As description for DIV_ROUND_CLOSEST in file include/linux/kernel.h. "Result is undefined for negative divisors if the dividend variable type is unsigned and for negative dividends if the divisor variable type is unsigned." In current code, the FIXPT_DIV uses DIV_ROUND_CLOSEST but has not checked sign of divisor before using. It makes undefined temperature value in case the value is negative. This patch fixes to satisfy DIV_ROUND_CLOSEST description and fix bug too. Note that the variable name "reg" is not good because it should be the same type as rcar_gen3_thermal_read(). However, it's better to rename the "reg" in a further patch as cleanup. Signed-off-by: Van Do <van.do.xw@renesas.com> Signed-off-by: Dien Pham <dien.pham.ry@renesas.com> [shimoda: minor fixes, add Fixes tag] Fixes: 564e73d283af ("thermal: rcar_gen3_thermal: Add R-Car Gen3 thermal driver") Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Reviewed-by: Niklas Soderlund <niklas.soderlund+renesas@ragnatech.se> Tested-by: Niklas Soderlund <niklas.soderlund+renesas@ragnatech.se> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/1593085099-2057-1-git-send-email-yoshihiro.shimoda.uh@renesas.com
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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