linux-kernel - RE: [PATCH 5/6] can: flexcan: add CAN wakeup function for i.MX8QM

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Date:   Fri, 16 Oct 2020 10:57:29 +0000
From:   Joakim Zhang <qiangqing.zhang@....com>
To:     Marc Kleine-Budde <mkl@...gutronix.de>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>
CC:     "kernel@...gutronix.de" <kernel@...gutronix.de>,
        dl-linux-imx <linux-imx@....com>, Ying Liu <victor.liu@....com>,
        Peng Fan <peng.fan@....com>,
        "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>,
        Pankaj Bansal <pankaj.bansal@....com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 5/6] can: flexcan: add CAN wakeup function for i.MX8QM


Hi Marc,

> -----Original Message-----
> From: Marc Kleine-Budde <mkl@...gutronix.de>
> Sent: 2020年10月16日 18:40
> To: Joakim Zhang <qiangqing.zhang@....com>; robh+dt@...nel.org;
> shawnguo@...nel.org; s.hauer@...gutronix.de
> Cc: kernel@...gutronix.de; dl-linux-imx <linux-imx@....com>; Ying Liu
> <victor.liu@....com>; Peng Fan <peng.fan@....com>;
> linux-can@...r.kernel.org; Pankaj Bansal <pankaj.bansal@....com>;
> netdev@...r.kernel.org; devicetree@...r.kernel.org;
> linux-kernel@...r.kernel.org
> Subject: Re: [PATCH 5/6] can: flexcan: add CAN wakeup function for i.MX8QM
> 
> On 10/16/20 12:00 PM, Joakim Zhang wrote:
> >>>> +static int flexcan_stop_mode_enable_scfw(struct flexcan_priv
> >>>> +*priv, bool enabled) {
> >>>> +	u8 idx = priv->can_idx;
> >>>> +	u32 rsrc_id, val;
> >>>> +
> >>>> +	if (idx == 0)
> >>>> +		rsrc_id = IMX_SC_R_CAN_0;
> >>>> +	else if (idx == 1)
> >>>> +		rsrc_id = IMX_SC_R_CAN_1;
> >>>> +	else
> >>>> +		rsrc_id = IMX_SC_R_CAN_2;
> >>>
> >>> Can you introduce something like and make use of it:
> >>>
> >>> #define IMX_SC_R_CAN(x)			(105 + (x))
> >> OK.
> >
> > I thought it over again, from my point of view, use macro here
> > directly could be more intuitive, and can achieve a direct jump.
> > If change to above wrapper, on the contrary make confusion, and
> > generate the magic number 105. ☹
> 
> The define should go into the rsrc.h, and probably be:
> 
> #define IMX_SC_R_CAN(x)		(IMX_SC_R_CAN_0 + (x))
> 
> and if you change the firmware interface, you probably have more problems :)

rsrc.h:
 /*
  * These defines are used to indicate a resource. Resources include peripherals
  * and bus masters (but not memory regions). Note items from list should
  * never be changed or removed (only added to at the end of the list).
  */
Hmm, it just list all resource id, and never be changed. Anyway, if you think above way is better, I will turn to it.

> >>>> +
> >>>> +	if (enabled)
> >>>> +		val = 1;
> >>>> +	else
> >>>> +		val = 0;
> >>>> +
> >>>> +	/* stop mode request via scu firmware */
> >>>> +	return imx_sc_misc_set_control(priv->sc_ipc_handle, rsrc_id,
> >>>> +IMX_SC_C_IPG_STOP, val); }
> >
> > We still need use IMX_SC_C_IPG_STOP, why not be consistent?
> 
> Sorry I don't get what you want to tell me here.

Need me add IMX_SC_C_IPG_STOP macro in the driver directly?

Such as, #define IMX_SC_C_IPG_STOP 52, so that no need to include rsrc.h file in the driver.

Best Regards,
Joakim Zhang
> Marc
> 
> --
> Pengutronix e.K.                 | Marc Kleine-Budde           |
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