Re: [PATCH v2 3/3] power: domain: Add Apple pmgr driver

Mark Kettenis
2021-12-28T14:27:10Z

> From: Simon Glass <sjg@chromium.org>
> Date: Tue, 28 Dec 2021 01:34:16 -0700
>
> Hi Mark,
>
> On Thu, 23 Dec 2021 at 14:35, Mark Kettenis <kettenis@openbsd.org> wrote:
> >
> > This driver supports power domains for the power management
> > controller found on Apple SoCs.
> >
> > Signed-off-by: Mark Kettenis <kettenis@openbsd.org>
> > ---
> > arch/arm/Kconfig | 3 +
> > drivers/power/domain/Kconfig | 8 +++
> > drivers/power/domain/Makefile | 1 +
> > drivers/power/domain/apple-pmgr.c | 113 ++++++++++++++++++++++++++++++
> > 4 files changed, 125 insertions(+)
> > create mode 100644 drivers/power/domain/apple-pmgr.c
>
> Reviewed-by: Simon Glass <sjg@chromium.org>
>
> nits below
>
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 59e031de04..40d3f66acb 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -938,6 +938,9 @@ config ARCH_APPLE
> > select OF_BOARD
> > select PINCTRL
> > select POSITION_INDEPENDENT
> > + select POWER_DOMAIN
> > + select REGMAP
> > + select SYSCON
> > select SYSRESET
> > select SYSRESET_WATCHDOG
> > select SYSRESET_WATCHDOG_AUTO
> > diff --git a/drivers/power/domain/Kconfig b/drivers/power/domain/Kconfig
> > index 99b3f9ae71..6ef7a3b3a7 100644
> > --- a/drivers/power/domain/Kconfig
> > +++ b/drivers/power/domain/Kconfig
> > @@ -9,6 +9,14 @@ config POWER_DOMAIN
> > domains). This may be used to save power. This API provides the
> > means to control such power management hardware.
> >
> > +config APPLE_PMGR_POWER_DOMAIN
> > + bool "Enable the Apple PMGR power domain driver"
> > + depends on POWER_DOMAIN
> > + default y if ARCH_APPLE
> > + help
> > + Enable support for manipulating the Apple M1 power domains via
> > + MMIO mapped registers.
>
> Needs more detail here, perhaps a pointer to docs, or something about
> what the driver supports.

Struggling to come up with more. The "via MMIO mapped registers" is
already a bit silly. There are no docs. And the one line already
indicates what the driver supports. Do you want me to add a sentence
that says the same thing but in different words?

> > +
> > config BCM6328_POWER_DOMAIN
> > bool "Enable the BCM6328 power domain driver"
> > depends on POWER_DOMAIN && ARCH_BMIPS
> > diff --git a/drivers/power/domain/Makefile b/drivers/power/domain/Makefile
> > index 3d1e5f073c..530ae35671 100644
> > --- a/drivers/power/domain/Makefile
> > +++ b/drivers/power/domain/Makefile
> > @@ -4,6 +4,7 @@
> > #
> >
> > obj-$(CONFIG_$(SPL_)POWER_DOMAIN) += power-domain-uclass.o
> > +obj-$(CONFIG_APPLE_PMGR_POWER_DOMAIN) += apple-pmgr.o
> > obj-$(CONFIG_BCM6328_POWER_DOMAIN) += bcm6328-power-domain.o
> > obj-$(CONFIG_IMX8_POWER_DOMAIN) += imx8-power-domain-legacy.o imx8-power-domain.o
> > obj-$(CONFIG_IMX8M_POWER_DOMAIN) += imx8m-power-domain.o
> > diff --git a/drivers/power/domain/apple-pmgr.c b/drivers/power/domain/apple-pmgr.c
> > new file mode 100644
> > index 0000000000..08a30c8ebf
> > --- /dev/null
> > +++ b/drivers/power/domain/apple-pmgr.c
> > @@ -0,0 +1,113 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2021 Mark Kettenis <kettenis@openbsd.org>
> > + */
> > +
> > +#include <common.h>
> > +#include <asm/io.h>
> > +#include <dm.h>
> > +#include <linux/err.h>
> > +#include <linux/bitfield.h>
> > +#include <power-domain-uclass.h>
> > +#include <regmap.h>
> > +#include <syscon.h>
> > +
> > +#define APPLE_PMGR_PS_TARGET GENMASK(3, 0)
> > +#define APPLE_PMGR_PS_ACTUAL GENMASK(7, 4)
> > +
> > +#define APPLE_PMGR_PS_ACTIVE 0xf
> > +#define APPLE_PMGR_PS_PWRGATE 0x0
> > +
> > +#define APPLE_PMGR_PS_SET_TIMEOUT 100
>
> TIMEOUT_MS ?
> _US ?

