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

[Jaehoon Chung]

On 1/27/22 20:48, Mark Kettenis wrote:
>> Date: Thu, 27 Jan 2022 08:54:29 +0900
>> From: Jaehoon Chung <jh80.chung at samsung.com>
>>
>> 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.
> 
> Hi Jaehoon,
> 
>>> ---
>>>  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.
> 
> The names are taken from the Linux driver and I would prefer to keep
> them the same to make it easier to compare the two drivers since
> nobody outside of Apple has access to documentation for this block.

Thanks for explanation. 

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;
>>>  }
>>>  
>>
>>
>