Re: [PATCH v3 4/6] watchdog: w83627hf_wdt: Store Super I/O configurations in platform data

[Tzung-Bi Shih <tzungbi@kernel.org>]

On Sun, Oct 04, 2026 at 02:12:52PM +0200, Paul Louvel wrote:
>  static int wdt_probe(struct platform_device *pdev)
>  {
>  	const struct platform_device_id *id = platform_get_device_id(pdev);
> +	const struct wdt_pdata *pdata = pdev->dev.platform_data;

Use dev_get_platdata().

> @@ -522,12 +533,16 @@ static int wdt_probe(struct platform_device *pdev)
>   */
>  static int __init wdt_use_alt_key(const struct dmi_system_id *d)
>  {
> -	wdt_cfg_enter = 0x88;
> -	wdt_cfg_leave = 0xBB;
> +	struct wdt_pdata *pdata = d->driver_data;
> +
> +	pdata->siocfg_enter = 0x88;
> +	pdata->siocfg_leave = 0xBB;
>  
>  	return 0;
>  }
>  
> +static struct wdt_pdata pdata;
> +
>  static const struct dmi_system_id wdt_dmi_table[] __initconst = {
>  	{
>  		.matches = {
> @@ -537,6 +552,7 @@ static const struct dmi_system_id wdt_dmi_table[] __initconst = {
>  			DMI_EXACT_MATCH(DMI_BOARD_NAME, "SHARKBAY"),
>  		},
>  		.callback = wdt_use_alt_key,
> +		.driver_data = &pdata,
>  	},
>  	{}
>  };
> @@ -581,27 +597,33 @@ static struct platform_device *wdt_pdev;
>  
>  static int __init wdt_init(void)
>  {
> +	int sioaddr;
>  	int ret;
>  	int chip;
>  
> +	pdata.siocfg_enter = 0x87;
> +	pdata.siocfg_leave = 0xAA;
> +
>  	/* Apply system-specific quirks */
>  	dmi_check_system(wdt_dmi_table);
>  
> -	wdt_io = SIO_REG_CONF_ADDR0;
> -	chip = wdt_find(SIO_REG_CONF_ADDR0);
> +	sioaddr = SIO_REG_CONF_ADDR0;
> +	chip = wdt_find(sioaddr, pdata.siocfg_enter, pdata.siocfg_leave);
>  	if (chip < 0) {
> -		wdt_io = SIO_REG_CONF_ADDR1;
> -		chip = wdt_find(SIO_REG_CONF_ADDR1);
> +		sioaddr = SIO_REG_CONF_ADDR1;
> +		chip = wdt_find(sioaddr, pdata.siocfg_enter, pdata.siocfg_leave);
>  		if (chip < 0)
>  			return chip;
>  	}
>  
> +	pdata.sioaddr = sioaddr;
> +

`pdata` is still global.  Given that there are only a few settings, maybe
we can use the same method I proposed in [3/6] patch, and use
`dmi_first_match()` to avoid the global variable.  E.g.:

    struct w83627hf_sio_pdata {
        u16 sioaddr;
        u8 siocfg_enter;
        u8 siocfg_leave;
    };

    static const struct w83627hf_sio_pdata default_pdata = {
        .siocfg_enter = 0x87,
        .siocfg_leave = 0xaa,
    };

    static const struct w83627hf_sio_pdata alt_pdata = {
        .siocfg_enter = 0x88,
        .siocfg_leave = 0xbb,
    };

    static const struct dmi_system_id wdt_dmi_table[] __initconst = {
        {
            .matches = {
                DMI_EXACT_MATCH(DMI_SYS_VENDOR, "INVENTEC"),
                DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "Symphony"),
                DMI_EXACT_MATCH(DMI_BOARD_NAME, "SHARKBAY"),
            },
            .driver_data = (void *)&alt_pdata,
        },
        {}
    };

Then, in `wdt_init()`, it can define a local `pdata` and initialize it
based on the DMI match:

    const struct dmi_system_id *match;
    struct w83627hf_sio_pdata pdata;

    match = dmi_first_match(wdt_dmi_table);
    if (match)
        pdata = *(const struct w83627hf_sio_pdata *)match->driver_data;
    else
        pdata = default_pdata;

    pdata.sioaddr = SIO_REG_CONF_ADDR0;
    chip = wdt_find(pdata.sioaddr, pdata.siocfg_enter, pdata.siocfg_leave);