samples: boards: stm32: Power_mgmt: sample for standby shutdownn mode

STM32L4x power management (ultra_low_power) of Standby mode
and shutdown mode

Signed-off-by: Marc Desvaux <marc.desvaux-ext@st.com>

samples/boards/stm32/power_mgmt/standby_shutdown/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(stm32_pm_standby_shutdown)
+
+target_sources(app PRIVATE src/main.c)

samples/boards/stm32/power_mgmt/standby_shutdown/README.rst

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+.. _stm32-pm-standby_shutdown-sample:
+
+STM32 PM Standby shutdown
+#########################
+
+Overview
+********
+
+This sample is a minimum application to demonstrate basic power management of Standby mode and
+shutdown mode
+behavior in a basic blinking LED set up you can enter in shutdown mode or in standbymode mode.
+Press and hold the user button:
+when LED2 is OFF to enter to Shutdown Mode
+when LED2 is ON to enter to Standby Mode
+release the user button to exit from shutdown mode or from shutdown mode.
+
+.. _stm32-pm-standby_shutdown-sample-requirements:
+
+Requirements
+************
+
+The board should support enabling PM. For a STM32 based target, it means that
+it should support a clock source alternative to Cortex Systick that can be used
+in core sleep states, as LPTIM (:dtcompatible:`st,stm32-lptim`).
+For another board than nucleo_L476RG please adjust wakeup pin into config_wakeup_features().
+
+Building and Running
+********************
+
+Build and flash standby_shutdown as follows, changing ``nucleo_L476RG`` for your board:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/samples/boards/stm32/power_mgmt/standby_shutdown
+   :board: nucleo_L476RG
+   :goals: build flash
+   :compact:
+
+After flashing, the LED starts to blink.
+Press and hold the user button:
+when LED2 is OFF to enter to Shutdown Mode
+when LED2 is ON to enter to Standby Mode
+release the user button to exit from shutdown mode or from shutdown mode.
+
+PM configurations
+*****************
+
+By default, :kconfig:option:`CONFIG_PM` is enabled.

samples/boards/stm32/power_mgmt/standby_shutdown/prj.conf

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+CONFIG_PM=y
+CONFIG_PM_DEVICE=n
+CONFIG_PM_DEVICE_RUNTIME=n
+CONFIG_HWINFO=y

samples/boards/stm32/power_mgmt/standby_shutdown/sample.yaml

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+sample:
+  name: STM32 GPIO Power Management
+tests:
+  sample.boards.stm32.power_mgmt.standby_shutdown:
+    platform_allow: nucleo_l476rg disco_l475_iot1
+    tags: LED power
+    harness: console
+    harness_config:
+      type: multi_line
+      regex:
+        - "Reset cause: Reset pin"
+        - "Device ready: .*"
+        - "Press and hold the user button:"
+        - "when LED2 is OFF to enter to Shutdown Mode"
+        - "when LED2 is ON to enter to Standby Mode"
+    filter: dt_compat_enabled("zephyr,power-state") and
+            dt_enabled_alias_with_parent_compat("led0", "gpio-leds") and
+            dt_compat_enabled("st,stm32-lptim")
+    extra_args: "CONFIG_DEBUG=y"

