diff options
Diffstat (limited to 'drivers/tty/serial/omap-serial.c')
| -rw-r--r-- | drivers/tty/serial/omap-serial.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index c7517063eb9..2706c118739 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -40,8 +40,11 @@ #include <linux/pm_runtime.h> #include <linux/of.h> #include <linux/gpio.h> +#include <linux/of_gpio.h> #include <linux/platform_data/serial-omap.h> +#include <dt-bindings/gpio/gpio.h> + #define OMAP_MAX_HSUART_PORTS 6 #define UART_BUILD_REVISION(x, y) (((x) << 8) | (y)) @@ -162,6 +165,9 @@ struct uart_omap_port { int DTR_inverted; int DTR_active; + struct serial_rs485 rs485; + int rts_gpio; + struct pm_qos_request pm_qos_request; u32 latency; u32 calc_latency; @@ -277,13 +283,42 @@ static void serial_omap_enable_ms(struct uart_port *port) static void serial_omap_stop_tx(struct uart_port *port) { struct uart_omap_port *up = to_uart_omap_port(port); + struct circ_buf *xmit = &up->port.state->xmit; + int res; pm_runtime_get_sync(up->dev); + + /* handle rs485 */ + if (up->rs485.flags & SER_RS485_ENABLED) { + /* do nothing if current tx not yet completed */ + res = serial_in(up, UART_LSR) & UART_LSR_TEMT; + if (!res) + return; + + /* if there's no more data to send, turn off rts */ + if (uart_circ_empty(xmit)) { + /* if rts not already disabled */ + res = (up->rs485.flags & SER_RS485_RTS_AFTER_SEND) ? 1 : 0; + if (gpio_get_value(up->rts_gpio) != res) { + if (up->rs485.delay_rts_after_send > 0) { + mdelay(up->rs485.delay_rts_after_send); + } + gpio_set_value(up->rts_gpio, res); + } + } + } + if (up->ier & UART_IER_THRI) { up->ier &= ~UART_IER_THRI; serial_out(up, UART_IER, up->ier); } + if ((up->rs485.flags & SER_RS485_ENABLED) && + !(up->rs485.flags & SER_RS485_RX_DURING_TX)) { + up->ier = UART_IER_RLSI | UART_IER_RDI; + serial_out(up, UART_IER, up->ier); + } + pm_runtime_mark_last_busy(up->dev); pm_runtime_put_autosuspend(up->dev); } @@ -346,8 +381,26 @@ static inline void serial_omap_enable_ier_thri(struct uart_omap_port *up) static void serial_omap_start_tx(struct uart_port *port) { struct uart_omap_port *up = to_uart_omap_port(port); + int res; pm_runtime_get_sync(up->dev); + + /* handle rs485 */ + if (up->rs485.flags & SER_RS485_ENABLED) { + /* if rts not already enabled */ + res = (up->rs485.flags & SER_RS485_RTS_ON_SEND) ? 1 : 0; + if (gpio_get_value(up->rts_gpio) != res) { + gpio_set_value(up->rts_gpio, res); + if (up->rs485.delay_rts_before_send > 0) { + mdelay(up->rs485.delay_rts_before_send); + } + } + } + + if ((up->rs485.flags & SER_RS485_ENABLED) && + !(up->rs485.flags & SER_RS485_RX_DURING_TX)) + serial_omap_stop_rx(port); + serial_omap_enable_ier_thri(up); pm_runtime_mark_last_busy(up->dev); pm_runtime_put_autosuspend(up->dev); @@ -1262,6 +1315,79 @@ static inline void serial_omap_add_console_port(struct uart_omap_port *up) #endif +/* Enable or disable the rs485 support */ +static void +serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf) +{ + struct uart_omap_port *up = to_uart_omap_port(port); + unsigned long flags; + unsigned int mode; + int val; + + pm_runtime_get_sync(up->dev); + spin_lock_irqsave(&up->port.lock, flags); + + up->ier &= ~(UART_IER_RLSI | UART_IER_RDI); + serial_out(up, UART_IER, up->ier); + + /* Disable interrupts from this port */ + mode = up->ier; + up->ier = 0; + serial_out(up, UART_IER, 0); + + /* store new config */ + up->rs485 = *rs485conf; + + /* + * Just as a precaution, only allow rs485 + * to be enabled if the gpio pin is valid + */ + if (gpio_is_valid(up->rts_gpio)) { + /* enable / disable rts */ + val = (up->rs485.flags & SER_RS485_ENABLED) ? + SER_RS485_RTS_AFTER_SEND : SER_RS485_RTS_ON_SEND; + val = (up->rs485.flags & val) ? 