linux-kernel - [PATCH] regulator: core: Add debugfs for regulator always

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Message-ID: <1461331982-30960-1-git-send-email-rf@opensource.wolfsonmicro.com>
Date:	Fri, 22 Apr 2016 14:33:02 +0100
From:	Richard Fitzgerald <rf@...nsource.wolfsonmicro.com>
To:	<broonie@...nel.org>
CC:	<lgirdwood@...il.com>, <patches@...nsource.wolfsonmicro.com>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH] regulator: core: Add debugfs for regulator always_on flag

This patch adds a debugfs file for the always_on flag in struct regulator.
It's useful for debugging to be able to view the state of this flag and
as it's set by logic inside the regulator core it doesn't necessarily have
the same value as the always_on flag in constraints.

Signed-off-by: Richard Fitzgerald <rf@...nsource.wolfsonmicro.com>
---
 drivers/regulator/core.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 7338175..9b7ad25 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1273,6 +1273,23 @@ static void unset_regulator_supplies(struct regulator_dev *rdev)
 }
 
 #ifdef CONFIG_DEBUG_FS
+static ssize_t always_on_read_file(struct file *file, char __user *user_buf,
+				   size_t count, loff_t *ppos)
+{
+	const struct regulator *regulator = file->private_data;
+	char *buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	ssize_t ret;
+
+	if (!buf)
+		return -ENOMEM;
+
+	ret = snprintf(buf, PAGE_SIZE, "always_on: %u\n", regulator->always_on);
+	ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
+	kfree(buf);
+
+	return ret;
+}
+
 static ssize_t constraint_flags_read_file(struct file *file,
 					  char __user *user_buf,
 					  size_t count, loff_t *ppos)
@@ -1310,8 +1327,15 @@ static ssize_t constraint_flags_read_file(struct file *file,
 
 	return ret;
 }
+#endif
 
+static const struct file_operations always_on_fops = {
+#ifdef CONFIG_DEBUG_FS
+	.open = simple_open,
+	.read = always_on_read_file,
+	.llseek = default_llseek,
 #endif
+};
 
 static const struct file_operations constraint_flags_fops = {
 #ifdef CONFIG_DEBUG_FS
@@ -1376,6 +1400,8 @@ static struct regulator *create_regulator(struct regulator_dev *rdev,
 				   &regulator->min_uV);
 		debugfs_create_u32("max_uV", 0444, regulator->debugfs,
 				   &regulator->max_uV);
+		debugfs_create_file("always_on", 0444, regulator->debugfs,
+				    regulator, &always_on_fops);
 		debugfs_create_file("constraint_flags", 0444,
 				    regulator->debugfs, regulator,
 				    &constraint_flags_fops);
-- 
1.9.1