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529 lines
11 KiB
529 lines
11 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* A simple sysfs interface for the generic PWM framework |
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* |
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* Copyright (C) 2013 H Hartley Sweeten <[email protected]> |
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* |
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* Based on previous work by Lars Poeschel <[email protected]> |
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*/ |
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#include <linux/device.h> |
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#include <linux/mutex.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <linux/kdev_t.h> |
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#include <linux/pwm.h> |
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struct pwm_export { |
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struct device child; |
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struct pwm_device *pwm; |
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struct mutex lock; |
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struct pwm_state suspend; |
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}; |
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static struct pwm_export *child_to_pwm_export(struct device *child) |
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{ |
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return container_of(child, struct pwm_export, child); |
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} |
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static struct pwm_device *child_to_pwm_device(struct device *child) |
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{ |
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struct pwm_export *export = child_to_pwm_export(child); |
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return export->pwm; |
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} |
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static ssize_t period_show(struct device *child, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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const struct pwm_device *pwm = child_to_pwm_device(child); |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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return sprintf(buf, "%llu\n", state.period); |
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} |
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static ssize_t period_store(struct device *child, |
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struct device_attribute *attr, |
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const char *buf, size_t size) |
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{ |
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struct pwm_export *export = child_to_pwm_export(child); |
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struct pwm_device *pwm = export->pwm; |
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struct pwm_state state; |
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u64 val; |
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int ret; |
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ret = kstrtou64(buf, 0, &val); |
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if (ret) |
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return ret; |
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mutex_lock(&export->lock); |
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pwm_get_state(pwm, &state); |
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state.period = val; |
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ret = pwm_apply_state(pwm, &state); |
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mutex_unlock(&export->lock); |
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return ret ? : size; |
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} |
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static ssize_t duty_cycle_show(struct device *child, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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const struct pwm_device *pwm = child_to_pwm_device(child); |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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return sprintf(buf, "%llu\n", state.duty_cycle); |
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} |
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static ssize_t duty_cycle_store(struct device *child, |
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struct device_attribute *attr, |
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const char *buf, size_t size) |
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{ |
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struct pwm_export *export = child_to_pwm_export(child); |
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struct pwm_device *pwm = export->pwm; |
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struct pwm_state state; |
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u64 val; |
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int ret; |
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ret = kstrtou64(buf, 0, &val); |
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if (ret) |
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return ret; |
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mutex_lock(&export->lock); |
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pwm_get_state(pwm, &state); |
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state.duty_cycle = val; |
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ret = pwm_apply_state(pwm, &state); |
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mutex_unlock(&export->lock); |
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return ret ? : size; |
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} |
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static ssize_t enable_show(struct device *child, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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const struct pwm_device *pwm = child_to_pwm_device(child); |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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return sprintf(buf, "%d\n", state.enabled); |
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} |
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static ssize_t enable_store(struct device *child, |
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struct device_attribute *attr, |
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const char *buf, size_t size) |
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{ |
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struct pwm_export *export = child_to_pwm_export(child); |
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struct pwm_device *pwm = export->pwm; |
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struct pwm_state state; |
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int val, ret; |
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ret = kstrtoint(buf, 0, &val); |
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if (ret) |
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return ret; |
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mutex_lock(&export->lock); |
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pwm_get_state(pwm, &state); |
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switch (val) { |
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case 0: |
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state.enabled = false; |
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break; |
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case 1: |
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state.enabled = true; |
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break; |
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default: |
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ret = -EINVAL; |
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goto unlock; |
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} |
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ret = pwm_apply_state(pwm, &state); |
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unlock: |
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mutex_unlock(&export->lock); |
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return ret ? : size; |
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} |
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static ssize_t polarity_show(struct device *child, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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const struct pwm_device *pwm = child_to_pwm_device(child); |
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const char *polarity = "unknown"; |
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struct pwm_state state; |
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pwm_get_state(pwm, &state); |
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switch (state.polarity) { |
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case PWM_POLARITY_NORMAL: |
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polarity = "normal"; |
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break; |
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case PWM_POLARITY_INVERSED: |
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polarity = "inversed"; |
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break; |
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} |
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return sprintf(buf, "%s\n", polarity); |
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} |
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static ssize_t polarity_store(struct device *child, |
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struct device_attribute *attr, |
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const char *buf, size_t size) |
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{ |
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struct pwm_export *export = child_to_pwm_export(child); |
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struct pwm_device *pwm = export->pwm; |
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enum pwm_polarity polarity; |
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struct pwm_state state; |
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int ret; |
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if (sysfs_streq(buf, "normal")) |
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polarity = PWM_POLARITY_NORMAL; |
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else if (sysfs_streq(buf, "inversed")) |
