[PATCH v2] regulator: add a summary tree in debugfs

["Heiko Stübner" <heiko@sntech.de>]

On modern systems the regulator hierarchy can get quite long and nested
with regulators supplying other regulators. In some cases when debugging
it might be nice to get a tree of these regulators, their consumers
and the regulation constraints in one go.

To achieve this add a regulator_summary sysfs node, similar to
clk_summary in the common clock framework, that walks the regulator
list and creates a tree out of the regulators, their consumers and
core per-regulator settings.

On a rk3288-firefly the regulator_summary would for example look
something like:

 regulator                      use open bypass   value     min     max
-----------------------------------------------------------------------
 vcc_sys                          0   12      0  5000mV  5000mV  5000mV
    vcc_lan                       1    1      0  3300mV  3300mV  3300mV
       ff290000.ethernet                                    0mV     0mV
    vcca_33                       0    0      0  3300mV  3300mV  3300mV
    vcca_18                       0    0      0  1800mV  1800mV  1800mV
    vdd10_lcd                     0    0      0  1000mV  1000mV  1000mV
    vccio_sd                      0    0      0  3300mV  3300mV  3300mV
    vcc_20                        0    3      0  2000mV  2000mV  2000mV
       vcc18_lcd                  0    0      0  1800mV  1800mV  1800mV
       vcc_18                     0    2      0  1800mV  1800mV  1800mV
          ff100000.saradc                                   0mV     0mV
          ff0d0000.dwmmc                                 1650mV  1950mV
       vdd_10                     0    0      0  1000mV  1000mV  1000mV
    vdd_log                       0    0      0  1100mV  1100mV  1100mV
    vcc_io                        0    3      0  3300mV  3300mV  3300mV
       ff0f0000.dwmmc                                    3300mV  3400mV
       vcc_flash                  1    1      0  1800mV  1800mV  1800mV
          ff0f0000.dwmmc                                 1700mV  1950mV
       vcc_sd                     1    1      0  3300mV  3300mV  3300mV
          ff0c0000.dwmmc                                 3300mV  3400mV
    vcc_ddr                       0    0      0  1200mV  1200mV  1200mV
    vdd_gpu                       0    0      0  1000mV   850mV  1350mV
    vdd_cpu                       0    1      0   900mV   850mV  1350mV
       cpu0                                               900mV   900mV
    vcc_5v                        0    2      0  5000mV  5000mV  5000mV
       vcc_otg_5v                 0    0      0  5000mV  5000mV  5000mV
       vcc_host_5v                0    0      0  5000mV  5000mV  5000mV
 regulator-dummy                  0    0      0     0mV     0mV     0mV

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
changes since v1:
- comsetics: space instead of ","; decrease width of voltage/current columns
- output current-limit for current regulators

The questioned statement
>> +             if (!child->supply || child->supply->rdev != rdev)
>> +                     continue;
>> Shouldn't we be complaining if the supply of a child isn't the parent?

is meant to single out only those regulators from the global list that
are actual children of the current rdev. Regulators with !child->supply
are the root ones and handled in regulator_summary_show while regulators
with different parents will be handled when their parent is processed.

So there shouldn't be a need to complain. Or alternatively I'm just
overlooking a different way to do the whole parent->children resolution.


 drivers/regulator/core.c | 121 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index a4a8a6d..fb2c8d5 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3936,6 +3936,124 @@ static const struct file_operations supply_map_fops = {
 #endif
 };
 
+#ifdef CONFIG_DEBUG_FS
+static void regulator_summary_show_subtree(struct seq_file *s,
+					   struct regulator_dev *rdev,
+					   int level)
+{
+	struct list_head *list = s->private;
+	struct regulator_dev *child;
+	struct regulation_constraints *c;
+	struct regulator *consumer;
+
+	if (!rdev)
+		return;
+
+	mutex_lock(&rdev->mutex);
+
+	seq_printf(s, "%*s%-*s %3d %4d %6d ",
+		   level * 3 + 1, "",
+		   30 - level * 3, rdev_get_name(rdev),
+		   rdev->use_count, rdev->open_count, rdev->bypass_count);
+
+	switch (rdev->desc->type) {
+	case REGULATOR_VOLTAGE:
+		seq_printf(s, "%5dmV ",
+			   _regulator_get_voltage(rdev) / 1000);
+		break;
+	case REGULATOR_CURRENT:
+		seq_printf(s, "%5dmA ",
+			   _regulator_get_current_limit(rdev) / 1000);
+		break;
+	}
+
+	c = rdev->constraints;
+	if (c) {
+		switch (rdev->desc->type) {
+		case REGULATOR_VOLTAGE:
+			seq_printf(s, "%5dmV %5dmV ",
+				   c->min_uV / 1000, c->max_uV / 1000);
+			break;
+		case REGULATOR_CURRENT:
+			seq_printf(s, "%5dmA %5dmA ",
+				   c->min_uA / 1000, c->max_uA / 1000);
+			break;
+		}
+	}
+
+	seq_puts(s, "\n");
+
+	list_for_each_entry(consumer, &rdev->consumer_list, list) {
+		if (consumer->dev->class == &regulator_class)
+			continue;
+
+		seq_printf(s, "%*s%-*s ",
+			   (level + 1) * 3 + 1, "",
+			   30 - (level + 1) * 3, dev_name(consumer->dev));
+
+		switch (rdev->desc->type) {
+		case REGULATOR_VOLTAGE:
+			seq_printf(s, "%29dmV %5dmV",
+				   consumer->min_uV / 1000,
+				   consumer->max_uV / 1000);
+			break;
+		case REGULATOR_CURRENT:
+			seq_printf(s, "%37dmA",
+				regulator_get_current_limit(consumer) / 1000);
+			break;
+		}
+
+		seq_puts(s, "\n");
+	}
+
+	mutex_unlock(&rdev->mutex);
+
+	list_for_each_entry(child, list, list) {
+		/* handle only non-root regulators supplied by current rdev */
+		if (!child->supply || child->supply->rdev != rdev)
+			continue;
+
+		regulator_summary_show_subtree(s, child, level + 1);
+	}
+}
+
+static int regulator_summary_show(struct seq_file *s, void *data)
+{
+	struct list_head *list = s->private;
+	struct regulator_dev *rdev;
+
+	seq_puts(s, " regulator                      use open bypass   value     min     max\n");
+	seq_puts(s, "-----------------------------------------------------------------------\n");
+
+	mutex_lock(&regulator_list_mutex);
+
+	list_for_each_entry(rdev, list, list) {
+		if (rdev->supply)
+			continue;
+
+		regulator_summary_show_subtree(s, rdev, 0);
+	}
+
+	mutex_unlock(&regulator_list_mutex);
+
+	return 0;
+}
+
+static int regulator_summary_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, regulator_summary_show, inode->i_private);
+}
+#endif
+
+static const struct file_operations regulator_summary_fops = {
+#ifdef CONFIG_DEBUG_FS
+	.open		= regulator_summary_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+#endif
+};
+
 static int __init regulator_init(void)
 {
 	int ret;
@@ -3949,6 +4067,9 @@ static int __init regulator_init(void)
 	debugfs_create_file("supply_map", 0444, debugfs_root, NULL,
 			    &supply_map_fops);
 
+	debugfs_create_file("regulator_summary", 0444, debugfs_root,
+			    &regulator_list, &regulator_summary_fops);
+
 	regulator_dummy_init();
 
 	return ret;
-- 
2.1.4