2021-02-14 02:06:31

by Nicolas Boichat

[permalink] [raw]
Subject: Re: [v2,2/3] thermal: mediatek: Add LVTS drivers for SoC theraml zones

On Fri, Jan 29, 2021 at 5:40 PM Michael Kao <[email protected]> wrote:
>
> Add a LVTS (Low voltage thermal sensor) driver to report junction
> temperatures in Mediatek SoC and register the maximum temperature
> of sensors and each sensor as a thermal zone.
>
> Signed-off-by: Yu-Chia Chang <[email protected]>
> Signed-off-by: Michael Kao <[email protected]>
> ---
> drivers/thermal/mediatek/Kconfig | 10 +
> drivers/thermal/mediatek/Makefile | 1 +
> drivers/thermal/mediatek/soc_temp_lvts.c | 1287 ++++++++++++++++++++++
> drivers/thermal/mediatek/soc_temp_lvts.h | 312 ++++++
> 4 files changed, 1610 insertions(+)
> create mode 100644 drivers/thermal/mediatek/soc_temp_lvts.c
> create mode 100644 drivers/thermal/mediatek/soc_temp_lvts.h
>
> [snip]
> diff --git a/drivers/thermal/mediatek/Makefile b/drivers/thermal/mediatek/Makefile
> index f75313ddce5e..16ce166e5916 100644
> --- a/drivers/thermal/mediatek/Makefile
> +++ b/drivers/thermal/mediatek/Makefile
> @@ -1 +1,2 @@
> obj-$(CONFIG_MTK_SOC_THERMAL) += soc_temp.o
> +obj-$(CONFIG_MTK_SOC_THERMAL_LVTS) += soc_temp_lvts.o
> diff --git a/drivers/thermal/mediatek/soc_temp_lvts.c b/drivers/thermal/mediatek/soc_temp_lvts.c
> new file mode 100644
> index 000000000000..b56c2cd3cb39
> --- /dev/null
> +++ b/drivers/thermal/mediatek/soc_temp_lvts.c
> @@ -0,0 +1,1287 @@
> [snip]
> +
> +static unsigned int lvts_temp_to_raw(struct formula_coeff *co, int temp)
> +{
> + unsigned int msr_raw;
> +
> + msr_raw = ((long long)((co->golden_temp * 500 + co->b - temp)) << 14)
> + / (-1 * co->a);

This fails to build test on arm (32-bit):
ERROR: "__aeabi_ldivmod" [drivers/thermal/mediatek/soc_temp_lvts.ko] undefined!

Recommend using div_s64:
msr_raw = div_s64((s64)((co->golden_temp * 500 + co->b - temp)) << 14,
-1 * co->a);

> +
> + return msr_raw;
> +}
> [snip]