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polarity = PWM_POLARITY_INVERSED; |
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else |
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return -EINVAL; |
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mutex_lock(&export->lock); |
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pwm_get_state(pwm, &state); |
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state.polarity = polarity; |
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ret = pwm_apply_state(pwm, &state); |
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mutex_unlock(&export->lock); |
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return ret ? : size; |
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} |
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static ssize_t capture_show(struct device *child, |
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struct device_attribute *attr, |
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char *buf) |
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{ |
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struct pwm_device *pwm = child_to_pwm_device(child); |
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struct pwm_capture result; |
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int ret; |
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ret = pwm_capture(pwm, &result, jiffies_to_msecs(HZ)); |
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if (ret) |
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return ret; |
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return sprintf(buf, "%u %u\n", result.period, result.duty_cycle); |
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} |
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static DEVICE_ATTR_RW(period); |
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static DEVICE_ATTR_RW(duty_cycle); |
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static DEVICE_ATTR_RW(enable); |
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static DEVICE_ATTR_RW(polarity); |
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static DEVICE_ATTR_RO(capture); |
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static struct attribute *pwm_attrs[] = { |
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&dev_attr_period.attr, |
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&dev_attr_duty_cycle.attr, |
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&dev_attr_enable.attr, |
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&dev_attr_polarity.attr, |
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&dev_attr_capture.attr, |
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NULL |
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}; |
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ATTRIBUTE_GROUPS(pwm); |
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static void pwm_export_release(struct device *child) |
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{ |
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struct pwm_export *export = child_to_pwm_export(child); |
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kfree(export); |
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} |
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static int pwm_export_child(struct device *parent, struct pwm_device *pwm) |
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{ |
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struct pwm_export *export; |
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char *pwm_prop[2]; |
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int ret; |
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if (test_and_set_bit(PWMF_EXPORTED, &pwm->flags)) |
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return -EBUSY; |
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export = kzalloc(sizeof(*export), GFP_KERNEL); |
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if (!export) { |
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clear_bit(PWMF_EXPORTED, &pwm->flags); |
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return -ENOMEM; |
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} |
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export->pwm = pwm; |
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mutex_init(&export->lock); |
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export->child.release = pwm_export_release; |
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export->child.parent = parent; |
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export->child.devt = MKDEV(0, 0); |
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export->child.groups = pwm_groups; |
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dev_set_name(&export->child, "pwm%u", pwm->hwpwm); |
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ret = device_register(&export->child); |
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if (ret) { |
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clear_bit(PWMF_EXPORTED, &pwm->flags); |
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put_device(&export->child); |
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export = NULL; |
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return ret; |
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} |
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pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm); |
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pwm_prop[1] = NULL; |
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kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop); |
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kfree(pwm_prop[0]); |
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return 0; |
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} |
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static int pwm_unexport_match(struct device *child, void *data) |
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{ |
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return child_to_pwm_device(child) == data; |
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} |
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static int pwm_unexport_child(struct device *parent, struct pwm_device *pwm) |
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{ |
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struct device *child; |
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char *pwm_prop[2]; |
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if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags)) |
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return -ENODEV; |
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child = device_find_child(parent, pwm, pwm_unexport_match); |
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if (!child) |
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return -ENODEV; |
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pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm); |
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pwm_prop[1] = NULL; |
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kobject_uevent_env(&parent->kobj, KOBJ_CHANGE, pwm_prop); |
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kfree(pwm_prop[0]); |
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/* for device_find_child() */ |
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put_device(child); |
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device_unregister(child); |
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pwm_put(pwm); |
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return 0; |
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} |
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static ssize_t export_store(struct device *parent, |
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struct device_attribute *attr, |
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const char *buf, size_t len) |
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{ |
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struct pwm_chip *chip = dev_get_drvdata(parent); |
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struct pwm_device *pwm; |
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unsigned int hwpwm; |
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int ret; |
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ret = kstrtouint(buf, 0, &hwpwm); |
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if (ret < 0) |
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return ret; |
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if (hwpwm >= chip->npwm) |
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return -ENODEV; |
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pwm = pwm_request_from_chip(chip, hwpwm, "sysfs"); |
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if (IS_ERR(pwm)) |
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return PTR_ERR(pwm); |
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ret = pwm_export_child(parent, pwm); |
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if (ret < 0) |
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pwm_put(pwm); |
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return ret ? : len; |
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} |
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static DEVICE_ATTR_WO(export); |
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static ssize_t unexport_store(struct device *parent, |
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struct device_attribute *attr, |
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const char *buf, size_t len) |
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{ |
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struct pwm_chip *chip = dev_get_drvdata(parent); |
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unsigned int hwpwm; |
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int ret; |
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ret = kstrtouint(buf, 0, &hwpwm); |
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if (ret < 0) |
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return ret; |
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if (hwpwm >= chip->npwm) |
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return -ENODEV; |
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ret = pwm_unexport_child(parent, &chip->pwms[hwpwm]); |
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return ret ? : len; |
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} |
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static DEVICE_ATTR_WO(unexport); |
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static ssize_t npwm_show(struct device *parent, struct device_attribute *attr, |
