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drivers: display: smartbond: Optimize driver PM

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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: Ioannis Karachalios <ioannis.karachalios.px@renesas.com>
This commit is contained in:
Ioannis Karachalios 2024-05-21 19:30:40 +03:00 committed by Anas Nashif
parent 2958f691bb
commit 71a5f1b9fd
1 changed files with 30 additions and 22 deletions
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52
drivers/display/display_renesas_lcdc.c
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@ -22,6 +22,7 @@
#include <zephyr/linker/devicetree_regions.h>
#include <zephyr/pm/device.h>
#include <zephyr/pm/device_runtime.h>
#include <zephyr/pm/policy.h>
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(smartbond_display, CONFIG_DISPLAY_LOG_LEVEL);
@ -75,8 +76,7 @@ struct display_smartbond_data {
/* Granted DMA channel used for memory transfers */
int dma_channel;
#if defined(CONFIG_PM_DEVICE) || defined(CONFIG_PM_DEVICE_RUNTIME)
/* Flag to determine if device suspension is allowed */
bool is_sleep_allowed;
ATOMIC_DEFINE(pm_policy_state_flag, 1);
#endif
};
@ -99,6 +99,29 @@ struct display_smartbond_config {
enum display_pixel_format pixel_format;
};
static inline void lcdc_smartbond_pm_policy_state_lock_get(struct display_smartbond_data *data)
{
#if defined(CONFIG_PM_DEVICE) || defined(CONFIG_PM_DEVICE_RUNTIME)
if (atomic_test_and_set_bit(data->pm_policy_state_flag, 0) == 0) {
/*
* 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);
}
#endif
}
static inline void lcdc_smartbond_pm_policy_state_lock_put(struct display_smartbond_data *data)
{
#if defined(CONFIG_PM_DEVICE) || defined(CONFIG_PM_DEVICE_RUNTIME)
if (atomic_test_and_clear_bit(data->pm_policy_state_flag, 0) == 1) {
/* Allow the SoC to enter the nornmal sleep state once LCDC is inactive */
pm_policy_state_lock_put(PM_STATE_STANDBY, PM_ALL_SUBSTATES);
}
#endif
}
/* Display pixel to layer color format translation */
static uint8_t lcdc_smartbond_pixel_to_lcm(enum display_pixel_format pixel_format)
{
@ -319,11 +342,6 @@ static int display_smartbond_init(const struct device *dev)
pm_device_init_suspended(dev);
ret = pm_device_runtime_enable(dev);
/* Sleep is allowed until the device is explicitly resumed on application level. */
if (ret == 0) {
data->is_sleep_allowed = true;
}
#else
/* Resume if either PM is not used at all or if PM without runtime is used. */
ret = display_smartbond_resume(dev);
@ -355,13 +373,11 @@ static int display_smartbond_blanking_on(const struct device *dev)
}
}
#if defined(CONFIG_PM_DEVICE) || defined(CONFIG_PM_DEVICE_RUNTIME)
/*
* At this moment the display panel should be turned off and so the device
* can enter the suspend state.
*/
data->is_sleep_allowed = true;
#endif
lcdc_smartbond_pm_policy_state_lock_put(data);
k_sem_give(&data->device_sem);
@ -391,13 +407,11 @@ static int display_smartbond_blanking_off(const struct device *dev)
*/
LCDC->LCDC_MODE_REG &= ~LCDC_LCDC_MODE_REG_LCDC_FORCE_BLANK_Msk;
#if defined(CONFIG_PM_DEVICE) || defined(CONFIG_PM_DEVICE_RUNTIME)
/*
* At this moment the display should be turned on and so the device
* cannot enter the suspend state.
*/
data->is_sleep_allowed = false;
#endif
lcdc_smartbond_pm_policy_state_lock_get(data);
k_sem_give(&data->device_sem);
@ -566,20 +580,14 @@ static int display_smartbond_write(const struct device *dev,
#if defined(CONFIG_PM_DEVICE) || defined(CONFIG_PM_DEVICE_RUNTIME)
static int display_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 display_smartbond_data *data = dev->data;
int ret = 0;
switch (action) {
case PM_DEVICE_ACTION_SUSPEND:
/* Sleep is only allowed whne display blanking is activated */
if (data->is_sleep_allowed) {
(void)display_smartbond_suspend(dev);
ret = 0;
}
/* A non-zero value should not affect sleep */
(void)display_smartbond_suspend(dev);
break;
case PM_DEVICE_ACTION_RESUME:
__ASSERT_NO_MSG(data->is_sleep_allowed);
/*
* The resume error code should not be taken into consideration
* by the PM subsystem