Dedicated CTS and RTS pins are unusable together with a lot of other peripherals because they share the same line. Pinctrl is limited.
Moreover, the AUART controller doesn't handle DTR/DSR/DCD/RI signals, so we have to control them via GPIO. This patch permits to use GPIOs to control the CTS/RTS/DTR/DSR/DCD/RI signals. Signed-off-by: Janusz Uzycki <[email protected]> --- .../devicetree/bindings/serial/fsl-mxs-auart.txt | 10 +++++- drivers/tty/serial/Kconfig | 1 + drivers/tty/serial/mxs-auart.c | 37 ++++++++++++++++++++-- 3 files changed, 44 insertions(+), 4 deletions(-) diff --git a/Documentation/devicetree/bindings/serial/fsl-mxs-auart.txt b/Documentation/devicetree/bindings/serial/fsl-mxs-auart.txt index 59a40f1..7c408c8 100644 --- a/Documentation/devicetree/bindings/serial/fsl-mxs-auart.txt +++ b/Documentation/devicetree/bindings/serial/fsl-mxs-auart.txt @@ -11,8 +11,13 @@ Required properties: - dma-names: "rx" for RX channel, "tx" for TX channel. Optional properties: -- fsl,uart-has-rtscts : Indicate the UART has RTS and CTS lines, +- fsl,uart-has-rtscts : Indicate the UART has RTS and CTS lines + for hardware flow control, it also means you enable the DMA support for this UART. +- {rts,cts,dtr,dsr,rng,dcd}-gpios: specify a GPIO for RTS/CTS/DTR/DSR/RI/DCD + line respectively. It will use specified PIO instead of the peripheral + function pin for the USART feature. + If unsure, don't specify this property. Example: auart0: serial@8006a000 { @@ -21,6 +26,9 @@ auart0: serial@8006a000 { interrupts = <112>; dmas = <&dma_apbx 8>, <&dma_apbx 9>; dma-names = "rx", "tx"; + cts-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>; + dsr-gpios = <&gpio1 16 GPIO_ACTIVE_LOW>; + dcd-gpios = <&gpio1 17 GPIO_ACTIVE_LOW>; }; Note: Each auart port should have an alias correctly numbered in "aliases" diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig index 4fe8ca1..90e8516 100644 --- a/drivers/tty/serial/Kconfig +++ b/drivers/tty/serial/Kconfig @@ -1357,6 +1357,7 @@ config SERIAL_MXS_AUART depends on ARCH_MXS tristate "MXS AUART support" select SERIAL_CORE + select SERIAL_MCTRL_GPIO if GPIOLIB help This driver supports the MXS Application UART (AUART) port. diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c index c712108..fdfa8a9 100644 --- a/drivers/tty/serial/mxs-auart.c +++ b/drivers/tty/serial/mxs-auart.c @@ -42,6 +42,9 @@ #include <asm/cacheflush.h> +#include <linux/err.h> +#include "serial_mctrl_gpio.h" + #define MXS_AUART_PORTS 5 #define MXS_AUART_FIFO_SIZE 16 @@ -158,6 +161,8 @@ struct mxs_auart_port { struct scatterlist rx_sgl; struct dma_chan *rx_dma_chan; void *rx_dma_buf; + + struct mctrl_gpios *gpios; }; static struct platform_device_id mxs_auart_devtype[] = { @@ -405,6 +410,8 @@ static void mxs_auart_release_port(struct uart_port *u) static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl) { + struct mxs_auart_port *s = to_auart_port(u); + u32 ctrl = readl(u->membase + AUART_CTRL2); ctrl &= ~(AUART_CTRL2_RTSEN | AUART_CTRL2_RTS); @@ -416,10 +423,13 @@ static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl) } writel(ctrl, u->membase + AUART_CTRL2); + + mctrl_gpio_set(s->gpios, mctrl); } static u32 mxs_auart_get_mctrl(struct uart_port *u) { + struct mxs_auart_port *s = to_auart_port(u); u32 stat = readl(u->membase + AUART_STAT); int ctrl2 = readl(u->membase + AUART_CTRL2); u32 mctrl = 0; @@ -431,7 +441,7 @@ static u32 mxs_auart_get_mctrl(struct uart_port *u) if (ctrl2 & AUART_CTRL2_RTS) mctrl |= TIOCM_RTS; - return mctrl; + return mctrl_gpio_get(s->gpios, &mctrl); } static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s); @@ -635,7 +645,12 @@ static void mxs_auart_settermios(struct uart_port *u, ctrl |= AUART_LINECTRL_STP2; /* figure out the hardware flow control settings */ - if (cflag & CRTSCTS) { + /* FIXME: Likely DMA could be enabled not only for HW flow control */ + if (cflag & CRTSCTS && + (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(s->gpios, + UART_GPIO_RTS)) || + IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(s->gpios, + UART_GPIO_CTS)))) { /* * The DMA has a bug(see errata:2836) in mx23. * So we can not implement the DMA for auart in mx23, @@ -695,7 +710,10 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context) s->port.membase + AUART_INTR_CLR); if (istat & AUART_INTR_CTSMIS) { - uart_handle_cts_change(&s->port, stat & AUART_STAT_CTS); + if (IS_ERR_OR_NULL(mctrl_gpio_to_gpiod(s->gpios, + UART_GPIO_CTS))) + uart_handle_cts_change(&s->port, + stat & AUART_STAT_CTS); writel(AUART_INTR_CTSMIS, s->port.membase + AUART_INTR_CLR); istat &= ~AUART_INTR_CTSMIS; @@ -1019,6 +1037,14 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s, return 0; } +static int mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev) +{ + s->gpios = mctrl_gpio_init(dev, 0); + if (IS_ERR_OR_NULL(s->gpios)) + return -1; + return 0; +} + static int mxs_auart_probe(struct platform_device *pdev) { const struct of_device_id *of_id = @@ -1074,6 +1100,11 @@ static int mxs_auart_probe(struct platform_device *pdev) platform_set_drvdata(pdev, s); + ret = mxs_auart_init_gpios(s, &pdev->dev); + if (ret < 0) + dev_err(&pdev->dev, "%s", + "Failed to initialize GPIOs. The serial port may not work as expected"); + auart_port[s->port.line] = s; mxs_auart_reset(&s->port); -- 1.7.11.3 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
