serial: Allow uart_get_rs485_mode() to return errno

A patch from »serial: 8250: Add rs485 emulation to 8250_dw« in state Mainline for linux-kernel

From: Lukas Wunner <lukas@...> Date: Wed, 4 Dec 2019 11:51:26 +0100

Commit-Message

We're about to amend uart_get_rs485_mode() to support a GPIO pin for rs485 bus termination. Retrieving the GPIO descriptor may fail, so allow uart_get_rs485_mode() to return an errno and change all callers to check for failure. The GPIO descriptor is going to be stored in struct uart_port. Pass that struct to uart_get_rs485_mode() in lieu of a struct device and struct serial_rs485, both of which are directly accessible from struct uart_port. A few drivers call uart_get_rs485_mode() before setting the struct device pointer in struct uart_port. Shuffle those calls around where necessary. Signed-off-by: Lukas Wunner <lukas@...> [add ar933x_uart as well] Signed-off-by: Heiko Stuebner <heiko@...>

Patch-Comment

drivers/tty/serial/8250/8250_core.c | 4 +++- drivers/tty/serial/ar933x_uart.c | 6 ++++-- drivers/tty/serial/atmel_serial.c | 6 ++++-- drivers/tty/serial/fsl_lpuart.c | 5 ++++- drivers/tty/serial/imx.c | 6 +++++- drivers/tty/serial/omap-serial.c | 4 +++- drivers/tty/serial/serial_core.c | 6 +++++- drivers/tty/serial/stm32-usart.c | 8 ++++---- include/linux/serial_core.h | 2 +- 9 files changed, 33 insertions(+), 14 deletions(-)

Statistics

  • 33 lines added
  • 14 lines removed

Changes

--------------------- drivers/tty/serial/8250/8250_core.c ----------------------
index 45d9117cab68..cbf370e22344 100644
@@ -1026,7 +1026,9 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
if (up->port.dev) {
uart->port.dev = up->port.dev;
- uart_get_rs485_mode(uart->port.dev, &uart->port.rs485);
+ ret = uart_get_rs485_mode(&uart->port);
+ if (ret)
+ goto out_unlock;
}
if (up->port.flags & UPF_FIXED_TYPE)
----------------------- drivers/tty/serial/ar933x_uart.c -----------------------
index 7e7f1398019f..5bace041b94c 100644
@@ -766,8 +766,6 @@ static int ar933x_uart_probe(struct platform_device *pdev)
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;
@@ -780,6 +778,10 @@ static int ar933x_uart_probe(struct platform_device *pdev)
port->ops = &ar933x_uart_ops;
port->rs485_config = ar933x_config_rs485;
+ ret = uart_get_rs485_mode(port);
+ if (ret)
+ goto err_disable_clk;
+
baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
---------------------- drivers/tty/serial/atmel_serial.c -----------------------
index 8d7080efad9b..e43471b33710 100644
@@ -2491,8 +2491,6 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
atmel_init_property(atmel_port, pdev);
atmel_set_ops(port);
- uart_get_rs485_mode(&mpdev->dev, &port->rs485);
-
port->iotype = UPIO_MEM;
port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
port->ops = &atmel_pops;
@@ -2506,6 +2504,10 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));
+ ret = uart_get_rs485_mode(port);
+ if (ret)
+ return ret;
+
/* for console, the clock could already be configured */
if (!atmel_port->clk) {
atmel_port->clk = clk_get(&mpdev->dev, "usart");
----------------------- drivers/tty/serial/fsl_lpuart.c ------------------------
index 9c6a018b1390..4a1b507b4af1 100644
@@ -2611,7 +2611,9 @@ static int lpuart_probe(struct platform_device *pdev)
if (ret)
goto failed_attach_port;
- uart_get_rs485_mode(&pdev->dev, &sport->port.rs485);
+ ret = uart_get_rs485_mode(&sport->port);
+ if (ret)
+ goto failed_get_rs485;
if (sport->port.rs485.flags & SER_RS485_RX_DURING_TX)
dev_err(&pdev->dev, "driver doesn't support RX during TX\n");
@@ -2624,6 +2626,7 @@ static int lpuart_probe(struct platform_device *pdev)
return 0;
+failed_get_rs485:
failed_attach_port:
failed_irq_request:
lpuart_disable_clks(sport);
--------------------------- drivers/tty/serial/imx.c ---------------------------
index f4d68109bc8b..91f3910d6c44 100644
@@ -2302,7 +2302,11 @@ static int imx_uart_probe(struct platform_device *pdev)
sport->ucr4 = readl(sport->port.membase + UCR4);
sport->ufcr = readl(sport->port.membase + UFCR);
- uart_get_rs485_mode(&pdev->dev, &sport->port.rs485);
+ ret = uart_get_rs485_mode(&sport->port);
+ if (ret) {
+ clk_disable_unprepare(sport->clk_ipg);
+ return ret;
+ }
if (sport->port.rs485.flags & SER_RS485_ENABLED &&
(!sport->have_rtscts && !sport->have_rtsgpio))
----------------------- drivers/tty/serial/omap-serial.c -----------------------
index 48017cec7f2f..532fbc68e801 100644
@@ -1609,7 +1609,9 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
if (!np)
return 0;
- uart_get_rs485_mode(up->dev, rs485conf);
+ ret = uart_get_rs485_mode(&up->port);
+ if (ret)
+ return ret;
if (of_property_read_bool(np, "rs485-rts-active-high")) {
rs485conf->flags |= SER_RS485_RTS_ON_SEND;
----------------------- drivers/tty/serial/serial_core.c -----------------------
index 66a5e2faf57e..43b6682877d5 100644
@@ -3295,8 +3295,10 @@ EXPORT_SYMBOL(uart_remove_one_port);
* This function implements the device tree binding described in
* Documentation/devicetree/bindings/serial/rs485.txt.
*/
-void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
+int uart_get_rs485_mode(struct uart_port *port)
{
+ struct serial_rs485 *rs485conf = &port->rs485;
+ struct device *dev = port->dev;
u32 rs485_delay[2];
int ret;
@@ -3328,6 +3330,8 @@ void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
}
+
+ return 0;
}
EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
----------------------- drivers/tty/serial/stm32-usart.c -----------------------
index 5e93e8d40f59..e3db54398159 100644
@@ -158,9 +158,7 @@ static int stm32_init_rs485(struct uart_port *port,
if (!pdev->dev.of_node)
return -ENODEV;
- uart_get_rs485_mode(&pdev->dev, rs485conf);
-
- return 0;
+ return uart_get_rs485_mode(port);
}
static int stm32_pending_rx(struct uart_port *port, u32 *sr, int *last_res,
@@ -931,7 +929,9 @@ static int stm32_init_port(struct stm32_port *stm32port,
port->rs485_config = stm32_config_rs485;
- stm32_init_rs485(port, pdev);
+ ret = stm32_init_rs485(port, pdev);
+ if (ret)
+ return ret;
if (stm32port->info->cfg.has_wakeup) {
stm32port->wakeirq = platform_get_irq(pdev, 1);
------------------------- include/linux/serial_core.h --------------------------
index 92f5eba86052..b649a2b894e7 100644
@@ -472,5 +472,5 @@ extern int uart_handle_break(struct uart_port *port);
(cflag) & CRTSCTS || \
!((cflag) & CLOCAL))
-void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
+int uart_get_rs485_mode(struct uart_port *port);
#endif /* LINUX_SERIAL_CORE_H */
 
 

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