pwm: Move contents of sysfs.c into core.c

With the upcoming restructuring having all in a single file simplifies
things a bit. The relevant and somewhat visible changes are:

 - Some dropped prototypes from include/linux/pwm.h that were only
   necessary that core.c has a declaration of the symbols defined in
   sysfs.c. The respective functions are static now.

 - The pwm class now also exists if CONFIG_SYSFS isn't enabled. Having
   CONFIG_SYSFS is not very relevant today, but even without it the
   class and device stuff still provides lifetime tracking.

 - Both files had an initcall, these are merged into a single one now.
   Instead of a big #ifdef block for CONFIG_DEBUG_FS, a single
   if (IS_ENABLED(CONFIG_DEBUG_FS)) is used now. This increases compile
   coverage a bit and is a tad nicer on the eyes.

Link: https://lore.kernel.org/r/9e2d39a5280d7dda5bfc6682a8aef510148635b2.1710670958.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

1 files changed, 534 insertions, 6 deletions

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index d3f475eca97f..faa0f885e057 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -454,6 +454,535 @@ of_pwm_single_xlate(struct pwm_chip *chip, const struct of_phandle_args *args)
 }
 EXPORT_SYMBOL_GPL(of_pwm_single_xlate);
 
+struct pwm_export {
+	struct device pwm_dev;
+	struct pwm_device *pwm;
+	struct mutex lock;
+	struct pwm_state suspend;
+};
+
+static inline struct pwm_chip *pwmchip_from_dev(struct device *pwmchip_dev)
+{
+	return dev_get_drvdata(pwmchip_dev);
+}
+
+static inline struct pwm_export *pwmexport_from_dev(struct device *pwm_dev)
+{
+	return container_of(pwm_dev, struct pwm_export, pwm_dev);
+}
+
+static inline struct pwm_device *pwm_from_dev(struct device *pwm_dev)
+{
+	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
+
+	return export->pwm;
+}
+
+static ssize_t period_show(struct device *pwm_dev,
+			   struct device_attribute *attr,
+			   char *buf)
+{
+	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
+	struct pwm_state state;
+
+	pwm_get_state(pwm, &state);
+
+	return sysfs_emit(buf, "%llu\n", state.period);
+}
+
+static ssize_t period_store(struct device *pwm_dev,
+			    struct device_attribute *attr,
+			    const char *buf, size_t size)
+{
+	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
+	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_might_sleep(pwm, &state);
+	mutex_unlock(&export->lock);
+
+	return ret ? : size;
+}
+
+static ssize_t duty_cycle_show(struct device *pwm_dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
+	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 *pwm_dev,
+				struct device_attribute *attr,
+				const char *buf, size_t size)
+{
+	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
+	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_might_sleep(pwm, &state);
+	mutex_unlock(&export->lock);
+
+	return ret ? : size;
+}
+
+static ssize_t enable_show(struct device *pwm_dev,
+			   struct device_attribute *attr,
+			   char *buf)
+{
+	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
+	struct pwm_state state;
+
+	pwm_get_state(pwm, &state);
+
+	return sysfs_emit(buf, "%d\n", state.enabled);
+}
+
+static ssize_t enable_store(struct device *pwm_dev,
+			    struct device_attribute *attr,
+			    const char *buf, size_t size)
+{
+	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
+	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_might_sleep(pwm, &state);
+
+unlock:
+	mutex_unlock(&export->lock);
+	return ret ? : size;
+}
+
+static ssize_t polarity_show(struct device *pwm_dev,
+			     struct device_attribute *attr,
+			     char *buf)
+{
+	const struct pwm_device *pwm = pwm_from_dev(pwm_dev);
+	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 *pwm_dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t size)
+{
+	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
+	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_might_sleep(pwm, &state);
+	mutex_unlock(&export->lock);
+
+	return ret ? : size;
+}
+
+static ssize_t capture_show(struct device *pwm_dev,
+			    struct device_attribute *attr,
+			    char *buf)
+{
+	struct pwm_device *pwm = pwm_from_dev(pwm_dev);
+	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 *pwm_dev)
+{
+	struct pwm_export *export = pwmexport_from_dev(pwm_dev);
+
+	kfree(export);
+}
+
+static int pwm_export_child(struct device *pwmchip_dev, 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->pwm_dev.release = pwm_export_release;
+	export->pwm_dev.parent = pwmchip_dev;
+	export->pwm_dev.devt = MKDEV(0, 0);
+	export->pwm_dev.groups = pwm_groups;
+	dev_set_name(&export->pwm_dev, "pwm%u", pwm->hwpwm);
+
+	ret = device_register(&export->pwm_dev);
+	if (ret) {
+		clear_bit(PWMF_EXPORTED, &pwm->flags);
+		put_device(&export->pwm_dev);
+		export = NULL;
+		return ret;
+	}
+	pwm_prop[0] = kasprintf(GFP_KERNEL, "EXPORT=pwm%u", pwm->hwpwm);
+	pwm_prop[1] = NULL;
+	kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
+	kfree(pwm_prop[0]);
+
+	return 0;
+}
+
+static int pwm_unexport_match(struct device *pwm_dev, void *data)
+{
+	return pwm_from_dev(pwm_dev) == data;
