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From: Wolfram Sang <wsa@kernel.org>
To: Zhou Yanjie <zhouyanjie@wanyeetech.com>
Cc: paul@crapouillou.net, stable@vger.kernel.org,
	linux-mips@vger.kernel.org, linux-i2c@vger.kernel.org,
	linux-kernel@vger.kernel.org, dongsheng.qiu@ingenic.com,
	aric.pzqi@ingenic.com, sernia.zhou@foxmail.com
Subject: Re: [PATCH] I2C: JZ4780: Fix bug for Ingenic X1000.
Date: Wed, 31 Mar 2021 09:18:35 +0200	[thread overview]
Message-ID: <20210331071835.GB1025@ninjato> (raw)
In-Reply-To: <644d19d8-9444-4dde-a891-c9dfd523389e@wanyeetech.com>

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Hi, 

> > Any write operation? I wonder then why nobody noticed before?
> 
> 
> The standard I2C communication should look like this:
> 
> Read:
> 
> device_addr + w, reg_addr, device_addr + r, data;
> 
> Write:
> 
> device_addr + w, reg_addr, data;
> 
> 
> But without this patch, it looks like this:
> 
> Read:
> 
> device_addr + w, reg_addr, device_addr + r, data;
> 
> Write:
> 
> device_addr + w, reg_addr, device_addr + w, data;
> 
> This is clearly not correct.

Thanks for the additional information! I understand now. I added a bit
of this to the commit message of v2 to explain the situation.


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  reply	other threads:[~2021-03-31  7:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-18 16:25 Fix bug for Ingenic X1000 周琰杰 (Zhou Yanjie)
2021-03-18 16:25 ` [PATCH] I2C: JZ4780: " 周琰杰 (Zhou Yanjie)
2021-03-18 17:01   ` Greg KH
2021-03-18 17:06   ` Wolfram Sang
2021-03-19  6:58     ` Zhou Yanjie
2021-03-31  7:18       ` Wolfram Sang [this message]
2021-04-02 15:30         ` Zhou Yanjie

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