1 files changed, 407 insertions, 0 deletions
diff --git a/drivers/gnss/sirf.c b/drivers/gnss/sirf.c
new file mode 100644
index 000000000000..5fb0f730db48
--- /dev/null
+++ b/drivers/gnss/sirf.c
@@ -0,0 +1,407 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SiRFstar GNSS receiver driver
+ *
+ * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
+ */
+
+#include <linux/errno.h>
+#include <linux/gnss.h>
+#include <linux/gpio/consumer.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
+#include <linux/serdev.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+
+#define SIRF_BOOT_DELAY			500
+#define SIRF_ON_OFF_PULSE_TIME		100
+#define SIRF_ACTIVATE_TIMEOUT		200
+#define SIRF_HIBERNATE_TIMEOUT		200
+
+struct sirf_data {
+	struct gnss_device *gdev;
+	struct serdev_device *serdev;
+	speed_t	speed;
+	struct regulator *vcc;
+	struct gpio_desc *on_off;
+	struct gpio_desc *wakeup;
+	int irq;
+	bool active;
+	wait_queue_head_t power_wait;
+};
+
+static int sirf_open(struct gnss_device *gdev)
+{
+	struct sirf_data *data = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = data->serdev;
+	int ret;
+
+	ret = serdev_device_open(serdev);
+	if (ret)
+		return ret;
+
+	serdev_device_set_baudrate(serdev, data->speed);
+	serdev_device_set_flow_control(serdev, false);
+
+	ret = pm_runtime_get_sync(&serdev->dev);
+	if (ret < 0) {
+		dev_err(&gdev->dev, "failed to runtime resume: %d\n", ret);
+		pm_runtime_put_noidle(&serdev->dev);
+		goto err_close;
+	}
+
+	return 0;
+
+err_close:
+	serdev_device_close(serdev);
+
+	return ret;
+}
+
+static void sirf_close(struct gnss_device *gdev)
+{
+	struct sirf_data *data = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = data->serdev;
+
+	serdev_device_close(serdev);
+
+	pm_runtime_put(&serdev->dev);
+}
+
+static int sirf_write_raw(struct gnss_device *gdev, const unsigned char *buf,
+				size_t count)
+{
+	struct sirf_data *data = gnss_get_drvdata(gdev);
+	struct serdev_device *serdev = data->serdev;
+	int ret;
+
+	/* write is only buffered synchronously */
+	ret = serdev_device_write(serdev, buf, count, 0);
+	if (ret < 0)
+		return ret;
+
+	/* FIXME: determine if interrupted? */
+	serdev_device_wait_until_sent(serdev, 0);
+
+	return count;
+}
+
+static const struct gnss_operations sirf_gnss_ops = {
+	.open		= sirf_open,
+	.close		= sirf_close,
+	.write_raw	= sirf_write_raw,
+};
+
+static int sirf_receive_buf(struct serdev_device *serdev,
+				const unsigned char *buf, size_t count)
+{
+	struct sirf_data *data = serdev_device_get_drvdata(serdev);
+	struct gnss_device *gdev = data->gdev;
+
+	return gnss_insert_raw(gdev, buf, count);
+}
+
+static const struct serdev_device_ops sirf_serdev_ops = {
+	.receive_buf	= sirf_receive_buf,
+	.write_wakeup	= serdev_device_write_wakeup,
+};
+
+static irqreturn_t sirf_wakeup_handler(int irq, void *dev_id)
+{
+	struct sirf_data *data = dev_id;
+	struct device *dev = &data->serdev->dev;
+	int ret;
+
+	ret = gpiod_get_value_cansleep(data->wakeup);
+	dev_dbg(dev, "%s - wakeup = %d\n", __func__, ret);
+	if (ret < 0)
+		goto out;
+
+	data->active = !!ret;
+	wake_up_interruptible(&data->power_wait);
+out:
+	return IRQ_HANDLED;
+}
+
+static int sirf_wait_for_power_state(struct sirf_data *data, bool active,
+					unsigned long timeout)
+{
+	int ret;
+
+	ret = wait_event_interruptible_timeout(data->power_wait,
+			data->active == active, msecs_to_jiffies(timeout));
+	if (ret < 0)
+		return ret;
+
+	if (ret == 0) {
+		dev_warn(&data->serdev->dev, "timeout waiting for active state = %d\n",
+				active);
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static void sirf_pulse_on_off(struct sirf_data *data)
+{
+	gpiod_set_value_cansleep(data->on_off, 1);
+	msleep(SIRF_ON_OFF_PULSE_TIME);
+	gpiod_set_value_cansleep(data->on_off, 0);
+}
+
+static int sirf_set_active(struct sirf_data *data, bool active)
+{
+	unsigned long timeout;
+	int retries = 3;
+	int ret;
+
+	if (active)
+		timeout = SIRF_ACTIVATE_TIMEOUT;
+	else
+		timeout = SIRF_HIBERNATE_TIMEOUT;
+
+	while (retries-- > 0) {
+		sirf_pulse_on_off(data);
+		ret = sirf_wait_for_power_state(data, active, timeout);
+		if (ret < 0) {
+			if (ret == -ETIMEDOUT)
+				continue;
+
+			return ret;
+		}
+
+		break;
+	}
+
+	if (retries == 0)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int sirf_runtime_suspend(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+
+	if (!data->on_off)
+		return regulator_disable(data->vcc);
+
+	return sirf_set_active(data, false);
+}
+
+static int sirf_runtime_resume(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+
