linux-kernel - Re: [PATCH 2/2] soc: bcm: iproc: Add Broadcom iProc IDM driver

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Date:   Thu, 5 Dec 2019 16:22:35 -0800
From:   Florian Fainelli <f.fainelli@...il.com>
To:     Ray Jui <ray.jui@...adcom.com>, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
Cc:     devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org,
        bcm-kernel-feedback-list@...adcom.com,
        Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
Subject: Re: [PATCH 2/2] soc: bcm: iproc: Add Broadcom iProc IDM driver

On 12/2/19 3:31 PM, Ray Jui wrote:
> Add Broadcom iProc IDM driver that controls that IDM devices available
> on various iProc based SoCs for bus transaction timeout monitoring and
> error logging.
> 
> Signed-off-by: Ray Jui <ray.jui@...adcom.com>
> Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@...adcom.com>
> ---

Looks good to me, just a few suggestions below

[snip]

> --- /dev/null
> +++ b/drivers/soc/bcm/iproc/Kconfig
> @@ -0,0 +1,6 @@

You would want an

if SOC_BRCM_IPROC

> +config IPROC_IDM
> +	bool "Broadcom iProc IDM driver"
> +	depends on (ARCH_BCM_IPROC || COMPILE_TEST) && OF
> +	default ARCH_BCM_IPROC
> +	help
> +	  Enables support for iProc Interconnect and Device Management (IDM) control and monitoring

and endif here to make this a nice menu.

[snip]

> +
> +static int iproc_idm_dev_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct platform_device *elog_pdev;
> +	struct device_node *elog_np;
> +	struct iproc_idm *idm;
> +	const char *name;
> +	int ret;
> +	u32 val;
> +
> +	idm = devm_kzalloc(dev, sizeof(*idm), GFP_KERNEL);
> +	if (!idm)
> +		return -ENOMEM;
> +
> +	ret = of_property_read_string(np, "brcm,iproc-idm-bus", &name);
> +	if (ret) {
> +		dev_err(dev, "Unable to parse IDM bus name\n");
> +		return ret;
> +	}
> +	idm->name = name;
> +
> +	platform_set_drvdata(pdev, idm);
> +	idm->dev = dev;
> +
> +	idm->base = of_iomap(np, 0);
> +	if (!idm->base) {
> +		dev_err(dev, "Unable to map I/O\n");
> +		ret = -ENOMEM;
> +		goto err_exit;
> +	}
> +
> +	ret = of_irq_get(np, 0);
> +	if (ret <= 0) {
> +		dev_err(dev, "Unable to find IRQ number. ret=%d\n", ret);
> +		goto err_iounmap;
> +	}

Since this is a standard platform device, you can use the standard
platform_get_resource() and platform_get_irq(). If you ever needed to
support ACPI in the future, that would make it transparent and almost
already ready.

> +
> +	ret = devm_request_irq(dev, ret, iproc_idm_irq_handler, IRQF_SHARED,
> +			       idm->name, idm);
> +	if (ret < 0) {
> +		dev_err(dev, "Unable to request irq. ret=%d\n", ret);
> +		goto err_iounmap;
> +	}
> +
> +	/*
> +	 * ELOG phandle is optional. If ELOG phandle is specified, it indicates
> +	 * ELOG logging needs to be enabled
> +	 */
> +	elog_np = of_parse_phandle(dev->of_node, ELOG_IDM_COMPAT_STR, 0);
> +	if (elog_np) {
> +		elog_pdev = of_find_device_by_node(elog_np);
> +		if (!elog_pdev) {
> +			dev_err(dev, "Unable to find IDM ELOG device\n");
> +			ret = -ENODEV;
> +			goto err_iounmap;
> +		}
> +
> +		idm->elog = platform_get_drvdata(elog_pdev);
> +		if (!idm->elog) {
> +			dev_err(dev, "Unable to get IDM ELOG driver data\n");
> +			ret = -EINVAL;
> +			goto err_iounmap;
> +		}
> +	}
> +
> +	/* enable IDM timeout and its interrupt */
> +	val = readl(idm->base + IDM_CTRL_OFFSET);
> +	val |= IDM_CTRL_TIMEOUT_EXP_MASK | IDM_CTRL_TIMEOUT_ENABLE |
> +	       IDM_CTRL_TIMEOUT_IRQ;
> +	writel(val, idm->base + IDM_CTRL_OFFSET);
> +
> +	ret = device_create_file(dev, &dev_attr_no_panic);
> +	if (ret < 0)
> +		goto err_iounmap;
> +
> +	of_node_put(np);

Did not you intend to drop the reference count on elog_np here?

[snip]

> +static struct platform_driver iproc_idm_driver = {
> +	.probe = iproc_idm_probe,

Do not you need a remove function in order to unregister the sysfs file
that you created in iproc_idm_dev_probe() to avoid bind/unbind (or
rmmod/modprobe) to spit out an existing sysfs entry warning?
-- 
Florian