diff mbox

[v5,03/16] pwm: Add debugfs interface

Message ID 1332945238-14897-4-git-send-email-thierry.reding@avionic-design.de
State Superseded, archived
Headers show

Commit Message

Thierry Reding March 28, 2012, 2:33 p.m. UTC 
This commit adds a debugfs interface that can be used to list the
current internal state of the PWM devices registered with the PWM
framework.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
---
Changes in v5:
- new patch splitting off debugfs interface implementation
- use seq_file's iterator interface for debugfs support
- add missing forward declaration of struct seq_file

 drivers/pwm/core.c  |   90 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/pwm.h |    6 ++++
 2 files changed, 96 insertions(+)

Comments

Mark Brown March 29, 2012, 9:56 p.m. UTC | #1 
On Wed, Mar 28, 2012 at 04:33:45PM +0200, Thierry Reding wrote:
> This commit adds a debugfs interface that can be used to list the
> current internal state of the PWM devices registered with the PWM
> framework.

Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

I'm not sure I don't find the style with a file per chip more managable,
but I think that's mostly a thing for GPIOs since you get so many of
them in most systems that the file gets large which isn't such an issue
with pwms, you tend to get much fewer of them.  It's certainly a matter
of taste anyway.
Shawn Guo April 4, 2012, 6:47 a.m. UTC | #2 
On Wed, Mar 28, 2012 at 04:33:45PM +0200, Thierry Reding wrote:
> This commit adds a debugfs interface that can be used to list the
> current internal state of the PWM devices registered with the PWM
> framework.
> 
> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

Reviewed-by: Shawn Guo <shawn.guo@linaro.org>
diff mbox

Patch

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 46dcbe1..12a643d 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -27,6 +27,8 @@ 
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <linux/device.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 
 #define MAX_PWMS 1024
 
@@ -334,3 +336,91 @@  void pwm_disable(struct pwm_device *pwm)
 		pwm->chip->ops->disable(pwm->chip, pwm);
 }
 EXPORT_SYMBOL_GPL(pwm_disable);
+
+#ifdef CONFIG_DEBUG_FS
+static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
+{
+	unsigned int i;
+
+	for (i = 0; i < chip->npwm; i++) {
+		struct pwm_device *pwm = &chip->pwms[i];
+
+		seq_printf(s, " pwm-%-3d (%-20.20s):", i, pwm->label);
+
+		if (test_bit(PWMF_REQUESTED, &pwm->flags))
+			seq_printf(s, " requested");
+
+		if (test_bit(PWMF_ENABLED, &pwm->flags))
+			seq_printf(s, " enabled");
+
+		seq_printf(s, "\n");
+	}
+}
+
+static void *pwm_seq_start(struct seq_file *s, loff_t *pos)
+{
+	mutex_lock(&pwm_lock);
+	s->private = "";
+
+	return seq_list_start(&pwm_chips, *pos);
+}
+
+static void *pwm_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	s->private = "\n";
+
+	return seq_list_next(v, &pwm_chips, pos);
+}
+
+static void pwm_seq_stop(struct seq_file *s, void *v)
+{
+	mutex_unlock(&pwm_lock);
+}
+
+static int pwm_seq_show(struct seq_file *s, void *v)
+{
+	struct pwm_chip *chip = list_entry(v, struct pwm_chip, list);
+
+	seq_printf(s, "%s%s/%s, %d PWM device%s\n", (char *)s->private,
+		   chip->dev->bus ? chip->dev->bus->name : "no-bus",
+		   dev_name(chip->dev), chip->npwm,
+		   (chip->npwm != 1) ? "s" : "");
+
+	if (chip->ops->dbg_show)
+		chip->ops->dbg_show(chip, s);
+	else
+		pwm_dbg_show(chip, s);
+
+	return 0;
+}
+
+static const struct seq_operations pwm_seq_ops = {
+	.start = pwm_seq_start,
+	.next = pwm_seq_next,
+	.stop = pwm_seq_stop,
+	.show = pwm_seq_show,
+};
+
+static int pwm_seq_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &pwm_seq_ops);
+}
+
+static const struct file_operations pwm_debugfs_ops = {
+	.owner = THIS_MODULE,
+	.open = pwm_seq_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static int __init pwm_debugfs_init(void)
+{
+	debugfs_create_file("pwm", S_IFREG | S_IRUGO, NULL, NULL,
+			    &pwm_debugfs_ops);
+
+	return 0;
+}
+
+subsys_initcall(pwm_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 5710391..047cd53 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -2,6 +2,7 @@ 
 #define __LINUX_PWM_H
 
 struct pwm_device;
+struct seq_file;
 
 /*
  * pwm_request - request a PWM device
@@ -65,6 +66,7 @@  static inline unsigned int pwm_get_period(struct pwm_device *pwm)
  * @config: configure duty cycles and period length for this PWM
  * @enable: enable PWM output toggling
  * @disable: disable PWM output toggling
+ * @dbg_show: optional routine to show contents in debugfs
  * @owner: helps prevent removal of modules exporting active PWMs
  */
 struct pwm_ops {
@@ -79,6 +81,10 @@  struct pwm_ops {
 					  struct pwm_device *pwm);
 	void			(*disable)(struct pwm_chip *chip,
 					   struct pwm_device *pwm);
+#ifdef CONFIG_DEBUG_FS
+	void			(*dbg_show)(struct pwm_chip *chip,
+					    struct seq_file *s);
+#endif
 	struct module		*owner;
 };