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drivers: serial: rpi_pico: added functions for runtime uart configuration #49883

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Nov 15, 2022
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drivers: serial: rpi_pico: added functions for runtime uart configuration #49883

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102 changes: 96 additions & 6 deletions drivers/serial/uart_rpi_pico.c
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#include <zephyr/drivers/reset.h>
#include <zephyr/drivers/pinctrl.h>
#include <zephyr/irq.h>
#include <string.h>

/* pico-sdk includes */
#include <hardware/uart.h>
Expand All @@ -26,7 +27,7 @@ struct uart_rpi_config {
};

struct uart_rpi_data {
uint32_t baudrate;
struct uart_config uart_config;
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
uart_irq_callback_user_data_t irq_cb;
void *irq_cb_data;
Expand Down Expand Up @@ -64,7 +65,8 @@ static int uart_rpi_init(const struct device *dev)
uart_inst_t * const uart_inst = config->uart_dev;
uart_hw_t * const uart_hw = config->uart_regs;
struct uart_rpi_data * const data = dev->data;
int ret, baudrate;
uint baudrate;
int ret;

ret = pinctrl_apply_state(config->pcfg, PINCTRL_STATE_DEFAULT);
if (ret < 0) {
Expand All @@ -75,12 +77,27 @@ static int uart_rpi_init(const struct device *dev)
* uart_init() may be replaced by register based API once rpi-pico platform
* has a clock controller driver
*/
baudrate = uart_init(uart_inst, data->baudrate);
baudrate = uart_init(uart_inst, data->uart_config.baudrate);
/* Check if baudrate adjustment returned by 'uart_init' function is a positive value */
if (baudrate <= 0) {
if (baudrate == 0) {
return -EINVAL;
}

/*
* initialize uart_config with hardware reset values
* https://datasheets.raspberrypi.com/rp2040/rp2040-datasheet.pdf#tab-registerlist_uart page:431
* data bits set default to 8 instaed of hardware reset 5 to increase compatibility.
*/
data->uart_config = (struct uart_config){
.baudrate = baudrate,
.data_bits = UART_CFG_DATA_BITS_8,
.flow_ctrl = UART_CFG_FLOW_CTRL_NONE,
.parity = UART_CFG_PARITY_NONE,
.stop_bits = UART_CFG_STOP_BITS_1
};
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Do you need to call uart_set_format() here, since the hardware defaults to 5-bit at reset? Also might be a good idea to document that the data bit setting is different than hardware reset.

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Added an extra comment the deviation from hw default.
Added a call for uart_set_format()

uart_set_format(uart_inst,
data->uart_config.data_bits,
data->uart_config.stop_bits,
data->uart_config.parity);
hw_clear_bits(&uart_hw->lcr_h, UART_UARTLCR_H_FEN_BITS);
uart_hw->dr = 0U;

Expand All @@ -91,6 +108,75 @@ static int uart_rpi_init(const struct device *dev)
return 0;
}

static int uart_rpi_config_get(const struct device *dev, struct uart_config *cfg)
{
struct uart_rpi_data *data = dev->data;

memcpy(cfg, &data->uart_config, sizeof(struct uart_config));
return 0;
}

static int uart_rpi_configure(const struct device *dev, const struct uart_config *cfg)
{
const struct uart_rpi_config *config = dev->config;
uart_inst_t * const uart_inst = config->uart_dev;
struct uart_rpi_data *data = dev->data;
uart_parity_t parity = 0;
uint data_bits = 0;
uint stop_bits = 0;
uint baudrate = 0;

switch (cfg->data_bits) {
case UART_CFG_DATA_BITS_5:
data_bits = 5;
break;
case UART_CFG_DATA_BITS_6:
data_bits = 6;
break;
case UART_CFG_DATA_BITS_7:
data_bits = 7;
break;
case UART_CFG_DATA_BITS_8:
data_bits = 8;
break;
default:
return -EINVAL;
}

switch (cfg->stop_bits) {
case UART_CFG_STOP_BITS_1:
stop_bits = 1;
break;
case UART_CFG_STOP_BITS_2:
stop_bits = 2;
break;
default:
return -EINVAL;
}

switch (cfg->parity) {
case UART_CFG_PARITY_NONE:
parity = UART_PARITY_NONE;
break;
case UART_CFG_PARITY_EVEN:
parity = UART_PARITY_EVEN;
break;
case UART_CFG_PARITY_ODD:
parity = UART_PARITY_ODD;
break;
default:
return -EINVAL;
}

baudrate = uart_set_baudrate(uart_inst, cfg->baudrate);
if (baudrate == 0) {
return -EINVAL;
}
uart_set_format(uart_inst, data_bits, stop_bits, parity);
data->uart_config = *cfg;
return 0;
}

static int uart_rpi_err_check(const struct device *dev)
{
const struct uart_rpi_config * const config = dev->config;
Expand Down Expand Up @@ -264,6 +350,10 @@ static const struct uart_driver_api uart_rpi_driver_api = {
.poll_in = uart_rpi_poll_in,
.poll_out = uart_rpi_poll_out,
.err_check = uart_rpi_err_check,
#ifdef CONFIG_UART_USE_RUNTIME_CONFIGURE
.configure = uart_rpi_configure,
.config_get = uart_rpi_config_get,
#endif /* CONFIG_UART_USE_RUNTIME_CONFIGURE */
#ifdef CONFIG_UART_INTERRUPT_DRIVEN
.fifo_fill = uart_rpi_fifo_fill,
.fifo_read = uart_rpi_fifo_read,
Expand Down Expand Up @@ -310,7 +400,7 @@ static const struct uart_driver_api uart_rpi_driver_api = {
}; \
\
static struct uart_rpi_data uart##idx##_rpi_data = { \
.baudrate = DT_INST_PROP(idx, current_speed), \
.uart_config.baudrate = DT_INST_PROP(idx, current_speed), \
}; \
\
DEVICE_DT_INST_DEFINE(idx, &uart_rpi_init, \
Expand Down