memset(rs485->padding, 0, sizeof(rs485->padding));
port->rs485 = *rs485;
+ gpiod_set_value(port->rs485_term_gpio,
+ rs485->flags & SER_RS485_TERMINATE_BUS);
+
/*
* Both serial8250_em485_init() and serial8250_em485_destroy()
* are idempotent.
* to get to a defined state with the following properties:
*/
rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
+ SER_RS485_TERMINATE_BUS |
SER_RS485_RTS_AFTER_SEND);
rs485conf->flags |= SER_RS485_RTS_ON_SEND;
rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
}
+ /*
+ * Disabling termination by default is the safe choice: Else if many
+ * bus participants enable it, no communication is possible at all.
+ * Works fine for short cables and users may enable for longer cables.
+ */
+ port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
+ GPIOD_OUT_LOW);
+ if (IS_ERR(port->rs485_term_gpio)) {
+ ret = PTR_ERR(port->rs485_term_gpio);
+ port->rs485_term_gpio = NULL;
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "Cannot get rs485-term-gpios\n");
+ return ret;
+ }
+
return 0;
}
EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/console.h>
+#include <linux/gpio/consumer.h>
#include <linux/interrupt.h>
#include <linux/circ_buf.h>
#include <linux/spinlock.h>
struct attribute_group *attr_group; /* port specific attributes */
const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
struct serial_rs485 rs485;
+ struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
struct serial_iso7816 iso7816;
void *private_data; /* generic platform data pointer */
};