linux-kernel - Re: [PATCH v3 4/4] watchdog: mt7621-wdt: avoid ralink architecture dependent code

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Message-ID: <20230210184701.GE3670524@roeck-us.net>
Date:   Fri, 10 Feb 2023 10:47:01 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Sergio Paracuellos <sergio.paracuellos@...il.com>
Cc:     linux-watchdog@...r.kernel.org, wim@...ux-watchdog.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        matthias.bgg@...il.com, arinc.unal@...nc9.com,
        tsbogend@...ha.franken.de, p.zabel@...gutronix.de,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-mips@...r.kernel.org
Subject: Re: [PATCH v3 4/4] watchdog: mt7621-wdt: avoid ralink architecture
 dependent code

On Fri, Feb 10, 2023 at 06:38:41PM +0100, Sergio Paracuellos wrote:
> MT7621 SoC has a system controller node. Watchdog need to access to reset
> status register. Ralink architecture and related driver are old and from
> the beggining they are using some architecture dependent operations for
> accessing this shared registers through 'asm/mach-ralink/ralink_regs.h'
> header file. However this is not ideal from a driver perspective which can
> just access to the system controller registers in an arch independent way
> using regmap syscon APIs. Update Kconfig accordingly to select new added
> dependencies and allow driver to be compile tested.
> 
> Signed-off-by: Sergio Paracuellos <sergio.paracuellos@...il.com>

Reviewed-by: Guenter Roeck <linux@...ck-us.net>

> ---
>  drivers/watchdog/Kconfig      |  2 ++
>  drivers/watchdog/mt7621_wdt.c | 19 ++++++++++++++-----
>  2 files changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index b64bc49c7..0759de670 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -1865,6 +1865,8 @@ config GXP_WATCHDOG
>  config MT7621_WDT
>  	tristate "Mediatek SoC watchdog"
>  	select WATCHDOG_CORE
> +	select REGMAP_MMIO
> +	select MFD_SYSCON
>  	depends on SOC_MT7620 || SOC_MT7621
>  	help
>  	  Hardware driver for the Mediatek/Ralink MT7621/8 SoC Watchdog Timer.
> diff --git a/drivers/watchdog/mt7621_wdt.c b/drivers/watchdog/mt7621_wdt.c
> index 40fb2c9ba..9ed07c187 100644
> --- a/drivers/watchdog/mt7621_wdt.c
> +++ b/drivers/watchdog/mt7621_wdt.c
> @@ -15,8 +15,8 @@
>  #include <linux/moduleparam.h>
>  #include <linux/platform_device.h>
>  #include <linux/mod_devicetable.h>
> -
> -#include <asm/mach-ralink/ralink_regs.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
>  
>  #define SYSC_RSTSTAT			0x38
>  #define WDT_RST_CAUSE			BIT(1)
> @@ -34,6 +34,7 @@
>  struct mt7621_wdt_data {
>  	void __iomem *base;
>  	struct reset_control *rst;
> +	struct regmap *sysc;
>  	struct watchdog_device wdt;
>  };
>  
> @@ -104,9 +105,12 @@ static int mt7621_wdt_stop(struct watchdog_device *w)
>  	return 0;
>  }
>  
> -static int mt7621_wdt_bootcause(void)
> +static int mt7621_wdt_bootcause(struct mt7621_wdt_data *d)
>  {
> -	if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)
> +	u32 val;
> +
> +	regmap_read(d->sysc, SYSC_RSTSTAT, &val);
> +	if (val & WDT_RST_CAUSE)
>  		return WDIOF_CARDRESET;
>  
>  	return 0;
> @@ -134,6 +138,7 @@ static const struct watchdog_ops mt7621_wdt_ops = {
>  
>  static int mt7621_wdt_probe(struct platform_device *pdev)
>  {
> +	struct device_node *np = pdev->dev.of_node;
>  	struct device *dev = &pdev->dev;
>  	struct watchdog_device *mt7621_wdt;
>  	struct mt7621_wdt_data *drvdata;
> @@ -143,6 +148,10 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
>  	if (!drvdata)
>  		return -ENOMEM;
>  
> +	drvdata->sysc = syscon_regmap_lookup_by_phandle(np, "mediatek,sysctl");
> +	if (IS_ERR(drvdata->sysc))
> +		return PTR_ERR(drvdata->sysc);
> +
>  	drvdata->base = devm_platform_ioremap_resource(pdev, 0);
>  	if (IS_ERR(drvdata->base))
>  		return PTR_ERR(drvdata->base);
> @@ -158,7 +167,7 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
>  	mt7621_wdt->max_timeout = 0xfffful / 1000;
>  	mt7621_wdt->parent = dev;
>  
> -	mt7621_wdt->bootstatus = mt7621_wdt_bootcause();
> +	mt7621_wdt->bootstatus = mt7621_wdt_bootcause(drvdata);
>  
>  	watchdog_init_timeout(mt7621_wdt, mt7621_wdt->max_timeout, dev);
>  	watchdog_set_nowayout(mt7621_wdt, nowayout);
> -- 
> 2.25.1
>