From: Jean-Jacques Hiblot <jjhiblot@ti.com>
To: Pavel Machek <pavel@ucw.cz>,
Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: <daniel.thompson@linaro.org>, <linux-leds@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <dmurphy@ti.com>,
<tomi.valkeinen@ti.com>
Subject: Re: [PATCH v5 3/3] leds: Add control of the voltage/current regulator to the LED core
Date: Mon, 14 Oct 2019 12:49:07 +0200 [thread overview]
Message-ID: <eb8c0df1-0d5b-11d0-9965-3192fa5675f3@ti.com> (raw)
In-Reply-To: <20191013120937.GK5653@amd>
On 13/10/2019 14:09, Pavel Machek wrote:
> Hi!
>
>> I must say I'm not a big fan of this change.
>> It adds a bunch of code to the LED core and gives small
>> functionality in a reward. It may also influence maximum
>> software blinking rate, so I'd rather avoid calling
>> regulator_enable/disable when timer trigger is set.
>>
>> It will of course require more code.
>>
>> Since AFAIR Pavel was original proponent of this change then
>> I'd like to see his opinion before we move on to discussing
>> possible improvements to this patch.
> Was I?
>
> Okay, this series looks quite confusing to me. First, 1/3 looks
> "interesting" (would have to analyze it way more).
>
> Second, 3/3... So we have a LED driver _and_ a regulator? So yes, the
> chip driving a LED is usually ... voltage/current regulator. What is
> second regulator doing there? Is that a common setup?
This is quite common with current-sink LED drivers.
The setup looks like this:
+-----------+
| |
| Regulator |
| +------------------------+
| | |
+-----------+ __|__
\ /
+---------------------+ \ / led
| | V
| Led Driver | --+--
| | |
| | |
| +----------+
| \ |
| \ |
| + |
| | |
+---------------------+
|
+--+--+
///////
Only the regulator usually does not supply only one LED.
JJ
>
> Best regards,
> Pavel
>
next prev parent reply other threads:[~2019-10-14 10:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-23 10:20 [PATCH v5 0/3] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
2019-09-23 10:20 ` [PATCH v5 1/3] led: make led_set_brightness_sync() use led_set_brightness_nosleep() Jean-Jacques Hiblot
2019-09-23 10:20 ` [PATCH v5 2/3] dt-bindings: leds: document the "power-supply" property Jean-Jacques Hiblot
2019-09-23 10:20 ` [PATCH v5 3/3] leds: Add control of the voltage/current regulator to the LED core Jean-Jacques Hiblot
2019-09-24 18:58 ` Jacek Anaszewski
2019-09-25 8:41 ` Jean-Jacques Hiblot
2019-10-13 12:09 ` Pavel Machek
2019-10-13 16:40 ` Jacek Anaszewski
2019-10-14 10:49 ` Jean-Jacques Hiblot [this message]
2019-10-14 12:38 ` Daniel Thompson
2019-10-14 18:48 ` Jacek Anaszewski
2019-10-16 8:13 ` Jean-Jacques Hiblot
2019-10-17 19:05 ` Jacek Anaszewski
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