/* * 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; }; 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 pwm_period_show(struct device *child, struct device_attribute *attr, char *buf) { const struct pwm_device *pwm = child_to_pwm_device(child); return sprintf(buf, "%u\n", pwm->period); } static ssize_t pwm_period_store(struct device *child, struct device_attribute *attr, const char *buf, size_t size) { struct pwm_device *pwm = child_to_pwm_device(child); unsigned int val; int ret; ret = kstrtouint(buf, 0, &val); if (ret) return ret; ret = pwm_config(pwm, pwm->duty_cycle, val); return ret ? : size; } static ssize_t pwm_duty_cycle_show(struct device *child, struct device_attribute *attr, char *buf) { const struct pwm_device *pwm = child_to_pwm_device(child); return sprintf(buf, "%u\n", pwm->duty_cycle); } static ssize_t pwm_duty_cycle_store(struct device *child, struct device_attribute *attr, const char *buf, size_t size) { struct pwm_device *pwm = child_to_pwm_device(child); unsigned int val; int ret; ret = kstrtouint(buf, 0, &val); if (ret) return ret; ret = pwm_config(pwm, val, pwm->period); return ret ? : size; } static ssize_t pwm_enable_show(struct device *child, struct device_attribute *attr, char *buf) { const struct pwm_device *pwm = child_to_pwm_device(child); int enabled = test_bit(PWMF_ENABLED, &pwm->flags); return sprintf(buf, "%d\n", enabled); } static ssize_t pwm_enable_store(struct device *child, struct device_attribute *attr, const char *buf, size_t size) { struct pwm_device *pwm = child_to_pwm_device(child); int val, ret; ret = kstrtoint(buf, 0, &val); if (ret) return ret; switch (val) { case 0: pwm_disable(pwm); break; case 1: ret = pwm_enable(pwm); break; default: ret = -EINVAL; break; } return ret ? : size; } static ssize_t pwm_polarity_show(struct device *child, struct device_attribute *attr, char *buf) { const struct pwm_device *pwm = child_to_pwm_device(child); return sprintf(buf, "%s\n", pwm->polarity ? "inversed" : "normal"); } static ssize_t pwm_polarity_store(struct device *child, struct device_attribute *attr, const char *buf, size_t size) { struct pwm_device *pwm = child_to_pwm_device(child); enum pwm_polarity polarity; int ret; if (sysfs_streq(buf, "normal")) polarity = PWM_POLARITY_NORMAL; else if (sysfs_streq(buf, "inversed")) polarity = PWM_POLARITY_INVERSED; else return -EINVAL; ret = pwm_set_polarity(pwm, polarity); return ret ? : size; } static DEVICE_ATTR(period, 0644, pwm_period_show, pwm_period_store); static DEVICE_ATTR(duty_cycle, 0644, pwm_duty_cycle_show, pwm_duty_cycle_store); static DEVICE_ATTR(enable, 0644, pwm_enable_show, pwm_enable_store); static DEVICE_ATTR(polarity, 0644, pwm_polarity_show, pwm_polarity_store); static struct attribute *pwm_attrs[] = { &dev_attr_period.attr, &dev_attr_duty_cycle.attr, &dev_attr_enable.attr, &dev_attr_polarity.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 = pwm; 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); kfree(export); return ret; } 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; if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) return -ENODEV; child = device_find_child(parent, pwm, pwm_unexport_match); if (!child) return -ENODEV; /* for device_find_child() */ put_device(child); device_unregister(child); pwm_put(pwm); return 0; } static ssize_t pwm_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(export, 0200, NULL, pwm_export_store); static ssize_t pwm_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(unexport, 0200, NULL, pwm_unexport_store); 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 class pwm_class = { .name = "pwm", .owner = THIS_MODULE, .dev_groups = pwm_chip_groups, }; 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 its 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; parent = class_find_device(&pwm_class, NULL, chip, pwmchip_sysfs_match); if (parent) { /* for class_find_device() */ put_device(parent); device_unregister(parent); } } static int __init pwm_sysfs_init(void) { return class_register(&pwm_class); } subsys_initcall(pwm_sysfs_init);