linux-kernel - Re: [PATCH v2 3/4] Coresight: Add Coresight Control Unit driver

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Message-ID: <9b502ba5-7042-424e-b0a2-5659e4064462@linaro.org>
Date: Fri, 5 Jul 2024 11:11:19 +0200
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Jie Gan <quic_jiegan@...cinc.com>,
 Mathieu Poirier <mathieu.poirier@...aro.org>,
 Suzuki K Poulose <suzuki.poulose@....com>,
 Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
 Mike Leach <mike.leach@...aro.org>, Rob Herring <robh+dt@...nel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
 James Clark <james.clark@....com>
Cc: Jinlong Mao <quic_jinlmao@...cinc.com>, Leo Yan <leo.yan@...aro.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>,
 Tao Zhang <quic_taozha@...cinc.com>, Trilok Soni <quic_tsoni@...cinc.com>,
 Song Chai <quic_songchai@...cinc.com>, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v2 3/4] Coresight: Add Coresight Control Unit driver

On 05/07/2024 11:00, Jie Gan wrote:
> The Coresight Control Unit hosts miscellaneous configuration registers
> which control various features related to TMC ETR sink.
> 
> Based on the trace ID, which is programmed in the related CCU ATID register
> of a specific ETR, trace data with that trace ID gets into the ETR buffer,

....

> +static int ccu_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct coresight_platform_data *pdata;
> +	struct ccu_drvdata *drvdata;
> +	struct coresight_desc desc = { 0 };
> +	struct resource *res;
> +
> +	desc.name = coresight_alloc_device_name(&ccu_devs, dev);
> +	if (!desc.name)
> +		return -ENOMEM;
> +	pdata = coresight_get_platform_data(dev);
> +	if (IS_ERR(pdata))
> +		return PTR_ERR(pdata);
> +	pdev->dev.platform_data = pdata;
> +
> +	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> +	if (!drvdata)
> +		return -ENOMEM;
> +	drvdata->dev = &pdev->dev;

Use stored dev variable.

> +	drvdata->atid_offset = 0;
> +	platform_set_drvdata(pdev, drvdata);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ccu-base");
> +	if (!res)
> +		return -ENODEV;
> +	drvdata->pbase = res->start;

Drop.

> +
> +	drvdata->base = devm_ioremap(dev, res->start, resource_size(res));

Use proper wrapper for this two.

> +	if (!drvdata->base)
> +		return -ENOMEM;
> +
> +	desc.type = CORESIGHT_DEV_TYPE_HELPER;
> +	desc.pdata = pdev->dev.platform_data;
> +	desc.dev = &pdev->dev;
> +	desc.ops = &ccu_ops;
> +
> +	drvdata->csdev = coresight_register(&desc);
> +	if (IS_ERR(drvdata->csdev))
> +		return PTR_ERR(drvdata->csdev);
> +
> +	dev_dbg(dev, "CCU initialized: %s\n", desc.name);

Drop.

> +	return 0;
> +}
> +
> +static void ccu_remove(struct platform_device *pdev)
> +{
> +	struct ccu_drvdata *drvdata = platform_get_drvdata(pdev);
> +
> +	coresight_unregister(drvdata->csdev);
> +}
> +
> +static const struct of_device_id ccu_match[] = {
> +	{.compatible = "qcom,coresight-ccu"},
> +	{}
> +};
> +
> +static struct platform_driver ccu_driver = {
> +	.probe          = ccu_probe,
> +	.remove         = ccu_remove,
> +	.driver         = {
> +		.name   = "coresight-ccu",
> +		.of_match_table = ccu_match,
> +		.suppress_bind_attrs = true,

Why?

> +	},
> +};
> +
> +static int __init ccu_init(void)
> +{
> +	return platform_driver_register(&ccu_driver);
> +}
> +module_init(ccu_init);
> +
> +static void __exit ccu_exit(void)
> +{
> +	platform_driver_unregister(&ccu_driver);
> +}
> +module_exit(ccu_exit);

Why this is not just module platform driver?

Best regards,
Krzysztof