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drivers: serial: uart_max32: Add power management support #97449

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drivers: serial: uart_max32: Add power management support #97449

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65 changes: 62 additions & 3 deletions drivers/serial/uart_max32.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
#include <zephyr/drivers/uart.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>
#include <zephyr/pm/device.h>
#include <zephyr/drivers/clock_control/adi_max32_clock_control.h>

#include <wrap_max32_uart.h>
Expand Down Expand Up @@ -987,6 +988,63 @@ static void uart_max32_async_rx_timeout(struct k_work *work)

#endif

#ifdef CONFIG_PM_DEVICE
static int uart_max32_pm_action(const struct device *dev, enum pm_device_action action)
{
int ret;
const struct max32_uart_config *const cfg = dev->config;

switch (action) {
case PM_DEVICE_ACTION_RESUME:

/* Enable clock */
ret = clock_control_on(cfg->clock, (clock_control_subsys_t)&cfg->perclk);
if (ret != 0) {
LOG_ERR("cannot enable UART clock");
return ret;
}

/* Set pins to active state */
ret = pinctrl_apply_state(cfg->pctrl, PINCTRL_STATE_DEFAULT);
if (ret) {
return ret;
}

break;
case PM_DEVICE_ACTION_SUSPEND:
/* Flush uart before sleep */
while (MXC_UART_ReadyForSleep(cfg->regs) != E_NO_ERROR) {
}

/* Move pins to sleep state */
ret = pinctrl_apply_state(cfg->pctrl, PINCTRL_STATE_SLEEP);
if ((ret < 0) && (ret != -ENOENT)) {
/*
* If returning -ENOENT, no pins where defined for sleep mode :
* Do not output on console (might sleep already) when going to sleep,
* "(LP)UART pinctrl sleep state not available"
* and don't block PM suspend.
* Else return the error.
*/
return ret;
}

/* Disable clock */
ret = clock_control_off(cfg->clock, (clock_control_subsys_t)&cfg->perclk);
if (ret != 0) {
LOG_ERR("cannot disable UART clock");
return ret;
}

break;
default:
return -ENOTSUP;
}

return 0;
}
#endif /* CONFIG_PM_DEVICE */

static DEVICE_API(uart, uart_max32_driver_api) = {
.poll_in = api_poll_in,
.poll_out = api_poll_out,
Expand Down Expand Up @@ -1074,8 +1132,9 @@ static DEVICE_API(uart, uart_max32_driver_api) = {
MAX32_UART_USE_IRQ, (.irq_config_func = uart_max32_irq_init_##_num,))}; \
static struct max32_uart_data max32_uart_data##_num = { \
IF_ENABLED(CONFIG_UART_INTERRUPT_DRIVEN, (.cb = NULL,))}; \
DEVICE_DT_INST_DEFINE(_num, uart_max32_init, NULL, &max32_uart_data##_num, \
&max32_uart_config_##_num, PRE_KERNEL_1, \
CONFIG_SERIAL_INIT_PRIORITY, (void *)&uart_max32_driver_api);
PM_DEVICE_DT_INST_DEFINE(_num, uart_max32_pm_action); \
DEVICE_DT_INST_DEFINE(_num, uart_max32_init, PM_DEVICE_DT_INST_GET(_num), \
&max32_uart_data##_num, &max32_uart_config_##_num, PRE_KERNEL_1, \
CONFIG_SERIAL_INIT_PRIORITY, (void *)&uart_max32_driver_api);

DT_INST_FOREACH_STATUS_OKAY(MAX32_UART_INIT)