drivers: serial: stm32 uart implements driver enable
Enables the use of the hardware DE pin provided by an stm32 UART using
device tree flags.
Signed-off-by: Abram Early <abram.early@gmail.com>
diff --git a/drivers/serial/uart_stm32.c b/drivers/serial/uart_stm32.c
index 55d6b22..653e520 100644
--- a/drivers/serial/uart_stm32.c
+++ b/drivers/serial/uart_stm32.c
@@ -1705,6 +1705,23 @@
}
#endif
+#ifdef USART_CR3_DEM
+ if (config->de_enable) {
+ if (!IS_UART_DRIVER_ENABLE_INSTANCE(config->usart)) {
+ LOG_ERR("%s does not support driver enable", dev->name);
+ return -EINVAL;
+ }
+
+ LL_USART_EnableDEMode(config->usart);
+ LL_USART_SetDEAssertionTime(config->usart, config->de_assert_time);
+ LL_USART_SetDEDeassertionTime(config->usart, config->de_deassert_time);
+
+ if (config->de_invert) {
+ LL_USART_SetDESignalPolarity(config->usart, LL_USART_DE_POLARITY_LOW);
+ }
+ }
+#endif
+
LL_USART_Enable(config->usart);
#ifdef USART_ISR_TEACK
@@ -1918,6 +1935,10 @@
.tx_rx_swap = DT_INST_PROP_OR(index, tx_rx_swap, false), \
.rx_invert = DT_INST_PROP(index, rx_invert), \
.tx_invert = DT_INST_PROP(index, tx_invert), \
+ .de_enable = DT_INST_PROP(index, de_enable), \
+ .de_assert_time = DT_INST_PROP(index, de_assert_time), \
+ .de_deassert_time = DT_INST_PROP(index, de_deassert_time), \
+ .de_invert = DT_INST_PROP(index, de_invert), \
STM32_UART_IRQ_HANDLER_FUNC(index) \
STM32_UART_PM_WAKEUP(index) \
}; \
diff --git a/drivers/serial/uart_stm32.h b/drivers/serial/uart_stm32.h
index 9a4a4e7..15cf0a5 100644
--- a/drivers/serial/uart_stm32.h
+++ b/drivers/serial/uart_stm32.h
@@ -36,6 +36,14 @@
bool rx_invert;
/* enable tx pin inversion */
bool tx_invert;
+ /* enable de signal */
+ bool de_enable;
+ /* de signal assertion time in 1/16 of a bit */
+ uint8_t de_assert_time;
+ /* de signal deassertion time in 1/16 of a bit */
+ uint8_t de_deassert_time;
+ /* enable de pin inversion */
+ bool de_invert;
const struct pinctrl_dev_config *pcfg;
#if defined(CONFIG_UART_INTERRUPT_DRIVEN) || defined(CONFIG_UART_ASYNC_API) || \
defined(CONFIG_PM)
diff --git a/dts/bindings/serial/st,stm32-uart-base.yaml b/dts/bindings/serial/st,stm32-uart-base.yaml
index fbe5973..ed8a6e1 100644
--- a/dts/bindings/serial/st,stm32-uart-base.yaml
+++ b/dts/bindings/serial/st,stm32-uart-base.yaml
@@ -58,3 +58,31 @@
configured masked at boot (sm32wl55 for instance), preventing the device to wakeup
the core from stop mode(s).
Valid range: 0 - 31
+
+ de-enable:
+ type: boolean
+ description: |
+ Enable activating an external transeiver through the DE pin which must also be configured
+ using pinctrl.
+
+ de-assert-time:
+ type: int
+ default: 0
+ description: |
+ Defines the time between the activation of the DE signal and the beginning of the start bit.
+ It is expressed in 16th of a bit time.
+ Valid range: 0 - 31
+
+ de-deassert-time:
+ type: int
+ default: 0
+ description: |
+ Defines the time between the activation of the DE signal and the beginning of the start bit.
+ It is expressed in 16th of a bit time.
+ Valid range: 0 - 31
+
+ de-invert:
+ type: boolean
+ description: |
+ Invert the binary logic of the de pin. When enabled, physical logic levels are inverted and
+ we use 1=Low, 0=High instead of 1=High, 0=Low.
