memory: stm32-fmc2-ebi: keep power domain on

MP25 FMC2 domain has to be kept on. To handle it throw PSCI OS-initiated,
basic PM for keeping domain on is introduced.

Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
Link: https://lore.kernel.org/r/20240226101428.37791-6-christophe.kerello@foss.st.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Author: Christophe Kerello

drivers/memory/stm32-fmc2-ebi.c

@@ -11,6 +11,7 @@
 #include <linux/of_platform.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/reset.h>
 
@@ -1649,6 +1650,7 @@ static int stm32_fmc2_ebi_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ebi->dev = dev;
+	platform_set_drvdata(pdev, ebi);
 
 	ebi->data = of_device_get_match_data(dev);
 	if (!ebi->data)
@@ -1666,10 +1668,14 @@ static int stm32_fmc2_ebi_probe(struct platform_device *pdev)
 	if (PTR_ERR(rstc) == -EPROBE_DEFER)
 		return -EPROBE_DEFER;
 
-	ret = clk_prepare_enable(ebi->clk);
+	ret = devm_pm_runtime_enable(dev);
 	if (ret)
 		return ret;
 
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0)
+		return ret;
+
 	if (!IS_ERR(rstc)) {
 		reset_control_assert(rstc);
 		reset_control_deassert(rstc);
@@ -1705,16 +1711,14 @@ static int stm32_fmc2_ebi_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_release;
 
-	platform_set_drvdata(pdev, ebi);
-
 	return 0;
 
 err_release:
 	stm32_fmc2_ebi_disable_banks(ebi);
 	stm32_fmc2_ebi_disable(ebi);
 	if (ebi->data->put_sems)
 		ebi->data->put_sems(ebi);
-	clk_disable_unprepare(ebi->clk);
+	pm_runtime_put_sync_suspend(dev);
 
 	return ret;
 }
@@ -1728,7 +1732,23 @@ static void stm32_fmc2_ebi_remove(struct platform_device *pdev)
 	stm32_fmc2_ebi_disable(ebi);
 	if (ebi->data->put_sems)
 		ebi->data->put_sems(ebi);
+	pm_runtime_put_sync_suspend(&pdev->dev);
+}
+
+static int __maybe_unused stm32_fmc2_ebi_runtime_suspend(struct device *dev)
+{
+	struct stm32_fmc2_ebi *ebi = dev_get_drvdata(dev);
+
 	clk_disable_unprepare(ebi->clk);
+
+	return 0;
+}
+
+static int __maybe_unused stm32_fmc2_ebi_runtime_resume(struct device *dev)
+{
+	struct stm32_fmc2_ebi *ebi = dev_get_drvdata(dev);
+
+	return clk_prepare_enable(ebi->clk);
 }
 
 static int __maybe_unused stm32_fmc2_ebi_suspend(struct device *dev)
@@ -1738,7 +1758,7 @@ static int __maybe_unused stm32_fmc2_ebi_suspend(struct device *dev)
 	stm32_fmc2_ebi_disable(ebi);
 	if (ebi->data->put_sems)
 		ebi->data->put_sems(ebi);
-	clk_disable_unprepare(ebi->clk);
+	pm_runtime_put_sync_suspend(dev);
 	pinctrl_pm_select_sleep_state(dev);
 
 	return 0;
@@ -1751,8 +1771,8 @@ static int __maybe_unused stm32_fmc2_ebi_resume(struct device *dev)
 
 	pinctrl_pm_select_default_state(dev);
 
-	ret = clk_prepare_enable(ebi->clk);
-	if (ret)
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0)
 		return ret;
 
 	if (ebi->data->get_sems)
@@ -1763,8 +1783,11 @@ static int __maybe_unused stm32_fmc2_ebi_resume(struct device *dev)
 	return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(stm32_fmc2_ebi_pm_ops, stm32_fmc2_ebi_suspend,
-			 stm32_fmc2_ebi_resume);
+static const struct dev_pm_ops stm32_fmc2_ebi_pm_ops = {
+	SET_RUNTIME_PM_OPS(stm32_fmc2_ebi_runtime_suspend,
+			   stm32_fmc2_ebi_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(stm32_fmc2_ebi_suspend, stm32_fmc2_ebi_resume)
+};
 
 static const struct stm32_fmc2_ebi_data stm32_fmc2_ebi_mp1_data = {
 	.child_props = stm32_fmc2_child_props,