From 3bc531e9c6874eb04fea5c886dc725d75774e58f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wouter=20Horr=C3=A9?= <wouter@versasense.com>
Date: Wed, 23 Aug 2023 15:13:40 +0200
Subject: [PATCH] drivers: i2c: stm32: Support wakeup from STOP
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This commit adds support for wakeup from STOP mode when the i2c device is
configured as a target.

Signed-off-by: Wouter Horré <wouter@versasense.com>
---
 drivers/i2c/i2c_ll_stm32_v2.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/i2c/i2c_ll_stm32_v2.c b/drivers/i2c/i2c_ll_stm32_v2.c
index a05edd5c8cb..5d22380118b 100644
--- a/drivers/i2c/i2c_ll_stm32_v2.c
+++ b/drivers/i2c/i2c_ll_stm32_v2.c
@@ -17,6 +17,8 @@
 #include <stm32_ll_i2c.h>
 #include <errno.h>
 #include <zephyr/drivers/i2c.h>
+#include <zephyr/pm/device.h>
+#include <zephyr/pm/device_runtime.h>
 #include "i2c_ll_stm32.h"
 
 #define LOG_LEVEL CONFIG_I2C_LOG_LEVEL
@@ -227,6 +229,16 @@ int i2c_stm32_target_register(const struct device *dev,
 		return ret;
 	}
 
+#if defined(CONFIG_PM_DEVICE_RUNTIME)
+	if (pm_device_wakeup_is_capable(dev)) {
+		/* Mark device as active */
+		(void)pm_device_runtime_get(dev);
+		/* Enable wake-up from stop */
+		LOG_DBG("i2c: enabling wakeup from stop");
+		LL_I2C_EnableWakeUpFromStop(cfg->i2c);
+	}
+#endif /* defined(CONFIG_PM_DEVICE_RUNTIME) */
+
 	LL_I2C_Enable(i2c);
 
 	if (!data->slave_cfg) {
@@ -306,6 +318,16 @@ int i2c_stm32_target_unregister(const struct device *dev,
 
 	LL_I2C_Disable(i2c);
 
+#if defined(CONFIG_PM_DEVICE_RUNTIME)
+	if (pm_device_wakeup_is_capable(dev)) {
+		/* Disable wake-up from STOP */
+		LOG_DBG("i2c: disabling wakeup from stop");
+		LL_I2C_DisableWakeUpFromStop(i2c);
+		/* Release the device */
+		(void)pm_device_runtime_put(dev);
+	}
+#endif /* defined(CONFIG_PM_DEVICE_RUNTIME) */
+
 	data->slave_attached = false;
 
 	return 0;