[PATCH v2 7/9] power: domain: apple: Add reset support

[Jaehoon Chung]

Hi,

On 1/23/22 04:38, Mark Kettenis wrote:
> The power management controller found on Apple SoCs als provides
> a way to reset all devices within a power domain. This is needed
> to cleanly shutdown the NVMe controller before we hand over
> control to the OS.
> 
> Signed-off-by: Mark Kettenis <kettenis at openbsd.org>
> Reviewed-by: Simon Glass <sjg at chromium.org>
> Tested on: Macbook Air M1
> Tested-by: Simon Glass <sjg at chromium.org>

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

Add minor comment.

> ---
>  arch/arm/Kconfig                  |  1 +
>  drivers/power/domain/apple-pmgr.c | 73 ++++++++++++++++++++++++++++++-
>  2 files changed, 73 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index ecacd6860b..14c83ea19e 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -935,6 +935,7 @@ config ARCH_APPLE
>  	select DM_GPIO
>  	select DM_KEYBOARD
>  	select DM_MAILBOX
> +	select DM_RESET
>  	select DM_SERIAL
>  	select DM_USB
>  	select DM_VIDEO
> diff --git a/drivers/power/domain/apple-pmgr.c b/drivers/power/domain/apple-pmgr.c
> index d25f136b9d..4d06e76ff5 100644
> --- a/drivers/power/domain/apple-pmgr.c
> +++ b/drivers/power/domain/apple-pmgr.c
> @@ -6,14 +6,22 @@
>  #include <common.h>
>  #include <asm/io.h>
>  #include <dm.h>
> +#include <dm/device-internal.h>
>  #include <linux/err.h>
>  #include <linux/bitfield.h>
>  #include <power-domain-uclass.h>
> +#include <reset-uclass.h>
>  #include <regmap.h>
>  #include <syscon.h>
>  
> -#define APPLE_PMGR_PS_TARGET	GENMASK(3, 0)
> +#define APPLE_PMGR_RESET	BIT(31)
> +#define APPLE_PMGR_DEV_DISABLE	BIT(10)
> +#define APPLE_PMGR_WAS_CLKGATED	BIT(9)
> +#define APPLE_PMGR_WAS_PWRGATED BIT(8)

Bit description is specified "WAS_CLKGATED"?
I think it can be removed "WAS". CLKGATED has already similar meaning.

Best Regards,
Jaehoon Chung

>  #define APPLE_PMGR_PS_ACTUAL	GENMASK(7, 4)
> +#define APPLE_PMGR_PS_TARGET	GENMASK(3, 0)
> +
> +#define APPLE_PMGR_FLAGS	(APPLE_PMGR_WAS_CLKGATED | APPLE_PMGR_WAS_PWRGATED)
>  
>  #define APPLE_PMGR_PS_ACTIVE	0xf
>  #define APPLE_PMGR_PS_PWRGATE	0x0
> @@ -25,6 +33,65 @@ struct apple_pmgr_priv {
>  	u32 offset;		/* offset within regmap for this domain */
>  };
>  
> +static int apple_reset_of_xlate(struct reset_ctl *reset_ctl,
> +				struct ofnode_phandle_args *args)
> +{
> +	if (args->args_count != 0)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int apple_reset_request(struct reset_ctl *reset_ctl)
> +{
> +	return 0;
> +}
> +
> +static int apple_reset_free(struct reset_ctl *reset_ctl)
> +{
> +	return 0;
> +}
> +
> +static int apple_reset_assert(struct reset_ctl *reset_ctl)
> +{
> +	struct apple_pmgr_priv *priv = dev_get_priv(reset_ctl->dev->parent);
> +
> +	regmap_update_bits(priv->regmap, priv->offset,
> +			   APPLE_PMGR_FLAGS | APPLE_PMGR_DEV_DISABLE,
> +			   APPLE_PMGR_DEV_DISABLE);
> +	regmap_update_bits(priv->regmap, priv->offset,
> +			   APPLE_PMGR_FLAGS | APPLE_PMGR_RESET,
> +			   APPLE_PMGR_RESET);
> +
> +	return 0;
> +}
> +
> +static int apple_reset_deassert(struct reset_ctl *reset_ctl)
> +{
> +	struct apple_pmgr_priv *priv = dev_get_priv(reset_ctl->dev->parent);
> +
> +	regmap_update_bits(priv->regmap, priv->offset,
> +			   APPLE_PMGR_FLAGS | APPLE_PMGR_RESET, 0);
> +	regmap_update_bits(priv->regmap, priv->offset,
> +			   APPLE_PMGR_FLAGS | APPLE_PMGR_DEV_DISABLE, 0);
> +
> +	return 0;
> +}
> +
> +struct reset_ops apple_reset_ops = {
> +	.of_xlate = apple_reset_of_xlate,
> +	.request = apple_reset_request,
> +	.rfree = apple_reset_free,
> +	.rst_assert = apple_reset_assert,
> +	.rst_deassert = apple_reset_deassert,
> +};
> +
> +static struct driver apple_reset_driver = {
> +	.name = "apple_reset",
> +	.id = UCLASS_RESET,
> +	.ops = &apple_reset_ops,
> +};
> +
>  static int apple_pmgr_request(struct power_domain *power_domain)
>  {
>  	return 0;
> @@ -78,6 +145,7 @@ static const struct udevice_id apple_pmgr_ids[] = {
>  static int apple_pmgr_probe(struct udevice *dev)
>  {
>  	struct apple_pmgr_priv *priv = dev_get_priv(dev);
> +	struct udevice *child;
>  	int ret;
>  
>  	ret = dev_power_domain_on(dev);
> @@ -92,6 +160,9 @@ static int apple_pmgr_probe(struct udevice *dev)
>  	if (ret < 0)
>  		return ret;
>  
> +	device_bind(dev, &apple_reset_driver, "apple_reset", NULL,
> +		    dev_ofnode(dev), &child);
> +
>  	return 0;
>  }
>