From bcf2830200ecf30310307ebe28aa8e6de0836cdc Mon Sep 17 00:00:00 2001
From: MartDur <martin.durietz@gmail.com>
Date: Wed, 15 May 2024 15:29:56 +0200
Subject: [PATCH] drivers: i2c: stm32wl: fix i2c stm32wl power managment.

Fixes the power managment of the i2c driver for the stm32wl (#[37414]).
Initialisation parameters for the stm32wl were lost when going out of
power mode STOP2 leaving the i2c driver in a unitialize state.
Re-initialising i2c timing when pm device resume solves the issue.

Signed-off-by: MartDur <martin.durietz@gmail.com>
---
 drivers/i2c/i2c_ll_stm32.c | 39 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/i2c/i2c_ll_stm32.c b/drivers/i2c/i2c_ll_stm32.c
index 29f5a5ae08fe508..0c611f8acca3e0a 100644
--- a/drivers/i2c/i2c_ll_stm32.c
+++ b/drivers/i2c/i2c_ll_stm32.c
@@ -426,6 +426,42 @@ static int i2c_stm32_init(const struct device *dev)
 	return 0;
 }
 
+#if defined(CONFIG_SOC_SERIES_STM32WLX)
+static int i2c_stm32_reinit_timing(const struct device *dev)
+{
+    int ret;
+    const struct i2c_stm32_config *cfg = dev->config;
+    const struct device *const clk = DEVICE_DT_GET(STM32_CLOCK_CONTROL_NODE);
+    uint32_t i2c_clock = 0U;
+    
+    if (IS_ENABLED(STM32_I2C_DOMAIN_CLOCK_SUPPORT) && (cfg->pclk_len > 1)) {
+        if (clock_control_get_rate(clk, (clock_control_subsys_t)&cfg->pclken[1],
+                       &i2c_clock) < 0) {
+            LOG_ERR("Failed call clock_control_get_rate(pclken[1])");
+            return -EIO;
+        }
+    } else {
+        if (clock_control_get_rate(clk, (clock_control_subsys_t)&cfg->pclken[0],
+                       &i2c_clock) < 0) {
+            LOG_ERR("Failed call clock_control_get_rate(pclken[0])");
+            return -EIO;
+        }
+    }
+
+#ifdef CONFIG_PM_DEVICE_RUNTIME
+    ret = clock_control_on(clk, (clock_control_subsys_t)&cfg->pclken[0]);
+    if (ret < 0) {
+        LOG_ERR("failure Enabling I2C clock");
+        return ret;
+    }
+#endif
+
+    ret = stm32_i2c_configure_timing(dev, i2c_clock);
+
+    return ret;
+}
+#endif
+
 #ifdef CONFIG_PM_DEVICE
 
 static int i2c_stm32_pm_action(const struct device *dev, enum pm_device_action action)
@@ -435,6 +471,9 @@ static int i2c_stm32_pm_action(const struct device *dev, enum pm_device_action a
 	switch (action) {
 	case PM_DEVICE_ACTION_RESUME:
 		err = i2c_stm32_activate(dev);
+        #if defined(CONFIG_SOC_SERIES_STM32WLX)
+        i2c_stm32_reinit_timing(dev);
+        #endif
 		break;
 	case PM_DEVICE_ACTION_SUSPEND:
 		err = i2c_stm32_suspend(dev);