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drivers: serial: nrfx_uart: Allow TX only mode

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Extended nrf_uart driver to support TX only.
When RX pin is not provided then RX is not started at all. This
allows to achieve low power with logging/console enabled.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>
This commit is contained in:
Krzysztof Chruscinski 2020-02-19 11:46:05 +01:00 • committed by Maureen Helm
commit 6a6063b57a
2 changed files with 32 additions and 10 deletions
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40
drivers/serial/uart_nrfx_uart.c
View file

@ -12,6 +12,13 @@
#include <hal/nrf_uart.h>
#include <hal/nrf_gpio.h>
#ifdef DT_NORDIC_NRF_UART_UART_0_RX_PIN
#define RX_PIN DT_NORDIC_NRF_UART_UART_0_RX_PIN
#else
#define RX_PIN NRF_UART_PSEL_DISCONNECTED
#endif
#define RX_PIN_USED() (RX_PIN != NRF_UART_PSEL_DISCONNECTED)
static NRF_UART_Type *const uart0_addr =
(NRF_UART_Type *)DT_NORDIC_NRF_UART_UART_0_BASE_ADDRESS;
@ -441,9 +448,15 @@ static int uart_nrfx_tx_abort(struct device *dev)
static int uart_nrfx_rx_enable(struct device *dev, u8_t *buf, size_t len,
s32_t timeout)
{
if (!RX_PIN_USED()) {
__ASSERT(false, "TX only UART instance");
return -ENOTSUP;
}
if (uart0_cb.rx_buffer_length != 0) {
return -EBUSY;
}
uart0_cb.rx_enabled = 1;
uart0_cb.rx_buffer = buf;
uart0_cb.rx_buffer_length = len;
@ -925,12 +938,12 @@ static int uart_nrfx_init(struct device *dev)
nrf_gpio_pin_write(DT_NORDIC_NRF_UART_UART_0_TX_PIN, 1);
nrf_gpio_cfg_output(DT_NORDIC_NRF_UART_UART_0_TX_PIN);
nrf_gpio_cfg_input(DT_NORDIC_NRF_UART_UART_0_RX_PIN,
NRF_GPIO_PIN_NOPULL);
if (RX_PIN_USED()) {
nrf_gpio_cfg_input(RX_PIN, NRF_GPIO_PIN_NOPULL);
}
nrf_uart_txrx_pins_set(uart0_addr,
DT_NORDIC_NRF_UART_UART_0_TX_PIN,
DT_NORDIC_NRF_UART_UART_0_RX_PIN);
DT_NORDIC_NRF_UART_UART_0_TX_PIN, RX_PIN);
#if defined(DT_NORDIC_NRF_UART_UART_0_RTS_PIN) && \
defined(DT_NORDIC_NRF_UART_UART_0_CTS_PIN)
/* Setting default height state of the RTS PIN to avoid glitches
@ -959,9 +972,11 @@ static int uart_nrfx_init(struct device *dev)
*/
nrf_uart_enable(uart0_addr);
nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXDRDY);
if (RX_PIN_USED()) {
nrf_uart_event_clear(uart0_addr, NRF_UART_EVENT_RXDRDY);
nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTRX);
nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTRX);
}
#ifdef CONFIG_UART_0_INTERRUPT_DRIVEN
/* Simulate that the TXDRDY event is set, so that the transmitter status
@ -1041,7 +1056,9 @@ static void uart_nrfx_pins_enable(struct device *dev, bool enable)
if (enable) {
nrf_gpio_pin_write(tx_pin, 1);
nrf_gpio_cfg_output(tx_pin);
nrf_gpio_cfg_input(rx_pin, NRF_GPIO_PIN_NOPULL);
if (RX_PIN_USED()) {
nrf_gpio_cfg_input(rx_pin, NRF_GPIO_PIN_NOPULL);
}
if (get_dev_config(dev)->rts_cts_pins_set) {
nrf_gpio_pin_write(rts_pin, 1);
@ -1051,7 +1068,9 @@ static void uart_nrfx_pins_enable(struct device *dev, bool enable)
}
} else {
nrf_gpio_cfg_default(tx_pin);
nrf_gpio_cfg_default(rx_pin);
if (RX_PIN_USED()) {
nrf_gpio_cfg_default(rx_pin);
}
if (get_dev_config(dev)->rts_cts_pins_set) {
nrf_gpio_cfg_default(cts_pin);
nrf_gpio_cfg_default(rts_pin);
@ -1064,7 +1083,10 @@ static void uart_nrfx_set_power_state(struct device *dev, u32_t new_state)
if (new_state == DEVICE_PM_ACTIVE_STATE) {
uart_nrfx_pins_enable(dev, true);
nrf_uart_enable(uart0_addr);
nrf_uart_task_trigger(uart0_addr, NRF_UART_TASK_STARTRX);
if (RX_PIN_USED()) {
nrf_uart_task_trigger(uart0_addr,
NRF_UART_TASK_STARTRX);
}
} else {
__ASSERT_NO_MSG(new_state == DEVICE_PM_LOW_POWER_STATE ||
new_state == DEVICE_PM_SUSPEND_STATE ||

2
dts/bindings/serial/nordic,nrf-uart.yaml
View file

@ -19,7 +19,7 @@ properties:
rx-pin:
type: int
description: RX pin
required: true
required: false
rts-pin:
type: int