Re: [lm-sensors] [RFC PATCH 1/9] hwmon: lis3: pm_runtime support

[Jonathan Cameron <jic23-KWPb1pKIrIJaa/9Udqfwiw@public.gmane.org>]

On 10/01/10 12:46, Samu Onkalo wrote:
> Add pm_runtime support to lis3 core driver.
> Add pm_runtime support to lis3 i2c driver.
> 
> spi and hp_accel drivers are not yet supported. Old always
> on functionality remains for those.
> 
> For sysfs there is 5 second delay before turning off the
> chip to avoid long ramp up delay.
I'm not overly familiar with the runtime stuff so looking at this based
on a quick read of their documentation.

Note I'm also not that familiar with the driver :)

One real query about the logic in lis3lv02d_i2c_resume. My reading is
that if we are runtime suspended when coming out of a system suspend
then we don't want to power up the chip?  However I'm not entirely
sure how the two types of power management interact so sorry if I
have completely misunderstood this!

Jonathan
> 
> Signed-off-by: Samu Onkalo <samu.p.onkalo-xNZwKgViW5gAvxtiuMwx3w@public.gmane.org>
> ---
>  drivers/hwmon/lis3lv02d.c     |   59 +++++++++++++++++++++++++++++++++++++++++
>  drivers/hwmon/lis3lv02d.h     |    1 +
>  drivers/hwmon/lis3lv02d_i2c.c |   48 +++++++++++++++++++++++++--------
>  3 files changed, 96 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/hwmon/lis3lv02d.c b/drivers/hwmon/lis3lv02d.c
> index fc591ae..eaa5bf0 100644
> --- a/drivers/hwmon/lis3lv02d.c
> +++ b/drivers/hwmon/lis3lv02d.c
> @@ -34,6 +34,7 @@
>  #include <linux/freezer.h>
>  #include <linux/uaccess.h>
>  #include <linux/miscdevice.h>
> +#include <linux/pm_runtime.h>
>  #include <asm/atomic.h>
>  #include "lis3lv02d.h"
>  
> @@ -43,6 +44,9 @@
>  #define MDPS_POLL_INTERVAL 50
>  #define MDPS_POLL_MIN	   0
>  #define MDPS_POLL_MAX	   2000
> +
> +#define SYSFS_POWERDOWN_DELAY 5000 /* In milliseconds */
Name is rather generic...
> +
>  /*
>   * The sensor can also generate interrupts (DRDY) but it's pretty pointless
>   * because they are generated even if the data do not change. So it's better
> @@ -262,6 +266,18 @@ static void lis3lv02d_joystick_poll(struct input_polled_dev *pidev)
>  	mutex_unlock(&lis3_dev.mutex);
>  }
>  
> +static void lis3lv02d_joystick_open(struct input_polled_dev *pidev)
> +{
> +	if (lis3_dev.pm_dev)
> +		pm_runtime_get_sync(lis3_dev.pm_dev);
> +}
> +
> +static void lis3lv02d_joystick_close(struct input_polled_dev *pidev)
> +{
> +	if (lis3_dev.pm_dev)
> +		pm_runtime_put(lis3_dev.pm_dev);
> +}
> +
>  static irqreturn_t lis302dl_interrupt(int irq, void *dummy)
>  {
>  	if (!test_bit(0, &lis3_dev.misc_opened))
> @@ -356,6 +372,9 @@ static int lis3lv02d_misc_open(struct inode *inode, struct file *file)
>  	if (test_and_set_bit(0, &lis3_dev.misc_opened))
>  		return -EBUSY; /* already open */
>  
> +	if (lis3_dev.pm_dev)
> +		pm_runtime_get_sync(lis3_dev.pm_dev);
> +
>  	atomic_set(&lis3_dev.count, 0);
>  	return 0;
>  }
> @@ -364,6 +383,8 @@ static int lis3lv02d_misc_release(struct inode *inode, struct file *file)
>  {
>  	fasync_helper(-1, file, 0, &lis3_dev.async_queue);
>  	clear_bit(0, &lis3_dev.misc_opened); /* release the device */
> +	if (lis3_dev.pm_dev)
> +		pm_runtime_put(lis3_dev.pm_dev);
>  	return 0;
>  }
>  
> @@ -460,6 +481,8 @@ int lis3lv02d_joystick_enable(void)
>  		return -ENOMEM;
>  
>  	lis3_dev.idev->poll = lis3lv02d_joystick_poll;
> +	lis3_dev.idev->open = lis3lv02d_joystick_open;
