// SPDX-License-Identifier: GPL-2.0
/*
* SiRFstar GNSS receiver driver
*
* Copyright (C) 2018 Johan Hovold <[email protected]>
*/
#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/sched.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
/*
* If no data arrives for this time, we assume that the chip is off.
* REVISIT: The report cycle is configurable and can be several minutes long,
* so this will only work reliably if the report cycle is set to a reasonable
* low value. Also power saving settings (like send data only on movement)
* might things work even worse.
* Workaround might be to parse shutdown or bootup messages.
*/
#define SIRF_REPORT_CYCLE 2000
struct sirf_data {
struct gnss_device *gdev;
struct serdev_device *serdev;
speed_t speed;
struct regulator *vcc;
struct regulator *lna;
struct gpio_desc *on_off;
struct gpio_desc *wakeup;
int irq;
bool active;
struct mutex gdev_mutex;
bool open;
struct mutex serdev_mutex;
int serdev_count;
wait_queue_head_t power_wait;
};
static int sirf_serdev_open(struct sirf_data *data)
{
int ret = 0;
mutex_lock(&data->serdev_mutex);
if (++data->serdev_count == 1) {
ret = serdev_device_open(data->serdev);
if (ret) {
data->serdev_count--;
goto out_unlock;
}
serdev_device_set_baudrate(data->serdev, data->speed);
serdev_device_set_flow_control(data->serdev, false);
}
out_unlock:
mutex_unlock(&data->serdev_mutex);
return ret;
}
static void sirf_serdev_close(struct sirf_data *data)
{
mutex_lock(&data->serdev_mutex);
if (--data->serdev_count == 0)
serdev_device_close(data->serdev);
mutex_unlock(&data->serdev_mutex);
}
static int sirf_open(struct gnss_device *gdev)
{
struct sirf_data *data = gnss_get_drvdata(gdev);
struct serdev_device *serdev = data->serdev;
int ret;
mutex_lock(&data->gdev_mutex);
data->open = true;
mutex_unlock(&data->gdev_mutex);
ret = sirf_serdev_open(data);
if (ret) {
mutex_lock(&data->gdev_mutex);
data->open = false;
mutex_unlock(&data->gdev_mutex);
return ret;
}
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:
sirf_serdev_close(data);
mutex_lock(&data->gdev_mutex);
data->open = false;
mutex_unlock(&data->gdev_mutex);
return ret;
}
static void sirf_close(struct gnss_device *gdev)
{
struct sirf_data *data = gnss_get_drvdata(gdev);
struct serdev_device *serdev = data->serdev;
sirf_serdev_close(data);
pm_runtime_put(&serdev->dev);
mutex_lock(&data->gdev_mutex);
data->open = false;
mutex_unlock(&data->gdev_mutex);
}
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, MAX_SCHEDULE_TIMEOUT);
if (ret < 0 || ret < count)
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 size_t sirf_receive_buf(struct serdev_device *serdev,
const u8 *buf, size_t count)
{
struct sirf_data *data = serdev_device_get_drvdata(serdev);
struct gnss_device *gdev = data->gdev;
int ret = 0;
if (!data->wakeup && !data->active) {
data->active = true;
wake_up_interruptible(&data->power_wait);
}
mutex_lock(&data->gdev_mutex);
if (data->open)
ret = gnss_insert_raw(gdev, buf, count);
mutex_unlock(&data->gdev_mutex);
return ret;
}
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_nowakeup(struct sirf_data *data,
bool active,
unsigned long timeout)
{
int ret;
/* Wait for state change (including any shutdown messages). */
msleep(timeout);
/* Wait for data reception or timeout. */
data->active = false;
ret = wait_event_interruptible_timeout(data->power_wait,
data->active, msecs_to_jiffies(SIRF_REPORT_CYCLE));
if (ret < 0)
return ret;
if (ret > 0 && !active)
return -ETIMEDOUT;
if (ret == 0 && active)
