On Tue, Feb 14, 2023 at 9:31 AM Krzysztof Kozlowski
<krzysztof.kozlowski@xxxxxxxxxx> wrote:
>
> On 13/02/2023 21:05, 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@xxxxxxxxx>
> > ---
> > drivers/watchdog/Kconfig | 4 +++-
> > drivers/watchdog/mt7621_wdt.c | 18 +++++++++++++-----
> > 2 files changed, 16 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index b64bc49c7..cf752ad64 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -1865,7 +1865,9 @@ config GXP_WATCHDOG
> > config MT7621_WDT
> > tristate "Mediatek SoC watchdog"
> > select WATCHDOG_CORE
> > - depends on SOC_MT7620 || SOC_MT7621
> > + select REGMAP_MMIO
> > + select MFD_SYSCON
> > + depends on SOC_MT7620 || SOC_MT7621 || COMPILE_TEST
> > 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..22e979bdd 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;
> > @@ -143,6 +147,10 @@ static int mt7621_wdt_probe(struct platform_device *pdev)
> > if (!drvdata)
> > return -ENOMEM;
> >
> > + drvdata->sysc = syscon_regmap_lookup_by_compatible("mediatek,mt7621-sysc");
> > + if (IS_ERR(drvdata->sysc))
> > + return PTR_ERR(drvdata->sysc);
>
> This should be the backup/error path for original code using syscon
> property. Looking up by compatible is really not portable/re-usable.
I can change the code in the way you are pointing out here but...
Why is it not re-usable? Compatible is not supposed to be changed
since in other cases the DTB ABI will be broken. I am totally lost
about what is an ABI breakage, then.
Thanks in advance for clarification.
Best regards,
Sergio Paracuellos
>
> Best regards,
> Krzysztof
>
