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Commit 62099abf authored by Thierry Reding's avatar Thierry Reding
Browse files

pwm: Add debugfs interface 



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: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: default avatarShawn Guo <shawn.guo@linaro.org>
Signed-off-by: default avatarThierry Reding <thierry.reding@avionic-design.de>
parent f051c466

drivers/pwm/core.c

+90 −0
Original line number Diff line number Diff line
@@ -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
@@ -338,3 +340,91 @@ 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 */

include/linux/pwm.h

+6 −0
Original line number Diff line number Diff line
@@ -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;

};