Re: [PATCH v6 2/2] soc: loongson2_pm: add power management support

Ulf Hansson
2023-08-08T16:12:20Z

On Thu, 3 Aug 2023 at 09:03, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Thu, Aug 3, 2023, at 08:37, Yinbo Zhu wrote:
> > The Loongson-2's power management controller was ACPI, supports ACPI
> > S2Idle (Suspend To Idle), ACPI S3 (Suspend To RAM), ACPI S4 (Suspend To
> > Disk), ACPI S5 (Soft Shutdown) and supports multiple wake-up methods
> > (USB, GMAC, PWRBTN, etc.). This driver was to add power management
> > controller support that base on dts for Loongson-2 series SoCs.
> >
> > Co-developed-by: Liu Yun <liuyun@loongson.cn>
> > Signed-off-by: Liu Yun <liuyun@loongson.cn>
> > Co-developed-by: Liu Peibao <liupeibao@loongson.cn>
> > Signed-off-by: Liu Peibao <liupeibao@loongson.cn>
> > Cc: soc@kernel.org
> > Cc: Ulf Hansson <ulf.hansson@linaro.org>
> > Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
>
> I'm still waiting for Ulf to take a look here to see whether
> this should be in drivers/genpd instead, but he might still
> be on vacation.

I don't think this belongs in drivers/genpd/ as it's not a genpd
provider. Besides that, no further comments from me at this point.

Kind regards
Uffe

>
> A few minor comments from me in the meantime:
>
> > +#define loongson2_pm_readw(reg) readw(loongson2_pm.base + reg)
> > +#define loongson2_pm_readl(reg) readl(loongson2_pm.base + reg)
> > +#define loongson2_pm_writew(val, reg) writew(val, loongson2_pm.base +
> > reg)
> > +#define loongson2_pm_writel(val, reg) writel(val, loongson2_pm.base +
> > reg)
>
> I would prefer these to be 'static inline' functions rather than
> macros, or you can just open-code them, as each macro is only
> used once at the moment.
>
> > +static irqreturn_t loongson2_pm_irq_handler(int irq, void *dev_id)
> > +{
> > + u16 status = loongson2_pm_readw(LOONGSON2_PM1_STS_REG);
> > +
> > + if (!loongson2_pm.suspended && (status & LOONGSON2_PM1_PWRBTN_STS)) {
> > + pr_info("Power Button pressed...\n");
>
> The message is probably more appropriate as a pr_debug() than
> pr_info().
>
> > +static int __maybe_unused loongson2_pm_suspend(struct device *dev)
> > +{
> > + loongson2_pm.suspended = true;
> > +
> > + return 0;
> > +}
> > +
> > +static int __maybe_unused loongson2_pm_resume(struct device *dev)
> > +{
> > + loongson2_pm.suspended = false;
> > +
> > + return 0;
> > +}
> > +static SIMPLE_DEV_PM_OPS(loongson2_pm_ops, loongson2_pm_suspend,
> > loongson2_pm_resume);
>
> Please change this to DEFINE_SIMPLE_DEV_PM_OPS() and remove the
> __maybe_unused, this is what all drivers should have these days.
>
> > +
> > +static int loongson2_pm_probe(struct platform_device *pdev)
> > +{
> > + int irq, retval;
> > + u64 suspend_addr;
> > + struct device *dev = &pdev->dev;
> > +
> > + loongson2_pm.base = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(loongson2_pm.base))
> > + return PTR_ERR(loongson2_pm.base);
> > +
> > + irq = platform_get_irq(pdev, 0);
> > + if (irq < 0)
> > + return irq;
> > +
> > + if (!device_property_read_u64(dev, "loongson,suspend-address",
> > &suspend_addr))
> > + loongson_sysconf.suspend_addr = (u64)phys_to_virt(suspend_addr);
> > + else
>
> Having a custom "loongson,suspend-address" property here feels wrong
> to me. Can't this be moved into the "regs" property that holds
> the other mmio registers?
>
> Arnd