Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
hte: Add Tegra HTE test driver
The test driver uses IRQ and GPIO lines to timestamp using HTE
subsystem. The patch also adds compilation support in Kconfig and
Makefile.
Signed-off-by: Dipen Patel <dipenp@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
authored by
Dipen Patel
and committed by
Thierry Reding
9a75a7cd
ed94eb2e
+247
-1
+7
drivers/hte/Kconfig
+7
drivers/hte/Kconfig
···
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systems-on-chip. The driver supports 352 LIC IRQs and 39 AON GPIOs
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lines for timestamping in realtime.
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config HTE_TEGRA194_TEST
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tristate "NVIDIA Tegra194 HTE Test"
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depends on HTE_TEGRA194
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help
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The NVIDIA Tegra194 GTE test driver demonstrates how to use HTE
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framework to timestamp GPIO and LIC IRQ lines.
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endif
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-1
drivers/hte/Makefile
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-1
drivers/hte/Makefile
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drivers/hte/hte-tegra194-test.c
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drivers/hte/hte-tegra194-test.c
···
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (c) 2021-2022 NVIDIA Corporation
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*
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* Author: Dipen Patel <dipenp@nvidia.com>
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*/
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#include <linux/version.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/interrupt.h>
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#include <linux/gpio.h>
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#include <linux/timer.h>
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#include <linux/platform_device.h>
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#include <linux/workqueue.h>
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#include <linux/hte.h>
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/*
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* This sample HTE GPIO test driver demonstrates HTE API usage by enabling
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* hardware timestamp on gpio_in and specified LIC IRQ lines.
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*
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* Note: gpio_out and gpio_in need to be shorted externally in order for this
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* test driver to work for the GPIO monitoring. The test driver has been
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* tested on Jetson AGX Xavier platform by shorting pin 32 and 16 on 40 pin
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* header.
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*
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* Device tree snippet to activate this driver:
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* tegra_hte_test {
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* compatible = "nvidia,tegra194-hte-test";
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* in-gpio = <&gpio_aon TEGRA194_AON_GPIO(BB, 1)>;
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* out-gpio = <&gpio_aon TEGRA194_AON_GPIO(BB, 0)>;
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* timestamps = <&tegra_hte_aon TEGRA194_AON_GPIO(BB, 1)>,
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* <&tegra_hte_lic 0x19>;
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* timestamp-names = "hte-gpio", "hte-i2c-irq";
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* status = "okay";
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* };
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*
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* How to run test driver:
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* - Load test driver.
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* - For the GPIO, at regular interval gpio_out pin toggles triggering
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* HTE for rising edge on gpio_in pin.
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*
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* - For the LIC IRQ line, it uses 0x19 interrupt which is i2c controller 1.
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* - Run i2cdetect -y 1 1>/dev/null, this command will generate i2c bus
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* transactions which creates timestamp data.
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* - It prints below message for both the lines.
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* HW timestamp(<line id>:<ts seq number>): <timestamp>, edge: <edge>.
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* - Unloading the driver disables and deallocate the HTE.
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*/
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static struct tegra_hte_test {
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int gpio_in_irq;
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struct device *pdev;
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struct gpio_desc *gpio_in;
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struct gpio_desc *gpio_out;
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struct hte_ts_desc *desc;
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struct timer_list timer;
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struct kobject *kobj;
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} hte;
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static enum hte_return process_hw_ts(struct hte_ts_data *ts, void *p)
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{
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char *edge;
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struct hte_ts_desc *desc = p;
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if (!ts || !p)
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return HTE_CB_HANDLED;
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if (ts->raw_level < 0)
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edge = "Unknown";
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pr_info("HW timestamp(%u: %llu): %llu, edge: %s\n",
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desc->attr.line_id, ts->seq, ts->tsc,
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(ts->raw_level >= 0) ? ((ts->raw_level == 0) ?
