Add suspend and resume operations for being used by optional power
management.
The suspend function is switching off an GPIO which can be used by the
hardware to switch power off. The resume function is switching the GPIO
on and sleeps an adjustable time to give the device a chance to be up
and running.
If activated the driver gets into autosuspend after some time of
inactivity.
Suggested-by: Franz Parzer <[email protected]>
Signed-off-by: Andreas Klinger <[email protected]>
---
drivers/iio/proximity/srf04.c | 104 +++++++++++++++++++++++++++++++++-
1 file changed, 103 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/proximity/srf04.c b/drivers/iio/proximity/srf04.c
index 01eb8cc63076..b19d910298d6 100644
--- a/drivers/iio/proximity/srf04.c
+++ b/drivers/iio/proximity/srf04.c
@@ -45,6 +45,7 @@
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
+#include <linux/pm_runtime.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
@@ -56,6 +57,7 @@ struct srf04_data {
struct device *dev;
struct gpio_desc *gpiod_trig;
struct gpio_desc *gpiod_echo;
+ struct gpio_desc *gpiod_power;
struct mutex lock;
int irqnr;
ktime_t ts_rising;
@@ -63,6 +65,7 @@ struct srf04_data {
struct completion rising;
struct completion falling;
const struct srf04_cfg *cfg;
+ int startup_time_ms;
};
static const struct srf04_cfg srf04_cfg = {
@@ -97,6 +100,9 @@ static int srf04_read(struct srf04_data *data)
u64 dt_ns;
u32 time_ns, distance_mm;
+ if (data->gpiod_power)
+ pm_runtime_get_sync(data->dev);
+
/*
* just one read-echo-cycle can take place at a time
* ==> lock against concurrent reading calls
@@ -110,6 +116,11 @@ static int srf04_read(struct srf04_data *data)
udelay(data->cfg->trigger_pulse_us);
gpiod_set_value(data->gpiod_trig, 0);
+ if (data->gpiod_power) {
+ pm_runtime_mark_last_busy(data->dev);
+ pm_runtime_put_autosuspend(data->dev);
+ }
+
/* it should not take more than 20 ms until echo is rising */
ret = wait_for_completion_killable_timeout(&data->rising, HZ/50);
if (ret < 0) {
@@ -268,6 +279,26 @@ static int srf04_probe(struct platform_device *pdev)
return PTR_ERR(data->gpiod_echo);
}
+#ifdef CONFIG_PM
+ data->gpiod_power = devm_gpiod_get_optional(dev, "power",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(data->gpiod_power)) {
+ dev_err(dev, "failed to get power-gpios: err=%ld\n",
+ PTR_ERR(data->gpiod_power));
+ return PTR_ERR(data->gpiod_power);
+ }
+ if (data->gpiod_power) {
+
+ if (of_property_read_u32(dev->of_node, "startup-time-ms",
+ &data->startup_time_ms))
+ data->startup_time_ms = 100;
+ dev_dbg(dev, "using power gpio: startup-time-ms=%d\n",
+ data->startup_time_ms);
+ }
+#else
+ data->gpiod_power = NULL;
+#endif
+
if (gpiod_cansleep(data->gpiod_echo)) {
dev_err(data->dev, "cansleep-GPIOs not supported\n");
return -ENODEV;
@@ -296,14 +327,85 @@ static int srf04_probe(struct platform_device *pdev)
indio_dev->channels = srf04_chan_spec;
indio_dev->num_channels = ARRAY_SIZE(srf04_chan_spec);
- return devm_iio_device_register(dev, indio_dev);
+ ret = iio_device_register(indio_dev);
+ if (ret < 0) {
+ dev_err(data->dev, "iio_device_register: %d\n", ret);
+ return ret;
+ }
+
+ if (data->gpiod_power) {
+ pm_runtime_set_autosuspend_delay(data->dev, 1000);
+ pm_runtime_use_autosuspend(data->dev);
+
+ ret = pm_runtime_set_active(data->dev);
+ if (ret) {
+ dev_err(data->dev, "pm_runtime_set_active: %d\n", ret);
+ iio_device_unregister(indio_dev);
+ }
+
+ pm_runtime_enable(data->dev);
+ pm_runtime_idle(data->dev);
+ }
+
+ return ret;
}
+static int srf04_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct srf04_data *data = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ if (data->gpiod_power) {
+ pm_runtime_disable(data->dev);
+ pm_runtime_set_suspended(data->dev);
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int srf04_pm_runtime_suspend(struct device *dev)
