[PATCH v2 1/8] iio: cros_ec: Relax sampling frequency before suspending

From: Thierry Escande
Date: Fri Aug 11 2017 - 10:25:33 EST


From: Gwendal Grignou <gwendal@xxxxxxxxxxxx>

If an application set a tight sampling frequency, given the interrupt
use is a wakup source, suspend will not happen: the kernel will receive
a wake up interrupt and will cancel the suspend process.

Given cros_ec sensors type is non wake up, this patch adds prepare and
complete callbacks to set 1s sampling period just before suspend. This
ensures the sensor hub will not be a source of interrupt during the
suspend process.

Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
---
.../iio/common/cros_ec_sensors/cros_ec_sensors.c | 1 +
.../common/cros_ec_sensors/cros_ec_sensors_core.c | 49 ++++++++++++++++++++++
.../common/cros_ec_sensors/cros_ec_sensors_core.h | 2 +
drivers/iio/light/cros_ec_light_prox.c | 1 +
4 files changed, 53 insertions(+)

diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
index 38e8783..116da2c 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
@@ -292,6 +292,7 @@ MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
static struct platform_driver cros_ec_sensors_platform_driver = {
.driver = {
.name = "cros-ec-sensors",
+ .pm = &cros_ec_sensors_pm_ops,
},
.probe = cros_ec_sensors_probe,
.id_table = cros_ec_sensors_ids,
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
index 416cae5..a620eb5 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
@@ -446,5 +446,54 @@ int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_core_write);

+static int __maybe_unused cros_ec_sensors_prepare(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+
+ if (st->curr_sampl_freq == 0)
+ return 0;
+
+ /*
+ * If the sensors are sampled at high frequency, we will not be able to
+ * sleep. Set sampling to a long period if necessary.
+ */
+ if (st->curr_sampl_freq < CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY) {
+ mutex_lock(&st->cmd_lock);
+ st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
+ st->param.ec_rate.data = CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY;
+ cros_ec_motion_send_host_cmd(st, 0);
+ mutex_unlock(&st->cmd_lock);
+ }
+ return 0;
+}
+
+static void __maybe_unused cros_ec_sensors_complete(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
+
+ if (st->curr_sampl_freq == 0)
+ return;
+
+ if (st->curr_sampl_freq < CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY) {
+ mutex_lock(&st->cmd_lock);
+ st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
+ st->param.ec_rate.data = st->curr_sampl_freq;
+ cros_ec_motion_send_host_cmd(st, 0);
+ mutex_unlock(&st->cmd_lock);
+ }
+}
+
+const struct dev_pm_ops cros_ec_sensors_pm_ops = {
+#ifdef CONFIG_PM_SLEEP
+ .prepare = cros_ec_sensors_prepare,
+ .complete = cros_ec_sensors_complete
+#endif
+};
+EXPORT_SYMBOL_GPL(cros_ec_sensors_pm_ops);
+
MODULE_DESCRIPTION("ChromeOS EC sensor hub core functions");
MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
index 8bc2ca3..2edf68d 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
@@ -169,6 +169,8 @@ int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
struct iio_chan_spec const *chan,
int val, int val2, long mask);

+extern const struct dev_pm_ops cros_ec_sensors_pm_ops;
+
/* List of extended channel specification for all sensors */
extern const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[];

diff --git a/drivers/iio/light/cros_ec_light_prox.c b/drivers/iio/light/cros_ec_light_prox.c
index 7217223..f8658d4 100644
--- a/drivers/iio/light/cros_ec_light_prox.c
+++ b/drivers/iio/light/cros_ec_light_prox.c
@@ -279,6 +279,7 @@ MODULE_DEVICE_TABLE(platform, cros_ec_light_prox_ids);
static struct platform_driver cros_ec_light_prox_platform_driver = {
.driver = {
.name = "cros-ec-light-prox",
+ .pm = &cros_ec_sensors_pm_ops,
},
.probe = cros_ec_light_prox_probe,
.id_table = cros_ec_light_prox_ids,
--
2.7.4