[PATCH v2] i2c: axxia: enable clock before calling clk_get_rate()

From: Tobias Jordan
Date: Mon Apr 30 2018 - 10:49:37 EST


axxia_i2c_init() uses clk_get_rate() for idev->i2c_clk. clk_get_rate()
should only be called if the clock is enabled, so ensure that by moving
the clk_prepare_enable() call before the call to axxia_i2c_init().

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

Fixes: 08678b850cd0 ("i2c: axxia: Add I2C driver for AXM55xx")
Signed-off-by: Tobias Jordan <Tobias.Jordan@xxxxxxxxxxxxxx>
---
v2:
first version of the patch ignored that the clock should be disabled in
case we bail out later...
compile-tested and coccichecked.

drivers/i2c/busses/i2c-axxia.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/drivers/i2c/busses/i2c-axxia.c b/drivers/i2c/busses/i2c-axxia.c
index 13f07482ec68..12f92369888b 100644
--- a/drivers/i2c/busses/i2c-axxia.c
+++ b/drivers/i2c/busses/i2c-axxia.c
@@ -532,23 +532,23 @@ static int axxia_i2c_probe(struct platform_device *pdev)
if (idev->bus_clk_rate == 0)
idev->bus_clk_rate = 100000; /* default clock rate */

+ ret = clk_prepare_enable(idev->i2c_clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable clock\n");
+ return ret;
+ }
+
ret = axxia_i2c_init(idev);
if (ret) {
dev_err(&pdev->dev, "failed to initialize\n");
- return ret;
+ goto error_disable_clk;
}

ret = devm_request_irq(&pdev->dev, irq, axxia_i2c_isr, 0,
pdev->name, idev);
if (ret) {
dev_err(&pdev->dev, "failed to claim IRQ%d\n", irq);
- return ret;
- }
-
- ret = clk_prepare_enable(idev->i2c_clk);
- if (ret) {
- dev_err(&pdev->dev, "failed to enable clock\n");
- return ret;
+ goto error_disable_clk;
}

i2c_set_adapdata(&idev->adapter, idev);
@@ -563,12 +563,14 @@ static int axxia_i2c_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, idev);

ret = i2c_add_adapter(&idev->adapter);
- if (ret) {
- clk_disable_unprepare(idev->i2c_clk);
- return ret;
- }
+ if (ret)
+ goto error_disable_clk;

return 0;
+
+error_disable_clk:
+ clk_disable_unprepare(idev->i2c_clk);
+ return ret;
}

static int axxia_i2c_remove(struct platform_device *pdev)
--
2.11.0