24.03.2020 17:54, Dmitry Osipenko пишет: > 23.03.2020 05:25, Wang, Jiada пишет: >> Hello Dmitry >> >> On 2020/03/21 0:53, Dmitry Osipenko wrote: >>> Hello Jiada, >>> >>> 20.03.2020 06:37, Wang, Jiada пишет: >>>> Hello Dmitry >>>> >>>> I have submitted v8 patch-set to address your comments towards v7 >>>> patch-set, >>>> most of checkpatch warnings and errors have been addressed, >>>> >>>> But I didn't update for following two types of warnings >>>> since I want to keep consistency with legacy code >>>> >>>> WARNING: DEVICE_ATTR unusual permissions '0600' used >>>> #290: FILE: drivers/input/touchscreen/atmel_mxt_ts.c:3761: >>>> +static DEVICE_ATTR(debug_v2_enable, 0600, NULL, >>> >>> What will happen if you'll use 0644? Will an empty line be returned or >>> driver will crash? >>> >> debug_v2_enable doesn't have .show callback implemented, so after change >> permission to 644, read of it results in an I/O error, >> >> for other 0600 permission interfaces (t38_data, t25 and debug_enable) >> added in this series, >> change to 644 can return expected information when read. >> >> Do you think it's better to change debug_v2_enable to 0200, >> and others to 0644? > > Since the debug_enable has mxt_debug_enable_show(), the same should be > done for debug_v2_enable, for consistency. > > The permissions should be 0644 for everything that is read/write. > > The 0200 should be used for everything that is root-only and write-only. > Also, please take a look at [1], see DEVICE_ATTR_WO() and DEVICE_BOOL_ATTR() macros, which should be handy. [1] https://elixir.bootlin.com/linux/v5.6-rc7/source/include/linux/device.h#L125