> +	lis3_dev.idev->close = lis3lv02d_joystick_close;
>  	lis3_dev.idev->poll_interval = MDPS_POLL_INTERVAL;
>  	lis3_dev.idev->poll_interval_min = MDPS_POLL_MIN;
>  	lis3_dev.idev->poll_interval_max = MDPS_POLL_MAX;
> @@ -512,12 +535,30 @@ void lis3lv02d_joystick_disable(void)
>  EXPORT_SYMBOL_GPL(lis3lv02d_joystick_disable);
>  
>  /* Sysfs stuff */
> +static void lis3lv02d_sysfs_poweron(struct lis3lv02d *lis3)
> +{
> +	/*
> +	 * SYSFS functions are fast visitors so put-call
> +	 * immediately after the get-call. However, keep
> +	 * chip running for a while and schedule delayed
> +	 * suspend. This way periodic sysfs calls doesn't
> +	 * suffer from relatively long power up time.
> +	 */
> +
> +	if (lis3_dev.pm_dev) {
> +		pm_runtime_get_sync(lis3->pm_dev);
> +		pm_runtime_put_noidle(lis3->pm_dev);
> +		pm_schedule_suspend(lis3->pm_dev, SYSFS_POWERDOWN_DELAY);
> +	}
> +}
> +
>  static ssize_t lis3lv02d_selftest_show(struct device *dev,
>  				struct device_attribute *attr, char *buf)
>  {
>  	int result;
>  	s16 values[3];
>  
> +	lis3lv02d_sysfs_poweron(&lis3_dev);
>  	result = lis3lv02d_selftest(&lis3_dev, values);
>  	return sprintf(buf, "%s %d %d %d\n", result == 0 ? "OK" : "FAIL",
>  		values[0], values[1], values[2]);
> @@ -528,6 +569,7 @@ static ssize_t lis3lv02d_position_show(struct device *dev,
>  {
>  	int x, y, z;
>  
> +	lis3lv02d_sysfs_poweron(&lis3_dev);
>  	mutex_lock(&lis3_dev.mutex);
>  	lis3lv02d_get_xyz(&lis3_dev, &x, &y, &z);
>  	mutex_unlock(&lis3_dev.mutex);
> @@ -549,6 +591,7 @@ static ssize_t lis3lv02d_rate_set(struct device *dev,
>  	if (strict_strtoul(buf, 0, &rate))
>  		return -EINVAL;
>  
> +	lis3lv02d_sysfs_poweron(&lis3_dev);
>  	if (lis3lv02d_set_odr(rate))
>  		return -EINVAL;
>  
> @@ -585,6 +628,17 @@ int lis3lv02d_remove_fs(struct lis3lv02d *lis3)
>  {
>  	sysfs_remove_group(&lis3->pdev->dev.kobj, &lis3lv02d_attribute_group);
>  	platform_device_unregister(lis3->pdev);
> +	if (lis3_dev.pm_dev) {
> +		/* Barrier after the sysfs remove */
> +		pm_runtime_barrier(lis3->pm_dev);
> +
> +		/* SYSFS may have left chip running. Turn off if necessary */
> +		if (!pm_runtime_suspended(lis3->pm_dev))
> +			lis3lv02d_poweroff(&lis3_dev);
> +
> +		pm_runtime_disable(lis3->pm_dev);
> +		pm_runtime_set_suspended(lis3->pm_dev);
> +	}
>  	return 0;
>  }
>  EXPORT_SYMBOL_GPL(lis3lv02d_remove_fs);
> @@ -685,6 +739,11 @@ int lis3lv02d_init_device(struct lis3lv02d *dev)
>  	lis3lv02d_add_fs(dev);
>  	lis3lv02d_poweron(dev);
>  
> +	if (lis3_dev.pm_dev) {
> +		pm_runtime_set_active(dev->pm_dev);
> +		pm_runtime_enable(dev->pm_dev);
> +	}
> +
>  	if (lis3lv02d_joystick_enable())
>  		printk(KERN_ERR DRIVER_NAME ": joystick initialization failed\n");
>  
> diff --git a/drivers/hwmon/lis3lv02d.h b/drivers/hwmon/lis3lv02d.h
> index 8540913..3e8a208 100644
> --- a/drivers/hwmon/lis3lv02d.h
> +++ b/drivers/hwmon/lis3lv02d.h
> @@ -214,6 +214,7 @@ struct axis_conversion {
>  
>  struct lis3lv02d {
>  	void			*bus_priv; /* used by the bus layer only */
> +	struct device		*pm_dev; /* for pm_runtime purposes */
>  	int (*init) (struct lis3lv02d *lis3);
>  	int (*write) (struct lis3lv02d *lis3, int reg, u8 val);
>  	int (*read) (struct lis3lv02d *lis3, int reg, u8 *ret);
> diff --git a/drivers/hwmon/lis3lv02d_i2c.c b/drivers/hwmon/lis3lv02d_i2c.c
> index 8e5933b..b9ed1fb 100644
> --- a/drivers/hwmon/lis3lv02d_i2c.c
> +++ b/drivers/hwmon/lis3lv02d_i2c.c
> @@ -29,6 +29,7 @@
