RE: [PATCH RESEND 1/2] soc: imx: Add SCU SoC info driver support

[Anson Huang <anson.huang@nxp.com>]

> -----Original Message-----
> From: Daniel Baluta [mailto:daniel.baluta@gmail.com]
> Sent: Tuesday, May 14, 2019 4:39 PM
> To: Anson Huang <anson.huang@nxp.com>
> Cc: catalin.marinas@arm.com; will.deacon@arm.com;
> shawnguo@kernel.org; s.hauer@pengutronix.de; kernel@pengutronix.de;
> festevam@gmail.com; maxime.ripard@bootlin.com; agross@kernel.org;
> olof@lixom.net; horms+renesas@verge.net.au;
> jagan@amarulasolutions.com; bjorn.andersson@linaro.org; Leonard Crestez
> <leonard.crestez@nxp.com>; marc.w.gonzalez@free.fr;
> dinguyen@kernel.org; enric.balletbo@collabora.com; Aisheng Dong
> <aisheng.dong@nxp.com>; robh@kernel.org; Abel Vesa
> <abel.vesa@nxp.com>; l.stach@pengutronix.de; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; dl-linux-imx
> <linux-imx@nxp.com>; Daniel Baluta <daniel.baluta@nxp.com>
> Subject: Re: [PATCH RESEND 1/2] soc: imx: Add SCU SoC info driver support
> 
> On Tue, May 14, 2019 at 2:34 AM Anson Huang <anson.huang@nxp.com>
> wrote:
> >
> > Hi, Daniel
> >
> > > -----Original Message-----
> > > From: Daniel Baluta [mailto:daniel.baluta@gmail.com]
> > > Sent: Monday, May 13, 2019 10:30 PM
> > > To: Anson Huang <anson.huang@nxp.com>
> > > Cc: catalin.marinas@arm.com; will.deacon@arm.com;
> > > shawnguo@kernel.org; s.hauer@pengutronix.de;
> kernel@pengutronix.de;
> > > festevam@gmail.com; maxime.ripard@bootlin.com; agross@kernel.org;
> > > olof@lixom.net; horms+renesas@verge.net.au;
> > > jagan@amarulasolutions.com; bjorn.andersson@linaro.org; Leonard
> > > Crestez <leonard.crestez@nxp.com>; marc.w.gonzalez@free.fr;
> > > dinguyen@kernel.org; enric.balletbo@collabora.com; Aisheng Dong
> > > <aisheng.dong@nxp.com>; robh@kernel.org; Abel Vesa
> > > <abel.vesa@nxp.com>; l.stach@pengutronix.de; linux-arm-
> > > kernel@lists.infradead.org; linux-kernel@vger.kernel.org;
> > > dl-linux-imx <linux-imx@nxp.com>; Daniel Baluta
> > > <daniel.baluta@nxp.com>
> > > Subject: Re: [PATCH RESEND 1/2] soc: imx: Add SCU SoC info driver
> > > support
> > >
> > > <snip>
> > >
> > > > +
> > > > +static u32 imx8qxp_soc_revision(void) {
> > > > +       struct imx_sc_msg_misc_get_soc_id msg;
> > > > +       struct imx_sc_rpc_msg *hdr = &msg.hdr;
> > > > +       u32 rev = 0;
> > > > +       int ret;
> > > > +
> > > > +       hdr->ver = IMX_SC_RPC_VERSION;
> > > > +       hdr->svc = IMX_SC_RPC_SVC_MISC;
> > > > +       hdr->func = IMX_SC_MISC_FUNC_GET_CONTROL;
> > > > +       hdr->size = 3;
> > > > +
> > > > +       msg.data.send.control = IMX_SC_C_ID;
> > > > +       msg.data.send.resource = IMX_SC_R_SYSTEM;
> > > > +
> > > > +       ret = imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> > > > +       if (ret) {
> > > > +               dev_err(&imx_scu_soc_pdev->dev,
> > > > +                       "get soc info failed, ret %d\n", ret);
> > > > +               return rev;
> > >
> > > So you return 0 (rev  = 0) here in case of error? This doesn't seem to be
> right.
> > > Maybe return ret?
> >
> > This is intentional, similar with current i.MX8MQ soc info driver,
> > when getting revision failed, just return 0 as revision info and it will show
> "unknown" in sysfs.
> 
> Ok, I understand. Lets make this clear from the source code.
> 
>    ret = imx_scu_call_rpc(soc_ipc_handle, &msg, true);
> +       if (ret) {
> +               dev_err(&imx_scu_soc_pdev->dev,
> +                       "get soc info failed, ret %d\n", ret);
>                 /* returning 0 means getting revision failed */
> +               return 0;
> +       }

OK, will add a comment in V2.

Anson.