+	if (!data->on_off)
+		return regulator_enable(data->vcc);
+
+	return sirf_set_active(data, true);
+}
+
+static int __maybe_unused sirf_suspend(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (!pm_runtime_suspended(dev))
+		ret = sirf_runtime_suspend(dev);
+
+	if (data->wakeup)
+		disable_irq(data->irq);
+
+	return ret;
+}
+
+static int __maybe_unused sirf_resume(struct device *dev)
+{
+	struct sirf_data *data = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (data->wakeup)
+		enable_irq(data->irq);
+
+	if (!pm_runtime_suspended(dev))
+		ret = sirf_runtime_resume(dev);
+
+	return ret;
+}
+
+static const struct dev_pm_ops sirf_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sirf_suspend, sirf_resume)
+	SET_RUNTIME_PM_OPS(sirf_runtime_suspend, sirf_runtime_resume, NULL)
+};
+
+static int sirf_parse_dt(struct serdev_device *serdev)
+{
+	struct sirf_data *data = serdev_device_get_drvdata(serdev);
+	struct device_node *node = serdev->dev.of_node;
+	u32 speed = 9600;
+
+	of_property_read_u32(node, "current-speed", &speed);
+
+	data->speed = speed;
+
+	return 0;
+}
+
+static int sirf_probe(struct serdev_device *serdev)
+{
+	struct device *dev = &serdev->dev;
+	struct gnss_device *gdev;
+	struct sirf_data *data;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	gdev = gnss_allocate_device(dev);
+	if (!gdev)
+		return -ENOMEM;
+
+	gdev->ops = &sirf_gnss_ops;
+	gnss_set_drvdata(gdev, data);
+
+	data->serdev = serdev;
+	data->gdev = gdev;
+
+	init_waitqueue_head(&data->power_wait);
+
+	serdev_device_set_drvdata(serdev, data);
+	serdev_device_set_client_ops(serdev, &sirf_serdev_ops);
+
+	ret = sirf_parse_dt(serdev);
+	if (ret)
+		goto err_put_device;
+
+	data->vcc = devm_regulator_get(dev, "vcc");
+	if (IS_ERR(data->vcc)) {
+		ret = PTR_ERR(data->vcc);
+		goto err_put_device;
+	}
+
+	data->on_off = devm_gpiod_get_optional(dev, "sirf,onoff",
+			GPIOD_OUT_LOW);
+	if (IS_ERR(data->on_off))
+		goto err_put_device;
+
+	if (data->on_off) {
+		data->wakeup = devm_gpiod_get_optional(dev, "sirf,wakeup",
+				GPIOD_IN);
+		if (IS_ERR(data->wakeup))
+			goto err_put_device;
+
+		/*
+		 * Configurations where WAKEUP has been left not connected,
+		 * are currently not supported.
+		 */
+		if (!data->wakeup) {
+			dev_err(dev, "no wakeup gpio specified\n");
+			ret = -ENODEV;
+			goto err_put_device;
+		}
+	}
+
+	if (data->wakeup) {
+		ret = gpiod_to_irq(data->wakeup);
+		if (ret < 0)
+			goto err_put_device;
+
+		data->irq = ret;
+
+		ret = devm_request_threaded_irq(dev, data->irq, NULL,
+				sirf_wakeup_handler,
+				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+				"wakeup", data);
+		if (ret)
+			goto err_put_device;
+	}
+
+	if (data->on_off) {
+		ret = regulator_enable(data->vcc);
+		if (ret)
+			goto err_put_device;
+
+		/* Wait for chip to boot into hibernate mode */
+		msleep(SIRF_BOOT_DELAY);
+	}
+
+	if (IS_ENABLED(CONFIG_PM)) {
+		pm_runtime_set_suspended(dev);	/* clear runtime_error flag */
+		pm_runtime_enable(dev);
+	} else {
+		ret = sirf_runtime_resume(dev);
+		if (ret < 0)
+			goto err_disable_vcc;
+	}
+
+	ret = gnss_register_device(gdev);
+	if (ret)
+		goto err_disable_rpm;
+
+	return 0;
+
+err_disable_rpm:
+	if (IS_ENABLED(CONFIG_PM))
+		pm_runtime_disable(dev);
+	else
+		sirf_runtime_suspend(dev);
+err_disable_vcc:
+	if (data->on_off)
+		regulator_disable(data->vcc);
+err_put_device:
+	gnss_put_device(data->gdev);
+
+	return ret;
+}
+
+static void sirf_remove(struct serdev_device *serdev)
+{
+	struct sirf_data *data = serdev_device_get_drvdata(serdev);
+
+	gnss_deregister_device(data->gdev);
+
+	if (IS_ENABLED(CONFIG_PM))
+		pm_runtime_disable(&serdev->dev);
+	else
+		sirf_runtime_suspend(&serdev->dev);
+
+	if (data->on_off)
+		regulator_disable(data->vcc);
+
+	gnss_put_device(data->gdev);
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id sirf_of_match[] = {
+	{ .compatible = "fastrax,uc430" },
+	{ .compatible = "linx,r4" },
+	{ .compatible = "wi2wi,w2sg0008i" },
+	{ .compatible = "wi2wi,w2sg0084i" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, sirf_of_match);
+#endif
+
+static struct serdev_device_driver sirf_driver = {
+	.driver	= {
+		.name		= "gnss-sirf",
+		.of_match_table	= of_match_ptr(sirf_of_match),
+		.pm		= &sirf_pm_ops,
+	},
+	.probe	= sirf_probe,
+	.remove	= sirf_remove,
+};
+module_serdev_device_driver(sirf_driver);
+
+MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
+MODULE_DESCRIPTION("SiRFstar GNSS receiver driver");
+MODULE_LICENSE("GPL v2");