flash: spi_nor: automatically handle device runtime PM (remove IDLE_IN_DPD)

doc/releases/migration-guide-4.0.rst

@@ -113,6 +113,11 @@ Other Subsystems
 Flash map
 =========
 
+ * ``CONFIG_SPI_NOR_IDLE_IN_DPD`` has been removed from the :kconfig:option:`CONFIG_SPI_NOR`
+   driver. An enhanced version of this functionality can be obtained by enabling
+   :ref:`pm-device-runtime` on the device (Tunable with
+   :kconfig:option:`CONFIG_SPI_NOR_ACTIVE_DWELL_MS`).
+
 hawkBit
 =======
 

drivers/flash/Kconfig.nor

@@ -78,16 +78,15 @@ config SPI_NOR_FLASH_LAYOUT_PAGE_SIZE
 	  (32768), the sector size (4096), or any non-zero multiple of the
 	  sector size.
 
-config SPI_NOR_IDLE_IN_DPD
-	bool "Use Deep Power-Down mode when flash is not being accessed."
+config SPI_NOR_ACTIVE_DWELL_MS
+	int "Dwell period (ms) after last use to stay in active mode"
+	depends on PM_DEVICE_RUNTIME
+	default 10
 	help
-	  Where supported deep power-down mode can reduce current draw
-	  to as little as 0.1% of standby current.  However it takes
-	  some milliseconds to enter and exit from this mode.
-
-	  Select this option for applications where device power
-	  management is not enabled, the flash remains inactive for
-	  long periods, and when used the impact of waiting for mode
-	  enter and exit delays is acceptable.
+	  Flash accesses commonly occur in bursts, where entering and exiting DPD
+	  mode between each access adds significantly to the total operation time.
+	  This option controls how long to remain in active mode after each API
+	  call, eliminating the active->idle->active transition sequence if another
+	  transaction occurs before the dwell period expires.
 
 endif # SPI_NOR

drivers/flash/spi_nor.c

@@ -19,6 +19,7 @@
 #include <zephyr/logging/log.h>
 #include <zephyr/sys_clock.h>
 #include <zephyr/pm/device.h>
+#include <zephyr/pm/device_runtime.h>
 
 #include "spi_nor.h"
 #include "jesd216.h"
@@ -35,15 +36,10 @@ LOG_MODULE_REGISTER(spi_nor, CONFIG_FLASH_LOG_LEVEL);
  * * Some devices support a Deep Power-Down mode which reduces current
  *   to as little as 0.1% of standby.
  *
- * The power reduction from DPD is sufficient to warrant allowing its
- * use even in cases where Zephyr's device power management is not
- * available.  This is selected through the SPI_NOR_IDLE_IN_DPD
- * Kconfig option.
- *
  * When mapped to the Zephyr Device Power Management states:
  * * PM_DEVICE_STATE_ACTIVE covers both active and standby modes;
- * * PM_DEVICE_STATE_SUSPENDED, and PM_DEVICE_STATE_OFF all correspond to
- *   deep-power-down mode.
+ * * PM_DEVICE_STATE_SUSPENDED corresponds to deep-power-down mode;
+ * * PM_DEVICE_STATE_OFF covers the powered off state;
  */
 
 #define SPI_NOR_MAX_ADDR_WIDTH 4
@@ -70,6 +66,12 @@ LOG_MODULE_REGISTER(spi_nor, CONFIG_FLASH_LOG_LEVEL);
 #define ANY_INST_HAS_WP_GPIOS ANY_INST_HAS_PROP(wp_gpios)
 #define ANY_INST_HAS_HOLD_GPIOS ANY_INST_HAS_PROP(hold_gpios)
 
+#ifdef CONFIG_SPI_NOR_ACTIVE_DWELL_MS
+#define ACTIVE_DWELL_MS CONFIG_SPI_NOR_ACTIVE_DWELL_MS
+#else
+#define ACTIVE_DWELL_MS 0
+#endif
+
 #define DEV_CFG(_dev_) ((const struct spi_nor_config * const) (_dev_)->config)
 
