text: /*
   * Copyright (c) 2017, Christian Taedcke
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #include <errno.h>
  #include <uart.h>
  #include <em_usart.h>
  #include <em_gpio.h>
  #include <em_cmu.h>
  #include <soc.h>
  
  struct uart_gecko_config {
  	USART_TypeDef *base;
  	CMU_Clock_TypeDef clock;
  	u32_t baud_rate;
  	struct soc_gpio_pin pin_rx;
  	struct soc_gpio_pin pin_tx;
  	unsigned int loc;
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	void (*irq_config_func)(struct device *dev);
  #endif
  };
  
  struct uart_gecko_data {
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	uart_irq_callback_user_data_t callback;
  	void *cb_data;
  #endif
  };
  
  static int uart_gecko_poll_in(struct device *dev, unsigned char *c)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t flags = USART_StatusGet(config->base);
  
  	if (flags & USART_STATUS_RXDATAV) {
  		*c = USART_Rx(config->base);
  		return 0;
  	}
  
  	return -1;
  }
  
  static unsigned char uart_gecko_poll_out(struct device *dev, unsigned char c)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  
  	USART_Tx(config->base, c);
  
  	return c;
  }
  
  static int uart_gecko_err_check(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t flags = USART_IntGet(config->base);
  	int err = 0;
  
  	if (flags & USART_IF_RXOF) {
  		err |= UART_ERROR_OVERRUN;
  	}
  
  	if (flags & USART_IF_PERR) {
  		err |= UART_ERROR_PARITY;
  	}
  
  	if (flags & USART_IF_FERR) {
  		err |= UART_ERROR_FRAMING;
  	}
  
  	USART_IntClear(config->base, USART_IF_RXOF |
  		       USART_IF_PERR |
  		       USART_IF_FERR);
  
  	return err;
  }
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static int uart_gecko_fifo_fill(struct device *dev, const u8_t *tx_data,
  			       int len)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u8_t num_tx = 0;
  
  	while ((len - num_tx > 0) &&
  	       (config->base->STATUS & USART_STATUS_TXBL)) {
  
  		config->base->TXDATA = (u32_t)tx_data[num_tx++];
  	}
  
  	return num_tx;
  }
  
  static int uart_gecko_fifo_read(struct device *dev, u8_t *rx_data,
  			       const int len)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u8_t num_rx = 0;
  
  	while ((len - num_rx > 0) &&
  	       (config->base->STATUS & USART_STATUS_RXDATAV)) {
  
  		rx_data[num_rx++] = (u8_t)config->base->RXDATA;
  	}
  
  	return num_rx;
  }
  
  static void uart_gecko_irq_tx_enable(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t mask = USART_IEN_TXBL | USART_IEN_TXC;
  
  	USART_IntEnable(config->base, mask);
  }
  
  static void uart_gecko_irq_tx_disable(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t mask = USART_IEN_TXBL | USART_IEN_TXC;
  
  	USART_IntDisable(config->base, mask);
  }
  
  static int uart_gecko_irq_tx_complete(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t flags = USART_IntGet(config->base);
  
  	USART_IntClear(config->base, USART_IF_TXC);
  
  	return (flags & USART_IF_TXC) != 0;
  }
  
  static int uart_gecko_irq_tx_ready(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t flags = USART_IntGet(config->base);
  
  	return (flags & USART_IF_TXBL) != 0;
  }
  
  static void uart_gecko_irq_rx_enable(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t mask = USART_IEN_RXDATAV;
  
  	USART_IntEnable(config->base, mask);
  }
  
  static void uart_gecko_irq_rx_disable(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t mask = USART_IEN_RXDATAV;
  
  	USART_IntDisable(config->base, mask);
  }
  
  static int uart_gecko_irq_rx_full(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t flags = USART_IntGet(config->base);
  
  	return (flags & USART_IF_RXDATAV) != 0;
  }
  
  static int uart_gecko_irq_rx_ready(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	u32_t mask = USART_IEN_RXDATAV;
  
  	return (config->base->IEN & mask)
  		&& uart_gecko_irq_rx_full(dev);
  }
  
  static void uart_gecko_irq_err_enable(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  
  	USART_IntEnable(config->base, USART_IF_RXOF |
  			 USART_IF_PERR |
  			 USART_IF_FERR);
  }
  
  static void uart_gecko_irq_err_disable(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  
  	USART_IntDisable(config->base, USART_IF_RXOF |
  			 USART_IF_PERR |
  			 USART_IF_FERR);
  }
  
