275 lines
6.2 KiB
C
275 lines
6.2 KiB
C
/*
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* Copyright (c) 2017 Piotr Mienkowski
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* SPDX-License-Identifier: Apache-2.0
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*/
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/** @file
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* @brief UART driver for Atmel SAM MCU family.
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*
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* Note:
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* - Error handling is not implemented.
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* - The driver works only in polling mode, interrupt mode is not implemented.
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*/
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#include <errno.h>
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#include <misc/__assert.h>
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#include <device.h>
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#include <init.h>
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#include <soc.h>
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#include <uart.h>
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/*
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* Verify Kconfig configuration
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*/
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#if CONFIG_UART_SAM_PORT_0 == 1
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#if CONFIG_UART_SAM_PORT_0_BAUD_RATE == 0
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#error "CONFIG_UART_SAM_PORT_0_BAUD_RATE has to be bigger than 0"
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#endif
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#endif
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#if CONFIG_UART_SAM_PORT_1 == 1
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#if CONFIG_UART_SAM_PORT_1_BAUD_RATE == 0
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#error "CONFIG_UART_SAM_PORT_1_BAUD_RATE has to be bigger than 0"
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#endif
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#endif
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#if CONFIG_UART_SAM_PORT_2 == 1
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#if CONFIG_UART_SAM_PORT_2_BAUD_RATE == 0
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#error "CONFIG_UART_SAM_PORT_2_BAUD_RATE has to be bigger than 0"
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#endif
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#endif
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#if CONFIG_UART_SAM_PORT_3 == 1
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#if CONFIG_UART_SAM_PORT_3_BAUD_RATE == 0
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#error "CONFIG_UART_SAM_PORT_3_BAUD_RATE has to be bigger than 0"
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#endif
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#endif
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#if CONFIG_UART_SAM_PORT_4 == 1
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#if CONFIG_UART_SAM_PORT_4_BAUD_RATE == 0
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#error "CONFIG_UART_SAM_PORT_4_BAUD_RATE has to be bigger than 0"
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#endif
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#endif
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/* Device constant configuration parameters */
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struct uart_sam_dev_cfg {
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Uart *regs;
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u32_t periph_id;
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struct soc_gpio_pin pin_rx;
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struct soc_gpio_pin pin_tx;
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};
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/* Device run time data */
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struct uart_sam_dev_data {
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u32_t baud_rate;
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};
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#define DEV_CFG(dev) \
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((const struct uart_sam_dev_cfg *const)(dev)->config->config_info)
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#define DEV_DATA(dev) \
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((struct uart_sam_dev_data *const)(dev)->driver_data)
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static int baudrate_set(Uart *const uart, u32_t baudrate,
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u32_t mck_freq_hz);
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static int uart_sam_init(struct device *dev)
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{
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int retval;
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const struct uart_sam_dev_cfg *const cfg = DEV_CFG(dev);
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struct uart_sam_dev_data *const dev_data = DEV_DATA(dev);
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Uart *const uart = cfg->regs;
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/* Enable UART clock in PMC */
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soc_pmc_peripheral_enable(cfg->periph_id);
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/* Connect pins to the peripheral */
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soc_gpio_configure(&cfg->pin_rx);
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soc_gpio_configure(&cfg->pin_tx);
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/* Reset and disable UART */
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uart->UART_CR = UART_CR_RSTRX | UART_CR_RSTTX
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| UART_CR_RXDIS | UART_CR_TXDIS | UART_CR_RSTSTA;
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/* Disable Interrupts */
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uart->UART_IDR = 0xFFFFFFFF;
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/* 8 bits of data, no parity, 1 stop bit in normal mode, baud rate
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* driven by the peripheral clock, UART does not filter the receive line
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*/
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uart->UART_MR = UART_MR_PAR_NO
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| UART_MR_CHMODE_NORMAL;
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/* Set baud rate */
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retval = baudrate_set(uart, dev_data->baud_rate,
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SOC_ATMEL_SAM_MCK_FREQ_HZ);
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if (retval != 0) {
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return retval;
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};
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/* Enable receiver and transmitter */
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uart->UART_CR = UART_CR_RXEN | UART_CR_TXEN;
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return 0;
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}
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static int uart_sam_poll_in(struct device *dev, unsigned char *c)
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{
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Uart *const uart = DEV_CFG(dev)->regs;
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if (!(uart->UART_SR & UART_SR_RXRDY)) {
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return -EBUSY;
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}
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/* got a character */
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*c = (unsigned char)uart->UART_RHR;
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return 0;
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}
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static unsigned char uart_sam_poll_out(struct device *dev, unsigned char c)
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{
