On Wed, May 11, 2016 at 02:49:53PM +0200, Arnd Bergmann wrote:
> A rework of the exynos-mipi-video driver caused a warning
> about the new __set_phy_state function potentially accessing
> a variable before its initialization:
>
> drivers/phy/phy-exynos-mipi-video.c: In function '__set_phy_state':
> drivers/phy/phy-exynos-mipi-video.c:238:13: error: 'val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
> return val & data->resetn_val;
> ~~~~^~~~~~~~~~~~~~~~~~
> drivers/phy/phy-exynos-mipi-video.c:235:6: note: 'val' was declared here
> u32 val;
>
> The failure scenario here is the offset passed into a the
> stub regmap_read() function that does not modify its output,
> however regmap_read() can also fail for other reasons, so
> adding error handling (in this case, returning zero from
> is_running) seems the best solution.
>
> Note that this warning showed up with the ARM s5pv210_defconfig,
> indicating that we most likely want to either enable CONFIG_REGMAP
> in that defconfig as well, or disable the phy-exynos-mipi-video
> driver.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> Fixes: 97a3042f7616 ("phy: exynos-mipi-video: Rewrite handling of phy registers")
> ---
> drivers/phy/phy-exynos-mipi-video.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/phy/phy-exynos-mipi-video.c b/drivers/phy/phy-exynos-mipi-video.c
> index cc093ebfda94..8b851f718123 100644
> --- a/drivers/phy/phy-exynos-mipi-video.c
> +++ b/drivers/phy/phy-exynos-mipi-video.c
> @@ -233,8 +233,12 @@ static inline int __is_running(const struct exynos_mipi_phy_desc *data,
> struct exynos_mipi_video_phy *state)
> {
> u32 val;
Other way would be to initialize val=0 since there is no real error code
returned. Anyway:
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
Best regards,
Krzysztof
> + int ret;
> +
> + ret = regmap_read(state->regmaps[data->resetn_map], data->resetn_reg, &val);
> + if (ret)
> + return 0;
>
> - regmap_read(state->regmaps[data->resetn_map], data->resetn_reg, &val);
> return val & data->resetn_val;
> }
>
> --
> 2.7.0
>
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