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|
/*
* 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;
int ret;
ret = kstrtouint(buf, 0, &val);
if (ret)
return ret;
mutex_lock(&export->lock);
pwm_get_state(pwm, &state);
state.period = val;
ret = pwm_apply_state(pwm, &state);
mutex_unlock(&export->lock);
return ret ? : size;
}
static ssize_t duty_cycle_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.duty_cycle);
}
static ssize_t duty_cycle_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;
int ret;
ret = kstrtouint(buf, 0, &val);
if (ret)
return ret;
mutex_lock(&export->lock);
pwm_get_state(pwm, &state);
state.duty_cycle = val;
ret = pwm_apply_state(pwm, &state);
mutex_unlock(&export->lock);
return ret ? : size;
}
static ssize_t enable_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, "%d\n", state.enabled);
}
static ssize_t enable_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;
int val, ret;
ret = kstrtoint(buf, 0, &val);
if (ret)
return ret;
mutex_lock(&export->lock);
pwm_get_state(pwm, &state);
switch (val) {
case 0:
state.enabled = false;
break;
case 1:
state.enabled = true;
break;
default:
ret = -EINVAL;
goto unlock;
}
ret = pwm_apply_state(pwm, &state);
unlock:
mutex_unlock(&export->lock);
return ret ? : size;
}
static ssize_t polarity_show(struct device *child,
struct device_attribute *attr,
char *buf)
{
const struct pwm_device *pwm = child_to_pwm_device(child);
const char *polarity = "unknown";
struct pwm_state state;
pwm_get_state(pwm, &state);
switch (state.polarity) {
case PWM_POLARITY_NORMAL:
polarity = "normal";
break;
case PWM_POLARITY_INVERSED:
polarity = "inversed";
break;
}
return sprintf(buf, "%s\n", polarity);
}
static ssize_t polarity_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;
enum pwm_polarity polarity;
struct pwm_state state;
int ret;
if (sysfs_streq(buf, "normal"))
polarity = PWM_POLARITY_NORMAL;
else if (sysfs_streq(buf, "inversed"))
polarity = PWM_POLARITY_INVERSED;
else
return -EINVAL;
mutex_lock(&export->lock);
pwm_get_state(pwm, &state);
state.polarity = polarity;
ret = pwm_apply_state(pwm, &state);
mutex_unlock(&export->lock);
return ret ? : size;
}
static ssize_t capture_show(struct device *child,
struct device_attribute *attr,
char *buf)
{
struct pwm_device *pwm = child_to_pwm_device(child);
struct pwm_capture result;
int ret;
ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ));
if (ret)
return ret;
return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
}
static DEVICE_ATTR_RW(period);
static DEVICE_ATTR_RW(duty_cycle);
static DEVICE_ATTR_RW(enable);
static DEVICE_ATTR_RW(polarity);
static DEVICE_ATTR_RO(capture);
static struct attribute *pwm_attrs[] = {
&dev_attr_period.attr,
&dev_attr_duty_cycle.attr,
&dev_attr_enable.attr,
&dev_attr_polarity.attr,
&dev_attr_capture.attr,
NULL
};
ATTRIBUTE_GROUPS(pwm);
static void pwm_export_release(struct device *child)
{
struct pwm_export *export = child_to_pwm_export(child);
kfree(export);
}
static int pwm_export_child(struct device *parent, struct pwm_device *pwm)
{
struct pwm_export *export;
int ret;
if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags))
return -EBUSY;
export = kzalloc(sizeof(*export), GFP_KERNEL);
if (!export) {
clear_bit(PWMF_EXPORTED, &pwm->flags);
return -ENOMEM;
}
export->pwm =
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