--- /dev/null
+/*
+ * pps-gpio.c -- PPS client driver using GPIO
+ *
+ *
+ * Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
+ * Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#define PPS_GPIO_NAME "pps-gpio"
+#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/pps_kernel.h>
+#include <linux/pps-gpio.h>
+#include <linux/gpio.h>
+#include <linux/list.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>
+
+/* Info for each registered platform device */
+struct pps_gpio_device_data {
+ int irq; /* IRQ used as PPS source */
+ struct pps_device *pps; /* PPS source device */
+ struct pps_source_info info; /* PPS source information */
+ bool assert_falling_edge;
+ bool capture_clear;
+ unsigned int gpio_pin;
+};
+
+/*
+ * Report the PPS event
+ */
+
+static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
+{
+ const struct pps_gpio_device_data *info;
+ struct pps_event_time ts;
+ int rising_edge;
+
+ /* Get the time stamp first */
+ pps_get_ts(&ts);
+
+ info = data;
+
+ rising_edge = gpio_get_value(info->gpio_pin);
+ if ((rising_edge && !info->assert_falling_edge) ||
+ (!rising_edge && info->assert_falling_edge))
+ pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
+ else if (info->capture_clear &&
+ ((rising_edge && info->assert_falling_edge) ||
+ (!rising_edge && !info->assert_falling_edge)))
+ pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
+
+ return IRQ_HANDLED;
+}
+
+static unsigned long
+get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
+{
+ unsigned long flags = data->assert_falling_edge ?
+ IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
+
+ if (data->capture_clear) {
+ flags |= ((flags & IRQF_TRIGGER_RISING) ?
+ IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
+ }
+
+ return flags;
+}
+
+static int pps_gpio_probe(struct platform_device *pdev)
+{
+ struct pps_gpio_device_data *data;
+ const char *gpio_label;
+ int ret;
+ int pps_default_params;
+ const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
+ struct device_node *np = pdev->dev.of_node;
+
+ /* allocate space for device info */
+ data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ if (pdata) {
+ data->gpio_pin = pdata->gpio_pin;
+ gpio_label = pdata->gpio_label;
+
+ data->assert_falling_edge = pdata->assert_falling_edge;
+ data->capture_clear = pdata->capture_clear;
+ } else {
+ ret = of_get_gpio(np, 0);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get GPIO from device tree\n");
+ return ret;
+ }
+ data->gpio_pin = ret;
+ gpio_label = PPS_GPIO_NAME;
+
+ if (of_get_property(np, "assert-falling-edge", NULL))
+ data->assert_falling_edge = true;
+ }
+
+ /* GPIO setup */
+ ret = devm_gpio_request(&pdev->dev, data->gpio_pin, gpio_label);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to request GPIO %u\n",
+ data->gpio_pin);
+ return ret;
+ }
+
+ ret = gpio_direction_input(data->gpio_pin);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to set pin direction\n");
+ return -EINVAL;
+ }
+
+ /* IRQ setup */
+ ret = gpio_to_irq(data->gpio_pin);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
+ return -EINVAL;
+ }
+ data->irq = ret;
+
+ /* initialize PPS specific parts of the bookkeeping data structure. */
+ data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
+ PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
+ if (data->capture_clear)
+ data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
+ PPS_ECHOCLEAR;
+ data->info.owner = THIS_MODULE;
+ snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
+ pdev->name, pdev->id);
+
+ /* register PPS source */
+ pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
+ if (data->capture_clear)
+ pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
+ data->pps = pps_register_source(&data->info, pps_default_params);
+ if (data->pps == NULL) {
+ dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
+ data->irq);
+ return -EINVAL;
+ }
+
+ /* register IRQ interrupt handler */
+ ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
+ get_irqf_trigger_flags(data), data->info.name, data);
+ if (ret) {
+ pps_unregister_source(data->pps);
+ dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
+ return -EINVAL;
+ }
+
+ platform_set_drvdata(pdev, data);
+ dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
+ data->irq);
+
+ return 0;
+}
+
+static int pps_gpio_remove(struct platform_device *pdev)
+{
+ struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
+
+ pps_unregister_source(data->pps);
+ dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
+ return 0;
+}
+
+static const struct of_device_id pps_gpio_dt_ids[] = {
+ { .compatible = "pps-gpio", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
+
+static struct platform_driver pps_gpio_driver = {
+ .probe = pps_gpio_probe,
+ .remove = pps_gpio_remove,
+ .driver = {
+ .name = PPS_GPIO_NAME,
+ .of_match_table = pps_gpio_dt_ids,
+ },
+};
+
+module_platform_driver(pps_gpio_driver);
+MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
+MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
+MODULE_DESCRIPTION("Use GPIO pin as PPS source");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("1.0.0");
Code Review / kvmfornfv.git / blobdiff