netdev - Re: [PATCH 1/3] can: m_can: add Bosch M

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Date:	Mon, 30 Jun 2014 16:26:38 +0800
From:	Dong Aisheng <b29396@...escale.com>
To:	Oliver Hartkopp <socketcan@...tkopp.net>
CC:	<linux-can@...r.kernel.org>, <netdev@...r.kernel.org>,
	<wg@...ndegger.com>, <mkl@...gutronix.de>,
	<devicetree@...r.kernel.org>
Subject: Re: [PATCH 1/3] can: m_can: add Bosch M_CAN controller support

On Fri, Jun 27, 2014 at 08:03:20PM +0200, Oliver Hartkopp wrote:
> Hello Dong,
> 
> some general remarks from my side ...
> 
> On 27.06.2014 12:00, Dong Aisheng wrote:
> >
> > M_CAN also supports CANFD protocol features like data payload up to 64 bytes
> > and bitrate switch at runtime, however, this patch still does not add the
> > support for these features.
> 
> What is the reason for not supporting CAN FD?
> The infrastructure is ready for it since Linux 3.15.
> 
> http://www.can-newsletter.org/engineering/standardization/140513_can-fd-linux-tools-and-driver-infrastructure_peak_vw/
> 
> For details see my commits for Linux 3.15.
> 

Thanks for the information.
Of course i will add CAN FD support.
Mainly because the driver is just newly written these days, CAN FD feature
is still under development. :-)

> > +  The left cell are all the number of each elements inside the message ram.
> > +  Please refer to 2.4.1 Message RAM Con.guration in Bosch M_CAN user mannual
>                                          ^^^
> typo.
> 

Got it, thanks.

> > +  for each elements definition.
> > +
> > +Example:
> > +canfd1: canfd@...e8000 {
>    ^^^^^^  ^^^^^
> 
> There's no reason to name this canfd. The fact that the controller supports
> CAN FD is provided by priv->ctrlmode_supported and the CAN_CTRLMODE_FD bit.
> 

Just because mx6sx spec calling it CANFD at many places.
e.g.
Interrupts:
146 CANFD1 CANFD1 interrupt request
147 CANFD2 CANFD2 interrupt request
Memory Map:
020F_0000 020F_3FFF CANFD2 16 KB
020E_8000 020E_BFFF CANFD1 16 KB
So i used canfd firstly.
CCM:
CANFD
ips_clk can_clk_root CCGR1[CG15] (canfd_clk_enable)
m_can_0_cclk can_clk_root CCGR1[CG15] (canfd_clk_enable)
m_can_0_ips_clk can_clk_root CCGR1[CG15] (canfd_clk_enable)

> Just write
> 
> can1: can@...e8000 {
> 

I'm ok with this style.
Maybe the following is better:
m_can1: can@...e8000 {

> > +	compatible = "bosch,m_can";
> > +	reg = <0x020e8000 0x4000>, <0x02298000 0x4000>;
> > +	reg-names = "canfd", "message_ram";
>                      ^^^^^
> dito.
> 
How about m_can?
Since it's IP driver, not depends on how SoC naming it.

> > +	interrupts = <0 114 0x04>;
> > +	clocks = <&clks IMX6SX_CLK_CANFD>;
>                                    ^^^^^
> dito.
> 

Not for this one, because imx6sx spec calling it CANFD in Clock
chaptor.
We want to align with our spec since it's arch code.

> > --- a/drivers/net/can/Kconfig
> > +++ b/drivers/net/can/Kconfig
> > @@ -137,6 +137,11 @@ config CAN_XILINXCAN
> >  	  Xilinx CAN driver. This driver supports both soft AXI CAN IP and
> >  	  Zynq CANPS IP.
> >  
> > +config CAN_M_CAN
> > +	tristate "Bosch M_CAN devices"
> > +	---help---
> > +	  Say Y here if you want to support for Bosch M_CAN controller.
> > +
> 
> source "drivers/net/can/m_can/Kconfig"
> 
> >  source "drivers/net/can/mscan/Kconfig"
> >  
> >  source "drivers/net/can/sja1000/Kconfig"
> > diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
> > index 1697f22..69dee2c 100644
> > --- a/drivers/net/can/Makefile
> > +++ b/drivers/net/can/Makefile
> > @@ -17,6 +17,7 @@ obj-y				+= softing/
> >  obj-$(CONFIG_CAN_SJA1000)	+= sja1000/
> >  obj-$(CONFIG_CAN_MSCAN)		+= mscan/
> >  obj-$(CONFIG_CAN_C_CAN)		+= c_can/
> > +obj-$(CONFIG_CAN_M_CAN)		+= m_can.o
> 
> Please create a new m_can directory and a Kconfig in this directory analogue
> to the c_can IP core approach.
> 

Got it, thanks.

> >  obj-$(CONFIG_CAN_CC770)		+= cc770/
> >  obj-$(CONFIG_CAN_AT91)		+= at91_can.o
> >  obj-$(CONFIG_CAN_TI_HECC)	+= ti_hecc.o
> 
> Thanks for your contribution,
> Oliver
> 

Thanks for the review.

Regards
Dong Aisheng
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