
dev_warn(&pdev->dev,
@@ -125,12 +129,10 @@ static int mxc_w1_probe(struct platform_device *pdev)

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mdev->regs = devm_ioremap_resource(&pdev->dev, res);
- if (IS_ERR(mdev->regs))
- return PTR_ERR(mdev->regs);
-
- err = clk_prepare_enable(mdev->clk);
- if (err)
- return err;
+ if (IS_ERR(mdev->regs)) {
+ err = PTR_ERR(mdev->regs);
+ goto out_disable_clk;
+ }

/* Software reset 1-Wire module */
writeb(MXC_W1_RESET_RST, mdev->regs + MXC_W1_RESET);
@@ -146,8 +148,12 @@ static int mxc_w1_probe(struct platform_device *pdev)

err = w1_add_master_device(&mdev->bus_master);
if (err)
- clk_disable_unprepare(mdev->clk);
+ goto out_disable_clk;

+ return 0;
+
+out_disable_clk:
+ clk_disable_unprepare(mdev->clk);
return err;
}

--
2.17.0

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