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Date:   Sat, 2 Oct 2021 08:37:28 +0200
From:   Wolfram Sang <wsa@the-dreams.de>
To:     Kewei Xu <kewei.xu@mediatek.com>
Cc:     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,
        liguo.zhang@mediatek.com, caiyu.chen@mediatek.com,
        ot_daolong.zhu@mediatek.com, yuhan.wei@mediatek.com
Subject: Re: [PATCH v7 3/7] i2c: mediatek: Dump i2c/dma register when a
 timeout occurs
Message-ID: <YVf+KCztQI9XrdEq@kunai>
Mail-Followup-To: Wolfram Sang <wsa@the-dreams.de>,
        Kewei Xu <kewei.xu@mediatek.com>, matthias.bgg@gmail.com,
        robh+dt@kernel.org, linux-i2c@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
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        caiyu.chen@mediatek.com, ot_daolong.zhu@mediatek.com,
        yuhan.wei@mediatek.com
References: <20210917101416.20760-1-kewei.xu@mediatek.com>
 <20210917101416.20760-4-kewei.xu@mediatek.com>
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> @@ -837,6 +839,57 @@ static int mtk_i2c_set_speed(struct mtk_i2c *i2c, unsigned int parent_clk)
>  	return 0;
>  }

> +static void i2c_dump_register(struct mtk_i2c *i2c)
> +{
> +	dev_err(i2c->dev, "SLAVE_ADDR: 0x%x, INTR_MASK: 0x%x\n",
> +		mtk_i2c_readw(i2c, OFFSET_SLAVE_ADDR),
> +		mtk_i2c_readw(i2c, OFFSET_INTR_MASK));

I think this is too verbose and should be a debugging only patch not
really suited for upstream. But if you like it this way, then keep
the verbosity. However, dev_err is too strong, this really needs to be
dev_dbg. Timeouts can happen on an I2C bus, think about an EEPROM in a
long erase cycle while you want to read it. Perfectly normal.


>  	if (ret == 0) {
> -		dev_dbg(i2c->dev, "addr: %x, transfer timeout\n", msgs->addr);
> +		dev_err(i2c->dev, "addr: %x, transfer timeout\n", msgs->addr);
> +		i2c_dump_register(i2c);

Needs to stay dev_dbg as well.


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