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Diffstat (limited to '')
| -rw-r--r-- | drivers/hte/hte-tegra194-test.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/drivers/hte/hte-tegra194-test.c b/drivers/hte/hte-tegra194-test.c new file mode 100644 index 000000000..60f0ef2cb --- /dev/null +++ b/drivers/hte/hte-tegra194-test.c @@ -0,0 +1,241 @@ +// 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 GPIO 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) { + ret = cnt; + 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"); |