linux-imx

/*

 * A simple sysfs interface for the generic PWM framework

 *

 * Copyright (C) 2013 H Hartley Sweeten <hsweeten@visionengravers.com>

 *

 * Based on previous work by Lars Poeschel <poeschel@lemonage.de>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2, or (at your option)

 * any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */

​

#include <linux/device.h>

#include <linux/mutex.h>

#include <linux/err.h>

#include <linux/slab.h>

#include <linux/kdev_t.h>

#include <linux/pwm.h>

​

struct pwm_export {

    struct device child;

    struct pwm_device *pwm;

    struct mutex lock;

};

​

static struct pwm_export *child_to_pwm_export(struct device *child)

{

    return container_of(child, struct pwm_export, child);

}

​

static struct pwm_device *child_to_pwm_device(struct device *child)

{

    struct pwm_export *export = child_to_pwm_export(child);

​

    return export->pwm;

}

​

static ssize_t period_show(struct device *child,

               struct device_attribute *attr,

               char *buf)

{

    const struct pwm_device *pwm = child_to_pwm_device(child);

    struct pwm_state state;

​

    pwm_get_state(pwm, &state);

​

    return sprintf(buf, "%u\n", state.period);

}

​

static ssize_t period_store(struct device *child,

                struct device_attribute *attr,

                const char *buf, size_t size)

{

    struct pwm_export *export = child_to_pwm_export(child);

    struct pwm_device *pwm = export->pwm;

    struct pwm_state state;

    unsigned int val;