On Tue, Aug 08, 2023 at 07:10:08AM -0700, Guenter Roeck wrote: > On 8/8/23 04:46, Conor Dooley wrote: > > On Wed, Aug 02, 2023 at 09:31:51PM +0200, Naresh Solanki wrote: > > > From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx> > > > > > > The TDA38640 chip has different output control mechanisms depending on > > > its mode of operation. When the chip is in SVID mode, only > > > hardware-based output control is supported via ENABLE pin. However, when > > > it operates in PMBus mode, software control works perfectly. > > > > > > To enable software control as a workaround in SVID mode, add the DT > > > property 'infineon,en-svid-control'. This property will enable the > > > workaround, which utilizes ENABLE pin polarity flipping for output when > > > the chip is in SVID mode. > > > > Why do you need a custom property for this? How come it is not possible > > to determine what bus you are on? > > > > That is not the point. Yes, it can be detected if the control method is > PMBus or SVID. However, in SVID mode, SVID is supposed to control the > output, not PMBUs. This is bypassed by controlling the polarity of the > (physical) output enable signal. We do _not_ want this enabled automatically > in SVID mode. Its side effects on random boards using this chip are unknown. > Thus, this needs a property which specifically enables this functionality > for users who _really_ need to use it and (hopefully) know what they are > doing. Hmm, reading this it makes a lot more sense why this is a property - I guess I just struggled to understand the commit message here, particularly what the benefit of using the workaround is. I'm still having difficulty parsing the commit & property text though - its unclear to me when you would need to use it - so I will stay out of the way & let Rob or Krzysztof handle things.
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