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char *buf) |
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{ |
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const struct pwm_chip *chip = dev_get_drvdata(parent); |
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return sprintf(buf, "%u\n", chip->npwm); |
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} |
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static DEVICE_ATTR_RO(npwm); |
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static struct attribute *pwm_chip_attrs[] = { |
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&dev_attr_export.attr, |
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&dev_attr_unexport.attr, |
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&dev_attr_npwm.attr, |
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NULL, |
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}; |
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ATTRIBUTE_GROUPS(pwm_chip); |
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/* takes export->lock on success */ |
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static struct pwm_export *pwm_class_get_state(struct device *parent, |
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struct pwm_device *pwm, |
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struct pwm_state *state) |
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{ |
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struct device *child; |
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struct pwm_export *export; |
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if (!test_bit(PWMF_EXPORTED, &pwm->flags)) |
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return NULL; |
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child = device_find_child(parent, pwm, pwm_unexport_match); |
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if (!child) |
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return NULL; |
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export = child_to_pwm_export(child); |
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put_device(child); /* for device_find_child() */ |
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mutex_lock(&export->lock); |
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pwm_get_state(pwm, state); |
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return export; |
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} |
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static int pwm_class_apply_state(struct pwm_export *export, |
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struct pwm_device *pwm, |
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struct pwm_state *state) |
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{ |
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int ret = pwm_apply_state(pwm, state); |
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/* release lock taken in pwm_class_get_state */ |
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mutex_unlock(&export->lock); |
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return ret; |
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} |
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static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm) |
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{ |
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struct pwm_chip *chip = dev_get_drvdata(parent); |
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unsigned int i; |
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int ret = 0; |
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for (i = 0; i < npwm; i++) { |
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struct pwm_device *pwm = &chip->pwms[i]; |
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struct pwm_state state; |
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struct pwm_export *export; |
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export = pwm_class_get_state(parent, pwm, &state); |
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if (!export) |
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continue; |
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state.enabled = export->suspend.enabled; |
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ret = pwm_class_apply_state(export, pwm, &state); |
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if (ret < 0) |
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break; |
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} |
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return ret; |
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} |
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static int __maybe_unused pwm_class_suspend(struct device *parent) |
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{ |
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struct pwm_chip *chip = dev_get_drvdata(parent); |
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unsigned int i; |
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int ret = 0; |
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for (i = 0; i < chip->npwm; i++) { |
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struct pwm_device *pwm = &chip->pwms[i]; |
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struct pwm_state state; |
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struct pwm_export *export; |
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export = pwm_class_get_state(parent, pwm, &state); |
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if (!export) |
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continue; |
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export->suspend = state; |
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state.enabled = false; |
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ret = pwm_class_apply_state(export, pwm, &state); |
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if (ret < 0) { |
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/* |
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* roll back the PWM devices that were disabled by |
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* this suspend function. |
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*/ |
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pwm_class_resume_npwm(parent, i); |
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break; |
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} |
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} |
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return ret; |
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} |
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static int __maybe_unused pwm_class_resume(struct device *parent) |
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{ |
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struct pwm_chip *chip = dev_get_drvdata(parent); |
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return pwm_class_resume_npwm(parent, chip->npwm); |
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} |
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static SIMPLE_DEV_PM_OPS(pwm_class_pm_ops, pwm_class_suspend, pwm_class_resume); |
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static struct class pwm_class = { |
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.name = "pwm", |
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.owner = THIS_MODULE, |
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.dev_groups = pwm_chip_groups, |
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.pm = &pwm_class_pm_ops, |
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}; |
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static int pwmchip_sysfs_match(struct device *parent, const void *data) |
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{ |
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return dev_get_drvdata(parent) == data; |
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} |
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void pwmchip_sysfs_export(struct pwm_chip *chip) |
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{ |
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struct device *parent; |
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/* |
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* If device_create() fails the pwm_chip is still usable by |
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* the kernel it's just not exported. |
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*/ |
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parent = device_create(&pwm_class, chip->dev, MKDEV(0, 0), chip, |
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"pwmchip%d", chip->base); |
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if (IS_ERR(parent)) { |
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dev_warn(chip->dev, |
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"device_create failed for pwm_chip sysfs export\n"); |
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} |
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} |
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void pwmchip_sysfs_unexport(struct pwm_chip *chip) |
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{ |
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struct device *parent; |
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unsigned int i; |
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parent = class_find_device(&pwm_class, NULL, chip, |
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pwmchip_sysfs_match); |
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if (!parent) |
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return; |
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for (i = 0; i < chip->npwm; i++) { |
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struct pwm_device *pwm = &chip->pwms[i]; |
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if (test_bit(PWMF_EXPORTED, &pwm->flags)) |
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pwm_unexport_child(parent, pwm); |
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} |
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put_device(parent); |
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device_unregister(parent); |
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} |
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static int __init pwm_sysfs_init(void) |
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{ |
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return class_register(&pwm_class); |
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} |
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subsys_initcall(pwm_sysfs_init);
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