Re: [PATCH v8 0/3] pinctrl: pinmux: Add pinmux-select debugfs file

[Drew Fustini]

On Sat, Feb 20, 2021 at 12:27:47PM -0800, Drew Fustini wrote:
> This series first converts the debugfs files in the pinctrl subsystem to
> octal permissions and then adds a new debugfs file "pinmux-select".
> 
> Group name and function name can be written to "pinmux-select" which
> will cause the pin function for the specified group to be activated on
> the pin controller.
> 
> The final patch in this series documents the debugfs files for pinctrl.
> 
> Notes for PATCH v8:
> - add 'Reviewed-by:' from Geert Uytterhoeven for pinmux-select patch
> - add 'Tested-by:' from Geert Uytterhoeven for pinmux-select patch
> - change pinmux-select format to '<group-name function-name>' based on
>   feedback from Geert
> - rephrase parts of documentation per Geert's comments
> 
> Notes for PATCH v7:
> - add 'Reviewed-by:' from Andy Shevchenko for pinmux-select patch
> - add 'Reviewed-by:' from Andy Shevchenko for documentation patch
> - add 'Reviewed-by:' from Tony Lindgren to all patches
> - change order of '#include <linux/ctype.h>' per Andy's suggestion
> - change PINMUX_SELECT_MAX back to 128 as I had accidentally changed it
>   to 50 and Andy pointed this out.
> - grammer fixes as suggested by Andy
> - rework assignment of fsel and ret from pinmux_func_name_to_selector()
> - rework assignment of gsel and ret from pinctrl_get_group_selector()
> 
> Notes for PATCH v6:
> - add 'Suggested-by:' for Joe Perches to octal permissions patch
> - add 'Reviewed-by:' from Andy and Geert to octal permissions patch
> - reword example in the pinmux-select patch per Andy's advice
> - indent the example output per Andy's advice
> - remove usage error messages as Andy advised it is too verbose
> - return -ENOMEM when write is too big for the input buffer per Andy's advice
> - handle whitespace before, in between, and after the function name and
>   group name as suggested by Andy
> - rename free_buf to exit_free_buf per Andy's advice
> - add documentation patch to series which documents the debugfs files
>   for the pinctrl subsystem including the new pinmux-select file
> 
> Notes for PATCH v5:
> - convert permissions from symbolic to octal for debugfs_create_file()
>   calls in core.c that Joe Perches pointed out I had missed
> - Linus W: please let me know if I should break this series apart as you
>   already applied an earlier version of octal conversion patch today [1]
> - switch from sscanf() to just pointing to function name and group name
>   inside of the buffer. This also avoids having to allocate additional
>   buffers for fname and gname. Geert and Andy highlighted this security
>   issue and Andy suggested code to use instead of sscanf().
> - switch from devm_kfree() to kfree() after Dan Carpenter warned me
> - remove .read from pinmux_select_ops per Geert since it is write only
> - add usage format to error when unable find fname or gname in buffer
> 
> Notes for PATCH v4:
> - correct the commit message in the second patch to reference function
>   and group name instead of integer selectors. Apologies for not fixing
>   that in v3
> - fix typos in cover letter
> 
> Notes for PATCH v3:
> - add Suggested-by: Andy Shevchenko to the "pinctrl: use to octal
>   permissions for debugfs files" patch
> - change the octal permissions from 0400 to 0444 to correctly match the
>   symbolic permissions (thanks to Joe Perches and Geert Uytterhoeven)
> - note that S_IFREG flag is added to the mode in __debugfs_create_file()
>   (thanks to Andy for highlighting this and Joe for suggesting I should
>   add a note to the commit message)
> - fix order of the goto labels so that the buffers are freed correctly
>   as suggested by Dan Carpenter
> - move from devm_kzalloc() to kzalloc() as the buffers are only used
>   inside the pinmux_select() function and not related to the lifetime
>   of the pin controller device (thanks to Andy for pointing this out)
> - correct the pinmux-select example in commit message to use the
>   function and group name instead of selector (thanks to Geert)
> 
> Notes for PATCH v2:
> - create patch series that includes patch to switch all the debugfs
>   files in pinctrl subsystem over to octal permission
> - write function name and group name, instead of error-prone selector
>   numbers, to the 'pinmux-select' file
> - switch from static to dynamic allocation for the kernel buffer filled
>   by strncpy_from_user()
> - look up function selector from function name using
>   pinmux_func_name_to_selector()
> - validate group name with get_function_groups() and match_string()
> - look up selector for group name with pinctrl_get_group_selector()
> 
> Notes for PATCH v1:
> - posted seperate patch to switch all the debugfs files in pinctrl
>   subsystem over to octal permission
> - there is no existing documentation for any of the debugfs enteries for
>   pinctrl, so it seemed to have a bigger scope than just this patch. I
>   also noticed that rst documentation is confusingly named "pinctl" (no
>   'r') and started thread about that [2]. Linus suggested chaning that
>   to 'pin-control'. Thus I am planning a seperate documentation patch
>   series where the file is renamed, references changed and a section on
>   the pinctrl debugfs files is added.
> 
> Notes for RFC v2 [3]:
> - rename debugfs file "pinmux-set" to "pinmux-select"
> - renmae pinmux_set_write() to pinmux_select()
> - switch from memdup_user_nul() to strncpy_from_user()
> - switch from pr_warn() to dev_err()
> 
> [1] https://lore.kernel.org/linux-gpio/20210126044742.87602-1-drew@xxxxxxxxxxxxxxx/
> [2] https://lore.kernel.org/linux-gpio/20210126050817.GA187797@x1/
> [3] https://lore.kernel.org/linux-gpio/20210123064909.466225-1-drew@xxxxxxxxxxxxxxx/
> 
> Drew Fustini (3):
>   pinctrl: use to octal permissions for debugfs files
>   pinctrl: pinmux: Add pinmux-select debugfs file
>   docs/pinctrl: document debugfs files
> 
>  Documentation/driver-api/pinctl.rst |  37 ++++++++++
>  drivers/pinctrl/core.c              |  12 ++--
>  drivers/pinctrl/pinconf.c           |   4 +-
>  drivers/pinctrl/pinmux.c            | 106 +++++++++++++++++++++++++++-
>  4 files changed, 149 insertions(+), 10 deletions(-)
> 
> -- 
> 2.25.1
> 

Does any have any additional feedback for any of the patches in this
series?

Thank you!
DRew