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>

diff --git a/drivers/pinctrl/pinconf.c b/drivers/pinctrl/pinconf.c
index baee2cc46a17a7c5c328f98c7eaa25f8f10d8fba..6f14b62ae8ba8f16d8d4492ee2105a96419278df 100644 (file)
--- a/drivers/pinctrl/pinconf.c
+++ b/drivers/pinctrl/pinconf.c
@@ -17,6 +17,7 @@
 #include <linux/slab.h>
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
+#include <linux/uaccess.h>
 #include <linux/pinctrl/machine.h>
 #include <linux/pinctrl/pinctrl.h>
 #include <linux/pinctrl/pinconf.h>
@@ -574,6 +575,235 @@ static const struct file_operations pinconf_groups_ops = {
        .release        = single_release,
 };
 
+#define MAX_NAME_LEN 15
+
+struct dbg_cfg {
+       enum pinctrl_map_type map_type;
+       char dev_name[MAX_NAME_LEN+1];
+       char state_name[MAX_NAME_LEN+1];
+       char pin_name[MAX_NAME_LEN+1];
+};
+
+/*
+ * Goal is to keep this structure as global in order to simply read the
+ * pinconf-config file after a write to check config is as expected
+ */
+static struct dbg_cfg pinconf_dbg_conf;
+
+/**
+ * pinconf_dbg_config_print() - display the pinctrl config from the pinctrl
+ * map, of the dev/pin/state that was last written to pinconf-config file.
+ * @s: string filled in  with config description
+ * @d: not used
+ */
+static int pinconf_dbg_config_print(struct seq_file *s, void *d)
+{
+       struct pinctrl_maps *maps_node;
+       const struct pinctrl_map *map;
+       struct pinctrl_dev *pctldev = NULL;
+       const struct pinconf_ops *confops = NULL;
+       const struct pinctrl_map_configs *configs;
+       struct dbg_cfg *dbg = &pinconf_dbg_conf;
+       int i, j;
+       bool found = false;
+       unsigned long config;
+
+       mutex_lock(&pinctrl_mutex);
+
+       /* Parse the pinctrl map and look for the elected pin/state */
+       for_each_maps(maps_node, i, map) {
+               if (map->type != dbg->map_type)
+                       continue;
+               if (strcmp(map->dev_name, dbg->dev_name))
+                       continue;
+               if (strcmp(map->name, dbg->state_name))
+                       continue;
+
+               for (j = 0; j < map->data.configs.num_configs; j++) {
+                       if (!strcmp(map->data.configs.group_or_pin,
+                                       dbg->pin_name)) {
+                               /*
+                                * We found the right pin / state, read the
+                                * config and he pctldev for later use
+                                */
+                               configs = &map->data.configs;
+                               pctldev = get_pinctrl_dev_from_devname
+                                       (map->ctrl_dev_name);
+                               found = true;
+                               break;
+                       }
+               }
+       }
+
+       if (!found) {
+               seq_printf(s, "No config found for dev/state/pin, expected:\n");
+               seq_printf(s, "Searched dev:%s\n", dbg->dev_name);
+               seq_printf(s, "Searched state:%s\n", dbg->state_name);
+               seq_printf(s, "Searched pin:%s\n", dbg->pin_name);
+               seq_printf(s, "Use: modify config_pin <devname> "\
+                               "<state> <pinname> <value>\n");
+               goto exit;
+       }
+
+       config = *(configs->configs);
+       seq_printf(s, "Dev %s has config of %s in state %s: 0x%08lX\n",
+                       dbg->dev_name, dbg->pin_name,
+                       dbg->state_name, config);
+
+       if (pctldev)
+               confops = pctldev->desc->confops;
+
+       if (confops && confops->pin_config_config_dbg_show)
+               confops->pin_config_config_dbg_show(pctldev, s, config);
+
+exit:
+       mutex_unlock(&pinctrl_mutex);
+
+       return 0;
+}
+
+/**
+ * pinconf_dbg_config_write() - modify the pinctrl config in the pinctrl
+ * map, of a dev/pin/state entry based on user entries to pinconf-config
+ * @user_buf: contains the modification request with expected format:
+ *     modify config_pin <devicename> <state> <pinname> <newvalue>
+ * modify is literal string, alternatives like add/delete not supported yet
+ * config_pin is literal, alternatives like config_mux not supported yet
+ * <devicename> <state> <pinname> are values that should match the pinctrl-maps
+ * <newvalue> reflects the new config and is driver dependant
+ */
+static int pinconf_dbg_config_write(struct file *file,
+       const char __user *user_buf, size_t count, loff_t *ppos)
+{
+       struct pinctrl_maps *maps_node;
+       const struct pinctrl_map *map;
+       struct pinctrl_dev *pctldev = NULL;
+       const struct pinconf_ops *confops = NULL;
+       struct dbg_cfg *dbg = &pinconf_dbg_conf;
