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drivers: serial: stm32: add serial hw flow control

Adds RTS CTS hardware flow control support.

Signed-off-by: Georgij Cernysiov <g.cernysiov@elco-automation.de>
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Georgij Cernysiov authored and galak committed Mar 15, 2019
1 parent c74c131 commit 78eed34b78da0131ee61ec885c7fade600e92240
Showing with 61 additions and 4 deletions.
  1. +61 −4 drivers/serial/uart_stm32.c
@@ -7,7 +7,9 @@

/**
* @brief Driver for UART port on STM32 family processor.
*
* @note LPUART and U(S)ART have the same base and
* majority of operations are performed the same way.
* Please validate for newly added series.
*/

#include <kernel.h>
@@ -178,6 +180,20 @@ static inline u32_t uart_stm32_get_databits(struct device *dev)
#endif /* CONFIG_LPUART_1 */
}

static inline void uart_stm32_set_hwctrl(struct device *dev, u32_t hwctrl)
{
USART_TypeDef *UartInstance = UART_STRUCT(dev);

LL_USART_SetHWFlowCtrl(UartInstance, hwctrl);
}

static inline u32_t uart_stm32_get_hwctrl(struct device *dev)
{
USART_TypeDef *UartInstance = UART_STRUCT(dev);

return LL_USART_GetHWFlowCtrl(UartInstance);
}

static inline u32_t uart_stm32_cfg2ll_parity(enum uart_config_parity parity)
{
switch (parity) {
@@ -274,6 +290,38 @@ static inline enum uart_config_data_bits uart_stm32_ll2cfg_databits(u32_t db)
}
}

/**
* @brief Get LL hardware flow control define from
* Zephyr hardware flow control option.
* @note Supports only UART_CFG_FLOW_CTRL_RTS_CTS.
* @param fc: Zephyr hardware flow control option.
* @retval LL_USART_HWCONTROL_RTS_CTS, or LL_USART_HWCONTROL_NONE.
*/
static inline u32_t uart_stm32_cfg2ll_hwctrl(enum uart_config_flow_control fc)
{
if (fc == UART_CFG_FLOW_CTRL_RTS_CTS) {
return LL_USART_HWCONTROL_RTS_CTS;
}

return LL_USART_HWCONTROL_NONE;
}

/**
* @brief Get Zephyr hardware frlow control option from
* LL hardware flow control define.
* @note Supports only LL_USART_HWCONTROL_RTS_CTS.
* @param fc: LL hardware frlow control definition.
* @retval UART_CFG_FLOW_CTRL_RTS_CTS, or UART_CFG_PARITY_NONE.
*/
static inline enum uart_config_flow_control uart_stm32_ll2cfg_hwctrl(u32_t fc)
{
if (fc == LL_USART_HWCONTROL_RTS_CTS) {
return UART_CFG_FLOW_CTRL_RTS_CTS;
}

return UART_CFG_PARITY_NONE;
}

static int uart_stm32_configure(struct device *dev,
const struct uart_config *cfg)
{
@@ -282,6 +330,7 @@ static int uart_stm32_configure(struct device *dev,
const u32_t parity = uart_stm32_cfg2ll_parity(cfg->parity);
const u32_t stopbits = uart_stm32_cfg2ll_stopbits(cfg->stop_bits);
const u32_t databits = uart_stm32_cfg2ll_databits(cfg->data_bits);
const u32_t flowctrl = uart_stm32_cfg2ll_hwctrl(cfg->flow_ctrl);

/* Hardware doesn't support mark or space parity */
if ((UART_CFG_PARITY_MARK == cfg->parity) ||
@@ -321,9 +370,12 @@ static int uart_stm32_configure(struct device *dev,
return -ENOTSUP;
}

/* Driver currently doesn't support line ctrl */
/* Driver supports only RTS CTS flow control */
if (UART_CFG_FLOW_CTRL_NONE != cfg->flow_ctrl) {
return -ENOTSUP;
if (!IS_UART_HWFLOW_INSTANCE(UartInstance) ||
UART_CFG_FLOW_CTRL_RTS_CTS != cfg->flow_ctrl) {
return -ENOTSUP;
}
}

LL_USART_Disable(UartInstance);
@@ -340,6 +392,10 @@ static int uart_stm32_configure(struct device *dev,
uart_stm32_set_databits(dev, databits);
}

if (flowctrl != uart_stm32_get_hwctrl(dev)) {
uart_stm32_set_hwctrl(dev, flowctrl);
}

if (cfg->baudrate != data->baud_rate) {
uart_stm32_set_baudrate(dev, cfg->baudrate);
data->baud_rate = cfg->baudrate;
@@ -359,7 +415,8 @@ static int uart_stm32_config_get(struct device *dev, struct uart_config *cfg)
uart_stm32_get_stopbits(dev));
cfg->data_bits = uart_stm32_ll2cfg_databits(
uart_stm32_get_databits(dev));
cfg->flow_ctrl = UART_CFG_FLOW_CTRL_NONE;
cfg->flow_ctrl = uart_stm32_ll2cfg_hwctrl(
uart_stm32_get_hwctrl(dev));
return 0;
}

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