drivers/serial/uart_silabs_eusart.c

/*
 * Copyright (c) 2024, Yishai Jaffe
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT silabs_eusart_uart

#include <errno.h>
#include <zephyr/drivers/clock_control.h>
#include <zephyr/drivers/clock_control/clock_control_silabs.h>
#include <zephyr/drivers/pinctrl.h>
#include <zephyr/drivers/uart.h>
#include <zephyr/irq.h>
#include <zephyr/pm/device.h>
#include <em_eusart.h>

struct uart_silabs_eusart_config {
	EUSART_TypeDef *eusart;
	const struct pinctrl_dev_config *pcfg;
	const struct device *clock_dev;
	const struct silabs_clock_control_cmu_config clock_cfg;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
	void (*irq_config_func)(const struct device *dev);
#endif
};

struct uart_silabs_eusart_data {
	struct uart_config uart_cfg;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
	uart_irq_callback_user_data_t callback;
	void *cb_data;
#endif
};

static int uart_silabs_eusart_poll_in(const struct device *dev, unsigned char *c)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	if (EUSART_StatusGet(config->eusart) & EUSART_STATUS_RXFL) {
		*c = EUSART_Rx(config->eusart);
		return 0;
	}

	return -1;
}

static void uart_silabs_eusart_poll_out(const struct device *dev, unsigned char c)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	/* EUSART_Tx function already waits for the transmit buffer being empty
	 * and waits for the bus to be free to transmit.
	 */
	EUSART_Tx(config->eusart, c);
}

static int uart_silabs_eusart_err_check(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;
	uint32_t flags = EUSART_IntGet(config->eusart);
	int err = 0;

	if (flags & EUSART_IF_RXOF) {
		err |= UART_ERROR_OVERRUN;
	}

	if (flags & EUSART_IF_PERR) {
		err |= UART_ERROR_PARITY;
	}

	if (flags & EUSART_IF_FERR) {
		err |= UART_ERROR_FRAMING;
	}

	EUSART_IntClear(config->eusart, EUSART_IF_RXOF | EUSART_IF_PERR | EUSART_IF_FERR);

	return err;
}

#ifdef CONFIG_UART_INTERRUPT_DRIVEN
static int uart_silabs_eusart_fifo_fill(const struct device *dev,
				  const uint8_t *tx_data,
				  int len)
{
	const struct uart_silabs_eusart_config *config = dev->config;
	int num_tx = 0;

	while ((len - num_tx > 0) &&
	       (EUSART_StatusGet(config->eusart) & EUSART_STATUS_TXFL)) {

		config->eusart->TXDATA = (uint32_t)tx_data[num_tx++];
	}

	if (!(EUSART_StatusGet(config->eusart) & EUSART_STATUS_TXFL)) {
		EUSART_IntClear(config->eusart, EUSART_IF_TXFL);
	}

	return num_tx;
}

static int uart_silabs_eusart_fifo_read(const struct device *dev, uint8_t *rx_data,
				  const int len)
{
	const struct uart_silabs_eusart_config *config = dev->config;
	int num_rx = 0;

	while ((len - num_rx > 0) &&
	       (EUSART_StatusGet(config->eusart) & EUSART_STATUS_RXFL)) {
		rx_data[num_rx++] = (uint8_t)config->eusart->RXDATA;
	}

	if (!(EUSART_StatusGet(config->eusart) & EUSART_STATUS_RXFL)) {
		EUSART_IntClear(config->eusart, EUSART_IF_RXFL);
	}

	return num_rx;
}

static void uart_silabs_eusart_irq_tx_enable(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	EUSART_IntClear(config->eusart, EUSART_IEN_TXFL | EUSART_IEN_TXC);
	EUSART_IntEnable(config->eusart, EUSART_IEN_TXFL | EUSART_IEN_TXC);
}

static void uart_silabs_eusart_irq_tx_disable(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	EUSART_IntDisable(config->eusart, EUSART_IEN_TXFL | EUSART_IEN_TXC);
	EUSART_IntClear(config->eusart, EUSART_IEN_TXFL | EUSART_IEN_TXC);
}

static int uart_silabs_eusart_irq_tx_complete(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;
	uint32_t flags = EUSART_IntGet(config->eusart);

