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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2021-2022 NVIDIA Corporation
*
* Author: Dipen Patel <dipenp@nvidia.com>
*/
#include <linux/err.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/timer.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <linux/hte.h>
/*
* This sample HTE test driver demonstrates HTE API usage by enabling
* hardware timestamp on gpio_in and specified LIC IRQ lines.
*
* Note: gpio_out and gpio_in need to be shorted externally in order for this
* test driver to work for the GPIO monitoring. The test driver has been
* tested on Jetson AGX Xavier platform by shorting pin 32 and 16 on 40 pin
* header.
*
* Device tree snippet to activate this driver:
* tegra_hte_test {
* compatible = "nvidia,tegra194-hte-test";
* in-gpio = <&gpio_aon TEGRA194_AON_GPIO(BB, 1)>;
* out-gpio = <&gpio_aon TEGRA194_AON_GPIO(BB, 0)>;
* timestamps = <&tegra_hte_aon TEGRA194_AON_GPIO(BB, 1)>,
* <&tegra_hte_lic 0x19>;
* timestamp-names = "hte-gpio", "hte-i2c-irq";
* status = "okay";
* };
*
* How to run test driver:
* - Load test driver.
* - For the GPIO, at regular interval gpio_out pin toggles triggering
* HTE for rising edge on gpio_in pin.
*
* - For the LIC IRQ line, it uses 0x19 interrupt which is i2c controller 1.
* - Run i2cdetect -y 1 1>/dev/null, this command will generate i2c bus
* transactions which creates timestamp data.
* - It prints below message for both the lines.
* HW timestamp(<line id>:<ts seq number>): <timestamp>, edge: <edge>.
* - Unloading the driver disables and deallocate the HTE.
*/
static struct tegra_hte_test {
int gpio_in_irq;
struct device *pdev;
struct gpio_desc *gpio_in;
struct gpio_desc *gpio_out;
struct hte_ts_desc *desc;
struct timer_list timer;
struct kobject *kobj;
} hte;
static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
{
char *edge;
struct hte_ts_desc *desc = p;
if (!ts || !p)
return HTE_CB_HANDLED;
if (ts->raw_level < 0)
edge = "Unknown";
pr_info("HW timestamp(%u: %llu): %llu, edge: %s\n",
desc->attr.line_id, ts->seq, ts->tsc,
(ts->raw_level >= 0) ? ((ts->raw_level == 0) ?
"falling" : "rising") : edge);
return HTE_CB_HANDLED;
}
static void gpio_timer_cb(struct timer_list *t)
{
(void)t;
gpiod_set_value(hte.gpio_out, !gpiod_get_value(hte.gpio_out));
mod_timer(&hte.timer, jiffies + msecs_to_jiffies(8000));
}
static irqreturn_t tegra_hte_test_gpio_isr(int irq, void *data)
{
(void)irq;
(void)data;
return IRQ_HANDLED;
}
static const struct of_device_id tegra_hte_test_of_match[] = {
{ .compatible = "nvidia,tegra194-hte-test"},
{ }
};
MODULE_DEVICE_TABLE(of, tegra_hte_test_of_match);
static int tegra_hte_test_probe(struct platform_device *pdev)
{
int ret = 0;
int i, cnt;
dev_set_drvdata(&pdev->dev, &hte);
hte.pdev = &pdev->dev;
hte.gpio_out = gpiod_get(&pdev->dev, "out", 0);
if (IS_ERR(hte.gpio_out)) {
dev_err(&pdev->dev, "failed to get gpio out\n");
ret = -EINVAL;
goto out;
}
hte.gpio_in = gpiod_get(&pdev->dev, "in", 0);
if (IS_ERR(hte.gpio_in)) {
dev_err(&pdev->dev, "failed to get gpio in\n");
ret = -EINVAL;
goto free_gpio_out;
}
ret = gpiod_direction_output(hte.gpio_out, 0);
if (ret) {
dev_err(&pdev->dev, "failed to set output\n");
ret = -EINVAL;
goto free_gpio_in;
}
ret = gpiod_direction_input(hte.gpio_in);
if (ret) {
dev_err(&pdev->dev, "failed to set input\n");
ret = -EINVAL;
goto free_gpio_in;
}
ret = gpiod_to_irq(hte.gpio_in);
if (ret < 0) {
dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
ret = -ENXIO;
goto free_gpio_in;
}
hte.gpio_in_irq = ret;
ret = request_irq(ret, tegra_hte_test_gpio_isr,
IRQF_TRIGGER_RISING,
"tegra_hte_gpio_test_isr", &hte);
if (ret) {
dev_err(&pdev->dev, "failed to acquire IRQ\n");
ret = -ENXIO;
goto free_irq;
}
cnt = of_hte_req_count(hte.pdev);
if (cnt < 0)
goto free_irq;
dev_info(&pdev->dev, "Total requested lines:%d\n", cnt);
hte.desc = devm_kzalloc(hte.pdev, sizeof(*hte.desc) * cnt, GFP_KERNEL);
if (!hte.desc) {
ret = -ENOMEM;
goto free_irq;
}
for (i = 0; i < cnt; i++) {
if (i == 0)
/*
* GPIO hte init, line_id and name will be parsed from
* the device tree node. The edge_flag is implicitly
* set by request_irq call. Only line_data is needed to be
* set.
*/
hte_init_line_attr(&hte.desc[i], 0, 0, NULL,
hte.gpio_in);
else
/*
* same comment as above except that IRQ does not need
* line data.
*/
hte_init_line_attr(&hte.desc[i], 0, 0, NULL, NULL);
ret = hte_ts_get(hte.pdev, &hte.desc[i], i);
if (ret)
goto ts_put;
ret = devm_hte_request_ts_ns(hte.pdev, &hte.desc[i],
process_hw_ts, NULL,
&hte.desc[i]);
if (ret) /* no need to ts_put, request API takes care */
goto free_irq;
}
timer_setup(&hte.timer, gpio_timer_cb, 0);
mod_timer(&hte.timer, jiffies + msecs_to_jiffies(5000));
return 0;
ts_put:
cnt = i;
for (i = 0; i < cnt; i++)
hte_ts_put(&hte.desc[i]);
free_irq:
free_irq(hte.gpio_in_irq, &hte);
free_gpio_in:
gpiod_put(hte.gpio_in);
free_gpio_out:
gpiod_put(hte.gpio_out);
out:
return ret;
}
static int tegra_hte_test_remove(struct platform_device *pdev)
{
(void)pdev;
free_irq(hte.gpio_in_irq, &hte);
gpiod_put(hte.gpio_in);
gpiod_put(hte.gpio_out);
del_timer_sync(&hte.timer);
return 0;
}
static struct platform_driver tegra_hte_test_driver = {
.probe = tegra_hte_test_probe,
.remove = tegra_hte_test_remove,
.driver = {
.name = "tegra_hte_test",
.of_match_table = tegra_hte_test_of_match,
},
};
module_platform_driver(tegra_hte_test_driver);
MODULE_AUTHOR("Dipen Patel <dipenp@nvidia.com>");
MODULE_LICENSE("GPL");
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