return -ETIMEDOUT;
return 0;
}
static int sirf_wait_for_power_state(struct sirf_data *data, bool active,
unsigned long timeout)
{
int ret;
if (!data->wakeup)
return sirf_wait_for_power_state_nowakeup(data, active, timeout);
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;
if (!data->wakeup) {
ret = sirf_serdev_open(data);
if (ret)
return ret;
}
do {
sirf_pulse_on_off(data);
ret = sirf_wait_for_power_state(data, active, timeout);
} while (ret == -ETIMEDOUT && retries--);
if (!data->wakeup)
sirf_serdev_close(data);
if (ret)
return ret;
return 0;
}
static int sirf_runtime_suspend(struct device *dev)
{
struct sirf_data *data = dev_get_drvdata(dev);
int ret2;
int ret;
if (data->on_off)
ret = sirf_set_active(data, false);
else
ret = regulator_disable(data->vcc);
if (ret)
return ret;
ret = regulator_disable(data->lna);
if (ret)
goto err_reenable;
return 0;
err_reenable:
if (data->on_off)
ret2 = sirf_set_active(data, true);
else
ret2 = regulator_enable(data->vcc);
if (ret2)
dev_err(dev,
"failed to reenable power on failed suspend: %d\n",
ret2);
return ret;
}
static int sirf_runtime_resume(struct device *dev)
{
struct sirf_data *data = dev_get_drvdata(dev);
int ret;
ret = regulator_enable(data->lna);
if (ret)
return ret;
if (data->on_off)
ret = sirf_set_active(data, true);
else
ret = regulator_enable(data->vcc);
if (ret)
goto err_disable_lna;
return 0;
err_disable_lna:
regulator_disable(data->lna);
return ret;
}
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->type = GNSS_TYPE_SIRF;
gdev->ops = &sirf_gnss_ops;
gnss_set_drvdata(gdev, data);
data->serdev = serdev;
data->gdev = gdev;
mutex_init(&data->gdev_mutex);
mutex_init(&data->serdev_mutex);
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->lna = devm_regulator_get(dev, "lna");
if (IS_ERR(data->lna)) {
ret = PTR_ERR(data->lna);
goto err_put_device;
}
data->on_off = devm_gpiod_get_optional(dev, "sirf,onoff",
GPIOD_OUT_LOW);
if (IS_ERR(data->on_off)) {
ret = PTR_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)) {
ret = PTR_ERR(data->wakeup);
goto err_put_device;
}
ret = regulator_enable(data->vcc);
if (ret)
goto err_put_device;
/* Wait for chip to boot into hibernate mode. */
msleep(SIRF_BOOT_DELAY);
}
if (data->wakeup) {
ret = gpiod_get_value_cansleep(data->wakeup);
if (ret < 0)
goto err_disable_vcc;
data->active = ret;
ret = gpiod_to_irq(data->wakeup);
if (ret < 0)
goto err_disable_vcc;
data->irq = ret;
ret = request_threaded_irq(data->irq, NULL, sirf_wakeup_handler,
IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
"wakeup", data);
if (ret)
goto err_disable_vcc;
}
if (data->on_off) {
if (!data->wakeup) {
data->active = false;
ret = sirf_serdev_open(data);
if (ret)
goto err_disable_vcc;
msleep(SIRF_REPORT_CYCLE);
sirf_serdev_close(data);
}
/* Force hibernate mode if already active. */
if (data->active) {
ret = sirf_set_active(data, false);
if (ret) {
dev_err(dev, "failed to set hibernate mode: %d\n",
ret);
goto err_free_irq;
}
}
}
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_free_irq;
}
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_free_irq:
if (data->wakeup)
free_irq(data->irq, data);
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->wakeup)
free_irq(data->irq, data);
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,w2sg0004" },
{ .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 <[email protected]>");
MODULE_DESCRIPTION("SiRFstar GNSS receiver driver");
MODULE_LICENSE("GPL v2");
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