	EUSART_IntClear(config->eusart, EUSART_IF_TXC);

	return (flags & EUSART_IF_TXC) != 0;
}

static int uart_silabs_eusart_irq_tx_ready(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	return (config->eusart->IEN & EUSART_IEN_TXFL)
		&& (EUSART_IntGet(config->eusart) & EUSART_IF_TXFL);
}

static void uart_silabs_eusart_irq_rx_enable(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	EUSART_IntClear(config->eusart, EUSART_IEN_RXFL);
	EUSART_IntEnable(config->eusart, EUSART_IEN_RXFL);
}

static void uart_silabs_eusart_irq_rx_disable(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	EUSART_IntDisable(config->eusart, EUSART_IEN_RXFL);
	EUSART_IntClear(config->eusart, EUSART_IEN_RXFL);
}

static int uart_silabs_eusart_irq_rx_ready(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	return (config->eusart->IEN & EUSART_IEN_RXFL)
		&& (EUSART_IntGet(config->eusart) & EUSART_IF_RXFL);
}

static void uart_silabs_eusart_irq_err_enable(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	EUSART_IntClear(config->eusart, EUSART_IF_RXOF | EUSART_IF_PERR | EUSART_IF_FERR);
	EUSART_IntEnable(config->eusart, EUSART_IF_RXOF | EUSART_IF_PERR | EUSART_IF_FERR);
}

static void uart_silabs_eusart_irq_err_disable(const struct device *dev)
{
	const struct uart_silabs_eusart_config *config = dev->config;

	EUSART_IntDisable(config->eusart, EUSART_IF_RXOF | EUSART_IF_PERR | EUSART_IF_FERR);
	EUSART_IntClear(config->eusart, EUSART_IF_RXOF | EUSART_IF_PERR | EUSART_IF_FERR);
}

static int uart_silabs_eusart_irq_is_pending(const struct device *dev)
{
	return uart_silabs_eusart_irq_tx_ready(dev) || uart_silabs_eusart_irq_rx_ready(dev);
}

static int uart_silabs_eusart_irq_update(const struct device *dev)
{
	return 1;
}

static void uart_silabs_eusart_irq_callback_set(const struct device *dev,
					  uart_irq_callback_user_data_t cb,
					  void *cb_data)
{
	struct uart_silabs_eusart_data *data = dev->data;

	data->callback = cb;
	data->cb_data = cb_data;
}

static void uart_silabs_eusart_isr(const struct device *dev)
{
	struct uart_silabs_eusart_data *data = dev->data;

	if (data->callback) {
		data->callback(dev, data->cb_data);
	}
}
#endif /* CONFIG_UART_INTERRUPT_DRIVEN */

static inline EUSART_Parity_TypeDef uart_silabs_eusart_cfg2ll_parity(
	enum uart_config_parity parity)
{
	switch (parity) {
	case UART_CFG_PARITY_ODD:
		return eusartOddParity;
	case UART_CFG_PARITY_EVEN:
		return eusartEvenParity;
	case UART_CFG_PARITY_NONE:
	default:
		return eusartNoParity;
	}
}

static inline enum uart_config_parity uart_silabs_eusart_ll2cfg_parity(
	EUSART_Parity_TypeDef parity)
{
	switch (parity) {
	case eusartOddParity:
		return UART_CFG_PARITY_ODD;
	case eusartEvenParity:
		return UART_CFG_PARITY_EVEN;
	case eusartNoParity:
	default:
		return UART_CFG_PARITY_NONE;
	}
}

static inline EUSART_Stopbits_TypeDef uart_silabs_eusart_cfg2ll_stopbits(
	enum uart_config_stop_bits sb)
{
	switch (sb) {
	case UART_CFG_STOP_BITS_0_5:
		return eusartStopbits0p5;
	case UART_CFG_STOP_BITS_1:
		return eusartStopbits1;
	case UART_CFG_STOP_BITS_2:
		return eusartStopbits2;
	case UART_CFG_STOP_BITS_1_5:
		return eusartStopbits1p5;
	default:
		return eusartStopbits1;
	}
}

static inline enum uart_config_stop_bits uart_silabs_eusart_ll2cfg_stopbits(
	EUSART_Stopbits_TypeDef sb)
{
	switch (sb) {
	case eusartStopbits0p5:
		return UART_CFG_STOP_BITS_0_5;
	case eusartStopbits1:
		return UART_CFG_STOP_BITS_1;
	case eusartStopbits1p5:
		return UART_CFG_STOP_BITS_1_5;
	case eusartStopbits2:
		return UART_CFG_STOP_BITS_2;
	default:
		return UART_CFG_STOP_BITS_1;
	}
}

static inline EUSART_Databits_TypeDef uart_silabs_eusart_cfg2ll_databits(
	enum uart_config_data_bits db, enum uart_config_parity p)
{
	switch (db) {
	case UART_CFG_DATA_BITS_7:
		if (p == UART_CFG_PARITY_NONE) {
			return eusartDataBits7;
		} else {
			return eusartDataBits8;
		}
	case UART_CFG_DATA_BITS_9:
		return eusartDataBits9;
	case UART_CFG_DATA_BITS_8:
	default:
		if (p == UART_CFG_PARITY_NONE) {
			return eusartDataBits8;
		} else {
			return eusartDataBits9;
		}
		return eusartDataBits8;
	}
}

