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@xxxxxxxxxxxxxxxxx>
Reviewed-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Reviewed-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
---
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(+)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 8688754..7e13da1 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;
};
--
1.7.9.6
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