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"falling" : "rising") : edge);
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return HTE_CB_HANDLED;
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}
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static void gpio_timer_cb(struct timer_list *t)
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{
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(void)t;
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gpiod_set_value(hte.gpio_out, !gpiod_get_value(hte.gpio_out));
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mod_timer(&hte.timer, jiffies + msecs_to_jiffies(8000));
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}
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static irqreturn_t tegra_hte_test_gpio_isr(int irq, void *data)
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{
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(void)irq;
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(void)data;
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return IRQ_HANDLED;
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}
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static const struct of_device_id tegra_hte_test_of_match[] = {
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{ .compatible = "nvidia,tegra194-hte-test"},
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{ }
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};
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MODULE_DEVICE_TABLE(of, tegra_hte_test_of_match);
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static int tegra_hte_test_probe(struct platform_device *pdev)
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{
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int ret = 0;
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int i, cnt;
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dev_set_drvdata(&pdev->dev, &hte);
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hte.pdev = &pdev->dev;
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hte.gpio_out = gpiod_get(&pdev->dev, "out", 0);
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if (IS_ERR(hte.gpio_out)) {
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dev_err(&pdev->dev, "failed to get gpio out\n");
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ret = -EINVAL;
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goto out;
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}
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hte.gpio_in = gpiod_get(&pdev->dev, "in", 0);
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if (IS_ERR(hte.gpio_in)) {
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dev_err(&pdev->dev, "failed to get gpio in\n");
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ret = -EINVAL;
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goto free_gpio_out;
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}
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ret = gpiod_direction_output(hte.gpio_out, 0);
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if (ret) {
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dev_err(&pdev->dev, "failed to set output\n");
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ret = -EINVAL;
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goto free_gpio_in;
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}
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ret = gpiod_direction_input(hte.gpio_in);
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if (ret) {
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dev_err(&pdev->dev, "failed to set input\n");
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ret = -EINVAL;
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goto free_gpio_in;
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}
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ret = gpiod_to_irq(hte.gpio_in);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
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ret = -ENXIO;
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goto free_gpio_in;
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}
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hte.gpio_in_irq = ret;
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ret = request_irq(ret, tegra_hte_test_gpio_isr,
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IRQF_TRIGGER_RISING,
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"tegra_hte_gpio_test_isr", &hte);
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if (ret) {
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dev_err(&pdev->dev, "failed to acquire IRQ\n");
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ret = -ENXIO;
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goto free_irq;
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}
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cnt = of_hte_req_count(hte.pdev);
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if (cnt < 0)
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goto free_irq;
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dev_info(&pdev->dev, "Total requested lines:%d\n", cnt);
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hte.desc = devm_kzalloc(hte.pdev, sizeof(*hte.desc) * cnt, GFP_KERNEL);
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if (!hte.desc) {
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ret = -ENOMEM;
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goto free_irq;
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}
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for (i = 0; i < cnt; i++) {
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if (i == 0)
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/*
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* GPIO hte init, line_id and name will be parsed from
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* the device tree node. The edge_flag is implicitly
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* set by request_irq call. Only line_data is needed to be
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* set.
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*/
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hte_init_line_attr(&hte.desc[i], 0, 0, NULL,
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hte.gpio_in);
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else
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/*
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* same comment as above except that IRQ does not need
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* line data.
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*/
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hte_init_line_attr(&hte.desc[i], 0, 0, NULL, NULL);
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ret = hte_ts_get(hte.pdev, &hte.desc[i], i);
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if (ret)
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goto ts_put;
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ret = devm_hte_request_ts_ns(hte.pdev, &hte.desc[i],
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process_hw_ts, NULL,
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&hte.desc[i]);
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if (ret) /* no need to ts_put, request API takes care */
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goto free_irq;
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}
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timer_setup(&hte.timer, gpio_timer_cb, 0);
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mod_timer(&hte.timer, jiffies + msecs_to_jiffies(5000));
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return 0;
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ts_put:
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cnt = i;
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for (i = 0; i < cnt; i++)
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hte_ts_put(&hte.desc[i]);
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free_irq:
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free_irq(hte.gpio_in_irq, &hte);
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free_gpio_in:
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gpiod_put(hte.gpio_in);
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free_gpio_out:
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gpiod_put(hte.gpio_out);
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out:
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return ret;
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}
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static int tegra_hte_test_remove(struct platform_device *pdev)
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{
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(void)pdev;
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free_irq(hte.gpio_in_irq, &hte);
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gpiod_put(hte.gpio_in);
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gpiod_put(hte.gpio_out);
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del_timer(&hte.timer);
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return 0;
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}
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static struct platform_driver tegra_hte_test_driver = {
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.probe = tegra_hte_test_probe,
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.remove = tegra_hte_test_remove,
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.driver = {
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.name = "tegra_hte_test",
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.of_match_table = tegra_hte_test_of_match,
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},
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};
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module_platform_driver(tegra_hte_test_driver);
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MODULE_AUTHOR("Dipen Patel <dipenp@nvidia.com>");
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MODULE_LICENSE("GPL");