[lkml]   [2020]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v3] usb: dwc3: Add support for VBUS power control

Met vriendelijke groet / kind regards,

Mike Looijmans
System Expert

TOPIC Embedded Products B.V.
Materiaalweg 4, 5681 RJ Best
The Netherlands

T: +31 (0) 499 33 69 69

Please consider the environment before printing this e-mail
On 27-07-2020 12:23, Mark Brown wrote:
> On Sun, Jul 26, 2020 at 09:10:39AM +0200, Mike Looijmans wrote:
>> On 23-07-2020 13:05, Mark Brown wrote:
>>> Does the device actually support running without power so that's a thing
>>> that can happen? _get_optional() should only ever be used for supplies
>>> that may be physically absent.
>> It's the 5V VBUS power for the USB "plug" that's being controlled here. It
>> must turned on when the controller is in "host" mode. Some boards arrange
>> this in hardware through the PHY, and some just don't have any control at
>> all and have it permanently on or off. On a board where the 5V is controlled
>> using a GPIO line or an I2C chip, this patch is required to make it work.
> That sounds like the driver should not be using _get_optional() then.

Making it mandatory would break most (read: all except Topic's) existing
boards as they won't have it in their devicetree. I'm perfectly okay with
that, but others might disagree.

 \ /
  Last update: 2020-07-27 13:51    [W:1.059 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site