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

[Jaehoon Chung <jh80.chung@gmail.com>]

On 12/24/21 6:34 AM, Mark Kettenis wrote:
> This driver supports power domains for the power management
> controller found on Apple SoCs.
>
> Signed-off-by: Mark Kettenis <kettenis@openbsd.org>

Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung
> ---
>  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
>
> 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.
> +
>  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
> +
> +struct apple_pmgr_priv {
> +	struct regmap *regmap;
> +	u32 offset;
> +};
> +
> +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) {
> +		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),
> +};