linux-kernel - RE: [PATCH v1 2/2] Bluetooth: btnxpuart: Add GPIO support to power save feature

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Message-ID:
 <AS4PR04MB9692450A7DD14671CAEB3737E7722@AS4PR04MB9692.eurprd04.prod.outlook.com>
Date: Fri, 4 Oct 2024 07:42:14 +0000
From: Neeraj Sanjay Kale <neeraj.sanjaykale@....com>
To: Shenwei Wang <shenwei.wang@....com>, "marcel@...tmann.org"
	<marcel@...tmann.org>, "luiz.dentz@...il.com" <luiz.dentz@...il.com>,
	"robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
	<krzk+dt@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>
CC: "linux-bluetooth@...r.kernel.org" <linux-bluetooth@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, Amitkumar Karwar
	<amitkumar.karwar@....com>, Rohit Fule <rohit.fule@....com>, Sherry Sun
	<sherry.sun@....com>, Luke Wang <ziniu.wang_1@....com>, Bough Chen
	<haibo.chen@....com>, LnxRevLi <LnxRevLi@....com>
Subject: RE: [PATCH v1 2/2] Bluetooth: btnxpuart: Add GPIO support to power
 save feature

Hi Shenwei,

> >
> > The expected behavior is level trigger.
> > The piece of code you are referring to is from power save init, where
> > we are setting the initial value of GPIO as HIGH.
> > However, if the FW is already present and running, with unknown power
> > save state, a GPIO toggle ensures the chip wakes up, and FW and driver are
> in sync.
> >
> 
> If the module is already in a power-save state, waking it up only to
> immediately return it to power-save seems unnecessary. A more efficient
> approach would be to simply set the GPIO to LOW. This action should
> transition the module into a power-save state regardless of its previous
> condition.
> 
Yes, it seems more efficient. Let me make the change and test.
Ps_init() is expected to make the GPIO low to wake up the chip.
Will include the change in v3 patch.

Correction to my previous reply: 
> > The piece of code you are referring to is from power save init, where
> > we are setting the initial value of GPIO as "LOW".

Thanks,
Neeraj