linux-kernel - Re: [PATCH v1 1/4] bus: hisi_lpc: Don't dereference fwnode handle

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Message-ID: <ee6b33f5-c5c0-658e-8cf9-61031cd27dca@huawei.com>
Date:   Tue, 5 Jul 2022 16:02:19 +0100
From:   John Garry <john.garry@...wei.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 1/4] bus: hisi_lpc: Don't dereference fwnode handle

On 05/07/2022 12:43, Andy Shevchenko wrote:
> Use dev_fwnode() and acpi_fwnode_handle() instead of dereferencing
> an fwnode handle directly.

...which is a better coding practice, right? If so, it would be nice to 
mention it - well at least I think so.

> 
> While at it, reuse fwnode instead of ACPI_COMPANION().

Apart from above and nit, below:
Acked-by: John Garry <john.garry@...wei.com>

> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>   drivers/bus/hisi_lpc.c | 10 ++++------
>   1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
> index 2e564803e786..6d432a07cbba 100644
> --- a/drivers/bus/hisi_lpc.c
> +++ b/drivers/bus/hisi_lpc.c
> @@ -347,7 +347,7 @@ static int hisi_lpc_acpi_xlat_io_res(struct acpi_device *adev,
>   	unsigned long sys_port;
>   	resource_size_t len = resource_size(res);
>   
> -	sys_port = logic_pio_trans_hwaddr(&host->fwnode, res->start, len);
> +	sys_port = logic_pio_trans_hwaddr(acpi_fwnode_handle(host), res->start, len);

nit: currently the driver keeps to the old 80 character line limit. 
While the rules may have been relaxed, I'd rather we still maintain it.

>   	if (sys_port == ~0UL)
>   		return -EFAULT;
>   
> @@ -615,7 +615,6 @@ static void hisi_lpc_acpi_remove(struct device *hostdev)
>   static int hisi_lpc_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
> -	struct acpi_device *acpi_device = ACPI_COMPANION(dev);
>   	struct logic_pio_hwaddr *range;
>   	struct hisi_lpc_dev *lpcdev;
>   	resource_size_t io_end;
> @@ -637,7 +636,7 @@ static int hisi_lpc_probe(struct platform_device *pdev)
>   	if (!range)
>   		return -ENOMEM;
>   
> -	range->fwnode = dev->fwnode;
> +	range->fwnode = dev_fwnode(dev);
>   	range->flags = LOGIC_PIO_INDIRECT;
>   	range->size = PIO_INDIRECT_SIZE;
>   	range->hostdata = lpcdev;
> @@ -651,7 +650,7 @@ static int hisi_lpc_probe(struct platform_device *pdev)
>   	}
>   
>   	/* register the LPC host PIO resources */
> -	if (acpi_device)
> +	if (is_acpi_device_node(range->fwnode))
>   		ret = hisi_lpc_acpi_probe(dev);
>   	else
>   		ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
> @@ -672,11 +671,10 @@ static int hisi_lpc_probe(struct platform_device *pdev)
>   static int hisi_lpc_remove(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
> -	struct acpi_device *acpi_device = ACPI_COMPANION(dev);
>   	struct hisi_lpc_dev *lpcdev = dev_get_drvdata(dev);
>   	struct logic_pio_hwaddr *range = lpcdev->io_host;
>   
> -	if (acpi_device)
> +	if (is_acpi_device_node(range->fwnode))
>   		hisi_lpc_acpi_remove(dev);
>   	else
>   		of_platform_depopulate(dev);