linux-kernel - Re: [PATCH v2 4/6] soc: mediatek: Add SMI driver

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Date:	Thu, 21 May 2015 22:33:13 +0800
From:	Daniel Kurtz <djkurtz@...gle.com>
To:	Matthias Brugger <matthias.bgg@...il.com>
Cc:	Yong Wu <yong.wu@...iatek.com>, Rob Herring <robh+dt@...nel.org>,
	Joerg Roedel <joro@...tes.org>,
	Robin Murphy <robin.murphy@....com>,
	Will Deacon <will.deacon@....com>,
	Tomasz Figa <tfiga@...gle.com>,
	Lucas Stach <l.stach@...gutronix.de>,
	Mark Rutland <mark.rutland@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	linux-mediatek@...ts.infradead.org,
	Sasha Hauer <kernel@...gutronix.de>,
	srv_heupstream <srv_heupstream@...iatek.com>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"open list:IOMMU DRIVERS" <iommu@...ts.linux-foundation.org>,
	Paul Bolle <pebolle@...cali.nl>, Arnd Bergmann <arnd@...db.de>,
	mitchelh@...eaurora.org, k.zhang@...iatek.com,
	youhua.li@...iatek.com
Subject: Re: [PATCH v2 4/6] soc: mediatek: Add SMI driver

On Thu, May 21, 2015 at 3:30 PM, Matthias Brugger
<matthias.bgg@...il.com> wrote:
> 2015-05-21 8:16 GMT+02:00 Yong Wu <yong.wu@...iatek.com>:
>> Hi Matthias,
>>      Thanks very much for your suggestion.
>>      Abort the smi clock name, Could you help check below.
>>      The others I will improve in next time.
>>
>> On Tue, 2015-05-19 at 13:14 +0200, Matthias Brugger wrote:
>>> 2015-05-15 11:43 GMT+02:00 Yong Wu <yong.wu@...iatek.com>:
>>> >     This patch add SMI(Smart Multimedia Interface) driver. This driver is
>>> > responsible to enable/disable iommu and control the clocks of each local arbiter.
>>> >
>> [snip]
>>> > +
>>> > +#define SMI_LARB_MMU_EN                (0xf00)
>>> > +#define F_SMI_MMU_EN(port)     (1 << (port))
>>> > +
>>> > +enum {
>>> > +       MTK_CLK_APB,
>>> > +       MTK_CLK_SMI,
>>> > +       MTK_CLK_MAX,
>>>
>>> Maybe add something like:
>>> MTK_CLK_FIRST = MTK_CLK_APB,
>>> to make the for loops better readable.
>>>
>> Then, Is it like this? :
>>  enum {
>>         MTK_CLK_FIRST = MTK_CLK_APB,
>>         MTK_CLK_SMI,
>>         MTK_CLK_MAX,
>>  }
>> or the CLK_SMI also need MTK_CLK_SECOND = MTK_CLK_SMI.
>
>
> something like:
> enum {
>          MTK_CLK_FIRST,
>          MTK_CLK_APB = MTK_CLK_FIRST,
>          MTK_CLK_SMI,
>          MTK_CLK_LAST,
> }
>
> So you can rewrite the for loop:
> if (i = MTK_CLK_FIRST; i < MTK_CLK_LAST; i++)

Actually, do we ever plan to add more clks per smi node?
If not, perhaps the whole driver would be simpler if you just
explicitly handle the apb & smi clocks:

struct mtk_smi_larb {
       void __iomem            *base;
       spinlock_t              portlock; /* lock for config port */
       struct device           *smi;
       struct clk              *clk_apb;
       struct clk              *clk_smi;
};

And then all of the loops become just a pair of clock operations.

Best Regards,
-Dan

>
> Regards,
> Matthias
>
>>> > +};
>>> > +
>>> > +struct mtk_smi_common {
>>> > +       void __iomem            *base;
>>>
>>> That seems to be never used. Please delete it.
>>>
>>> > +       struct clk              *clk[MTK_CLK_MAX];
>>> > +};
>>> > +
>>> > +struct mtk_smi_larb {
>>> > +       void __iomem            *base;
>>> > +       spinlock_t              portlock; /* lock for config port */
>>> > +       struct clk              *clk[MTK_CLK_MAX];
>>> > +       struct device           *smi;
>>> > +};
>>> > +
>>> Thanks,
>>> Matthias
>>
>>
>
>
>
> --
> motzblog.wordpress.com



-- 
Daniel Kurtz | Software Engineer | djkurtz@...gle.com | 650.204.0722
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