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gnss: sirf: add support for configurations without wakeup signal

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Some Wi2Wi devices do not have a wakeup output, so device state can
only be indirectly detected by looking whether there is communication
over the serial lines.
This approach requires a report cycle set to a value less than 2 seconds
to be reliable.

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
[ johan: simplify sirf_set_active(), style changes ]
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Andreas Kemnade 2019-01-24 07:34:36 +01:00 committed by Johan Hovold
parent 196d918460
commit ccd0e4963f
1 changed files with 102 additions and 27 deletions
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129
drivers/gnss/sirf.c
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@ -25,6 +25,15 @@
#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;
@ -39,9 +48,42 @@ struct sirf_data {
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);
@ -52,7 +94,7 @@ static int sirf_open(struct gnss_device *gdev)
data->open = true;
mutex_unlock(&data->gdev_mutex);
ret = serdev_device_open(serdev);
ret = sirf_serdev_open(data);
if (ret) {
mutex_lock(&data->gdev_mutex);
data->open = false;
@ -60,10 +102,6 @@ static int sirf_open(struct gnss_device *gdev)
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);
@ -74,7 +112,7 @@ static int sirf_open(struct gnss_device *gdev)
return 0;
err_close:
serdev_device_close(serdev);
sirf_serdev_close(data);
mutex_lock(&data->gdev_mutex);
data->open = false;
@ -88,7 +126,7 @@ 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);
sirf_serdev_close(data);
pm_runtime_put(&serdev->dev);
@ -128,6 +166,11 @@ static int sirf_receive_buf(struct serdev_device *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);
@ -158,11 +201,39 @@ 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)
@ -195,21 +266,22 @@ static int sirf_set_active(struct sirf_data *data, bool active)
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);
if (ret < 0) {
if (ret == -ETIMEDOUT)
continue;
} while (ret == -ETIMEDOUT && retries--);
return ret;
}
if (!data->wakeup)
sirf_serdev_close(data);
break;
} while (retries--);
if (retries < 0)
return -ETIMEDOUT;
if (ret)
return ret;
return 0;
}
@ -303,6 +375,7 @@ static int sirf_probe(struct serdev_device *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);
@ -329,16 +402,6 @@ static int sirf_probe(struct serdev_device *serdev)
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;
}
ret = regulator_enable(data->vcc);
if (ret)
goto err_put_device;
@ -366,6 +429,17 @@ static int sirf_probe(struct serdev_device *serdev)
}
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);
@ -433,6 +507,7 @@ static void sirf_remove(struct serdev_device *serdev)
static const struct of_device_id sirf_of_match[] = {
{ .compatible = "fastrax,uc430" },
{ .compatible = "linx,r4" },
{ .compatible = "wi2wi,w2sg0004" },
{ .compatible = "wi2wi,w2sg0008i" },
{ .compatible = "wi2wi,w2sg0084i" },
{},