  static int uart_gecko_irq_is_pending(struct device *dev)
  {
  	return uart_gecko_irq_tx_ready(dev) || uart_gecko_irq_rx_ready(dev);
  }
  
  static int uart_gecko_irq_update(struct device *dev)
  {
  	return 1;
  }
  
  static void uart_gecko_irq_callback_set(struct device *dev,
  				       uart_irq_callback_user_data_t cb,
  				       void *cb_data)
  {
  	struct uart_gecko_data *data = dev->driver_data;
  
  	data->callback = cb;
  	data->cb_data = cb_data;
  }
  
  static void uart_gecko_isr(void *arg)
  {
  	struct device *dev = arg;
  	struct uart_gecko_data *data = dev->driver_data;
  
  	if (data->callback) {
  		data->callback(data->cb_data);
  	}
  }
  #endif /* CONFIG_UART_INTERRUPT_DRIVEN */
  
  static void uart_gecko_init_pins(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  
  	soc_gpio_configure(&config->pin_rx);
  	soc_gpio_configure(&config->pin_tx);
  #if defined(_USART_ROUTEPEN_MASK) || defined(_UART_ROUTEPEN_MASK)
  	config->base->ROUTEPEN = USART_ROUTEPEN_RXPEN | USART_ROUTEPEN_TXPEN;
  	config->base->ROUTELOC0 =
  		(config->loc << _USART_ROUTELOC0_TXLOC_SHIFT) |
  		(config->loc << _USART_ROUTELOC0_RXLOC_SHIFT);
  	config->base->ROUTELOC1 = _USART_ROUTELOC1_RESETVALUE;
  #else
  	config->base->ROUTE = USART_ROUTE_RXPEN | USART_ROUTE_TXPEN
  		| (config->loc << 8);
  #endif
  }
  
  static int uart_gecko_init(struct device *dev)
  {
  	const struct uart_gecko_config *config = dev->config->config_info;
  	USART_InitAsync_TypeDef usartInit = USART_INITASYNC_DEFAULT;
  
  	/* The peripheral and gpio clock are already enabled from soc and gpio
  	 * driver
  	 */
  
  	usartInit.baudrate = config->baud_rate;
  
  	/* Enable USART clock */
  	CMU_ClockEnable(config->clock, true);
  
  	/* Init USART */
  	USART_InitAsync(config->base, &usartInit);
  
  	/* Initialize USART pins */
  	uart_gecko_init_pins(dev);
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	config->irq_config_func(dev);
  #endif
  
  	return 0;
  }
  
  static const struct uart_driver_api uart_gecko_driver_api = {
  	.poll_in = uart_gecko_poll_in,
  	.poll_out = uart_gecko_poll_out,
  	.err_check = uart_gecko_err_check,
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	.fifo_fill = uart_gecko_fifo_fill,
  	.fifo_read = uart_gecko_fifo_read,
  	.irq_tx_enable = uart_gecko_irq_tx_enable,
  	.irq_tx_disable = uart_gecko_irq_tx_disable,
  	.irq_tx_complete = uart_gecko_irq_tx_complete,
  	.irq_tx_ready = uart_gecko_irq_tx_ready,
  	.irq_rx_enable = uart_gecko_irq_rx_enable,
  	.irq_rx_disable = uart_gecko_irq_rx_disable,
  	.irq_rx_ready = uart_gecko_irq_rx_ready,
  	.irq_err_enable = uart_gecko_irq_err_enable,
  	.irq_err_disable = uart_gecko_irq_err_disable,
  	.irq_is_pending = uart_gecko_irq_is_pending,
  	.irq_update = uart_gecko_irq_update,
  	.irq_callback_set = uart_gecko_irq_callback_set,
  #endif
  };
  
  #ifdef CONFIG_UART_GECKO_0
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void uart_gecko_config_func_0(struct device *dev);
  #endif
  
  static const struct uart_gecko_config uart_gecko_0_config = {
  	.base = (USART_TypeDef *)DT_UART_GECKO_0_BASE_ADDRESS,
  	.clock = cmuClock_UART0,
  	.baud_rate = DT_UART_GECKO_0_CURRENT_SPEED,
  	.pin_rx = PIN_UART0_RXD,
  	.pin_tx = PIN_UART0_TXD,
  	.loc = DT_UART_GECKO_0_LOCATION,
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	.irq_config_func = uart_gecko_config_func_0,
  #endif
  };
  
  static struct uart_gecko_data uart_gecko_0_data;
  