static inline enum uart_config_data_bits uart_silabs_eusart_ll2cfg_databits(
	EUSART_Databits_TypeDef db, EUSART_Parity_TypeDef p)
{
	switch (db) {
	case eusartDataBits7:
		if (p == eusartNoParity) {
			return UART_CFG_DATA_BITS_7;
		} else {
			return UART_CFG_DATA_BITS_6;
		}
	case eusartDataBits9:
		if (p == eusartNoParity) {
			return UART_CFG_DATA_BITS_9;
		} else {
			return UART_CFG_DATA_BITS_8;
		}
	case eusartDataBits8:
	default:
		if (p == eusartNoParity) {
			return UART_CFG_DATA_BITS_8;
		} else {
			return UART_CFG_DATA_BITS_7;
		}
	}
}

/**
 * @brief  Get LL hardware flow control define from
 *         Zephyr hardware flow control option.
 * @note   Supports only UART_CFG_FLOW_CTRL_RTS_CTS and UART_CFG_FLOW_CTRL_RS485.
 * @param  fc: Zephyr hardware flow control option.
 * @retval eusartHwFlowControlCtsAndRts, or eusartHwFlowControlNone.
 */
static inline EUSART_HwFlowControl_TypeDef uart_silabs_eusart_cfg2ll_hwctrl(
	enum uart_config_flow_control fc)
{
	if (fc == UART_CFG_FLOW_CTRL_RTS_CTS) {
		return eusartHwFlowControlCtsAndRts;
	}

	return eusartHwFlowControlNone;
}

/**
 * @brief  Get Zephyr hardware flow control option from
 *         LL hardware flow control define.
 * @note   Supports only eusartHwFlowControlCtsAndRts.
 * @param  fc: LL hardware flow control definition.
 * @retval UART_CFG_FLOW_CTRL_RTS_CTS, or UART_CFG_FLOW_CTRL_NONE.
 */
static inline enum uart_config_flow_control uart_silabs_eusart_ll2cfg_hwctrl(
	EUSART_HwFlowControl_TypeDef fc)
{
	if (fc == eusartHwFlowControlCtsAndRts) {
		return UART_CFG_FLOW_CTRL_RTS_CTS;
	}

	return UART_CFG_FLOW_CTRL_NONE;
}

/**
 * @brief Main initializer for UART
 *
 * @param dev UART device to be initialized
 * @return int 0
 */
static int uart_silabs_eusart_init(const struct device *dev)
{
	int err;
	const struct uart_silabs_eusart_config *config = dev->config;
	struct uart_silabs_eusart_data *data = dev->data;
	struct uart_config *uart_cfg = &data->uart_cfg;

	EUSART_UartInit_TypeDef eusartInit = EUSART_UART_INIT_DEFAULT_HF;
	EUSART_AdvancedInit_TypeDef advancedSettings = EUSART_ADVANCED_INIT_DEFAULT;

	/* The peripheral and gpio clock are already enabled from soc and gpio
	 * driver
	 */
	/* Enable EUSART clock */
	err = clock_control_on(config->clock_dev, (clock_control_subsys_t)&config->clock_cfg);
	if (err < 0) {
		return err;
	}

	err = pinctrl_apply_state(config->pcfg, PINCTRL_STATE_DEFAULT);
	if (err < 0) {
		return err;
	}

	/* Init EUSART */
	eusartInit.baudrate = uart_cfg->baudrate;
	eusartInit.parity = uart_silabs_eusart_cfg2ll_parity(uart_cfg->parity);
	eusartInit.stopbits = uart_silabs_eusart_cfg2ll_stopbits(uart_cfg->stop_bits);
	eusartInit.databits = uart_silabs_eusart_cfg2ll_databits(uart_cfg->data_bits,
								 uart_cfg->parity);
	advancedSettings.hwFlowControl = uart_silabs_eusart_cfg2ll_hwctrl(uart_cfg->flow_ctrl);
	eusartInit.advancedSettings = &advancedSettings;

	EUSART_UartInitHf(config->eusart, &eusartInit);

