soc: mediatek: SCPSYS: Add regulator support

The power domains are supplied by regulators. Add support for them so
that the regulators are properly turned on before a domain is powered up
and turned off when a domain is powered down.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

drivers/soc/mediatek/mtk-scpsys.c

@@ -21,6 +21,7 @@
 #include <linux/pm_domain.h>
 #include <linux/regmap.h>
 #include <linux/soc/mediatek/infracfg.h>
+#include <linux/regulator/consumer.h>
 #include <dt-bindings/power/mt8173-power.h>
 
 #define SPM_VDE_PWR_CON			0x0210
@@ -179,6 +180,7 @@ struct scp_domain {
 	u32 sram_pdn_ack_bits;
 	u32 bus_prot_mask;
 	bool active_wakeup;
+	struct regulator *supply;
 };
 
 struct scp {
@@ -221,6 +223,12 @@ static int scpsys_power_on(struct generic_pm_domain *genpd)
 	int ret;
 	int i;
 
+	if (scpd->supply) {
+		ret = regulator_enable(scpd->supply);
+		if (ret)
+			return ret;
+	}
+
 	for (i = 0; i < MAX_CLKS && scpd->clk[i]; i++) {
 		ret = clk_prepare_enable(scpd->clk[i]);
 		if (ret) {
@@ -299,6 +307,9 @@ static int scpsys_power_on(struct generic_pm_domain *genpd)
 			clk_disable_unprepare(scpd->clk[i]);
 	}
 err_clk:
+	if (scpd->supply)
+		regulator_disable(scpd->supply);
+
 	dev_err(scp->dev, "Failed to power on domain %s\n", genpd->name);
 
 	return ret;
@@ -379,6 +390,9 @@ static int scpsys_power_off(struct generic_pm_domain *genpd)
 	for (i = 0; i < MAX_CLKS && scpd->clk[i]; i++)
 		clk_disable_unprepare(scpd->clk[i]);
 
+	if (scpd->supply)
+		regulator_disable(scpd->supply);
+
 	return 0;
 
 out:
@@ -448,6 +462,19 @@ static int __init scpsys_probe(struct platform_device *pdev)
 		return PTR_ERR(scp->infracfg);
 	}
 
+	for (i = 0; i < NUM_DOMAINS; i++) {
+		struct scp_domain *scpd = &scp->domains[i];
+		const struct scp_domain_data *data = &scp_domain_data[i];
+
+		scpd->supply = devm_regulator_get_optional(&pdev->dev, data->name);
+		if (IS_ERR(scpd->supply)) {
+			if (PTR_ERR(scpd->supply) == -ENODEV)
+				scpd->supply = NULL;
+			else
+				return PTR_ERR(scpd->supply);
+		}
+	}
+
 	pd_data->num_domains = NUM_DOMAINS;
 
 	for (i = 0; i < NUM_DOMAINS; i++) {