linux-kernel - Re: [PATCH v1 5/6] pmdomain: rockchip: add regulator support

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Message-ID: <2224005.vXnMlVU4IS@diego>
Date: Wed, 11 Sep 2024 11:46:58 +0200
From: Heiko Stübner <heiko@...ech.de>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Ulf Hansson <ulf.hansson@...aro.org>,
 Sebastian Reichel <sebastian.reichel@...labora.com>
Cc: 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,
 Sebastian Reichel <sebastian.reichel@...labora.com>, kernel@...labora.com,
 Chen-Yu Tsai <wenst@...omium.org>
Subject: Re: [PATCH v1 5/6] pmdomain: rockchip: add regulator support

Am Dienstag, 10. September 2024, 19:57:14 CEST schrieb Sebastian Reichel:
> 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.
> 
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>

It does look like Chen-Yu Tsai is working on a similar problem [0].

I.e. this really is a hack, so I started looking around the regulator API
and found of_regulator_bulk_get existing but unused that already
operates on a of-node.

Googling further I stumbled upon the linked patch from some days
ago ;-) . So maybe that could be a cleaner way forward?


[0] https://patchwork.kernel.org/project/linux-mediatek/patch/20240904090016.2841572-6-wenst@chromium.org/

> ---
>  drivers/pmdomain/rockchip/pm-domains.c | 57 +++++++++++++++++++++++++-
>  1 file changed, 55 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pmdomain/rockchip/pm-domains.c b/drivers/pmdomain/rockchip/pm-domains.c
> index 663d390faaeb..ae6990897928 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 +574,67 @@ 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");
> +		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 +715,7 @@ 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) {
>