soc/tegra: pmc: Disable PMC state syncing

Disable PMC state syncing in order to ensure that we won't break older
kernels once device-trees will be updated with the addition of the power
domains. This also allows to apply device-tree PM patches independently
from the driver patches.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/soc/tegra/pmc.c

@@ -360,6 +360,7 @@ struct tegra_pmc_soc {
 	unsigned int num_pmc_clks;
 	bool has_blink_output;
 	bool has_usb_sleepwalk;
+	bool supports_core_domain;
 };
 
 /**
@@ -3041,6 +3042,7 @@ static void tegra20_pmc_setup_irq_polarity(struct tegra_pmc *pmc,
 }
 
 static const struct tegra_pmc_soc tegra20_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = ARRAY_SIZE(tegra20_powergates),
 	.powergates = tegra20_powergates,
 	.num_cpu_powergates = 0,
@@ -3101,6 +3103,7 @@ static const char * const tegra30_reset_sources[] = {
 };
 
 static const struct tegra_pmc_soc tegra30_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = ARRAY_SIZE(tegra30_powergates),
 	.powergates = tegra30_powergates,
 	.num_cpu_powergates = ARRAY_SIZE(tegra30_cpu_powergates),
@@ -3157,6 +3160,7 @@ static const u8 tegra114_cpu_powergates[] = {
 };
 
 static const struct tegra_pmc_soc tegra114_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = ARRAY_SIZE(tegra114_powergates),
 	.powergates = tegra114_powergates,
 	.num_cpu_powergates = ARRAY_SIZE(tegra114_cpu_powergates),
@@ -3273,6 +3277,7 @@ static const struct pinctrl_pin_desc tegra124_pin_descs[] = {
 };
 
 static const struct tegra_pmc_soc tegra124_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = ARRAY_SIZE(tegra124_powergates),
 	.powergates = tegra124_powergates,
 	.num_cpu_powergates = ARRAY_SIZE(tegra124_cpu_powergates),
@@ -3398,6 +3403,7 @@ static const struct tegra_wake_event tegra210_wake_events[] = {
 };
 
 static const struct tegra_pmc_soc tegra210_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = ARRAY_SIZE(tegra210_powergates),
 	.powergates = tegra210_powergates,
 	.num_cpu_powergates = ARRAY_SIZE(tegra210_cpu_powergates),
@@ -3555,6 +3561,7 @@ static const struct tegra_wake_event tegra186_wake_events[] = {
 };
 
 static const struct tegra_pmc_soc tegra186_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = 0,
 	.powergates = NULL,
 	.num_cpu_powergates = 0,
@@ -3689,6 +3696,7 @@ static const struct tegra_wake_event tegra194_wake_events[] = {
 };
 
 static const struct tegra_pmc_soc tegra194_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = 0,
 	.powergates = NULL,
 	.num_cpu_powergates = 0,
@@ -3757,6 +3765,7 @@ static const char * const tegra234_reset_sources[] = {
 };
 
 static const struct tegra_pmc_soc tegra234_pmc_soc = {
+	.supports_core_domain = false,
 	.num_powergates = 0,
 	.powergates = NULL,
 	.num_cpu_powergates = 0,
@@ -3803,6 +3812,14 @@ static void tegra_pmc_sync_state(struct device *dev)
 {
 	int err;
 
+	/*
+	 * Newer device-trees have power domains, but we need to prepare all
+	 * device drivers with runtime PM and OPP support first, otherwise
+	 * state syncing is unsafe.
+	 */
+	if (!pmc->soc->supports_core_domain)
+		return;
+
 	/*
 	 * Older device-trees don't have core PD, and thus, there are
 	 * no dependencies that will block the state syncing. We shouldn't