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Subject: Re: [PATCH] net: dsa: b53: mmap: Add device tree support
To:     =?UTF-8?Q?=c3=81lvaro_Fern=c3=a1ndez_Rojas?= <noltari@gmail.com>,
        jonas.gorski@gmail.com, Andrew Lunn <andrew@lunn.ch>,
        Vivien Didelot <vivien.didelot@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20210308180715.18571-1-noltari@gmail.com>
From:   Florian Fainelli <f.fainelli@gmail.com>
Message-ID: <06dab800-d554-e807-8a72-427c6e99e4de@gmail.com>
Date:   Mon, 8 Mar 2021 10:29:52 -0800
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On 3/8/21 10:07 AM, Álvaro Fernández Rojas wrote:
> Add device tree support to b53_mmap.c while keeping platform devices support.
> 
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> ---
>  drivers/net/dsa/b53/b53_mmap.c | 36 ++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/drivers/net/dsa/b53/b53_mmap.c b/drivers/net/dsa/b53/b53_mmap.c
> index c628d0980c0b..b897b4263930 100644
> --- a/drivers/net/dsa/b53/b53_mmap.c
> +++ b/drivers/net/dsa/b53/b53_mmap.c
> @@ -228,12 +228,48 @@ static const struct b53_io_ops b53_mmap_ops = {
>  	.write64 = b53_mmap_write64,
>  };
>  
> +static int b53_mmap_probe_of(struct platform_device *pdev,
> +			     struct b53_platform_data **ppdata)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct b53_platform_data *pdata;
> +	void __iomem *mem;
> +
> +	mem = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(mem))
> +		return PTR_ERR(mem);
> +
> +	pdata = devm_kzalloc(dev, sizeof(struct b53_platform_data),
> +			     GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;
> +
> +	pdata->regs = mem;
> +	pdata->chip_id = BCM63XX_DEVICE_ID;
> +	pdata->big_endian = of_property_read_bool(np, "big-endian");
> +	of_property_read_u16(np, "brcm,ports", &pdata->enabled_ports);
> +
> +	*ppdata = pdata;
> +
> +	return 0;
> +}
> +
>  static int b53_mmap_probe(struct platform_device *pdev)
>  {
> +	struct device_node *np = pdev->dev.of_node;
>  	struct b53_platform_data *pdata = pdev->dev.platform_data;
>  	struct b53_mmap_priv *priv;
>  	struct b53_device *dev;
>  
> +	if (np) {
> +		int ret = b53_mmap_probe_of(pdev, &pdata);
> +		if (ret) {
> +			dev_err(&pdev->dev, "OF probe error\n");
> +			return ret;
> +		}
> +	}

I would be keen on making this less "OF-centric" and just have it happen
whenever pdata is NULL such that we have an easier transition path if we
wanted to migrate bcm63xx to passing down the switch base register
address a platform_device source in the future (not that I expect it to
happen though).

Other than that, the logic looks sound.
-- 
Florian