 /* MXICY Related defines*/
@@ -552,34 +554,26 @@ static int exit_dpd(const struct device *const dev)
 	return ret;
 }
 
-/* Everything necessary to acquire owning access to the device.
- *
- * This means taking the lock and, if necessary, waking the device
- * from deep power-down mode.
- */
+/* Everything necessary to acquire owning access to the device. */
 static void acquire_device(const struct device *dev)
 {
+	const struct spi_nor_config *cfg = dev->config;
+
 	if (IS_ENABLED(CONFIG_MULTITHREADING)) {
 		struct spi_nor_data *const driver_data = dev->data;
 
 		k_sem_take(&driver_data->sem, K_FOREVER);
 	}
 
-	if (IS_ENABLED(CONFIG_SPI_NOR_IDLE_IN_DPD)) {
-		exit_dpd(dev);
-	}
+	(void)pm_device_runtime_get(cfg->spi.bus);
 }
 
-/* Everything necessary to release access to the device.
- *
- * This means (optionally) putting the device into deep power-down
- * mode, and releasing the lock.
- */
+/* Everything necessary to release access to the device. */
 static void release_device(const struct device *dev)
 {
-	if (IS_ENABLED(CONFIG_SPI_NOR_IDLE_IN_DPD)) {
-		enter_dpd(dev);
-	}
+	const struct spi_nor_config *cfg = dev->config;
+
+	(void)pm_device_runtime_put(cfg->spi.bus);
 
 	if (IS_ENABLED(CONFIG_MULTITHREADING)) {
 		struct spi_nor_data *const driver_data = dev->data;
@@ -783,11 +777,19 @@ static int spi_nor_read(const struct device *dev, off_t addr, void *dest,
 		return -EINVAL;
 	}
 
+	/* Ensure flash is powered before read */
+	if (pm_device_runtime_get(dev) < 0) {
+		return -EIO;
+	}
+
 	acquire_device(dev);
 
 	ret = spi_nor_cmd_addr_read(dev, SPI_NOR_CMD_READ, addr, dest, size);
 
 	release_device(dev);
+
+	/* Release flash power requirement */
+	(void)pm_device_runtime_put_async(dev, K_MSEC(ACTIVE_DWELL_MS));
 	return ret;
 }
 
@@ -800,6 +802,10 @@ static int flash_spi_nor_ex_op(const struct device *dev, uint16_t code,
 	ARG_UNUSED(in);
 	ARG_UNUSED(out);
 
+	if (pm_device_runtime_get(dev) < 0) {
+		return -EIO;
+	}
+
 	acquire_device(dev);
 
 	switch (code) {
@@ -815,6 +821,7 @@ static int flash_spi_nor_ex_op(const struct device *dev, uint16_t code,
 	}
 
 	release_device(dev);
+	(void)pm_device_runtime_put_async(dev, K_MSEC(ACTIVE_DWELL_MS));
 	return ret;
 }
 #endif
@@ -832,6 +839,11 @@ static int spi_nor_write(const struct device *dev, off_t addr,
 		return -EINVAL;
 	}
 
+	/* Ensure flash is powered before write */
+	if (pm_device_runtime_get(dev) < 0) {
+		return -EIO;
+	}
+
 	acquire_device(dev);
 	ret = spi_nor_write_protection_set(dev, false);
 	if (ret == 0) {
@@ -879,6 +891,9 @@ static int spi_nor_write(const struct device *dev, off_t addr,
 	}
 
 	release_device(dev);
+
+	/* Release flash power requirement */
+	(void)pm_device_runtime_put_async(dev, K_MSEC(ACTIVE_DWELL_MS));
 	return ret;
 }
 
@@ -902,6 +917,11 @@ static int spi_nor_erase(const struct device *dev, off_t addr, size_t size)
 		return -EINVAL;
 	}
 
