linux-kernel - Re: [PATCH v1 2/3] i2c: mux: gpio: Don't dereference fwnode from struct device

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Message-ID: <d6e2f855-81c0-118f-96f3-f29c2059c8c8@axentia.se>
Date:   Thu, 18 Nov 2021 10:48:17 +0100
From:   Peter Rosin <peda@...ntia.se>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Evan Green <evgreen@...omium.org>, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Peter Korsgaard <peter.korsgaard@...co.com>
Subject: Re: [PATCH v1 2/3] i2c: mux: gpio: Don't dereference fwnode from
 struct device

Hi!

On 2021-11-15 16:42, Andy Shevchenko wrote:
> We have a special helper to get fwnode out of struct device.
> Moreover, dereferencing it directly prevents the fwnode
> modifications in the future.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  drivers/i2c/muxes/i2c-mux-gpio.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/muxes/i2c-mux-gpio.c b/drivers/i2c/muxes/i2c-mux-gpio.c
> index 31e6eb1591bb..b09c10f36ddb 100644
> --- a/drivers/i2c/muxes/i2c-mux-gpio.c
> +++ b/drivers/i2c/muxes/i2c-mux-gpio.c
> @@ -53,6 +53,7 @@ static int i2c_mux_gpio_probe_fw(struct gpiomux *mux,
>  				 struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> +	struct fwnode_handle *fwnode = dev_fwnode(dev);
>  	struct device_node *np = dev->of_node;

It feels like there is opportunity to get rid of np, but I suppose that can be
done later...

Acked-by: Peter Rosin <peda@...ntia.se>

Cheers,
Peter

>  	struct device_node *adapter_np;
>  	struct i2c_adapter *adapter = NULL;
> @@ -60,7 +61,7 @@ static int i2c_mux_gpio_probe_fw(struct gpiomux *mux,
>  	unsigned *values;
>  	int rc, i = 0;
>  
> -	if (is_of_node(dev->fwnode)) {
> +	if (is_of_node(fwnode)) {
>  		if (!np)
>  			return -ENODEV;
>  
> @@ -72,7 +73,7 @@ static int i2c_mux_gpio_probe_fw(struct gpiomux *mux,
>  		adapter = of_find_i2c_adapter_by_node(adapter_np);
>  		of_node_put(adapter_np);
>  
> -	} else if (is_acpi_node(dev->fwnode)) {
> +	} else if (is_acpi_node(fwnode)) {
>  		/*
>  		 * In ACPI land the mux should be a direct child of the i2c
>  		 * bus it muxes.
> @@ -111,7 +112,7 @@ static int i2c_mux_gpio_probe_fw(struct gpiomux *mux,
>  	}
>  	mux->data.values = values;
>  
> -	if (fwnode_property_read_u32(dev->fwnode, "idle-state", &mux->data.idle))
> +	if (device_property_read_u32(dev, "idle-state", &mux->data.idle))
>  		mux->data.idle = I2C_MUX_GPIO_NO_IDLE;
>  
>  	return 0;
>