  DEVICE_AND_API_INIT(uart_0, DT_UART_GECKO_0_LABEL, &uart_gecko_init, &uart_gecko_0_data,
  		    &uart_gecko_0_config, PRE_KERNEL_1,
  		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_gecko_driver_api);
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void uart_gecko_config_func_0(struct device *dev)
  {
  	IRQ_CONNECT(DT_UART_GECKO_0_IRQ_RX,
  		    DT_UART_GECKO_0_IRQ_RX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(uart_0), 0);
  	IRQ_CONNECT(DT_UART_GECKO_0_IRQ_TX,
  		    DT_UART_GECKO_0_IRQ_TX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(uart_0), 0);
  
  	irq_enable(DT_UART_GECKO_0_IRQ_RX);
  	irq_enable(DT_UART_GECKO_0_IRQ_TX);
  }
  #endif
  
  #endif /* CONFIG_UART_GECKO_0 */
  
  #ifdef CONFIG_UART_GECKO_1
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void uart_gecko_config_func_1(struct device *dev);
  #endif
  
  static const struct uart_gecko_config uart_gecko_1_config = {
  	.base = (USART_TypeDef *)DT_UART_GECKO_1_BASE_ADDRESS,
  	.clock = cmuClock_UART1,
  	.baud_rate = DT_UART_GECKO_1_CURRENT_SPEED,
  	.pin_rx = PIN_UART1_RXD,
  	.pin_tx = PIN_UART1_TXD,
  	.loc = DT_UART_GECKO_1_LOCATION,
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	.irq_config_func = uart_gecko_config_func_1,
  #endif
  };
  
  static struct uart_gecko_data uart_gecko_1_data;
  
  DEVICE_AND_API_INIT(uart_1, DT_UART_GECKO_1_LABEL, &uart_gecko_init, &uart_gecko_1_data,
  		    &uart_gecko_1_config, PRE_KERNEL_1,
  		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_gecko_driver_api);
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void uart_gecko_config_func_1(struct device *dev)
  {
  	IRQ_CONNECT(DT_UART_GECKO_1_IRQ_RX,
  		    DT_UART_GECKO_1_IRQ_RX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(uart_1), 0);
  	IRQ_CONNECT(DT_UART_GECKO_1_IRQ_TX,
  		    DT_UART_GECKO_1_IRQ_TX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(uart_1), 0);
  
  	irq_enable(DT_UART_GECKO_1_IRQ_RX);
  	irq_enable(DT_UART_GECKO_1_IRQ_TX);
  }
  #endif
  
  #endif /* CONFIG_UART_GECKO_1 */
  
  #ifdef CONFIG_USART_GECKO_0
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_0(struct device *dev);
  #endif
  
  static const struct uart_gecko_config usart_gecko_0_config = {
  	.base = (USART_TypeDef *)DT_USART_GECKO_0_BASE_ADDRESS,
  	.clock = cmuClock_USART0,
  	.baud_rate = DT_USART_GECKO_0_CURRENT_SPEED,
  	.pin_rx = PIN_USART0_RXD,
  	.pin_tx = PIN_USART0_TXD,
  	.loc = DT_USART_GECKO_0_LOCATION,
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	.irq_config_func = usart_gecko_config_func_0,
  #endif
  };
  
  static struct uart_gecko_data usart_gecko_0_data;
  
  DEVICE_AND_API_INIT(usart_0, DT_USART_GECKO_0_LABEL, &uart_gecko_init,
  		    &usart_gecko_0_data, &usart_gecko_0_config, PRE_KERNEL_1,
  		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_gecko_driver_api);
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_0(struct device *dev)
  {
  	IRQ_CONNECT(DT_USART_GECKO_0_IRQ_RX,
  		    DT_USART_GECKO_0_IRQ_RX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_0), 0);
  	IRQ_CONNECT(DT_USART_GECKO_0_IRQ_TX,
  		    DT_USART_GECKO_0_IRQ_TX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_0), 0);
  
  	irq_enable(DT_USART_GECKO_0_IRQ_RX);
  	irq_enable(DT_USART_GECKO_0_IRQ_TX);
  }
  #endif
  
  #endif /* CONFIG_USART_GECKO_0 */
  
  #ifdef CONFIG_USART_GECKO_1
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_1(struct device *dev);
  #endif
  
  static const struct uart_gecko_config usart_gecko_1_config = {
  	.base = (USART_TypeDef *)DT_USART_GECKO_1_BASE_ADDRESS,
  	.clock = cmuClock_USART1,
  	.baud_rate = DT_USART_GECKO_1_CURRENT_SPEED,
  	.pin_rx = PIN_USART1_RXD,
  	.pin_tx = PIN_USART1_TXD,
  	.loc = DT_USART_GECKO_1_LOCATION,
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	.irq_config_func = usart_gecko_config_func_1,
  #endif
  };
  
  static struct uart_gecko_data usart_gecko_1_data;
  
