diff options
Diffstat (limited to 'drivers/counter/interrupt-cnt.c')
| -rw-r--r-- | drivers/counter/interrupt-cnt.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c new file mode 100644 index 000000000000..a99ee7996977 --- /dev/null +++ b/drivers/counter/interrupt-cnt.c @@ -0,0 +1,244 @@ +// 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; + struct counter_signal signals; + struct counter_synapse synapses; + struct counter_count cnts; +}; + +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 = 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 = 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; + + if (!priv->gpio) + return -EINVAL; + + ret = gpiod_get_value(priv->gpio); + if (ret < 0) + return ret; + + *val = ret ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW; + + return 0; +} + +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->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d", + priv->irq); + if (!priv->signals.name) + return -ENOMEM; + + priv->counter.signals = &priv->signals; + priv->counter.num_signals = 1; + + priv->synapses.actions_list = interrupt_cnt_synapse_actionss; + priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actionss); + 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); + + priv->counter.priv = priv; + priv->counter.name = dev_name(dev); + priv->counter.parent = dev; + priv->counter.ops = &interrupt_cnt_ops; + priv->counter.counts = &priv->cnts; + priv->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), 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"); |