linux-kernel - Re: [PATCH v3 04/11] coresight-tpdm: Add reset node to TPDM node

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Date:   Mon, 27 Mar 2023 14:59:39 +0800
From:   Tao Zhang <quic_taozha@...cinc.com>
To:     Suzuki K Poulose <suzuki.poulose@....com>,
        Mathieu Poirier <mathieu.poirier@...aro.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Konrad Dybcio <konradybcio@...il.com>,
        Mike Leach <mike.leach@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
CC:     Jinlong Mao <quic_jinlmao@...cinc.com>,
        Leo Yan <leo.yan@...aro.org>,
        "Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
        <coresight@...ts.linaro.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        Tingwei Zhang <quic_tingweiz@...cinc.com>,
        Yuanfang Zhang <quic_yuanfang@...cinc.com>,
        Trilok Soni <quic_tsoni@...cinc.com>,
        Hao Zhang <quic_hazha@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>,
        Bjorn Andersson <andersson@...nel.org>
Subject: Re: [PATCH v3 04/11] coresight-tpdm: Add reset node to TPDM node

Hi Suzuki,

On 3/23/2023 10:41 PM, Suzuki K Poulose wrote:
> On 23/03/2023 06:04, Tao Zhang wrote:
>> TPDM device need a node to reset the configurations and status of
>> it. This change provides a node to reset the configurations and
>> disable the TPDM if it has been enabled.
>>
>> Signed-off-by: Tao Zhang <quic_taozha@...cinc.com>
>> ---
>>   drivers/hwtracing/coresight/coresight-tpdm.c | 28 
>> ++++++++++++++++++++++++++++
>>   1 file changed, 28 insertions(+)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-tpdm.c 
>> b/drivers/hwtracing/coresight/coresight-tpdm.c
>> index 5e1e2ba..104638d 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpdm.c
>> +++ b/drivers/hwtracing/coresight/coresight-tpdm.c
>> @@ -161,6 +161,33 @@ static void tpdm_datasets_setup(struct 
>> tpdm_drvdata *drvdata)
>>       drvdata->datasets |= pidr & GENMASK(TPDM_DATASETS - 1, 0);
>>   }
>>   +static ssize_t reset_store(struct device *dev,
>> +                      struct device_attribute *attr,
>> +                      const char *buf,
>> +                      size_t size)
>> +{
>> +    int ret = 0;
>> +    unsigned long val;
>> +    struct tpdm_drvdata *drvdata = dev_get_drvdata(dev->parent);
>> +
>> +    ret = kstrtoul(buf, 10, &val);
>> +    if (ret || val != 1)
>> +        return -EINVAL;
>> +
>> +    spin_lock(&drvdata->spinlock);
>> +    /* Reset all datasets to ZERO, and init the default data*/
>> +    tpdm_init_datasets(drvdata);
>
> With the suggested rename in the previous patch, you wouldn't need
> a comment here.
I will update this in the next patch series.
>
>> +
>> +    spin_unlock(&drvdata->spinlock);
>> +
>
>
>> +    /* Disable tpdm if enabled */
>> +    if (drvdata->enable)
>> +        coresight_disable(drvdata->csdev);
>
> Couldn't this be done via disable_source ? Please don't overload
> the sysfs handle.
I will update this in the next patch series.
>
>> +
>> +    return size;
>> +}
>> +static DEVICE_ATTR_WO(reset);
>
> Documentation for the sysfs node please ?
I will update this in the next patch series.
>
> Suzuki
>