@@ -0,0 +1,249 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
+ */
+
+#include <linux/counter.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define INTERRUPT_CNT_NAME "interrupt-cnt"
+
+struct interrupt_cnt_priv {
+ atomic_t count;
+ struct counter_device counter;
+ struct gpio_desc *gpio;
+ int irq;
+ bool enabled;
+};
+
+static irqreturn_t interrupt_cnt_isr(int irq, void *dev_id)
+{
+ struct interrupt_cnt_priv *priv = dev_id;
+
+ atomic_inc(&priv->count);
+
+ return IRQ_HANDLED;
+}
+
+static ssize_t interrupt_cnt_enable_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *private, char *buf)
+{
+ struct interrupt_cnt_priv *priv = counter->priv;
+
+ return sysfs_emit(buf, "%d\n", priv->enabled);
+}
+
+static ssize_t interrupt_cnt_enable_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *private, const char *buf,
+ size_t len)
+{
+ struct interrupt_cnt_priv *priv = counter->priv;
+ bool enable;
+ ssize_t ret;
+
+ ret = kstrtobool(buf, &enable);
+ if (ret)
+ return ret;
+
+ if (priv->enabled == enable)
+ return len;
+
+ if (enable) {
+ priv->enabled = true;
+ enable_irq(priv->irq);
+ } else {
+ disable_irq(priv->irq);
+ priv->enabled = false;
+ }
+
+ return len;
+}
+
+static const struct counter_count_ext interrupt_cnt_ext[] = {
+ {
+ .name = "enable",
+ .read = interrupt_cnt_enable_read,
+ .write = interrupt_cnt_enable_write,
+ },
+};
+
+static enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
+ COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+};
+
+static int interrupt_cnt_action_get(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_synapse *synapse,
+ size_t *action)
+{
+ *action = interrupt_cnt_synapse_actionss[0];
+
+ return 0;
+}
+
+static int interrupt_cnt_read(struct counter_device *counter,
+ struct counter_count *count, unsigned long *val)
+{
+ struct interrupt_cnt_priv *priv = counter->priv;
+
+ *val = atomic_read(&priv->count);
+
+ return 0;
+}
+
+static int interrupt_cnt_write(struct counter_device *counter,
+ struct counter_count *count,
+ const unsigned long val)
+{
+ struct interrupt_cnt_priv *priv = counter->priv;
+
+ atomic_set(&priv->count, val);
+
+ return 0;
+}
+
+static enum counter_count_function interrupt_cnt_functions[] = {
+ COUNTER_COUNT_FUNCTION_INCREASE,
+};
+
+static int interrupt_cnt_function_get(struct counter_device *counter,
+ struct counter_count *count,
+ size_t *function)
+{
+ *function = interrupt_cnt_functions[0];
+
+ return 0;
+}
+
+static int interrupt_cnt_signal_read(struct counter_device *counter,
+ struct counter_signal *signal,
+ enum counter_signal_value *val)
+{
+ struct interrupt_cnt_priv *priv = counter->priv;
+ int ret;
+
+ ret = gpiod_get_value(priv->gpio);
+ if (ret < 0)
+ return ret;
+
+ *val = ret ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+
+ return 0;
+}
+
+static struct counter_signal interrupt_cnt_signals[] = {
+ {
+ .id = 0,
+ .name = "Channel 0, GPIO line state",
+ },
+};
+
+static struct counter_synapse interrupt_cnt_synapses[] = {
+ {
+ .actions_list = interrupt_cnt_synapse_actionss,
+ .num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actionss),
+ .signal = &interrupt_cnt_signals[0]
+ },
+};
+
+static struct counter_count interrupt_cnts[] = {
+ {
+ .id = 0,
+ .name = "Channel 0 Count",
+ .functions_list = interrupt_cnt_functions,
+ .num_functions = ARRAY_SIZE(interrupt_cnt_functions),
+ .synapses = interrupt_cnt_synapses,
+ .num_synapses = ARRAY_SIZE(interrupt_cnt_synapses),
+ .ext = interrupt_cnt_ext,
+ .num_ext = ARRAY_SIZE(interrupt_cnt_ext),
+ },
+};
+
+static const struct counter_ops interrupt_cnt_ops = {
+ .action_get = interrupt_cnt_action_get,
+ .count_read = interrupt_cnt_read,
+ .count_write = interrupt_cnt_write,
+ .function_get = interrupt_cnt_function_get,
+ .signal_read = interrupt_cnt_signal_read,
+};
+
+static int interrupt_cnt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct interrupt_cnt_priv *priv;
+ int ret;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->irq = platform_get_irq_optional(pdev, 0);
+ if (priv->irq == -ENXIO)
+ priv->irq = 0;
+ else if (priv->irq < 0)
+ return dev_err_probe(dev, priv->irq, "failed to get IRQ\n");
+
+ priv->gpio = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
+ if (IS_ERR(priv->gpio))
+ return dev_err_probe(dev, PTR_ERR(priv->gpio), "failed to get GPIO\n");
+
+ if (!priv->irq && !priv->gpio) {
+ dev_err(dev, "IRQ and GPIO are not found. At least one source should be provided\n");
+ return -ENODEV;
+ }
+
+ if (!priv->irq) {
+ int irq = gpiod_to_irq(priv->gpio);
+
+ if (irq < 0)
+ return dev_err_probe(dev, irq, "failed to get IRQ from GPIO\n");
+
+ priv->irq = irq;
+ }
+
+ priv->counter.priv = priv;
+ priv->counter.name = dev_name(dev);
+ priv->counter.parent = dev;
+ priv->counter.ops = &interrupt_cnt_ops;
+ priv->counter.counts = interrupt_cnts;
+ priv->counter.num_counts = ARRAY_SIZE(interrupt_cnts);
+ priv->counter.signals = interrupt_cnt_signals;
+ priv->counter.num_signals = priv->gpio ?
+ ARRAY_SIZE(interrupt_cnt_signals) : 0;
+
+ irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
+ ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
+ IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
+ INTERRUPT_CNT_NAME, priv);
+ if (ret)
+ return ret;
+
+ return devm_counter_register(dev, &priv->counter);
+}
+
+static const struct of_device_id interrupt_cnt_of_match[] = {
+ { .compatible = "interrupt-counter", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, interrupt_cnt_of_match);
+
+static struct platform_driver interrupt_cnt_driver = {
+ .probe = interrupt_cnt_probe,
+ .driver = {
+ .name = INTERRUPT_CNT_NAME,
+ .of_match_table = interrupt_cnt_of_match,
+ },
+};
+module_platform_driver(interrupt_cnt_driver);
+
+MODULE_ALIAS("platform:interrupt-counter");
+MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
+MODULE_DESCRIPTION("Interrupt counter driver");
+MODULE_LICENSE("GPL v2");