| // 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; |
| |
| 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; |
| |
| 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 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", |
| .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); |