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drivers: uart_sam0: add support for collision detection error

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Automatic collision detection for half-duplex mode can be enabled
by setting `collision-detection` proprety for uart hardware
in the dts file. If the transmitted bit does not match the received
bit an error is raised. This is useful in RS-485 half-duplex mode.

Signed-off-by: Arvin Farahmand <arvinf@ip-logix.com>
This commit is contained in:
Arvin Farahmand 2021-04-16 22:03:29 -04:00 committed by Anas Nashif
parent bc839c8707
commit a687610b80
2 changed files with 19 additions and 0 deletions
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15
drivers/serial/uart_sam0.c
View file

@ -32,6 +32,7 @@ struct uart_sam0_dev_cfg {
SercomUsart *regs;
uint32_t baudrate;
uint32_t pads;
bool collision_detect;
#ifdef MCLK
volatile uint32_t *mclk;
uint32_t mclk_mask;
@ -479,6 +480,10 @@ static int uart_sam0_configure(const struct device *dev,
dev_data->config_cache.data_bits = new_cfg->data_bits;
#if defined(SERCOM_REV500)
CTRLB_temp.bit.COLDEN = cfg->pads;
#endif
usart->CTRLA = CTRLA_temp;
wait_synchronization(usart);
@ -846,9 +851,14 @@ static int uart_sam0_err_check(const struct device *dev)
err |= UART_BREAK;
}
if (regs->STATUS.reg & SERCOM_USART_STATUS_COLL) {
err |= UART_ERROR_COLLISION;
}
regs->STATUS.reg |= SERCOM_USART_STATUS_BUFOVF
| SERCOM_USART_STATUS_FERR
| SERCOM_USART_STATUS_PERR
| SERCOM_USART_STATUS_COLL
| SERCOM_USART_STATUS_ISF;
#else
regs->STATUS.reg |= SERCOM_USART_STATUS_BUFOVF
@ -1188,6 +1198,9 @@ static void uart_sam0_irq_config_##n(const struct device *dev) \
(DT_INST_PROP(n, rxpo) << SERCOM_USART_CTRLA_RXPO_Pos) | \
(DT_INST_PROP(n, txpo) << SERCOM_USART_CTRLA_TXPO_Pos)
#define UART_SAM0_SERCOM_COLLISION_DETECT(n) \
(DT_INST_PROP(n, collision_detect))
#ifdef MCLK
#define UART_SAM0_CONFIG_DEFN(n) \
static const struct uart_sam0_dev_cfg uart_sam0_config_##n = { \
@ -1197,6 +1210,7 @@ static const struct uart_sam0_dev_cfg uart_sam0_config_##n = { \
.mclk_mask = BIT(DT_INST_CLOCKS_CELL_BY_NAME(n, mclk, bit)), \
.gclk_core_id = DT_INST_CLOCKS_CELL_BY_NAME(n, gclk, periph_ch),\
.pads = UART_SAM0_SERCOM_PADS(n), \
.collision_detect = UART_SAM0_SERCOM_PADS(n), \
UART_SAM0_IRQ_HANDLER_FUNC(n) \
UART_SAM0_DMA_CHANNELS(n) \
}
@ -1208,6 +1222,7 @@ static const struct uart_sam0_dev_cfg uart_sam0_config_##n = { \
.pm_apbcmask = BIT(DT_INST_CLOCKS_CELL_BY_NAME(n, pm, bit)), \
.gclk_clkctrl_id = DT_INST_CLOCKS_CELL_BY_NAME(n, gclk, clkctrl_id),\
.pads = UART_SAM0_SERCOM_PADS(n), \
.collision_detect = UART_SAM0_SERCOM_PADS(n), \
UART_SAM0_IRQ_HANDLER_FUNC(n) \
UART_SAM0_DMA_CHANNELS(n) \
}

4
dts/bindings/serial/atmel,sam0-uart.yaml
View file

@ -27,6 +27,10 @@ properties:
required: true
description: Transmit Data Pinout
collision-detection:
type: boolean
description: Enable collision detection for half-duplex mode.
dmas:
description: |
Optional TX & RX dma specifiers. Each specifier will have a phandle