diff options
author | Vladimir Zapolskiy <vz@mleia.com> | 2019-01-23 00:18:22 +0300 |
---|---|---|
committer | Linus Walleij <linus.walleij@linaro.org> | 2019-01-28 16:39:52 +0300 |
commit | e73339037f6b6d65e84f5fd42e56dd3cdf0d9e9c (patch) | |
tree | 3a1fa2ab93a9378e79d36b175df795021e5d4e01 /include/linux/pinctrl/pinconf.h | |
parent | 87eff9af7efb154cc4a940ed12efc803a0bf3fba (diff) | |
download | linux-e73339037f6b6d65e84f5fd42e56dd3cdf0d9e9c.tar.xz |
pinctrl: remove unused 'pinconf-config' debugfs interface
The main goal of the change is to remove .pin_config_dbg_parse_modify
callback before a driver with its support appears. So far the in-kernel
interface did not attract any users since its introduction 5 years ago.
Originally .pin_config_dbg_parse_modify callback and the associated
'pinconf-config' debugfs file were introduced in commit f07512e615dd
("pinctrl/pinconfig: add debug interface"), a short description of
'pinconf-config' usage for debugging can be expressed this way:
Write to 'pinconf-config' (see pinconf_dbg_config_write() function):
% echo -n modify $map_type $device_name $state_name $pin_name $config > \
/sys/kernel/debug/pinctrl/$pinctrl/pinconf-config
It supposes to update a global (therefore single!) 'pinconf_dbg_conf'
variable with an alternative setting, the arguments should match
an existing pinconf device and some registered pinctrl mapping 'map':
* $map_type is either 'config_pin' or 'config_group', it should match
'map->type' value of PIN_MAP_TYPE_CONFIGS_PIN or
PIN_MAP_TYPE_CONFIGS_GROUP accordingly,
* $device_name should match 'map->dev_name' string value,
* $state_name should match 'map->name' string value,
* $pin_name should match 'map->data.configs.group_or_pin' string value,
If all above has matched, then $config is a new value to be set by calling
pinconfops->pin_config_dbg_parse_modify(pctldev, config, matched_config).
After a successful write into 'pinconf-config' a user can read the file
to get information about that single modified pin configuration.
The fact is .pin_config_dbg_parse_modify callback has never been defined
in 'struct pinconf_ops' of any pinconf driver, thus an actual modification
of a pin or group state on any present pinconf controller does not happen,
and it declares that all related code is no more than dead code.
I discovered the issue while attempting to add .pin_config_dbg_parse_modify
support in some drivers and found that too short 'MAX_NAME_LEN' set by
drivers/pinctrl/pinconf.c:372:#define MAX_NAME_LEN 15
is practically insufficient to store a regular pinctrl device name,
which are like 'e6060000.pin-controller-sh-pfc' or pin names like
'MX6QDL_PAD_ENET_REF_CLK', thus it is another indicator that the code
is barely usable, insufficiently tested and unprepossessing.
Of course it might be possible to increase MAX_NAME_LEN, and then add
.pin_config_dbg_parse_modify callbacks to the drivers, but the whole
idea of such a limited debug option looks inviable. A more flexible
way to functionally substitute the original approach is to implicitly
or explicitly use pinctrl_select_state() function whenever needed.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Cc: Laurent Meunier <laurent.meunier@st.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'include/linux/pinctrl/pinconf.h')
-rw-r--r-- | include/linux/pinctrl/pinconf.h | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/include/linux/pinctrl/pinconf.h b/include/linux/pinctrl/pinconf.h index 109468d9d849..93c9dd133e9d 100644 --- a/include/linux/pinctrl/pinconf.h +++ b/include/linux/pinctrl/pinconf.h @@ -29,7 +29,6 @@ struct seq_file; * @pin_config_group_get: get configurations for an entire pin group; should * return -ENOTSUPP and -EINVAL using the same rules as pin_config_get. * @pin_config_group_set: configure all pins in a group - * @pin_config_dbg_parse_modify: optional debugfs to modify a pin configuration * @pin_config_dbg_show: optional debugfs display hook that will provide * per-device info for a certain pin in debugfs * @pin_config_group_dbg_show: optional debugfs display hook that will provide @@ -55,9 +54,6 @@ struct pinconf_ops { unsigned selector, unsigned long *configs, unsigned num_configs); - int (*pin_config_dbg_parse_modify) (struct pinctrl_dev *pctldev, - const char *arg, - unsigned long *config); void (*pin_config_dbg_show) (struct pinctrl_dev *pctldev, struct seq_file *s, unsigned offset); |