w1: mxc_w1: Enable clock before calling clk_get_rate() on it

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@elektrobit.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files 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;
 }