pinctrl/pinconfig: add debug interface

This update adds a debugfs interface to modify a pin configuration
for a given state in the pinctrl map. This allows to modify the
configuration for a non-active state, typically sleep state.
This configuration is not applied right away, but only when the state
will be entered.

This solution is mandated for us by HW validation: in order
to test and verify several pin configurations during sleep without
recompiling the software.

Change log in this patch set;
Take into account latest feedback from Stephen Warren:
- stale comments update
- improved code efficiency and readibility
- limit size of global variable pinconf_dbg_conf
- remove req_type as it can easily be added later when
add/delete requests support is implemented

Signed-off-by: Laurent Meunier <laurent.meunier@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/pinctrl/pinconf.h b/include/linux/pinctrl/pinconf.h
index e7a720104a47..1ad4f31ef6b8 100644
--- a/include/linux/pinctrl/pinconf.h
+++ b/include/linux/pinctrl/pinconf.h
@@ -14,6 +14,8 @@
 
 #ifdef CONFIG_PINCONF
 
+#include <linux/pinctrl/machine.h>
+
 struct pinctrl_dev;
 struct seq_file;
 
@@ -28,6 +30,7 @@ struct seq_file;
  * @pin_config_set: configure an individual pin
  * @pin_config_group_get: get configurations for an entire pin group
  * @pin_config_group_set: configure all pins in a group
+ * @pin_config_group_dbg_set: 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
@@ -51,6 +54,9 @@ struct pinconf_ops {
         int (*pin_config_group_set) (struct pinctrl_dev *pctldev,
                                      unsigned selector,
                                      unsigned long config);
+        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);