* 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>
*/
#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;
struct pwm_state suspend;
};
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, "%llu\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;
u64 val;
int ret;
ret = kstrtou64(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, "%llu\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;
u64 val;
int ret;
ret = kstrtou64(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;
}
#ifdef CONFIG_PWM_ROCKCHIP_ONESHOT
static ssize_t oneshot_count_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, "%llu\n", state.oneshot_count);
}
static ssize_t oneshot_count_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.oneshot_count = val;
ret = pwm_apply_state(pwm, &state);
mutex_unlock(&export->lock);
return ret ?: size;
}
#endif
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);
#ifdef CONFIG_PWM_ROCKCHIP_ONESHOT
static DEVICE_ATTR_RW(oneshot_count);
#endif
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,
#ifdef CONFIG_PWM_ROCKCHIP_ONESHOT
&dev_attr_oneshot_count.attr,
#endif
&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;
char *pwm_prop[2];
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 = pwm;
mutex_init(&export->lock);
export->child.release = pwm_export_release;
export->child.parent = parent;
export->child.devt = MKDEV(0, 0);
export->child.groups = pwm_groups;
dev_set_name(&export->child, "pwm%u", pwm->hwpwm);
ret = device_register(&export->child);
if (ret) {
clear_bit(PWMF_EXPORTED, &pwm->flags);
put_device(&export->child);
export = NULL;
return ret;
}
pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
pwm_prop[1] = NULL;
kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
kfree(pwm_prop[0]);
return 0;
}
static int pwm_unexport_match(struct device *child, void *data)
{
return child_to_pwm_device(child) == data;
}
static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm)
{
struct device *child;
char *pwm_prop[2];
if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) {
return -ENODEV;
}
child = device_find_child(parent, pwm, pwm_unexport_match);
if (!child) {
return -ENODEV;
}
pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
pwm_prop[1] = NULL;
kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop);
kfree(pwm_prop[0]);
put_device(child);
device_unregister(child);
pwm_put(pwm);
return 0;
}
static ssize_t export_store(struct device *parent, struct device_attribute *attr, const char *buf, size_t len)
{
struct pwm_chip *chip = dev_get_drvdata(parent);
struct pwm_device *pwm;
unsigned int hwpwm;
int ret;
ret = kstrtouint(buf, 0, &hwpwm);
if (ret < 0) {
return ret;
}
if (hwpwm >= chip->npwm) {
return -ENODEV;
}
pwm = pwm_request_from_chip(chip, hwpwm, "sysfs");
if (IS_ERR(pwm)) {
return PTR_ERR(pwm);
}
ret = pwm_export_child(parent, pwm);
if (ret < 0) {
pwm_put(pwm);
}
return ret ?: len;
}
static DEVICE_ATTR_WO(export);
static ssize_t unexport_store(struct device *parent, struct device_attribute *attr, const char *buf, size_t len)
{
struct pwm_chip *chip = dev_get_drvdata(parent);
unsigned int hwpwm;
int ret;
ret = kstrtouint(buf, 0, &hwpwm);
if (ret < 0) {
return ret;
}
if (hwpwm >= chip->npwm) {
return -ENODEV;
}
ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]);
return ret ?: len;
}
static DEVICE_ATTR_WO(unexport);
static ssize_t npwm_show(struct device *parent, struct device_attribute *attr, char *buf)
{
const struct pwm_chip *chip = dev_get_drvdata(parent);
return sprintf(buf, "%u\n", chip->npwm);
}
static DEVICE_ATTR_RO(npwm);
static struct attribute *pwm_chip_attrs[] = {
&dev_attr_export.attr,
&dev_attr_unexport.attr,
&dev_attr_npwm.attr,
NULL,
};
ATTRIBUTE_GROUPS(pwm_chip);
static struct pwm_export *pwm_class_get_state(struct device *parent, struct pwm_device *pwm, struct pwm_state *state)
{
struct device *child;
struct pwm_export *export;
if (!test_bit(PWMF_EXPORTED, &pwm->flags)) {
return NULL;
}
child = device_find_child(parent, pwm, pwm_unexport_match);
if (!child) {
return NULL;
}
export = child_to_pwm_export(child);
put_device(child);
mutex_lock(&export->lock);
pwm_get_state(pwm, state);
return export;
}
static int pwm_class_apply_state(struct pwm_export *export, struct pwm_device *pwm, struct pwm_state *state)
{
int ret = pwm_apply_state(pwm, state);
mutex_unlock(&export->lock);
return ret;
}
static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm)
{
struct pwm_chip *chip = dev_get_drvdata(parent);
unsigned int i;
int ret = 0;
for (i = 0; i < npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
struct pwm_state state;
struct pwm_export *export;
export = pwm_class_get_state(parent, pwm, &state);
if (!export) {
continue;
}
state.enabled = export->suspend.enabled;
ret = pwm_class_apply_state(export, pwm, &state);
if (ret < 0) {
break;
}
}
return ret;
}
static int __maybe_unused pwm_class_suspend(struct device *parent)
{
struct pwm_chip *chip = dev_get_drvdata(parent);
unsigned int i;
int ret = 0;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
struct pwm_state state;
struct pwm_export *export;
export = pwm_class_get_state(parent, pwm, &state);
if (!export) {
continue;
}
export->suspend = state;
state.enabled = false;
ret = pwm_class_apply_state(export, pwm, &state);
if (ret < 0) {
* roll back the PWM devices that were disabled by
* this suspend function.
*/
pwm_class_resume_npwm(parent, i);
break;
}
}
return ret;
}
static int __maybe_unused pwm_class_resume(struct device *parent)
{
struct pwm_chip *chip = dev_get_drvdata(parent);
return pwm_class_resume_npwm(parent, chip->npwm);
}
static SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume);
static struct class pwm_class = {
.name = "pwm",
.owner = THIS_MODULE,
.dev_groups = pwm_chip_groups,
.pm = &pwm_class_pm_ops,
};
static int pwmchip_sysfs_match(struct device *parent, const void *data)
{
return dev_get_drvdata(parent) == data;
}
void pwmchip_sysfs_export(struct pwm_chip *chip)
{
struct device *parent;
* If device_create() fails the pwm_chip is still usable by
* the kernel it's just not exported.
*/
parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip, "pwmchip%d", chip->base);
if (IS_ERR(parent)) {
dev_warn(chip->dev, "device_create failed for pwm_chip sysfs export\n");
}
}
void pwmchip_sysfs_unexport(struct pwm_chip *chip)
{
struct device *parent;
unsigned int i;
parent = class_find_device(&pwm_class, NULL, chip, pwmchip_sysfs_match);
if (!parent) {
return;
}
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
if (test_bit(PWMF_EXPORTED, &pwm->flags)) {
pwm_unexport_child(parent, pwm);
}
}
put_device(parent);
device_unregister(parent);
}
static int __init pwm_sysfs_init(void)
{
return class_register(&pwm_class);
}
subsys_initcall(pwm_sysfs_init);