linux-kernel - Re: [PATCH v2 3/3] i2c: mv64xxx: add support for FSM based recovery

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Message-ID: <d8074039-27b0-40b7-9e67-10c459e2a5d6@alliedtelesis.co.nz>
Date:   Thu, 12 Oct 2023 20:25:18 +0000
From:   Chris Packham <Chris.Packham@...iedtelesis.co.nz>
To:     Andi Shyti <andi.shyti@...nel.org>
CC:     "gregory.clement@...tlin.com" <gregory.clement@...tlin.com>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "conor+dt@...nel.org" <conor+dt@...nel.org>,
        "pierre.gondois@....com" <pierre.gondois@....com>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/3] i2c: mv64xxx: add support for FSM based recovery


On 13/10/23 09:15, Andi Shyti wrote:
> Hi Chris,
>
> ...
>
>> +static int
>> +mv64xxx_i2c_recover_bus(struct i2c_adapter *adap)
>> +{
>> +	struct mv64xxx_i2c_data *drv_data = i2c_get_adapdata(adap);
>> +	int ret;
>> +	u32 val;
>> +
>> +	dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
>> +	writel(MV64XXX_I2C_UNSTUCK_TRIGGER, drv_data->unstuck_reg);
>> +	ret = readl_poll_timeout_atomic(drv_data->unstuck_reg, val,
>> +					!(val & MV64XXX_I2C_UNSTUCK_INPROGRESS),
>> +					10, 1000);
> mmmhhh... still a bit skeptical about waiting 100 times 10us in
> atomic.
>
> I'm still of the opinion that this should run in a separate
> thread. Any different opinion from the network?
>
> BTW, first question, considering that you decreased the time
> considerably... does it work?
Yes it still works. It did stop working with a really low timeout (10, 
100) but I didn't look hard for anything in-between.
>
> Andi