+{
+ struct platform_device *pdev = container_of(dev,
+ struct platform_device, dev);
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct srf04_data *data = iio_priv(indio_dev);
+
+ gpiod_set_value(data->gpiod_power, 0);
+
+ return 0;
+}
+
+static int srf04_pm_runtime_resume(struct device *dev)
+{
+ struct platform_device *pdev = container_of(dev,
+ struct platform_device, dev);
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct srf04_data *data = iio_priv(indio_dev);
+
+ gpiod_set_value(data->gpiod_power, 1);
+ msleep(data->startup_time_ms);
+
+ return 0;
+}
+
+static const struct dev_pm_ops srf04_pm_ops = {
+ SET_RUNTIME_PM_OPS(srf04_pm_runtime_suspend,
+ srf04_pm_runtime_resume, NULL)
+};
+#endif
+
static struct platform_driver srf04_driver = {
.probe = srf04_probe,
+ .remove = srf04_remove,
.driver = {
.name = "srf04-gpio",
.of_match_table = of_srf04_match,
+#ifdef CONFIG_PM
+ .pm = &srf04_pm_ops,
+#endif
},
};
--
2.20.1
On Thu, 9 Jan 2020 09:39:28 +0100
Andreas Klinger <[email protected]> wrote:
> Add suspend and resume operations for being used by optional power
> management.
>
> The suspend function is switching off an GPIO which can be used by the
> hardware to switch power off. The resume function is switching the GPIO
> on and sleeps an adjustable time to give the device a chance to be up
> and running.
>
> If activated the driver gets into autosuspend after some time of
> inactivity.
>
Generally we try to avoid introducing ifdef CONFIG_PM where
possible, because it tends to be error prone. Mostly
marking functions __maybe_unused is sufficient.
Otherwise looks good to me.
Jonathan
> Suggested-by: Franz Parzer <[email protected]>
> Signed-off-by: Andreas Klinger <[email protected]>
> ---
> drivers/iio/proximity/srf04.c | 104 +++++++++++++++++++++++++++++++++-
> 1 file changed, 103 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/proximity/srf04.c b/drivers/iio/proximity/srf04.c
> index 01eb8cc63076..b19d910298d6 100644
> --- a/drivers/iio/proximity/srf04.c
> +++ b/drivers/iio/proximity/srf04.c
> @@ -45,6 +45,7 @@
> #include <linux/sched.h>
> #include <linux/interrupt.h>
> #include <linux/delay.h>
> +#include <linux/pm_runtime.h>
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
>
> @@ -56,6 +57,7 @@ struct srf04_data {
> struct device *dev;
> struct gpio_desc *gpiod_trig;
> struct gpio_desc *gpiod_echo;
> + struct gpio_desc *gpiod_power;
> struct mutex lock;
> int irqnr;
> ktime_t ts_rising;
> @@ -63,6 +65,7 @@ struct srf04_data {
> struct completion rising;
> struct completion falling;
> const struct srf04_cfg *cfg;
> + int startup_time_ms;
> };
>
> static const struct srf04_cfg srf04_cfg = {
> @@ -97,6 +100,9 @@ static int srf04_read(struct srf04_data *data)
> u64 dt_ns;
> u32 time_ns, distance_mm;
>
> + if (data->gpiod_power)
> + pm_runtime_get_sync(data->dev);
> +
> /*
> * just one read-echo-cycle can take place at a time
> * ==> lock against concurrent reading calls
> @@ -110,6 +116,11 @@ static int srf04_read(struct srf04_data *data)
> udelay(data->cfg->trigger_pulse_us);
> gpiod_set_value(data->gpiod_trig, 0);
>
> + if (data->gpiod_power) {
> + pm_runtime_mark_last_busy(data->dev);
> + pm_runtime_put_autosuspend(data->dev);
> + }
> +
> /* it should not take more than 20 ms until echo is rising */
> ret = wait_for_completion_killable_timeout(&data->rising, HZ/50);
> if (ret < 0) {
> @@ -268,6 +279,26 @@ static int srf04_probe(struct platform_device *pdev)
> return PTR_ERR(data->gpiod_echo);
> }
>
> +#ifdef CONFIG_PM
> + data->gpiod_power = devm_gpiod_get_optional(dev, "power",
> + GPIOD_OUT_LOW);
As the gpio is optional anyway and the various runtime pm calls will be stubbed
out if CONFIG_PM is not enabled, it seems to me that we can just always leave
this code in place. So drop the CONFIG_PM protection.
