RE: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision register error

["Pankaj Dubey" <pankaj.dubey@samsung.com>]

> -----Original Message-----
> From: Krzysztof Kozlowski <krzk@kernel.org>
> Sent: Tuesday, December 8, 2020 12:35 AM
> To: Krzysztof Kozlowski <krzk@kernel.org>; linux-arm-
> kernel@lists.infradead.org; linux-samsung-soc@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Cc: Sylwester Nawrocki <snawrocki@kernel.org>; Marek Szyprowski
> <m.szyprowski@samsung.com>; Bartlomiej Zolnierkiewicz
> <b.zolnierkie@samsung.com>; Arnd Bergmann <arnd@arndb.de>; Chanwoo
> Choi <cw00.choi@samsung.com>; Alim Akhtar <alim.akhtar@samsung.com>;
> Pankaj Dubey <pankaj.dubey@samsung.com>; stable@vger.kernel.org
> Subject: [PATCH v2 2/4] soc: samsung: exynos-asv: handle reading revision
> register error
> 
> 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>
> ---
>  drivers/soc/samsung/exynos-asv.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/soc/samsung/exynos-asv.c
> b/drivers/soc/samsung/exynos-asv.c
> index f653e3533f0f..5daeadc36382 100644
> --- 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:
> --
> 2.25.1

Reviewed-by: Pankaj Dubey <pankaj.dubey@samsung.com>