soc: samsung: exynos-asv: handle reading revision register error

commit 4561560dfb4f847a0b327d48bdd1f45bf1b6261f upstream.

If regmap_read() fails, the product_id local variable will contain
random value from the stack.  Do not try to parse such value and fail
the ASV driver probe.

Fixes: 5ea428595cc5 ("soc: samsung: Add Exynos Adaptive Supply Voltage driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Link: https://lore.kernel.org/r/20201207190517.262051-3-krzk@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/soc/samsung/exynos-asv.c b/drivers/soc/samsung/exynos-asv.c
index f653e3533f0faf0eee2040216f5c8f67d0e9d091..5daeadc36382945a22bb5eea8d00ead11559caf6 100644 (file)
--- a/drivers/soc/samsung/exynos-asv.c
+++ b/drivers/soc/samsung/exynos-asv.c
@@ -129,7 +129,13 @@ static int exynos_asv_probe(struct platform_device *pdev)
                return PTR_ERR(asv->chipid_regmap);
        }
 
-       regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID, &product_id);
+       ret = regmap_read(asv->chipid_regmap, EXYNOS_CHIPID_REG_PRO_ID,
+                         &product_id);
+       if (ret < 0) {
+               dev_err(&pdev->dev, "Cannot read revision from ChipID: %d\n",
+                       ret);
+               return -ENODEV;
+       }
 
        switch (product_id & EXYNOS_MASK) {
        case 0xE5422000: