1 files changed, 425 insertions, 0 deletions
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
new file mode 100644
index 000000000..72bdda4cc
--- /dev/null
+++ b/drivers/pwm/sysfs.c
@@ -0,0 +1,425 @@
+/*
+ * 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;
+	struct mutex lock;
+};
+
+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 sprintf(buf, "%u\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;
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint(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 sprintf(buf, "%u\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;
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint(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 sprintf(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 sprintf(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 sprintf(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;
+	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;
+	}
+
+	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 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 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;
+	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);