_US

> > +
> > +struct apple_pmgr_priv {
> > + struct regmap *regmap;
> > + u32 offset;
>
> Needs comment for struct

Really? I mean, I can add a "Device private data" comment, but that's
pretty much implied by the _priv and the vast majority of the drivers
don't do such a thing.

>
> > +};
> > +
> > +static int apple_pmgr_request(struct power_domain *power_domain)
> > +{
> > + return 0;
> > +}
> > +
> > +static int apple_pmgr_rfree(struct power_domain *power_domain)
> > +{
> > + return 0;
> > +}
> > +
> > +static int apple_pmgr_ps_set(struct power_domain *power_domain, u32 pstate)
> > +{
> > + struct apple_pmgr_priv *priv = dev_get_priv(power_domain->dev);
> > + uint reg;
> > +
> > + regmap_update_bits(priv->regmap, priv->offset, APPLE_PMGR_PS_TARGET,
> > + FIELD_PREP(APPLE_PMGR_PS_TARGET, pstate));
> > +
> > + return regmap_read_poll_timeout(
> > + priv->regmap, priv->offset, reg,
> > + (FIELD_GET(APPLE_PMGR_PS_ACTUAL, reg) == pstate), 1,
> > + APPLE_PMGR_PS_SET_TIMEOUT);
> > +}
> > +
> > +static int apple_pmgr_on(struct power_domain *power_domain)
> > +{
> > + return apple_pmgr_ps_set(power_domain, APPLE_PMGR_PS_ACTIVE);
> > +}
> > +
> > +static int apple_pmgr_off(struct power_domain *power_domain)
> > +{
> > + return 0;
> > +}
> > +
> > +static int apple_pmgr_of_xlate(struct power_domain *power_domain,
> > + struct ofnode_phandle_args *args)
> > +{
> > + if (args->args_count != 0) {
>
> s/ != 0//

!= 0 seems better here since that is the value we're checking for.

>
> > + debug("Invalid args_count: %d\n", args->args_count);
> > + return -EINVAL;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static const struct udevice_id apple_pmgr_ids[] = {
> > + { .compatible = "apple,pmgr-pwrstate" },
> > + { /* sentinel */ }
> > +};
> > +
> > +static int apple_pmgr_probe(struct udevice *dev)
> > +{
> > + struct apple_pmgr_priv *priv = dev_get_priv(dev);
> > + int ret;
> > +
> > + ret = dev_power_domain_on(dev);
> > + if (ret)
> > + return ret;
> > +
> > + priv->regmap = syscon_get_regmap(dev->parent);
> > + if (IS_ERR(priv->regmap))
> > + return PTR_ERR(priv->regmap);
> > +
> > + ret = dev_read_u32(dev, "reg", &priv->offset);
> > + if (ret < 0)
> > + return ret;
> > +
> > + return 0;
> > +}
> > +
> > +struct power_domain_ops apple_pmgr_ops = {
> > + .request = apple_pmgr_request,
> > + .rfree = apple_pmgr_rfree,
> > + .on = apple_pmgr_on,
> > + .off = apple_pmgr_off,
> > + .of_xlate = apple_pmgr_of_xlate,
> > +};
> > +
> > +U_BOOT_DRIVER(apple_pmgr) = {
> > + .name = "apple_pmgr",
> > + .id = UCLASS_POWER_DOMAIN,
> > + .of_match = apple_pmgr_ids,
> > + .ops = &apple_pmgr_ops,
> > + .probe = apple_pmgr_probe,
> > + .priv_auto = sizeof(struct apple_pmgr_priv),
> > +};
> > --
> > 2.34.1
> >
>
> Regards,
> Simon
>