[OpenWrt-Devel] [PATCH v5 1/2] serial: ar933x_uart: add rs485 support
Daniel Golle
daniel at makrotopia.org
Wed Feb 12 09:37:36 EST 2020
Implement half-duplex as well as mctrl-gpio for RS-485 support.
Signed-off-by: Daniel Golle <daniel at makrotopia.org>
---
...61-tty-serial-ar933x-uart-rs485-gpio.patch | 206 ++++++++++++++++++
1 file changed, 206 insertions(+)
create mode 100644 target/linux/ath79/patches-4.19/0061-tty-serial-ar933x-uart-rs485-gpio.patch
diff --git a/target/linux/ath79/patches-4.19/0061-tty-serial-ar933x-uart-rs485-gpio.patch b/target/linux/ath79/patches-4.19/0061-tty-serial-ar933x-uart-rs485-gpio.patch
new file mode 100644
index 0000000000..ab309363b7
--- /dev/null
+++ b/target/linux/ath79/patches-4.19/0061-tty-serial-ar933x-uart-rs485-gpio.patch
@@ -0,0 +1,206 @@
+--- a/drivers/tty/serial/Kconfig
++++ b/drivers/tty/serial/Kconfig
+@@ -1296,6 +1296,7 @@ config SERIAL_AR933X
+ tristate "AR933X serial port support"
+ depends on HAVE_CLK && ATH79
+ select SERIAL_CORE
++ select SERIAL_MCTRL_GPIO if GPIOLIB
+ help
+ If you have an Atheros AR933X SOC based board and want to use the
+ built-in UART of the SoC, say Y to this option.
+--- a/drivers/tty/serial/ar933x_uart.c
++++ b/drivers/tty/serial/ar933x_uart.c
+@@ -29,6 +29,8 @@
+
+ #include <asm/mach-ath79/ar933x_uart.h>
+
++#include "serial_mctrl_gpio.h"
++
+ #define DRIVER_NAME "ar933x-uart"
+
+ #define AR933X_UART_MAX_SCALE 0xff
+@@ -47,6 +49,7 @@ struct ar933x_uart_port {
+ unsigned int min_baud;
+ unsigned int max_baud;
+ struct clk *clk;
++ struct mctrl_gpios *gpios;
+ };
+
+ static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
+@@ -100,6 +103,18 @@ static inline void ar933x_uart_stop_tx_i
+ ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
+ }
+
++static inline void ar933x_uart_start_rx_interrupt(struct ar933x_uart_port *up)
++{
++ up->ier |= AR933X_UART_INT_RX_VALID;
++ ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
++}
++
++static inline void ar933x_uart_stop_rx_interrupt(struct ar933x_uart_port *up)
++{
++ up->ier &= ~AR933X_UART_INT_RX_VALID;
++ ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
++}
++
+ static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
+ {
+ unsigned int rdata;
+@@ -125,11 +140,21 @@ static unsigned int ar933x_uart_tx_empty
+
+ static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
+ {
+- return TIOCM_CAR;
++ struct ar933x_uart_port *up =
++ container_of(port, struct ar933x_uart_port, port);
++ int ret = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
++
++ mctrl_gpio_get(up->gpios, &ret);
++
++ return ret;
+ }
+
+ static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+ {
++ struct ar933x_uart_port *up =
++ container_of(port, struct ar933x_uart_port, port);
++
++ mctrl_gpio_set(up->gpios, mctrl);
+ }
+
+ static void ar933x_uart_start_tx(struct uart_port *port)
+@@ -140,6 +165,43 @@ static void ar933x_uart_start_tx(struct
+ ar933x_uart_start_tx_interrupt(up);
+ }
+
++static void ar933x_uart_wait_tx_complete(struct ar933x_uart_port *up)
++{
++ unsigned int status;
++ unsigned int timeout = 60000;
++
++ /* Wait up to 60ms for the character(s) to be sent. */
++ do {
++ status = ar933x_uart_read(up, AR933X_UART_CS_REG);
++ if (--timeout == 0)
++ break;
++ udelay(1);
++ } while (status & AR933X_UART_CS_TX_BUSY);
++
++ if (timeout == 0)
++ dev_err(up->port.dev, "waiting for TX timed out\n");
++}
++
++static void ar933x_uart_rx_flush(struct ar933x_uart_port *up)
++{
++ unsigned int status;
++
++ /* clear RX_VALID interrupt */
++ ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_RX_VALID);
++
++ /* remove characters from the RX FIFO */
++ do {
++ ar933x_uart_write(up, AR933X_UART_DATA_REG, AR933X_UART_DATA_RX_CSR);
++ status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
++ } while (status & AR933X_UART_DATA_RX_CSR);
++}
++
++static inline int ar933x_uart_is_half_duplex(struct ar933x_uart_port *up)
++{
++ return (up->port.rs485.flags & SER_RS485_ENABLED) &&
++ !(up->port.rs485.flags & SER_RS485_RX_DURING_TX);
++}
++
+ static void ar933x_uart_stop_tx(struct uart_port *port)
+ {
+ struct ar933x_uart_port *up =
+@@ -153,8 +215,7 @@ static void ar933x_uart_stop_rx(struct u
+ struct ar933x_uart_port *up =
+ container_of(port, struct ar933x_uart_port, port);
+
+- up->ier &= ~AR933X_UART_INT_RX_VALID;
+- ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
++ ar933x_uart_stop_rx_interrupt(up);
+ }
+
+ static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
+@@ -341,6 +402,9 @@ static void ar933x_uart_tx_chars(struct
+ if (uart_tx_stopped(&up->port))
+ return;
+
++ if (ar933x_uart_is_half_duplex(up))
++ ar933x_uart_stop_rx_interrupt(up);
++
+ count = up->port.fifosize;
+ do {
+ unsigned int rdata;
+@@ -368,8 +432,13 @@ static void ar933x_uart_tx_chars(struct
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&up->port);
+
+- if (!uart_circ_empty(xmit))
++ if (!uart_circ_empty(xmit)) {
+ ar933x_uart_start_tx_interrupt(up);
++ } else if (ar933x_uart_is_half_duplex(up)) {
++ ar933x_uart_wait_tx_complete(up);
++ ar933x_uart_rx_flush(up);
++ ar933x_uart_start_rx_interrupt(up);
++ }
+ }
+
+ static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
+@@ -427,8 +496,7 @@ static int ar933x_uart_startup(struct ua
+ AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
+
+ /* Enable RX interrupts */
+- up->ier = AR933X_UART_INT_RX_VALID;
+- ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
++ ar933x_uart_start_rx_interrupt(up);
+
+ spin_unlock_irqrestore(&up->port.lock, flags);
+
+@@ -511,10 +579,16 @@ static const struct uart_ops ar933x_uart
+ .verify_port = ar933x_uart_verify_port,
+ };
+
++static int ar933x_config_rs485(struct uart_port *port,
++ struct serial_rs485 *rs485conf)
++{
++ port->rs485 = *rs485conf;
++ return 0;
++}
++
+ #ifdef CONFIG_SERIAL_AR933X_CONSOLE
+ static struct ar933x_uart_port *
+ ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
+-
+ static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
+ {
+ unsigned int status;
+@@ -680,6 +754,8 @@ static int ar933x_uart_probe(struct plat
+ goto err_disable_clk;
+ }
+
++ uart_get_rs485_mode(&pdev->dev, &port->rs485);
++
+ port->mapbase = mem_res->start;
+ port->line = id;
+ port->irq = irq_res->start;
+@@ -690,6 +766,7 @@ static int ar933x_uart_probe(struct plat
+ port->regshift = 2;
+ port->fifosize = AR933X_UART_FIFO_SIZE;
+ port->ops = &ar933x_uart_ops;
++ port->rs485_config = ar933x_config_rs485;
+
+ baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
+ up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
+@@ -697,6 +774,10 @@ static int ar933x_uart_probe(struct plat
+ baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
+ up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
+
++ up->gpios = mctrl_gpio_init(port, 0);
++ if (IS_ERR(up->gpios) && PTR_ERR(up->gpios) != -ENOSYS)
++ return PTR_ERR(up->gpios);
++
+ #ifdef CONFIG_SERIAL_AR933X_CONSOLE
+ ar933x_console_ports[up->port.line] = up;
+ #endif
--
2.25.0
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