> + if (IS_ERR(data->gpiod_power)) {
> + dev_err(dev, "failed to get power-gpios: err=%ld\n",
> + PTR_ERR(data->gpiod_power));
> + return PTR_ERR(data->gpiod_power);
> + }
> + if (data->gpiod_power) {
> +
> + if (of_property_read_u32(dev->of_node, "startup-time-ms",
> + &data->startup_time_ms))
> + data->startup_time_ms = 100;
> + dev_dbg(dev, "using power gpio: startup-time-ms=%d\n",
> + data->startup_time_ms);
> + }
> +#else
> + data->gpiod_power = NULL;
> +#endif
> +
> if (gpiod_cansleep(data->gpiod_echo)) {
> dev_err(data->dev, "cansleep-GPIOs not supported\n");
> return -ENODEV;
> @@ -296,14 +327,85 @@ static int srf04_probe(struct platform_device *pdev)
> indio_dev->channels = srf04_chan_spec;
> indio_dev->num_channels = ARRAY_SIZE(srf04_chan_spec);
>
> - return devm_iio_device_register(dev, indio_dev);
> + ret = iio_device_register(indio_dev);
> + if (ret < 0) {
> + dev_err(data->dev, "iio_device_register: %d\n", ret);
> + return ret;
> + }
> +
> + if (data->gpiod_power) {
> + pm_runtime_set_autosuspend_delay(data->dev, 1000);
> + pm_runtime_use_autosuspend(data->dev);
> +
> + ret = pm_runtime_set_active(data->dev);
> + if (ret) {
> + dev_err(data->dev, "pm_runtime_set_active: %d\n", ret);
> + iio_device_unregister(indio_dev);
> + }
> +
> + pm_runtime_enable(data->dev);
> + pm_runtime_idle(data->dev);
> + }
> +
> + return ret;
> }
>
> +static int srf04_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct srf04_data *data = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> +
> + if (data->gpiod_power) {
> + pm_runtime_disable(data->dev);
> + pm_runtime_set_suspended(data->dev);
> + }
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
If we drop CONFIG_PM these will need to be marked __maybe_unused.
> +static int srf04_pm_runtime_suspend(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev,
> + struct platform_device, dev);
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct srf04_data *data = iio_priv(indio_dev);
> +
> + gpiod_set_value(data->gpiod_power, 0);
> +
> + return 0;
> +}
> +
> +static int srf04_pm_runtime_resume(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev,
> + struct platform_device, dev);
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct srf04_data *data = iio_priv(indio_dev);
> +
> + gpiod_set_value(data->gpiod_power, 1);
> + msleep(data->startup_time_ms);
> +
> + return 0;
> +}
> +
> +static const struct dev_pm_ops srf04_pm_ops = {
> + SET_RUNTIME_PM_OPS(srf04_pm_runtime_suspend,
> + srf04_pm_runtime_resume, NULL)
> +};
> +#endif
> +
> static struct platform_driver srf04_driver = {
> .probe = srf04_probe,
> + .remove = srf04_remove,
> .driver = {
> .name = "srf04-gpio",
> .of_match_table = of_srf04_match,
> +#ifdef CONFIG_PM
> + .pm = &srf04_pm_ops,
> +#endif
> },
> };
>