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From:   Daniel Baluta <daniel.baluta@gmail.com>
Date:   Tue, 14 May 2019 11:38:51 +0300
Message-ID: <CAEnQRZB0fs2g=h4pq97t+E9U9LOxSafYhx07Xia_J+snjqefEw@mail.gmail.com>
Subject: Re: [PATCH RESEND 1/2] soc: imx: Add SCU SoC info driver support
To:     Anson Huang <anson.huang@nxp.com>
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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;
+       }