Hi Matt,
You shouldn't define your own pm ops in the driver - it is already
accomplished in drivers/leds/led-class.c:
static int __init leds_init(void)
{
leds_class = class_create(THIS_MODULE, "leds");
if (IS_ERR(leds_class))
return PTR_ERR(leds_class);
leds_class->pm = &leds_class_dev_pm_ops; <--------------
leds_class->dev_groups = led_groups;
return 0;
}
LED class drivers shouldn't use pm_runtime API directly, but rely
on the pm ops defined for the class instead.
Every call to led_classdev_register() results in a call to
device_create_with_groups(leds_class, parent, 0,
led_cdev, led_cdev->groups, "%s", name);
As you see led_class is passed in the first argument. Beneath it results
in adding a device to the PM core's list of active devices, with pm ops
defined for the leds_class.
Any suspend/resume event results in calling relevant pm op for each
registered LED class device, not per LED class driver. LED class
define generic pm ops for the whole LED subsystem:
void led_classdev_suspend(struct led_classdev *led_cdev)
{
led_cdev->flags |= LED_SUSPENDED;
led_set_brightness_nopm(led_cdev, 0);
}
void led_classdev_resume(struct led_classdev *led_cdev)
{
led_set_brightness_nopm(led_cdev, led_cdev->brightness);
if (led_cdev->flash_resume)
led_cdev->flash_resume(led_cdev);
led_cdev->flags &= ~LED_SUSPENDED;
}
The only thing a LED class driver needs to to know is the number
of LEDs with brightness greater than 0. If it drops to 0, then it
should put the device in a power down mode. If the number is greater
then 0 it should power the device up.
On 10/18/2016 05:17 PM, Matt Ranostay wrote:
Allow chip to enter low power state when no LEDs are being lit or in
blink mode.
Cc: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
---
drivers/leds/leds-pca963x.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/drivers/leds/leds-pca963x.c b/drivers/leds/leds-pca963x.c
index 407eba11e187..a6b954b31fcd 100644
--- a/drivers/leds/leds-pca963x.c
+++ b/drivers/leds/leds-pca963x.c
@@ -35,6 +35,7 @@
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/platform_data/leds-pca963x.h>
+#include <linux/pm_runtime.h>
/* LED select registers determine the source that drives LED outputs */
#define PCA963X_LED_OFF 0x0 /* LED driver off */
@@ -108,6 +109,7 @@ struct pca963x_led {
struct pca963x *chip;
struct led_classdev led_cdev;
int led_num; /* 0 .. 15 potentially */
+ enum led_brightness brightness;
char name[32];
u8 gdc;
u8 gfrq;
@@ -116,6 +118,8 @@ struct pca963x_led {
static int pca963x_brightness(struct pca963x_led *pca963x,
enum led_brightness brightness)
{
+ struct i2c_client *client = pca963x->chip->client;
+ enum led_brightness prev_brightness = pca963x->brightness;
u8 ledout_addr = pca963x->chip->chipdef->ledout_base
+ (pca963x->led_num / 4);
u8 ledout;
@@ -123,8 +127,12 @@ static int pca963x_brightness(struct pca963x_led *pca963x,
u8 mask = 0x3 << shift;
int ret;
+ if (brightness == prev_brightness)
+ return 0;
+
mutex_lock(&pca963x->chip->mutex);
ledout = i2c_smbus_read_byte_data(pca963x->chip->client, ledout_addr);
+
switch (brightness) {
case LED_FULL:
ret = i2c_smbus_write_byte_data(pca963x->chip->client,
@@ -132,6 +140,9 @@ static int pca963x_brightness(struct pca963x_led *pca963x,
(ledout & ~mask) | (PCA963X_LED_ON << shift));
break;
case LED_OFF:
+ ret = pm_runtime_put(&client->dev);
+ if (ret < 0)
+ goto unlock;
Here you should check the number of the LEDs with brightness > 0
instead. If the number is 0 then you should call
pca963x_runtime_suspend().
ret = i2c_smbus_write_byte_data(pca963x->chip->client,
ledout_addr, ledout & ~mask);
break;
@@ -146,7 +157,15 @@ static int pca963x_brightness(struct pca963x_led *pca963x,
(ledout & ~mask) | (PCA963X_LED_PWM << shift));
break;
}
+
+ if (prev_brightness == LED_OFF) {
+ ret = pm_runtime_get_sync(&client->dev);
Similarly here pca963x_runtime_resume() should be called.
Of course a counter for the LEDs with brightness greater than 0
should be added and maintained.
+ if (ret < 0)
+ goto unlock;
+ }
unlock:
+ pca963x->brightness = brightness;
+
mutex_unlock(&pca963x->chip->mutex);
return ret;
}
@@ -350,6 +369,7 @@ static int pca963x_probe(struct i2c_client *client,
return -ENOMEM;
i2c_set_clientdata(client, pca963x_chip);
+ dev_set_drvdata(&client->dev, client);
mutex_init(&pca963x_chip->mutex);
pca963x_chip->chipdef = chip;
@@ -402,6 +422,12 @@ static int pca963x_probe(struct i2c_client *client,
i2c_smbus_write_byte_data(client, PCA963X_MODE2, 0x05);
}
+ err = pm_runtime_set_active(&client->dev);
+ if (err)
+ goto exit;
+ pm_runtime_enable(&client->dev);
+ pm_runtime_idle(&client->dev);
+
return 0;
exit:
@@ -416,16 +442,37 @@ static int pca963x_remove(struct i2c_client *client)
struct pca963x *pca963x = i2c_get_clientdata(client);
int i;
+ pm_runtime_disable(&client->dev);
+
for (i = 0; i < pca963x->chipdef->n_leds; i++)
led_classdev_unregister(&pca963x->leds[i].led_cdev);
return 0;
}
+static int pca963x_runtime_suspend(struct device *dev)
+{
+ struct i2c_client *client = dev_get_drvdata(dev);
+
+ return i2c_smbus_write_byte_data(client, PCA963X_MODE1, BIT(4));
+}
+
+static int pca963x_runtime_resume(struct device *dev)
+{
+ struct i2c_client *client = dev_get_drvdata(dev);
+
+ return i2c_smbus_write_byte_data(client, PCA963X_MODE1, 0x00);
+}
+
+const static struct dev_pm_ops pca963x_pms = {
+ SET_RUNTIME_PM_OPS(pca963x_runtime_suspend, pca963x_runtime_resume, NULL)
+};
+
static struct i2c_driver pca963x_driver = {
.driver = {
.name = "leds-pca963x",
.of_match_table = of_match_ptr(of_pca963x_match),
+ .pm = &pca963x_pms,
},
.probe = pca963x_probe,
.remove = pca963x_remove,
--
Best regards,
Jacek Anaszewski
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