  DEVICE_AND_API_INIT(usart_1, DT_USART_GECKO_1_LABEL, &uart_gecko_init,
  		    &usart_gecko_1_data, &usart_gecko_1_config, PRE_KERNEL_1,
  		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_gecko_driver_api);
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_1(struct device *dev)
  {
  	IRQ_CONNECT(DT_USART_GECKO_1_IRQ_RX,
  		    DT_USART_GECKO_1_IRQ_RX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_1), 0);
  	IRQ_CONNECT(DT_USART_GECKO_1_IRQ_TX,
  		    DT_USART_GECKO_1_IRQ_TX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_1), 0);
  
  	irq_enable(DT_USART_GECKO_1_IRQ_RX);
  	irq_enable(DT_USART_GECKO_1_IRQ_TX);
  }
  #endif
  
  #endif /* CONFIG_USART_GECKO_1 */
  
  #ifdef CONFIG_USART_GECKO_2
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_2(struct device *dev);
  #endif
  
  static const struct uart_gecko_config usart_gecko_2_config = {
  	.base = (USART_TypeDef *)DT_USART_GECKO_2_BASE_ADDRESS,
  	.clock = cmuClock_USART2,
  	.baud_rate = DT_USART_GECKO_2_CURRENT_SPEED,
  	.pin_rx = PIN_USART2_RXD,
  	.pin_tx = PIN_USART2_TXD,
  	.loc = DT_USART_GECKO_2_LOCATION,
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	.irq_config_func = usart_gecko_config_func_2,
  #endif
  };
  
  static struct uart_gecko_data usart_gecko_2_data;
  
  DEVICE_AND_API_INIT(usart_2, DT_USART_GECKO_2_LABEL, &uart_gecko_init,
  		    &usart_gecko_2_data, &usart_gecko_2_config, PRE_KERNEL_1,
  		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_gecko_driver_api);
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_2(struct device *dev)
  {
  	IRQ_CONNECT(DT_USART_GECKO_2_IRQ_RX,
  		    DT_USART_GECKO_2_IRQ_RX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_2), 0);
  	IRQ_CONNECT(DT_USART_GECKO_2_IRQ_TX,
  		    DT_USART_GECKO_2_IRQ_TX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_2), 0);
  
  	irq_enable(DT_USART_GECKO_2_IRQ_RX);
  	irq_enable(DT_USART_GECKO_2_IRQ_TX);
  }
  #endif
  
  #endif /* CONFIG_USART_GECKO_2 */
  
  #ifdef CONFIG_USART_GECKO_3
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_3(struct device *dev);
  #endif
  
  static const struct uart_gecko_config usart_gecko_3_config = {
  	.base = (USART_TypeDef *)DT_USART_GECKO_3_BASE_ADDRESS,
  	.clock = cmuClock_USART3,
  	.baud_rate = DT_USART_GECKO_3_CURRENT_SPEED,
  	.pin_rx = PIN_USART3_RXD,
  	.pin_tx = PIN_USART3_TXD,
  	.loc = DT_USART_GECKO_3_LOCATION,
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  	.irq_config_func = usart_gecko_config_func_3,
  #endif
  };
  
  static struct uart_gecko_data usart_gecko_3_data;
  
  DEVICE_AND_API_INIT(usart_3, DT_USART_GECKO_3_LABEL, &uart_gecko_init,
  		    &usart_gecko_3_data, &usart_gecko_3_config, PRE_KERNEL_1,
  		    CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_gecko_driver_api);
  
  #ifdef CONFIG_UART_INTERRUPT_DRIVEN
  static void usart_gecko_config_func_3(struct device *dev)
  {
  	IRQ_CONNECT(DT_USART_GECKO_3_IRQ_RX,
  		    DT_USART_GECKO_3_IRQ_RX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_3), 0);
  	IRQ_CONNECT(DT_USART_GECKO_3_IRQ_TX,
  		    DT_USART_GECKO_3_IRQ_TX_PRIORITY, uart_gecko_isr,
  		    DEVICE_GET(usart_3), 0);
  
  	irq_enable(DT_USART_GECKO_3_IRQ_RX);
  	irq_enable(DT_USART_GECKO_3_IRQ_TX);
  }
  #endif
  
  #endif /* CONFIG_USART_GECKO_3 */
  