[PATCH 4.9 35/39] w1: mxc_w1: Enable clock before calling clk_get_rate() on it

Greg Kroah-Hartman
2018-06-24T15:52:31Z

From: Stefan Potyra <Stefan.Potyra@elektrobit.com>

commit 955bc61328dc0a297fb3baccd84e9d3aee501ed8 upstream.

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>

---
drivers/w1/masters/mxc_w1.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)

--- a/drivers/w1/masters/mxc_w1.c
+++ b/drivers/w1/masters/mxc_w1.c
@@ -113,6 +113,10 @@ static int mxc_w1_probe(struct platform_
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,
@@ -126,12 +130,10 @@ static int mxc_w1_probe(struct platform_

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);
@@ -147,8 +149,12 @@ static int mxc_w1_probe(struct platform_

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;
}