+	/* Ensure flash is powered before erase */
+	if (pm_device_runtime_get(dev) < 0) {
+		return -EIO;
+	}
+
 	acquire_device(dev);
 	ret = spi_nor_write_protection_set(dev, false);
 
@@ -957,6 +977,8 @@ static int spi_nor_erase(const struct device *dev, off_t addr, size_t size)
 
 	release_device(dev);
 
+	/* Release flash power requirement */
+	(void)pm_device_runtime_put_async(dev, K_MSEC(ACTIVE_DWELL_MS));
 	return ret;
 }
 
@@ -998,12 +1020,18 @@ static int spi_nor_write_protection_set(const struct device *dev,
 static int spi_nor_sfdp_read(const struct device *dev, off_t addr,
 			     void *dest, size_t size)
 {
+	if (pm_device_runtime_get(dev) < 0) {
+		return -EIO;
+	}
+
 	acquire_device(dev);
 
 	int ret = read_sfdp(dev, addr, dest, size);
 
 	release_device(dev);
 
+	(void)pm_device_runtime_put_async(dev, K_MSEC(ACTIVE_DWELL_MS));
+
 	return ret;
 }
 
@@ -1016,12 +1044,18 @@ static int spi_nor_read_jedec_id(const struct device *dev,
 		return -EINVAL;
 	}
 
+	if (pm_device_runtime_get(dev) < 0) {
+		return -EIO;
+	}
+
 	acquire_device(dev);
 
 	int ret = spi_nor_cmd_read(dev, SPI_NOR_CMD_RDID, id, SPI_NOR_MAX_ID_LEN);
 
 	release_device(dev);
 
+	(void)pm_device_runtime_put_async(dev, K_MSEC(ACTIVE_DWELL_MS));
+
 	return ret;
 }
 
@@ -1439,11 +1473,6 @@ static int spi_nor_pm_control(const struct device *dev, enum pm_device_action ac
 	int rc = 0;
 
 	switch (action) {
-#ifdef CONFIG_SPI_NOR_IDLE_IN_DPD
-	case PM_DEVICE_ACTION_SUSPEND:
-	case PM_DEVICE_ACTION_RESUME:
-		break;
-#else
 	case PM_DEVICE_ACTION_SUSPEND:
 		acquire_device(dev);
 		rc = enter_dpd(dev);
@@ -1454,11 +1483,9 @@ static int spi_nor_pm_control(const struct device *dev, enum pm_device_action ac
 		rc = exit_dpd(dev);
 		release_device(dev);
 		break;
-#endif /* CONFIG_SPI_NOR_IDLE_IN_DPD */
 	case PM_DEVICE_ACTION_TURN_ON:
 		/* Coming out of power off */
 		rc = spi_nor_configure(dev);
-#ifndef CONFIG_SPI_NOR_IDLE_IN_DPD
 		if (rc == 0) {
 			/* Move to DPD, the correct device state
 			 * for PM_DEVICE_STATE_SUSPENDED
@@ -1467,7 +1494,6 @@ static int spi_nor_pm_control(const struct device *dev, enum pm_device_action ac
 			rc = enter_dpd(dev);
 			release_device(dev);
 		}
-#endif /* CONFIG_SPI_NOR_IDLE_IN_DPD */
 		break;
 	case PM_DEVICE_ACTION_TURN_OFF:
 		break;

samples/drivers/spi_flash/sample.yaml

@@ -20,13 +20,3 @@ tests:
         - "Attempting to write 4 bytes"
         - "Data read matches data written. Good!!"
     depends_on: spi
-  sample.drivers.spi.flash_dpd:
-    tags:
-      - spi
-      - flash
-    filter: dt_compat_enabled("jedec,spi-nor")
-    platform_exclude: hifive_unmatched
-    build_only: true
-    extra_configs:
-      - CONFIG_SPI_NOR_IDLE_IN_DPD=y
-    depends_on: spi