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Uart *const uart = DEV_CFG(dev)->regs;
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/* Wait for transmitter to be ready */
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while (!(uart->UART_SR & UART_SR_TXRDY))
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;
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/* send a character */
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uart->UART_THR = (u32_t)c;
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return c;
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}
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static int baudrate_set(Uart *const uart, u32_t baudrate,
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u32_t mck_freq_hz)
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{
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u32_t divisor;
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__ASSERT(baudrate,
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"baud rate has to be bigger than 0");
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__ASSERT(mck_freq_hz/16 >= baudrate,
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"MCK frequency is too small to set required baud rate");
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divisor = mck_freq_hz / 16 / baudrate;
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if (divisor > 0xFFFF) {
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return -EINVAL;
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};
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uart->UART_BRGR = UART_BRGR_CD(divisor);
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return 0;
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}
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static const struct uart_driver_api uart_sam_driver_api = {
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.poll_in = uart_sam_poll_in,
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.poll_out = uart_sam_poll_out,
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};
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/* UART0 */
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#ifdef CONFIG_UART_SAM_PORT_0
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static const struct uart_sam_dev_cfg uart0_sam_config = {
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.regs = UART0,
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.periph_id = ID_UART0,
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.pin_rx = PIN_UART0_RXD,
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.pin_tx = PIN_UART0_TXD,
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};
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static struct uart_sam_dev_data uart0_sam_data = {
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.baud_rate = CONFIG_UART_SAM_PORT_0_BAUD_RATE,
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};
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DEVICE_AND_API_INIT(uart0_sam, CONFIG_UART_SAM_PORT_0_NAME, &uart_sam_init,
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&uart0_sam_data, &uart0_sam_config, PRE_KERNEL_1,
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CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_sam_driver_api);
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#endif
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/* UART1 */
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#ifdef CONFIG_UART_SAM_PORT_1
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static const struct uart_sam_dev_cfg uart1_sam_config = {
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.regs = UART1,
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.periph_id = ID_UART1,
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.pin_rx = PIN_UART1_RXD,
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.pin_tx = PIN_UART1_TXD,
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};
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static struct uart_sam_dev_data uart1_sam_data = {
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.baud_rate = CONFIG_UART_SAM_PORT_1_BAUD_RATE,
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};
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DEVICE_AND_API_INIT(uart1_sam, CONFIG_UART_SAM_PORT_1_NAME, &uart_sam_init,
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&uart1_sam_data, &uart1_sam_config, PRE_KERNEL_1,
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CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_sam_driver_api);
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#endif
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/* UART2 */
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#ifdef CONFIG_UART_SAM_PORT_2
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static const struct uart_sam_dev_cfg uart2_sam_config = {
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.regs = UART2,
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.periph_id = ID_UART2,
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.pin_rx = PIN_UART2_RXD,
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.pin_tx = PIN_UART2_TXD,
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};
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static struct uart_sam_dev_data uart2_sam_data = {
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.baud_rate = CONFIG_UART_SAM_PORT_2_BAUD_RATE,
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};
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DEVICE_AND_API_INIT(uart2_sam, CONFIG_UART_SAM_PORT_2_NAME, &uart_sam_init,
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&uart2_sam_data, &uart2_sam_config, PRE_KERNEL_1,
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CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_sam_driver_api);
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#endif
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/* UART3 */
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#ifdef CONFIG_UART_SAM_PORT_3
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static const struct uart_sam_dev_cfg uart3_sam_config = {
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.regs = UART3,
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.periph_id = ID_UART3,
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.pin_rx = PIN_UART3_RXD,
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.pin_tx = PIN_UART3_TXD,
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};
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static struct uart_sam_dev_data uart3_sam_data = {
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.baud_rate = CONFIG_UART_SAM_PORT_3_BAUD_RATE,
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};
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DEVICE_AND_API_INIT(uart3_sam, CONFIG_UART_SAM_PORT_3_NAME, &uart_sam_init,
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&uart3_sam_data, &uart3_sam_config, PRE_KERNEL_1,
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CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_sam_driver_api);
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#endif
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/* UART4 */
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#ifdef CONFIG_UART_SAM_PORT_4
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static const struct uart_sam_dev_cfg uart4_sam_config = {
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.regs = UART4,
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.periph_id = ID_UART4,
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.pin_rx = PIN_UART4_RXD,
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.pin_tx = PIN_UART4_TXD,
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};
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static struct uart_sam_dev_data uart4_sam_data = {
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.baud_rate = CONFIG_UART_SAM_PORT_4_BAUD_RATE,
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};
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DEVICE_AND_API_INIT(uart4_sam, CONFIG_UART_SAM_PORT_4_NAME, &uart_sam_init,
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&uart4_sam_data, &uart4_sam_config, PRE_KERNEL_1,
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CONFIG_KERNEL_INIT_PRIORITY_DEVICE, &uart_sam_driver_api);
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#endif
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