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-rw-r--r--drivers/pwm/sysfs.c546
1 files changed, 546 insertions, 0 deletions
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
new file mode 100644
index 000000000..ba1252538
--- /dev/null
+++ b/drivers/pwm/sysfs.c
@@ -0,0 +1,546 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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 sysfs_emit(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 sysfs_emit(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;
+}
+
+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 sysfs_emit(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 sysfs_emit(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 sysfs_emit(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;
+ 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]);
+
+ /* for device_find_child() */
+ 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 sysfs_emit(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);
+
+/* takes export->lock on success */
+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); /* for device_find_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);
+
+ /* release lock taken in pwm_class_get_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;
+
+ /* If pwmchip was not enabled before suspend, do nothing. */
+ if (!export->suspend.enabled) {
+ /* release lock taken in pwm_class_get_state */
+ mutex_unlock(&export->lock);
+ continue;
+ }
+
+ state.enabled = export->suspend.enabled;
+ ret = pwm_class_apply_state(export, pwm, &state);
+ if (ret < 0)
+ break;
+ }
+
+ return ret;
+}
+
+static int 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;
+
+ /*
+ * If pwmchip was not enabled before suspend, save
+ * state for resume time and do nothing else.
+ */
+ export->suspend = state;
+ if (!state.enabled) {
+ /* release lock taken in pwm_class_get_state */
+ mutex_unlock(&export->lock);
+ continue;
+ }
+
+ 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 pwm_class_resume(struct device *parent)
+{
+ struct pwm_chip *chip = dev_get_drvdata(parent);
+
+ return pwm_class_resume_npwm(parent, chip->npwm);
+}
+
+static DEFINE_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 = pm_sleep_ptr(&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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-27 00:47:09 +0000