>  #include <linux/init.h>
>  #include <linux/err.h>
>  #include <linux/i2c.h>
> +#include <linux/pm_runtime.h>
>  #include "lis3lv02d.h"
>  
>  #define DRV_NAME 	"lis3lv02d_i2c"
> @@ -95,6 +96,7 @@ static int __devinit lis3lv02d_i2c_probe(struct i2c_client *client,
>  	lis3_dev.write	  = lis3_i2c_write;
>  	lis3_dev.irq	  = client->irq;
>  	lis3_dev.ac	  = lis3lv02d_axis_map;
> +	lis3_dev.pm_dev	  = &client->dev;
>  
>  	i2c_set_clientdata(client, &lis3_dev);
>  	ret = lis3lv02d_init_device(&lis3_dev);
> @@ -111,14 +113,14 @@ static int __devexit lis3lv02d_i2c_remove(struct i2c_client *client)
>  		pdata->release_resources();
>  
>  	lis3lv02d_joystick_disable();
> -	lis3lv02d_poweroff(lis3);
>  
>  	return lis3lv02d_remove_fs(&lis3_dev);
>  }
>  
>  #ifdef CONFIG_PM
> -static int lis3lv02d_i2c_suspend(struct i2c_client *client, pm_message_t mesg)
> +static int lis3lv02d_i2c_suspend(struct device *dev)
>  {
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
>  	struct lis3lv02d *lis3 = i2c_get_clientdata(client);
>  
>  	if (!lis3->pdata || !lis3->pdata->wakeup_flags)
> @@ -126,18 +128,16 @@ static int lis3lv02d_i2c_suspend(struct i2c_client *client, pm_message_t mesg)
>  	return 0;
>  }
>  
> -static int lis3lv02d_i2c_resume(struct i2c_client *client)
> +static int lis3lv02d_i2c_resume(struct device *dev)
>  {
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
>  	struct lis3lv02d *lis3 = i2c_get_clientdata(client);
>  
> -	if (!lis3->pdata || !lis3->pdata->wakeup_flags)
> +	if (!lis3->pdata || !lis3->pdata->wakeup_flags ||
> +		pm_runtime_suspended(dev))
I may be misunderstanding the docs on this, but I would have thought
we only want to power it up if it isn't in suspended state?
>  		lis3lv02d_poweron(lis3);
> -	return 0;
> -}
>  
> -static void lis3lv02d_i2c_shutdown(struct i2c_client *client)
> -{
> -	lis3lv02d_i2c_suspend(client, PMSG_SUSPEND);
> +	return 0;
>  }
>  #else
>  #define lis3lv02d_i2c_suspend	NULL
> @@ -145,6 +145,24 @@ static void lis3lv02d_i2c_shutdown(struct i2c_client *client)
>  #define lis3lv02d_i2c_shutdown	NULL
>  #endif
>  
> +static int lis3_i2c_runtime_suspend(struct device *dev)
> +{
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> +	struct lis3lv02d *lis3 = i2c_get_clientdata(client);
> +
> +	lis3lv02d_poweroff(lis3);
> +	return 0;
> +}
> +
> +static int lis3_i2c_runtime_resume(struct device *dev)
> +{
> +	struct i2c_client *client = container_of(dev, struct i2c_client, dev);
> +	struct lis3lv02d *lis3 = i2c_get_clientdata(client);
> +
> +	lis3lv02d_poweron(lis3);
> +	return 0;
> +}
> +
>  static const struct i2c_device_id lis3lv02d_id[] = {
>  	{"lis3lv02d", 0 },
>  	{}
> @@ -152,14 +170,20 @@ static const struct i2c_device_id lis3lv02d_id[] = {
>  
>  MODULE_DEVICE_TABLE(i2c, lis3lv02d_id);
>  
> +static const struct dev_pm_ops lis3_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(lis3lv02d_i2c_suspend,
> +				lis3lv02d_i2c_resume)
> +	SET_RUNTIME_PM_OPS(lis3_i2c_runtime_suspend,
> +			   lis3_i2c_runtime_resume,
> +			   NULL)
> +};
> +
>  static struct i2c_driver lis3lv02d_i2c_driver = {
>  	.driver	 = {
>  		.name   = DRV_NAME,
>  		.owner  = THIS_MODULE,
> +		.pm     = &lis3_pm_ops,
>  	},
> -	.suspend = lis3lv02d_i2c_suspend,
> -	.shutdown = lis3lv02d_i2c_shutdown,
> -	.resume = lis3lv02d_i2c_resume,
>  	.probe	= lis3lv02d_i2c_probe,
>  	.remove	= __devexit_p(lis3lv02d_i2c_remove),
>  	.id_table = lis3lv02d_id,