Re: [PATCH 1/9] mfd: Add driver for Photonicat power management MCU

[Markus Elfring]

…
> +++ b/include/linux/mfd/photonicat-pmu.h
> @@ -0,0 +1,86 @@
…
> +#ifndef _PHOTONICAT_PMU_H
> +#define _PHOTONICAT_PMU_H
…

I suggest to omit leading underscores from such identifiers.
https://wiki.sei.cmu.edu/confluence/display/c/DCL37-C.+Do+not+declare+or+define+a+reserved+identifier

Regards,
Markus