On Sat, Sep 3, 2016 at 11:42 PM, Jacek Anaszewski <jacek.anaszewski@xxxxxxxxx> wrote: > On 09/03/2016 05:35 PM, Amitesh Singh wrote: >> >> Hello Jacek, >> >> >> On Sat, Sep 3, 2016 at 7:14 PM, Jacek Anaszewski >> <jacek.anaszewski@xxxxxxxxx <mailto:jacek.anaszewski@xxxxxxxxx>> wrote: >> >> Hi Amitesh, >> >> >> On 09/03/2016 11:03 AM, Amitesh Singh wrote: >> >> This patch facilates the blink delay to be passed as >> an argument at the time of module loading. >> e.g. >> insmod ledtrigg-oneshot.ko default_delay=100 >> --- >> drivers/leds/trigger/ledtrig-oneshot.c | 7 +++++-- >> 1 file changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/leds/trigger/ledtrig-oneshot.c >> b/drivers/leds/trigger/ledtrig-oneshot.c >> index b8ea9f0..95933a1 100644 >> --- a/drivers/leds/trigger/ledtrig-oneshot.c >> +++ b/drivers/leds/trigger/ledtrig-oneshot.c >> @@ -22,6 +22,9 @@ >> >> #define DEFAULT_DELAY 100 >> >> +static unsigned long default_delay = DEFAULT_DELAY; >> +module_param(default_delay, ulong, S_IRUGO|S_IWUSR); >> + >> struct oneshot_trig_data { >> unsigned int invert; >> }; >> @@ -146,8 +149,8 @@ static void oneshot_trig_activate(struct >> led_classdev *led_cdev) >> if (rc) >> goto err_out_invert; >> >> - led_cdev->blink_delay_on = DEFAULT_DELAY; >> - led_cdev->blink_delay_off = DEFAULT_DELAY; >> + led_cdev->blink_delay_on = default_delay; >> + led_cdev->blink_delay_off = default_delay; >> >> led_cdev->activated = true; >> >> >> >> >> Why do you need this module parameter? You can change >> delay_on and delay_off values from sysfs. >> >> Yes, indeed. If someone wants to change blink_delay, he has to change >> both delay_on and delay_off in case you want to blink with constant time >> ON and OFF (1 / (T + T) = 1/2T) >> This patch facilitates you to modify delay in one step in case of delay >> on and off are same which I think, is most used case. > > > I don't think this is real improvement. We spare two sysfs file > write operations only in case the default_delay param value passed > on module loading won't need to be altered later on. > > Moreover, three sysfs file writes needed for configuring oneshot > trigger (e.g. echo "oneshot" > trigger; echo 100 > delay_on; > echo 50 > delay_off) are not too expensive taking into account > usual frequency of setting LED trigger (surely less often than > once per second). > > This is for configuring the led trigger delay on/off parameter when I instantiate the driver from kernel space. I am instantiating oneshot trigger at the time of boot up. > -- > Best regards, > Jacek Anaszewski -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