+       const struct pinctrl_map_configs *configs;
+       char config[MAX_NAME_LEN+1];
+       bool found = false;
+       char buf[128];
+       char *b = &buf[0];
+       int buf_size;
+       char *token;
+       int i;
+
+       /* Get userspace string and assure termination */
+       buf_size = min(count, (sizeof(buf)-1));
+       if (copy_from_user(buf, user_buf, buf_size))
+               return -EFAULT;
+       buf[buf_size] = 0;
+
+       /*
+        * need to parse entry and extract parameters:
+        * modify configs_pin devicename state pinname newvalue
+        */
+
+       /* Get arg: 'modify' */
+       token = strsep(&b, " ");
+       if (!token)
+               return -EINVAL;
+       if (strcmp(token, "modify"))
+               return -EINVAL;
+
+       /* Get arg type: "config_pin" type supported so far */
+       token = strsep(&b, " ");
+       if (!token)
+               return -EINVAL;
+       if (strcmp(token, "config_pin"))
+               return -EINVAL;
+       dbg->map_type = PIN_MAP_TYPE_CONFIGS_PIN;
+
+       /* get arg 'device_name' */
+       token = strsep(&b, " ");
+       if (token == NULL)
+               return -EINVAL;
+       if (strlen(token) >= MAX_NAME_LEN)
+               return -EINVAL;
+       strncpy(dbg->dev_name, token, MAX_NAME_LEN);
+
+       /* get arg 'state_name' */
+       token = strsep(&b, " ");
+       if (token == NULL)
+               return -EINVAL;
+       if (strlen(token) >= MAX_NAME_LEN)
+               return -EINVAL;
+       strncpy(dbg->state_name, token, MAX_NAME_LEN);
+
+       /* get arg 'pin_name' */
+       token = strsep(&b, " ");
+       if (token == NULL)
+               return -EINVAL;
+       if (strlen(token) >= MAX_NAME_LEN)
+               return -EINVAL;
+       strncpy(dbg->pin_name, token, MAX_NAME_LEN);
+
+       /* get new_value of config' */
+       token = strsep(&b, " ");
+       if (token == NULL)
+               return -EINVAL;
+       if (strlen(token) >= MAX_NAME_LEN)
+               return -EINVAL;
+       strncpy(config, token, MAX_NAME_LEN);
+
+       mutex_lock(&pinctrl_mutex);
+
+       /* Parse the pinctrl map and look for the selected dev/state/pin */
+       for_each_maps(maps_node, i, map) {
+               if (strcmp(map->dev_name, dbg->dev_name))
+                       continue;
+               if (map->type != dbg->map_type)
+                       continue;
+               if (strcmp(map->name, dbg->state_name))
+                       continue;
+
+               /*  we found the right pin / state, so overwrite config */
+               if (!strcmp(map->data.configs.group_or_pin, dbg->pin_name)) {
+                       found = true;
+                       pctldev = get_pinctrl_dev_from_devname(
+                                       map->ctrl_dev_name);
+                       configs = &map->data.configs;
+                       break;
+               }
+       }
+
+       if (!found) {
+               goto exit;
+               count = -EINVAL;
+       }
+
+       if (pctldev)
+               confops = pctldev->desc->confops;
+
+       if (confops && confops->pin_config_dbg_parse_modify) {
+               for (i = 0; i < configs->num_configs; i++) {
+                       confops->pin_config_dbg_parse_modify(pctldev,
+                                                    config,
+                                                    &configs->configs[i]);
+               }
+       }
+
+exit:
+       mutex_unlock(&pinctrl_mutex);
+
+       return count;
+}
+
+static int pinconf_dbg_config_open(struct inode *inode, struct file *file)
+{
+       return single_open(file, pinconf_dbg_config_print, inode->i_private);
+}
+
+static const struct file_operations pinconf_dbg_pinconfig_fops = {
+       .open = pinconf_dbg_config_open,
+       .write = pinconf_dbg_config_write,
+       .read = seq_read,
+       .llseek = seq_lseek,
+       .release = single_release,
+       .owner = THIS_MODULE,
+};
+
 void pinconf_init_device_debugfs(struct dentry *devroot,
                         struct pinctrl_dev *pctldev)
 {
@@ -581,6 +811,8 @@ void pinconf_init_device_debugfs(struct dentry *devroot,
                            devroot, pctldev, &pinconf_pins_ops);
        debugfs_create_file("pinconf-groups", S_IFREG | S_IRUGO,
                            devroot, pctldev, &pinconf_groups_ops);
+       debugfs_create_file("pinconf-config",  (S_IRUGO | S_IWUSR | S_IWGRP),
+                           devroot, pctldev, &pinconf_dbg_pinconfig_fops);
 }
 
 #endif

diff --git a/include/linux/pinctrl/pinconf.h b/include/linux/pinctrl/pinconf.h
index e7a720104a471ba5df4dfc8c7e15a04646c31f4d..1ad4f31ef6b8e2074546443465338b8f04b04e69 100644 (file)
--- 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);