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// 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/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
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, MAX_SCHEDULE_TIMEOUT);
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;
do {
sirf_pulse_on_off(data);
ret = sirf_wait_for_power_state(data, active, timeout);
if (ret < 0) {
if (ret == -ETIMEDOUT)
continue;
return ret;
}
break;
} while (retries--);
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->type = GNSS_TYPE_SIRF;
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->
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