[PATCH] Input: apanel - switch to using brightness_set_blocking()

[PATCH] Input: apanel - switch to using brightness_set_blocking()

[Dmitry Torokhov]

Now that LEDs core allows "blocking" flavor of "set brightness" method we
can use it and get rid of private work item. As a bonus, we are no longer
forgetting to cancel it when we unbind the driver.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/misc/apanel.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/input/misc/apanel.c b/drivers/input/misc/apanel.c
index 094bddf56755..2e138fef1274 100644
--- a/drivers/input/misc/apanel.c
+++ b/drivers/input/misc/apanel.c
@@ -22,7 +22,6 @@
 #include <linux/io.h>
 #include <linux/input-polldev.h>
 #include <linux/i2c.h>
-#include <linux/workqueue.h>
 #include <linux/leds.h>
 
 #define APANEL_NAME	"Fujitsu Application Panel"
@@ -60,7 +59,6 @@ struct apanel {
 	unsigned short keymap[MAX_PANEL_KEYS];
 	u16    nkeys;
 	u16    led_bits;
-	struct work_struct led_work;
 	struct led_classdev mail_led;
 };
 
@@ -109,15 +107,7 @@ static void apanel_poll(struct input_polled_dev *ipdev)
 			report_key(idev, ap->keymap[i]);
 }
 
-/* Track state changes of LED */
-static void led_update(struct work_struct *work)
-{
-	struct apanel *ap = container_of(work, struct apanel, led_work);
-
-	i2c_smbus_write_word_data(ap->client, 0x10, ap->led_bits);
-}
-
-static void mail_led_set(struct led_classdev *led,
+static int mail_led_set(struct led_classdev *led,
 			 enum led_brightness value)
 {
 	struct apanel *ap = container_of(led, struct apanel, mail_led);
@@ -127,7 +117,7 @@ static void mail_led_set(struct led_classdev *led,
 	else
 		ap->led_bits &= ~0x8000;
 
-	schedule_work(&ap->led_work);
+	return i2c_smbus_write_word_data(ap->client, 0x10, ap->led_bits);
 }
 
 static int apanel_remove(struct i2c_client *client)
@@ -179,7 +169,7 @@ static struct apanel apanel = {
 	},
 	.mail_led = {
 		.name = "mail:blue",
-		.brightness_set = mail_led_set,
+		.brightness_set_blocking = mail_led_set,
 	},
 };
 
@@ -235,7 +225,6 @@ static int apanel_probe(struct i2c_client *client,
 	if (err)
 		goto out3;
 
-	INIT_WORK(&ap->led_work, led_update);
 	if (device_chip[APANEL_DEV_LED] != CHIP_NONE) {
 		err = led_classdev_register(&client->dev, &ap->mail_led);
 		if (err)
-- 
2.20.1.791.gb4d0f1c61a-goog


-- 
Dmitry

Re: [PATCH] Input: apanel - switch to using brightness_set_blocking()

[Sven Van Asbroeck]

Hi Dmitry,

On Sat, Feb 9, 2019 at 12:19 PM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> Now that LEDs core allows "blocking" flavor of "set brightness" method we
> can use it and get rid of private work item. As a bonus, we are no longer
> forgetting to cancel it when we unbind the driver.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

This is the blocking set_brightness callback after applying the patch :
(it's not immediately obvious when looking at only the patch)

struct apanel {
...
        u16    led_bits;
...
};

static int mail_led_set(struct led_classdev *led,
             enum led_brightness value)
{
    struct apanel *ap = container_of(led, struct apanel, mail_led);

    if (value != LED_OFF)
        ap->led_bits |= 0x8000;
    else
        ap->led_bits &= ~0x8000;

    return i2c_smbus_write_word_data(ap->client, 0x10, ap->led_bits);
}

ap->led_bits was previously used as a 'mailslot' between the
set_brightness callback and the deferred work, right?

After the patch, it's used only in this function. Maybe it could be
replaced by a local variable? As a bonus, that would make
the driver's private struct slightly smaller.