soc: mediatek: pm-domains: Add buck isolation setting in power domain

In some chipsets, we need to disable EXT_BUCK_ISO before turning on the
specific power pm-domains (mtcmos), such as ADSP in MT8192 and CAM_VCORE
in MT8188.

Add the MTK_SCPD_EXT_BUCK_ISO flag to control the buck isolation setting
in the mediatek power domain driver.
Signed-off-by: Allen-KH Cheng <allen-kh.cheng@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230117032640.13504-3-allen-kh.cheng@mediatek.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

drivers/soc/mediatek/mtk-pm-domains.c

@@ -219,6 +219,10 @@ static int scpsys_power_on(struct generic_pm_domain *genpd)
 	if (ret)
 		goto err_reg;
 
+	if (pd->data->ext_buck_iso_offs && MTK_SCPD_CAPS(pd, MTK_SCPD_EXT_BUCK_ISO))
+		regmap_clear_bits(scpsys->base, pd->data->ext_buck_iso_offs,
+				  pd->data->ext_buck_iso_mask);
+
 	/* subsys power on */
 	regmap_set_bits(scpsys->base, pd->data->ctl_offs, PWR_ON_BIT);
 	regmap_set_bits(scpsys->base, pd->data->ctl_offs, PWR_ON_2ND_BIT);
@@ -273,6 +277,10 @@ static int scpsys_power_off(struct generic_pm_domain *genpd)
 	if (ret < 0)
 		return ret;
 
+	if (pd->data->ext_buck_iso_offs && MTK_SCPD_CAPS(pd, MTK_SCPD_EXT_BUCK_ISO))
+		regmap_set_bits(scpsys->base, pd->data->ext_buck_iso_offs,
+				pd->data->ext_buck_iso_mask);
+
 	clk_bulk_disable_unprepare(pd->num_subsys_clks, pd->subsys_clks);
 
 	/* subsys power off */

drivers/soc/mediatek/mtk-pm-domains.h

@@ -10,6 +10,7 @@
 #define MTK_SCPD_DOMAIN_SUPPLY		BIT(4)
 /* can't set MTK_SCPD_KEEP_DEFAULT_OFF at the same time */
 #define MTK_SCPD_ALWAYS_ON		BIT(5)
+#define MTK_SCPD_EXT_BUCK_ISO		BIT(6)
 #define MTK_SCPD_CAPS(_scpd, _x)	((_scpd)->data->caps & (_x))
 
 #define SPM_VDE_PWR_CON			0x0210