linux-kernel - Re: [PATCH v7 3/7] i2c: mediatek: Dump i2c/dma register when a timeout occurs

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Date:   Sat, 2 Oct 2021 08:37:28 +0200
From:   Wolfram Sang <wsa@...-dreams.de>
To:     Kewei Xu <kewei.xu@...iatek.com>
Cc:     matthias.bgg@...il.com, robh+dt@...nel.org,
        linux-i2c@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        linux-mediatek@...ts.infradead.org, srv_heupstream@...iatek.com,
        leilk.liu@...iatek.com, qii.wang@...iatek.com,
        liguo.zhang@...iatek.com, caiyu.chen@...iatek.com,
        ot_daolong.zhu@...iatek.com, yuhan.wei@...iatek.com
Subject: Re: [PATCH v7 3/7] i2c: mediatek: Dump i2c/dma register when a
 timeout occurs


> @@ -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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