diff options
Diffstat (limited to 'kernel/drivers/pwm/sysfs.c')
| -rw-r--r-- | kernel/drivers/pwm/sysfs.c | 347 |
1 files changed, 347 insertions, 0 deletions
diff --git a/kernel/drivers/pwm/sysfs.c b/kernel/drivers/pwm/sysfs.c new file mode 100644 index 000000000..4bd0c639e --- /dev/null +++ b/kernel/drivers/pwm/sysfs.c @@ -0,0 +1,347 @@ +/* + * 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); |