+}
+
+static int pwm_unexport_child(struct device *pwmchip_dev, struct pwm_device *pwm)
+{
+	struct device *pwm_dev;
+	char *pwm_prop[2];
+
+	if (!test_and_clear_bit(PWMF_EXPORTED, &pwm->flags))
+		return -ENODEV;
+
+	pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
+	if (!pwm_dev)
+		return -ENODEV;
+
+	pwm_prop[0] = kasprintf(GFP_KERNEL, "UNEXPORT=pwm%u", pwm->hwpwm);
+	pwm_prop[1] = NULL;
+	kobject_uevent_env(&pwmchip_dev->kobj, KOBJ_CHANGE, pwm_prop);
+	kfree(pwm_prop[0]);
+
+	/* for device_find_child() */
+	put_device(pwm_dev);
+	device_unregister(pwm_dev);
+	pwm_put(pwm);
+
+	return 0;
+}
+
+static ssize_t export_store(struct device *pwmchip_dev,
+			    struct device_attribute *attr,
+			    const char *buf, size_t len)
+{
+	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
+	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(pwmchip_dev, pwm);
+	if (ret < 0)
+		pwm_put(pwm);
+
+	return ret ? : len;
+}
+static DEVICE_ATTR_WO(export);
+
+static ssize_t unexport_store(struct device *pwmchip_dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t len)
+{
+	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
+	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(pwmchip_dev, &chip->pwms[hwpwm]);
+
+	return ret ? : len;
+}
+static DEVICE_ATTR_WO(unexport);
+
+static ssize_t npwm_show(struct device *pwmchip_dev, struct device_attribute *attr,
+			 char *buf)
+{
+	const struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
+
+	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 *pwmchip_dev,
+					      struct pwm_device *pwm,
+					      struct pwm_state *state)
+{
+	struct device *pwm_dev;
+	struct pwm_export *export;
+
+	if (!test_bit(PWMF_EXPORTED, &pwm->flags))
+		return NULL;
+
+	pwm_dev = device_find_child(pwmchip_dev, pwm, pwm_unexport_match);
+	if (!pwm_dev)
+		return NULL;
+
+	export = pwmexport_from_dev(pwm_dev);
+	put_device(pwm_dev);	/* 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_might_sleep(pwm, state);
+
+	/* release lock taken in pwm_class_get_state */
+	mutex_unlock(&export->lock);
+
+	return ret;
+}
+
+static int pwm_class_resume_npwm(struct device *pwmchip_dev, unsigned int npwm)
+{
+	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
+	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(pwmchip_dev, pwm, &state);
+		if (!export)
+			continue;
+
+		/* If pwmchip was not enabled before suspend, do nothing. */
+		if (!export->suspend.enabled) {
+			/* release lock taken in pwm_class_get_state */
+			mutex_unlock(&export->lock);
+			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 *pwmchip_dev)
+{
+	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
+	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(pwmchip_dev, pwm, &state);
+		if (!export)
+			continue;
+
+		/*
+		 * If pwmchip was not enabled before suspend, save
+		 * state for resume time and do nothing else.
+		 */
+		export->suspend = state;
+		if (!state.enabled) {
+			/* release lock taken in pwm_class_get_state */
+			mutex_unlock(&export->lock);
+			continue;
+		}
+
+		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(pwmchip_dev, i);
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static int pwm_class_resume(struct device *pwmchip_dev)
+{
+	struct pwm_chip *chip = pwmchip_from_dev(pwmchip_dev);
+
+	return pwm_class_resume_npwm(pwmchip_dev, 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 *pwmchip_dev, const void *data)
+{
+	return pwmchip_from_dev(pwmchip_dev) == data;
+}
+
+static void pwmchip_sysfs_export(struct pwm_chip *chip)
+{
+	struct device *pwmchip_dev;
+
+	/*
+	 * If device_create() fails the pwm_chip is still usable by
+	 * the kernel it's just not exported.
+	 */
+	pwmchip_dev = device_create(&pwm_class, pwmchip_parent(chip), MKDEV(0, 0), chip,
+			       "pwmchip%d", chip->id);
+	if (IS_ERR(pwmchip_dev)) {
+		dev_warn(pwmchip_parent(chip),
+			 "device_create failed for pwm_chip sysfs export\n");
+	}
+}
+
+static void pwmchip_sysfs_unexport(struct pwm_chip *chip)
+{
+	struct device *pwmchip_dev;
+	unsigned int i;
+
+	pwmchip_dev = class_find_device(&pwm_class, NULL, chip,
+					pwmchip_sysfs_match);
+	if (!pwmchip_dev)
+		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(pwmchip_dev, pwm);
+	}
+
+	put_device(pwmchip_dev);
+	device_unregister(pwmchip_dev);
+}
+
 #define PWMCHIP_ALIGN ARCH_DMA_MINALIGN
 
 static void *pwmchip_priv(struct pwm_chip *chip)
@@ -1086,7 +1615,6 @@ struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_fwnode_pwm_get);
 
-#ifdef CONFIG_DEBUG_FS
 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 {
 	unsigned int i;
@@ -1171,11 +1699,11 @@ static const struct seq_operations pwm_debugfs_sops = {
 
 DEFINE_SEQ_ATTRIBUTE(pwm_debugfs);
 
-static int __init pwm_debugfs_init(void)
+static int __init pwm_init(void)
 {
-	debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
+	if (IS_ENABLED(CONFIG_DEBUG_FS))
+		debugfs_create_file("pwm", 0444, NULL, NULL, &pwm_debugfs_fops);
 
-	return 0;
+	return class_register(&pwm_class);
 }
-subsys_initcall(pwm_debugfs_init);
-#endif /* CONFIG_DEBUG_FS */
+subsys_initcall(pwm_init);