Message-ID: <CAGb2v66SNkrkXa4Q2gy7fNFZq74WTkxTMYymOKAiYY4HdsRPfg@mail.gmail.com>
Date: Sat, 21 Sep 2024 01:03:26 +0200
From: Chen-Yu Tsai <wens@...e.org>
To: Sebastian Reichel <sebastian.reichel@...labora.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
	Conor Dooley <conor+dt@...nel.org>, Heiko Stuebner <heiko@...ech.de>, 
	Ulf Hansson <ulf.hansson@...aro.org>, Elaine Zhang <zhangqing@...k-chips.com>, 
	Adrián Martínez Larumbe <adrian.larumbe@...labora.com>, 
	Boris Brezillon <boris.brezillon@...labora.com>, devicetree@...r.kernel.org, 
	linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	linux-pm@...r.kernel.org, kernel@...labora.com
Subject: Re: [PATCH v2 5/6] pmdomain: rockchip: add regulator support

On Thu, Sep 19, 2024 at 11:27 AM Sebastian Reichel
<sebastian.reichel@...labora.com> wrote:
>
> Some power domains require extra voltages to be applied. For example
> trying to enable the GPU domain on RK3588 fails when the SoC does not
> have VDD GPU enabled.
>
> The solution to temporarily change the device's device tree node has
> been taken over from the Mediatek power domain driver.
>
> The regulator is not acquired at probe time, since that creates circular
> dependencies. The power domain driver must be probed early, since SoC
> peripherals need it. Regulators on the other hand depend on SoC
> peripherals like SPI, I2C or GPIO.
>
> Reviewed-by: Heiko Stuebner <heiko@...ech.de>
> Tested-by: Adrian Larumbe <adrian.larumbe@...labora.com> # On Rock 5B
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
> ---
>  drivers/pmdomain/rockchip/pm-domains.c | 56 +++++++++++++++++++++++++-
>  1 file changed, 54 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pmdomain/rockchip/pm-domains.c b/drivers/pmdomain/rockchip/pm-domains.c
> index 663d390faaeb..4bc17b588419 100644
> --- a/drivers/pmdomain/rockchip/pm-domains.c
> +++ b/drivers/pmdomain/rockchip/pm-domains.c
> @@ -18,6 +18,7 @@
>  #include <linux/of_clk.h>
>  #include <linux/clk.h>
>  #include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/mfd/syscon.h>
>  #include <soc/rockchip/pm_domains.h>
>  #include <dt-bindings/power/px30-power.h>
> @@ -89,6 +90,8 @@ struct rockchip_pm_domain {
>         u32 *qos_save_regs[MAX_QOS_REGS_NUM];
>         int num_clks;
>         struct clk_bulk_data *clks;
> +       struct device_node *node;
> +       struct regulator *supply;
>  };
>
>  struct rockchip_pmu {
> @@ -571,18 +574,66 @@ static int rockchip_pd_power(struct rockchip_pm_domain *pd, bool power_on)
>         return 0;
>  }
>
> +static int rockchip_pd_regulator_disable(struct rockchip_pm_domain *pd)
> +{
> +       return pd->supply ? regulator_disable(pd->supply) : 0;
> +}
> +
> +static int rockchip_pd_regulator_enable(struct rockchip_pm_domain *pd)
> +{
> +       struct rockchip_pmu *pmu = pd->pmu;
> +       struct device_node *main_node;
> +
> +       if (!pd->supply) {
> +               /*
> +                * Find regulator in current power domain node.
> +                * devm_regulator_get() finds regulator in a node and its child
> +                * node, so set of_node to current power domain node then change
> +                * back to original node after regulator is found for current
> +                * power domain node.
> +                */
> +               main_node = pmu->dev->of_node;
> +               pmu->dev->of_node = pd->node;
> +               pd->supply = devm_regulator_get(pmu->dev, "domain");

How do you differentiate between a power domain not needing a supply,
vs a power domain that is missing its supply in DT?

You're using the normal "devm_regulator_get()" here (no "_optional),
which gives the dummy supply if no supply is specified in the DT, and
I think that wouldn't work properly.

I'm trying to work out if having "devm_of_regulator_get()" is needed or
not.

Also, this could return -EPROBE_DEFER. I guess it works with the initial
pm_domain_attach() from the driver core?


Thanks
ChenYu


> +               pmu->dev->of_node = main_node;
> +               if (IS_ERR(pd->supply)) {
> +                       pd->supply = NULL;
> +                       return 0;
> +               }
> +       }
> +
> +       return regulator_enable(pd->supply);
> +}
> +
>  static int rockchip_pd_power_on(struct generic_pm_domain *domain)
>  {
>         struct rockchip_pm_domain *pd = to_rockchip_pd(domain);
> +       int ret;
> +
> +       ret = rockchip_pd_regulator_enable(pd);
> +       if (ret) {
> +               dev_err(pd->pmu->dev, "Failed to enable supply: %d\n", ret);
> +               return ret;
> +       }
>
> -       return rockchip_pd_power(pd, true);
> +       ret = rockchip_pd_power(pd, true);
> +       if (ret)
> +               rockchip_pd_regulator_disable(pd);
> +
> +       return ret;
>  }
>
>  static int rockchip_pd_power_off(struct generic_pm_domain *domain)
>  {
>         struct rockchip_pm_domain *pd = to_rockchip_pd(domain);
> +       int ret;
>
> -       return rockchip_pd_power(pd, false);
> +       ret = rockchip_pd_power(pd, false);
> +       if (ret)
> +               return ret;
> +
> +       rockchip_pd_regulator_disable(pd);
> +       return ret;
>  }
>
>  static int rockchip_pd_attach_dev(struct generic_pm_domain *genpd,
> @@ -663,6 +714,7 @@ static int rockchip_pm_add_one_domain(struct rockchip_pmu *pmu,
>
>         pd->info = pd_info;
>         pd->pmu = pmu;
> +       pd->node = node;
>
>         pd->num_clks = of_clk_get_parent_count(node);
>         if (pd->num_clks > 0) {
> --
> 2.45.2
>

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