[PATCH v2 5/6] pmdomain: rockchip: add regulator support

[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.

Reviewed-by: Heiko Stuebner <heiko at sntech.de>
Tested-by: Adrian Larumbe <adrian.larumbe at collabora.com> # On Rock 5B
Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.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");
+		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