#ifdef CONFIG_UART_INTERRUPT_DRIVEN
	config->irq_config_func(dev);
#endif

	return 0;
}

#ifdef CONFIG_PM_DEVICE
static int uart_silabs_eusart_pm_action(const struct device *dev, enum pm_device_action action)
{
	__maybe_unused const struct uart_silabs_eusart_config *config = dev->config;

	switch (action) {
	case PM_DEVICE_ACTION_SUSPEND:
#ifdef EUSART_STATUS_TXIDLE
		/* Wait for TX FIFO to flush before suspending */
		while (!(EUSART_StatusGet(config->eusart) & EUSART_STATUS_TXIDLE)) {
		}
#endif
		break;

	case PM_DEVICE_ACTION_RESUME:
		break;

	default:
		return -ENOTSUP;
	}

	return 0;
}
#endif

static DEVICE_API(uart, uart_silabs_eusart_driver_api) = {
	.poll_in = uart_silabs_eusart_poll_in,
	.poll_out = uart_silabs_eusart_poll_out,
	.err_check = uart_silabs_eusart_err_check,
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
	.fifo_fill = uart_silabs_eusart_fifo_fill,
	.fifo_read = uart_silabs_eusart_fifo_read,
	.irq_tx_enable = uart_silabs_eusart_irq_tx_enable,
	.irq_tx_disable = uart_silabs_eusart_irq_tx_disable,
	.irq_tx_complete = uart_silabs_eusart_irq_tx_complete,
	.irq_tx_ready = uart_silabs_eusart_irq_tx_ready,
	.irq_rx_enable = uart_silabs_eusart_irq_rx_enable,
	.irq_rx_disable = uart_silabs_eusart_irq_rx_disable,
	.irq_rx_ready = uart_silabs_eusart_irq_rx_ready,
	.irq_err_enable = uart_silabs_eusart_irq_err_enable,
	.irq_err_disable = uart_silabs_eusart_irq_err_disable,
	.irq_is_pending = uart_silabs_eusart_irq_is_pending,
	.irq_update = uart_silabs_eusart_irq_update,
	.irq_callback_set = uart_silabs_eusart_irq_callback_set,
#endif
};

#ifdef CONFIG_UART_INTERRUPT_DRIVEN
#define UART_IRQ_HANDLER_FUNC(idx)							\
	.irq_config_func = uart_silabs_eusart_config_func_##idx,
#define UART_IRQ_HANDLER(idx)								\
	static void uart_silabs_eusart_config_func_##idx(const struct device *dev)	\
	{										\
		IRQ_CONNECT(DT_INST_IRQ_BY_NAME(idx, rx, irq),				\
			    DT_INST_IRQ_BY_NAME(idx, rx, priority),			\
			    uart_silabs_eusart_isr, DEVICE_DT_INST_GET(idx), 0);	\
		IRQ_CONNECT(DT_INST_IRQ_BY_NAME(idx, tx, irq),				\
			    DT_INST_IRQ_BY_NAME(idx, tx, priority),			\
			    uart_silabs_eusart_isr, DEVICE_DT_INST_GET(idx), 0);	\
											\
		irq_enable(DT_INST_IRQ_BY_NAME(idx, rx, irq));				\
		irq_enable(DT_INST_IRQ_BY_NAME(idx, tx, irq));				\
	}
#else
#define UART_IRQ_HANDLER_FUNC(idx)
#define UART_IRQ_HANDLER(idx)
#endif

#define UART_INIT(idx)								\
UART_IRQ_HANDLER(idx)								\
										\
PINCTRL_DT_INST_DEFINE(idx);							\
										\
static const struct uart_silabs_eusart_config uart_silabs_eusart_cfg_##idx = {	\
	.eusart = (EUSART_TypeDef *)DT_INST_REG_ADDR(idx),			\
	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(idx),				\
	.clock_dev = DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(idx)),			\
	.clock_cfg = SILABS_DT_INST_CLOCK_CFG(idx),				\
	UART_IRQ_HANDLER_FUNC(idx)						\
};										\
										\
static struct uart_silabs_eusart_data uart_silabs_eusart_data_##idx = {		\
	.uart_cfg = {								\
		.baudrate  = DT_INST_PROP(idx, current_speed),			\
		.parity	   = DT_INST_ENUM_IDX(idx, parity),			\
		.stop_bits = DT_INST_ENUM_IDX(idx, stop_bits),			\
		.data_bits = DT_INST_ENUM_IDX(idx, data_bits),			\
		.flow_ctrl = DT_INST_PROP(idx, hw_flow_control)			\
					? UART_CFG_FLOW_CTRL_RTS_CTS		\
					: UART_CFG_FLOW_CTRL_NONE,		\
	},									\
};										\
										\
PM_DEVICE_DT_INST_DEFINE(idx, uart_silabs_eusart_pm_action);			\
										\
DEVICE_DT_INST_DEFINE(idx, uart_silabs_eusart_init, PM_DEVICE_DT_INST_GET(idx),	\
		      &uart_silabs_eusart_data_##idx,				\
		      &uart_silabs_eusart_cfg_##idx, PRE_KERNEL_1,		\
		      CONFIG_SERIAL_INIT_PRIORITY,				\
		      &uart_silabs_eusart_driver_api);

DT_INST_FOREACH_STATUS_OKAY(UART_INIT)