#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>
#include <linux/types.h>
#define INTERRUPT_CNT_NAME "interrupt-cnt"
struct interrupt_cnt_priv {
atomic_t count;
struct gpio_desc *gpio;
int irq;
bool enabled;
struct counter_signal signals;
struct counter_synapse synapses;
struct counter_count cnts;
};
static irqreturn_t interrupt_cnt_isr(int irq, void *dev_id)
{
struct counter_device *counter = dev_id;
struct interrupt_cnt_priv *priv = counter_priv(counter);
atomic_inc(&priv->count);
counter_push_event(counter, COUNTER_EVENT_CHANGE_OF_STATE, 0);
return IRQ_HANDLED;
}
static int interrupt_cnt_enable_read(struct counter_device *counter,
struct counter_count *count, u8 *enable)
{
struct interrupt_cnt_priv *priv = counter_priv(counter);
*enable = priv->enabled;
return 0;
}
static int interrupt_cnt_enable_write(struct counter_device *counter,
struct counter_count *count, u8 enable)
{
struct interrupt_cnt_priv *priv = counter_priv(counter);
if (priv->enabled == enable)
return 0;
if (enable) {
priv->enabled = true;
enable_irq(priv->irq);
} else {
disable_irq(priv->irq);
priv->enabled = false;
}
return 0;
}
static struct counter_comp interrupt_cnt_ext[] = {
COUNTER_COMP_ENABLE(interrupt_cnt_enable_read,
interrupt_cnt_enable_write),
};
static const enum counter_synapse_action interrupt_cnt_synapse_actions[] = {
COUNTER_SYNAPSE_ACTION_RISING_EDGE,
};
static int interrupt_cnt_action_read(struct counter_device *counter,
struct counter_count *count,
struct counter_synapse *synapse,
enum counter_synapse_action *action)
{
*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
return 0;
}
static int interrupt_cnt_read(struct counter_device *counter,
struct counter_count *count, u64 *val)
{
struct interrupt_cnt_priv *priv = counter_priv(counter);
*val = atomic_read(&priv->count);
return 0;
}
static int interrupt_cnt_write(struct counter_device *counter,
struct counter_count *count, const u64 val)
{
struct interrupt_cnt_priv *priv = counter_priv(counter);
if (val != (typeof(priv->count.counter))val)
return -ERANGE;
atomic_set(&priv->count, val);
return 0;
}
static const enum counter_function interrupt_cnt_functions[] = {
COUNTER_FUNCTION_INCREASE,
};
static int interrupt_cnt_function_read(struct counter_device *counter,
struct counter_count *count,
enum counter_function *function)
{
*function = COUNTER_FUNCTION_INCREASE;
return 0;
}
static int interrupt_cnt_signal_read(struct counter_device *counter,
struct counter_signal *signal,
enum counter_signal_level *level)
{
struct interrupt_cnt_priv *priv = counter_priv(counter);
int ret;
if (!priv->gpio)
return -EINVAL;
ret = gpiod_get_value(priv->gpio);
if (ret < 0)
return ret;
*level = ret ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
return 0;
}
static int interrupt_cnt_watch_validate(struct counter_device *counter,
const struct counter_watch *watch)
{
if (watch->channel != 0 ||
watch->event != COUNTER_EVENT_CHANGE_OF_STATE)
return -EINVAL;
return 0;
}
static const struct counter_ops interrupt_cnt_ops = {
.action_read = interrupt_cnt_action_read,
.count_read = interrupt_cnt_read,
.count_write = interrupt_cnt_write,
.function_read = interrupt_cnt_function_read,
.signal_read = interrupt_cnt_signal_read,
.watch_validate = interrupt_cnt_watch_validate,
};
static int interrupt_cnt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct counter_device *counter;
struct interrupt_cnt_priv *priv;
int ret;
counter = devm_counter_alloc(dev, sizeof(*priv));
if (!counter)
return -ENOMEM;
priv = counter_priv(counter);
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->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d",
priv->irq);
if (!priv->signals.name)
return -ENOMEM;
counter->signals = &priv->signals;
counter->num_signals = 1;
priv->synapses.actions_list = interrupt_cnt_synapse_actions;
priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actions);
priv->synapses.signal = &priv->signals;
priv->cnts.name = "Channel 0 Count";
priv->cnts.functions_list = interrupt_cnt_functions;
priv->cnts.num_functions = ARRAY_SIZE(interrupt_cnt_functions);
priv->cnts.synapses = &priv->synapses;
priv->cnts.num_synapses = 1;
priv->cnts.ext = interrupt_cnt_ext;
priv->cnts.num_ext = ARRAY_SIZE(interrupt_cnt_ext);
counter->name = dev_name(dev);
counter->parent = dev;
counter->ops = &interrupt_cnt_ops;
counter->counts = &priv->cnts;
counter->num_counts = 1;
irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
dev_name(dev), counter);
if (ret)
return ret;
ret = devm_counter_add(dev, counter);
if (ret < 0)
return dev_err_probe(dev, ret, "Failed to add counter\n");
return 0;
}
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");
MODULE_IMPORT_NS