RE: [EXT] Re: [PATCH v2] pmdomain: imx: Make IMX8M/IMX9 BLK_CTRL tristate

[Zhipeng Wang <zhipeng.wang_1@nxp.com>]

> -----Original Message-----
> From: Daniel Baluta (OSS) <daniel.baluta@oss.nxp.com>
> Sent: 2026年4月16日 14:04
> To: Zhipeng Wang <zhipeng.wang_1@nxp.com>; Marco Felsch
> <m.felsch@pengutronix.de>
> Cc: ulfh@kernel.org; Frank Li <frank.li@nxp.com>; s.hauer@pengutronix.de;
> imx@lists.linux.dev; linux-pm@vger.kernel.org; Xuegang Liu
> <xuegang.liu@nxp.com>; Jindong Yue <jindong.yue@nxp.com>;
> linux-kernel@vger.kernel.org; kernel@pengutronix.de; festevam@gmail.com;
> linux-arm-kernel@lists.infradead.org
> Subject: Re: [EXT] Re: [PATCH v2] pmdomain: imx: Make IMX8M/IMX9
> BLK_CTRL tristate
> 
> On 4/14/26 04:59, Zhipeng Wang wrote:
> >  > On 26-04-13, Zhipeng Wang wrote:
> >>> Convert IMX8M_BLK_CTRL and IMX9_BLK_CTRL from bool to tristate to
> >>> allow building as loadable modules.
> >> Out of curiosity, why do you want to have a PM driver to be buildable
> >> as module?
> >>
> >> Regards,
> >>   Marco
> >>
> > Hi Marco,
> >
> > Thank you for your question.
> >
> > The primary motivation is to support Google's GKI (Generic Kernel
> > Image) requirement for Android devices.
> >
> > GKI separates the kernel into two parts:
> > 1. A unified kernel image (GKI) that is common across all Android
> > devices 2. Vendor-specific drivers that must be built as loadable
> > modules
> >
> > Under the GKI architecture, SoC-specific drivers like IMX8M/IMX9
> > BLK_CTRL cannot be built into the core kernel image. Instead, they
> > must be loadable modules that vendors can ship separately. This allows:
> >
> > - A single kernel binary to support multiple hardware platforms
> > - Vendors to update their drivers independently without rebuilding the
> > entire kernel
> > - Better compliance with Android's kernel update and security policies
> >
> Can you please add the below line in the commit message?

Hi Daniel,

Thank you! V4 sent.

BRs,
Zhipeng
> > For i.MX8M/i.MX9 devices running Android with GKI kernels, the
> > BLK_CTRL drivers need to be loaded as modules during boot. Without
> > tristate support, these devices cannot properly initialize their power
> > domains, making them non-functional under GKI.
>