samples/boards/stm32/power_mgmt/standby_shutdown/src/main.c

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+/*
+ * Copyright (c) 2023 STMicroelectronics
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/drivers/hwinfo.h>
+#include <zephyr/kernel.h>
+#include <zephyr/device.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/sys/printk.h>
+#include <zephyr/pm/pm.h>
+#include <stm32_ll_pwr.h>
+
+#if !defined(CONFIG_SOC_SERIES_STM32L4X)
+#error Not implemented for other series
+#endif  /* CONFIG_SOC_SERIES_STM32L4X */
+
+#define STACKSIZE 1024
+#define PRIORITY 7
+#define SLEEP_TIME_MS   3000
+
+#define SW0_NODE	DT_ALIAS(sw0)
+#if !DT_NODE_HAS_STATUS(SW0_NODE, okay)
+#error "Unsupported board: sw0 devicetree alias is not defined"
+#endif
+
+/* Semaphore used to control button pressed value */
+static struct k_sem button_sem;
+
+static int led_is_on;
+
+static const struct gpio_dt_spec button =
+	GPIO_DT_SPEC_GET_OR(SW0_NODE, gpios, {0});
+
+static const struct gpio_dt_spec led =
+	GPIO_DT_SPEC_GET(DT_ALIAS(led0), gpios);
+
+static struct gpio_callback button_cb_data;
+
+void config_wakeup_features(void)
+{
+	/* Configure wake-up features */
+	/* WKUP2(PC13) only , - active low, pull-up */
+	/* Set pull-ups for standby modes */
+	LL_PWR_EnableGPIOPullUp(LL_PWR_GPIO_C, LL_PWR_GPIO_BIT_13);
+	LL_PWR_IsWakeUpPinPolarityLow(LL_PWR_WAKEUP_PIN2);
+	/* Enable pin pull up configurations and wakeup pins */
+	LL_PWR_EnablePUPDCfg();
+	LL_PWR_EnableWakeUpPin(LL_PWR_WAKEUP_PIN2);
+	/* Clear wakeup flags */
+	LL_PWR_ClearFlag_WU();
+}
+
+void button_pressed(const struct device *dev, struct gpio_callback *cb,
+		    uint32_t pins)
+{
+	k_sem_give(&button_sem);
+}
+
+void thread_shutdown_standby_mode(void)
+{
+	k_sem_init(&button_sem, 0, 1);
+	k_sem_take(&button_sem, K_FOREVER);
+	gpio_pin_configure(led.port, led.pin, GPIO_DISCONNECTED);
+	printk("User button pressed\n");
+	config_wakeup_features();
+	if (led_is_on == false) {
+		printk("Shutdown Mode requested\n");
+		printk("Release the user button to exit from Shutdown Mode\n\n");
+#ifdef CONFIG_LOG
+		k_msleep(2000);
+#endif /* CONFIG_LOG */
+		pm_state_force(0u, &(struct pm_state_info) {PM_STATE_SOFT_OFF, 0, 0});
+		/* stay in Shutdown mode until wakeup line activated */
+	} else {
+		printk("Standby Mode requested\n");
+		printk("Release the user button to exit from Standby Mode\n\n");
+#ifdef CONFIG_LOG
+		k_msleep(2000);
+#endif /* CONFIG_LOG */
+		pm_state_force(0u, &(struct pm_state_info) {PM_STATE_STANDBY, 0, 0});
+		/* stay in Standby mode until wakeup line activated */
+	}
+}
+
+K_THREAD_DEFINE(thread_shutdown_standby_mode_id, STACKSIZE, thread_shutdown_standby_mode,
+	NULL, NULL, NULL, PRIORITY, 0, 0);
+
+void main(void)
+{
+	int ret;
+	uint32_t cause;
+
+	hwinfo_get_reset_cause(&cause);
+	hwinfo_clear_reset_cause();
+
+	if ((LL_PWR_IsActiveFlag_SB() == true) && (cause == 0))	{
+		LL_PWR_ClearFlag_SB();
+		LL_PWR_ClearFlag_WU();
+		printk("\nReset cause: Standby mode\n\n");
+	}
+
+	if (cause == (RESET_PIN | RESET_BROWNOUT)) {
+		LL_PWR_ClearFlag_WU();
+		printk("\nReset cause: Shutdown mode or power up\n\n");
+	}
+
+	if (cause == RESET_PIN) {
+		LL_PWR_ClearFlag_WU();
+		printk("\nReset cause: Reset pin\n\n");
+	}
+
+
+	__ASSERT_NO_MSG(device_is_ready(led.port));
+	if (!gpio_is_ready_dt(&button)) {
+		printk("Error: button device %s is not ready\n",
+			button.port->name);
+		return;
+	}
+
+	ret = gpio_pin_configure_dt(&button, GPIO_INPUT);
+	if (ret != 0) {
+		printk("Error %d: failed to configure %s pin %d\n",
+			ret, button.port->name, button.pin);
+		return;
+	}
+
+	ret = gpio_pin_interrupt_configure_dt(&button,
+					      GPIO_INT_EDGE_TO_ACTIVE);
+	if (ret != 0) {
+		printk("Error %d: failed to configure interrupt on %s pin %d\n",
+			ret, button.port->name, button.pin);
+		return;
+	}
+
+	gpio_init_callback(&button_cb_data, button_pressed, BIT(button.pin));
+	gpio_add_callback(button.port, &button_cb_data);
+
+	printk("Device ready: %s\n\n\n", CONFIG_BOARD);
+
+	printk("Press and hold the user button:\n");
+	printk("  when LED2 is OFF to enter to Shutdown Mode\n");
+	printk("  when LED2 is ON to enter to Standby Mode\n\n");
+
+	led_is_on = true;
+	while (true) {
+		gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);
+		gpio_pin_set(led.port, led.pin, (int)led_is_on);
+		k_msleep(SLEEP_TIME_MS);
+		led_is_on = !led_is_on;
+	}
+
+}