1 : 0; + gpio_set_value(up->rts_gpio, val); + } else + up->rs485.flags &= ~SER_RS485_ENABLED; + + /* Enable interrupts */ + up->ier = mode; + serial_out(up, UART_IER, up->ier); + + spin_unlock_irqrestore(&up->port.lock, flags); + pm_runtime_mark_last_busy(up->dev); + pm_runtime_put_autosuspend(up->dev); +} + +static int +serial_omap_ioctl(struct uart_port *port, unsigned int cmd, unsigned long arg) +{ + struct serial_rs485 rs485conf; + + switch (cmd) { + case TIOCSRS485: + if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg, + sizeof(rs485conf))) + return -EFAULT; + + serial_omap_config_rs485(port, &rs485conf); + break; + + case TIOCGRS485: + if (copy_to_user((struct serial_rs485 *) arg, + &(to_uart_omap_port(port)->rs485), + sizeof(rs485conf))) + return -EFAULT; + break; + + default: + return -ENOIOCTLCMD; + } + return 0; +} + + static struct uart_ops serial_omap_pops = { .tx_empty = serial_omap_tx_empty, .set_mctrl = serial_omap_set_mctrl, @@ -1283,6 +1409,7 @@ static struct uart_ops serial_omap_pops = { .request_port = serial_omap_request_port, .config_port = serial_omap_config_port, .verify_port = serial_omap_verify_port, + .ioctl = serial_omap_ioctl, #ifdef CONFIG_CONSOLE_POLL .poll_put_char = serial_omap_poll_put_char, .poll_get_char = serial_omap_poll_get_char, @@ -1405,6 +1532,53 @@ static struct omap_uart_port_info *of_get_uart_port_info(struct device *dev) return omap_up_info; } +static int serial_omap_probe_rs485(struct uart_omap_port *up, + struct device_node *np) +{ + struct serial_rs485 *rs485conf = &up->rs485; + u32 rs485_delay[2]; + enum of_gpio_flags flags; + int ret; + + rs485conf->flags = 0; + up->rts_gpio = -EINVAL; + + if (!np) + return 0; + + if (of_property_read_bool(np, "rs485-rts-active-high")) + rs485conf->flags |= SER_RS485_RTS_ON_SEND; + else + rs485conf->flags |= SER_RS485_RTS_AFTER_SEND; + + /* check for tx enable gpio */ + up->rts_gpio = of_get_named_gpio_flags(np, "rts-gpio", 0, &flags); + if (gpio_is_valid(up->rts_gpio)) { + ret = gpio_request(up->rts_gpio, "omap-serial"); + if (ret < 0) + return ret; + ret = gpio_direction_output(up->rts_gpio, + flags & SER_RS485_RTS_AFTER_SEND); + if (ret < 0) + return ret; + } else + up->rts_gpio = -EINVAL; + + if (of_property_read_u32_array(np, "rs485-rts-delay", + rs485_delay, 2) == 0) { + rs485conf->delay_rts_before_send = rs485_delay[0]; + rs485conf->delay_rts_after_send = rs485_delay[1]; + } + + if (of_property_read_bool(np, "rs485-rx-during-tx")) + rs485conf->flags |= SER_RS485_RX_DURING_TX; + + if (of_property_read_bool(np, "linux,rs485-enabled-at-boot-time")) + rs485conf->flags |= SER_RS485_ENABLED; + + return 0; +} + static int serial_omap_probe(struct platform_device *pdev) { struct uart_omap_port *up; @@ -1480,6 +1654,10 @@ static int serial_omap_probe(struct platform_device *pdev) goto err_port_line; } + ret = serial_omap_probe_rs485(up, pdev->dev.of_node); + if (ret < 0) + goto err_rs485; + sprintf(up->name, "OMAP UART%d", up->port.line); up->port.mapbase = mem->start; up->port.membase = devm_ioremap(&pdev->dev, mem->start, @@ -1535,6 +1713,7 @@ err_add_port: pm_runtime_put(&pdev->dev); pm_runtime_disable(&pdev->dev); err_ioremap: +err_rs485: err_port_line: dev_err(&pdev->dev, "[UART%d]: failure [%s]: %d\n", pdev->id, __func__, ret); |