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From: Kewei Xu <kewei.xu@mediatek.com>
To: Tzung-Bi Shih <tzungbi@google.com>
Cc: <wsa@the-dreams.de>, <matthias.bgg@gmail.com>,
	<robh+dt@kernel.org>, <linux-i2c@vger.kernel.org>,
	<devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	<linux-mediatek@lists.infradead.org>,
	<srv_heupstream@mediatek.com>, <leilk.liu@mediatek.com>,
	<qii.wang@mediatek.com>, <qiangming.xia@mediatek.com>,
	<ot_daolong.zhu@mediatek.com>
Subject: Re: [PATCH 8/8] i2c: mediatek: modify bus speed calculation formula
Date: Fri, 16 Jul 2021 17:53:57 +0800	[thread overview]
Message-ID: <1626429237.29703.16.camel@mhfsdcap03> (raw)
In-Reply-To: <CA+Px+wWNcSkxvsEoUrgBN73+jhq8qjFJodYjQnY1zW2d0a5yRA@mail.gmail.com>

On Thu, 2021-07-15 at 15:09 +0800, Tzung-Bi Shih wrote:
> On Thu, Jul 15, 2021 at 10:32 AM Kewei Xu <kewei.xu@mediatek.com> wrote:
> > When clock-div is 0 or greater than 1, the bus speed
> > calculated by the old speed calculation formula will be
> > larger than the target speed. So we update the formula.
> The patch sounds like a fix up.  Need a "Fixes" tag.
> 
> >         for (clk_div = 1; clk_div <= max_clk_div; clk_div++) {
> >                 clk_src = parent_clk / clk_div;
> > +               i2c->ac_timing.inter_clk_div = clk_div - 1;
> Using the way to pass the parameter "inter_clk_div" to
> mtk_i2c_calculate_speed() looks like a hack.  inter_clk_div is set
> again[1] next to the for loop.
> 
> [1]: https://elixir.bootlin.com/linux/v5.14-rc1/source/drivers/i2c/busses/i2c-mt65xx.c#L831
> 
> 
> 
> I have no domain knowledge of what/how the patch fixes.  But if this
> is a standalone fixup patch, suggest separating to an independent
> patch.

Hi Tzung-Bi,

1. This Patch is not for fixing previous commit,it is just for the bad
speed formula.

2. I will fix this problem according to your suggestion in the next
patch.

Thanks
Kewei

  reply	other threads:[~2021-07-16  9:54 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-15  2:29 [PATCH 0/8] Due to changes in hardware design, add patch to Kewei Xu
2021-07-15  2:29 ` [PATCH 1/8] dt-bindings: i2c: update bindings for MT8195 SoC Kewei Xu
2021-07-15  4:09   ` Chen-Yu Tsai
2021-07-15  2:29 ` [PATCH 2/8] i2c: mediatek: Dump i2c/dma register when a timeout occurs Kewei Xu
2021-07-15  6:21   ` Chen-Yu Tsai
2021-07-15  2:29 ` [PATCH 3/8] i2c: mediatek: fixing the incorrect register offset Kewei Xu
2021-07-15  5:23   ` Chen-Yu Tsai
2021-07-16  9:09     ` Kewei Xu
2021-07-15  2:29 ` [PATCH 4/8] i2c: mediatek: Reset the handshake signal between i2c and dma Kewei Xu
2021-07-15  2:29 ` [PATCH 5/8] i2c: mediatek: Add OFFSET_EXT_CONF setting back Kewei Xu
2021-07-15  2:29 ` [PATCH 6/8] dt-bindings: i2c: add attribute default-timing-adjust Kewei Xu
2021-07-15  2:29 ` [PATCH 7/8] i2c: mediatek: Isolate speed setting via dts for special devices Kewei Xu
2021-07-15  2:29 ` [PATCH 8/8] i2c: mediatek: modify bus speed calculation formula Kewei Xu
2021-07-15  7:09   ` Tzung-Bi Shih
2021-07-16  9:53     ` Kewei Xu [this message]
2021-07-15  3:03 ` [PATCH 0/8] Due to changes in hardware design, add patch to Chen-Yu Tsai
2021-07-17  9:05   ` Kewei Xu

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