Commit 2958f691 authored by Ioannis Karachalios's avatar Ioannis Karachalios Committed by Anas Nashif
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drivers: mipi_dbi: smartbond: Optimize driver PM 



This commit should optimize the way the device is allowed
to enter the suspended state. Instead of returning a PM
error code to abort the PM process, the standby power state
is constrained as long as the device is not allowed to enter
suspension. With that approach, acquiring PD_SYS is not needed
when in PM device runtime mode.

Signed-off-by: default avatarIoannis Karachalios <ioannis.karachalios.px@renesas.com>
parent 33665348

drivers/mipi_dbi/mipi_dbi_smartbond.c

+21 −43
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <zephyr/device.h>

#include <zephyr/pm/device.h>

#include <zephyr/pm/device_runtime.h>

#include <zephyr/pm/policy.h>

#include <DA1469xAB.h>

#include <zephyr/drivers/clock_control.h>

#include <zephyr/drivers/clock_control/smartbond_clock_control.h>
@@ -62,10 +63,6 @@ struct mipi_dbi_smartbond_data { 
	struct k_sem sync_sem;

	/* Flag indicating whether or not an underflow took place */

	volatile bool underflow_flag;

#if defined(CONFIG_PM_DEVICE) || defined(CONFIG_PM_DEVICE_RUNTIME)

	/* Flag to designate whether or not a frame update is in progress */

	bool is_active;

#endif

	/* Layer settings */

	lcdc_smartbond_layer_cfg layer;

};
@@ -82,23 +79,20 @@ struct mipi_dbi_smartbond_config { 
};



/* Mark the device is is progress and so it's not allowed to enter the sleep state. */

static void mipi_dbi_pm_get(const struct device *dev)

static inline void mipi_dbi_smartbond_pm_policy_state_lock_get(void)

{

#ifdef CONFIG_PM_DEVICE

	struct mipi_dbi_smartbond_data *data = dev->data;



	data->is_active = true;

#endif

	/*

	 * Prevent the SoC from etering the normal sleep state as PDC does not support

	 * waking up the application core following LCDC events.

	 */

	pm_policy_state_lock_get(PM_STATE_STANDBY, PM_ALL_SUBSTATES);

}



/* Mark that device is inactive and so it's allowed to enter the sleep state */

static void mipi_dbi_pm_put(const struct device *dev)

static inline void mipi_dbi_smartbond_pm_policy_state_lock_put(void)

{

#ifdef CONFIG_PM_DEVICE

	struct mipi_dbi_smartbond_data *data = dev->data;



	data->is_active = false;

#endif

	/* Allow the SoC to enter the nornmal sleep state once LCDC is inactive */

	pm_policy_state_lock_put(PM_STATE_STANDBY, PM_ALL_SUBSTATES);

}



/* Helper function to trigger the LCDC fetching data from frame buffer to the connected display */
@@ -217,6 +211,8 @@ static int mipi_dbi_smartbond_command_read(const struct device *dev, 


	k_sem_take(&data->device_sem, K_FOREVER);



	mipi_dbi_smartbond_pm_policy_state_lock_get();



	/*

	 * Add an arbitrary valid color format to satisfy subroutine. The MIPI DBI command/data

	 * engine should not be affected.
@@ -283,6 +279,8 @@ _mipi_dbi_read_exit: 
		LOG_ERR("Could not apply MIPI DBI pins' default state (%d)", ret);

	}



	mipi_dbi_smartbond_pm_policy_state_lock_put();



	k_sem_give(&data->device_sem);



	return ret;
@@ -300,7 +298,7 @@ static int mipi_dbi_smartbond_command_write(const struct device *dev, 


	k_sem_take(&data->device_sem, K_FOREVER);



	mipi_dbi_pm_get(dev);

	mipi_dbi_smartbond_pm_policy_state_lock_get();



	/*

	 * Add an arbitrary valid color format to satisfy subroutine. The MIPI DBI command/data
@@ -321,7 +319,7 @@ static int mipi_dbi_smartbond_command_write(const struct device *dev, 
		da1469x_lcdc_send_cmd_data(false, data_buf, len);

	}



	mipi_dbi_pm_put(dev);

	mipi_dbi_smartbond_pm_policy_state_lock_put();



	k_sem_give(&data->device_sem);
@@ -349,7 +347,7 @@ static int mipi_dbi_smartbond_write_display(const struct device *dev, 


	k_sem_take(&data->device_sem, K_FOREVER);



	mipi_dbi_pm_get(dev);

	mipi_dbi_smartbond_pm_policy_state_lock_get();



	/*

	 * Mainly check if the frame generator is busy with a pending frame update (might happen
@@ -388,7 +386,7 @@ static int mipi_dbi_smartbond_write_display(const struct device *dev, 


_mipi_dbi_write_exit:



	mipi_dbi_pm_put(dev);

	mipi_dbi_smartbond_pm_policy_state_lock_put();



	k_sem_give(&data->device_sem);
@@ -488,33 +486,14 @@ static int mipi_dbi_smartbond_suspend(const struct device *dev) 


static int mipi_dbi_smartbond_pm_action(const struct device *dev, enum pm_device_action action)

{

	/* Initialize with an error code that should abort sleeping */

	int ret = -EBUSY;

	struct mipi_dbi_smartbond_data *data = dev->data;

	int ret = 0;



	switch (action) {

	case PM_DEVICE_ACTION_SUSPEND:

		/* Sleep is only allowed when there are no active LCDC operations */

		if (!data->is_active) {

		/* A non-zero value should not affect sleep */

		(void)mipi_dbi_smartbond_suspend(dev);

			/*

			 * Once the display block is turned off, its power domain

			 * can be released as well.

			 */

			da1469x_pd_release_nowait(MCU_PD_DOMAIN_SYS);

			ret = 0;

		}

		break;

	case PM_DEVICE_ACTION_RESUME:

		__ASSERT_NO_MSG(!data->is_active);



		/*

		 * Although PD_SYS should already be turned on, make sure LCD controller's

		 * power domain is up and running before accessing the display block.

		 * Acquiring PD_SYS is mandatory when in PM runtime mode.

		 */

		da1469x_pd_acquire(MCU_PD_DOMAIN_SYS);



		/*

		 * The resume error code should not be taken into consideration

		 * by the PM subsystem.
@@ -559,7 +538,6 @@ static int mipi_dbi_smartbond_init(const struct device *dev) 


	ret = pm_device_runtime_enable(dev);

#else

	da1469x_pd_acquire(MCU_PD_DOMAIN_SYS);

	/* Resme if either PM is not used at all or if PM without runtime is used. */

	ret = mipi_dbi_smartbond_resume(dev);

#endif

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