[PATCH 2/3] soc: apple: apple-pmgr-pwrstate: Add auto-PM min level support

[Sven Peter]

On Thu, Dec 9, 2021, at 05:45, Hector Martin wrote:
> This is seemingly required for DCP/DCPEXT, without which they refuse to
> boot properly. They need to be set to minimum state 4 (clock gated).
>
> Signed-off-by: Hector Martin <marcan at marcan.st>
> ---
>  drivers/soc/apple/apple-pmgr-pwrstate.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/soc/apple/apple-pmgr-pwrstate.c 
> b/drivers/soc/apple/apple-pmgr-pwrstate.c
> index 8ad9d5fdefbf..590bb7439372 100644
> --- a/drivers/soc/apple/apple-pmgr-pwrstate.c
> +++ b/drivers/soc/apple/apple-pmgr-pwrstate.c
> @@ -20,6 +20,7 @@
>  #define APPLE_PMGR_RESET        BIT(31)
>  #define APPLE_PMGR_AUTO_ENABLE  BIT(28)
>  #define APPLE_PMGR_PS_AUTO      GENMASK(27, 24)
> +#define APPLE_PMGR_PS_MIN       GENMASK(19, 16)
>  #define APPLE_PMGR_PARENT_OFF   BIT(11)
>  #define APPLE_PMGR_DEV_DISABLE  BIT(10)
>  #define APPLE_PMGR_WAS_CLKGATED BIT(9)
> @@ -42,6 +43,7 @@ struct apple_pmgr_ps {
>  	struct reset_controller_dev rcdev;
>  	struct regmap *regmap;
>  	u32 offset;
> +	u32 min_state;
>  };
> 
>  #define genpd_to_apple_pmgr_ps(_genpd) container_of(_genpd, struct 
> apple_pmgr_ps, genpd)
> @@ -224,6 +226,12 @@ static int apple_pmgr_ps_probe(struct 
> platform_device *pdev)
>  	ps->genpd.power_on = apple_pmgr_ps_power_on;
>  	ps->genpd.power_off = apple_pmgr_ps_power_off;
> 
> +	ret = of_property_read_u32(node, "apple,min-state", &ps->min_state);
> +	if (ret >= 0) {


I think of_property_read_u32 never returns anything > 0 such that
"if (ret == 0)" should be enough. You could also add a check that min_state
must be <= 0b1111 here if you're feeling paranoid.

Either way,

Reviewed-by: Sven Peter <sven at svenpeter.dev>



> +		regmap_update_bits(regmap, ps->offset, APPLE_PMGR_FLAGS | APPLE_PMGR_PS_MIN,
> +				   FIELD_PREP(APPLE_PMGR_PS_MIN, ps->min_state));
> +	}
> +
>  	active = apple_pmgr_ps_is_active(ps);
>  	if (of_property_read_bool(node, "apple,always-on")) {
>  		ps->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
> -- 
> 2.33.0