diff options
Diffstat (limited to 'drivers/tty/serial/st-asc.c')
| -rw-r--r-- | drivers/tty/serial/st-asc.c | 101 |
1 files changed, 92 insertions, 9 deletions
diff --git a/drivers/tty/serial/st-asc.c b/drivers/tty/serial/st-asc.c index 379e5bd37df9..bcf1d33e6ffe 100644 --- a/drivers/tty/serial/st-asc.c +++ b/drivers/tty/serial/st-asc.c @@ -18,6 +18,7 @@ #include <linux/serial.h> #include <linux/console.h> #include <linux/sysrq.h> +#include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/irq.h> @@ -30,15 +31,23 @@ #include <linux/of_platform.h> #include <linux/serial_core.h> #include <linux/clk.h> +#include <linux/gpio/consumer.h> #define DRIVER_NAME "st-asc" #define ASC_SERIAL_NAME "ttyAS" #define ASC_FIFO_SIZE 16 #define ASC_MAX_PORTS 8 +/* Pinctrl states */ +#define DEFAULT 0 +#define NO_HW_FLOWCTRL 1 + struct asc_port { struct uart_port port; + struct gpio_desc *rts; struct clk *clk; + struct pinctrl *pinctrl; + struct pinctrl_state *states[2]; unsigned int hw_flow_control:1; unsigned int force_m1:1; }; @@ -287,9 +296,19 @@ static void asc_transmit_chars(struct uart_port *port) static void asc_receive_chars(struct uart_port *port) { struct tty_port *tport = &port->state->port; - unsigned long status; + unsigned long status, mode; unsigned long c = 0; char flag; + bool ignore_pe = false; + + /* + * Datasheet states: If the MODE field selects an 8-bit frame then + * this [parity error] bit is undefined. Software should ignore this + * bit when reading 8-bit frames. + */ + mode = asc_in(port, ASC_CTL) & ASC_CTL_MODE_MSK; + if (mode == ASC_CTL_MODE_8BIT || mode == ASC_CTL_MODE_8BIT_PAR) + ignore_pe = true; if (port->irq_wake) pm_wakeup_event(tport->tty->dev, 0); @@ -299,8 +318,8 @@ static void asc_receive_chars(struct uart_port *port) flag = TTY_NORMAL; port->icount.rx++; - if ((c & (ASC_RXBUF_FE | ASC_RXBUF_PE)) || - status & ASC_STA_OE) { + if (status & ASC_STA_OE || c & ASC_RXBUF_FE || + (c & ASC_RXBUF_PE && !ignore_pe)) { if (c & ASC_RXBUF_FE) { if (c == (ASC_RXBUF_FE | ASC_RXBUF_DUMMY_RX)) { @@ -381,12 +400,27 @@ static unsigned int asc_tx_empty(struct uart_port *port) static void asc_set_mctrl(struct uart_port *port, unsigned int mctrl) { + struct asc_port *ascport = to_asc_port(port); + /* - * This routine is used for seting signals of: DTR, DCD, CTS/RTS - * We use ASC's hardware for CTS/RTS, so don't need any for that. - * Some boards have DTR and DCD implemented using PIO pins, - * code to do this should be hooked in here. + * This routine is used for seting signals of: DTR, DCD, CTS and RTS. + * We use ASC's hardware for CTS/RTS when hardware flow-control is + * enabled, however if the RTS line is required for another purpose, + * commonly controlled using HUP from userspace, then we need to toggle + * it manually, using GPIO. + * + * Some boards also have DTR and DCD implemented using PIO pins, code to + * do this should be hooked in here. */ + + if (!ascport->rts) + return; + + /* If HW flow-control is enabled, we can't fiddle with the RTS line */ + if (asc_in(port, ASC_CTL) & ASC_CTL_CTSENABLE) + return; + + gpiod_set_value(ascport->rts, mctrl & TIOCM_RTS); } static unsigned int asc_get_mctrl(struct uart_port *port) @@ -479,6 +513,8 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old) { struct asc_port *ascport = to_asc_port(port); + struct device_node *np = port->dev->of_node; + struct gpio_desc *gpiod; unsigned int baud; u32 ctrl_val; tcflag_t cflag; @@ -522,9 +558,32 @@ static void asc_set_termios(struct uart_port *port, struct ktermios *termios, ctrl_val |= ASC_CTL_PARITYODD; /* hardware flow control */ - if ((cflag & CRTSCTS)) + if ((cflag & CRTSCTS)) { ctrl_val |= ASC_CTL_CTSENABLE; + /* If flow-control selected, stop handling RTS manually */ + if (ascport->rts) { + devm_gpiod_put(port->dev, ascport->rts); + ascport->rts = NULL; + + pinctrl_select_state(ascport->pinctrl, + ascport->states[DEFAULT]); + } + } else { + /* If flow-control disabled, it's safe to handle RTS manually */ + if (!ascport->rts && ascport->states[NO_HW_FLOWCTRL]) { + pinctrl_select_state(ascport->pinctrl, + ascport->states[NO_HW_FLOWCTRL]); + + gpiod = devm_get_gpiod_from_child(port->dev, "rts", + &np->fwnode); + if (!IS_ERR(gpiod)) { + gpiod_direction_output(gpiod, 0); + ascport->rts = gpiod; + } + } + } + if ((baud < 19200) && !ascport->force_m1) { asc_out(port, ASC_BAUDRATE, (port->uartclk / (16 * baud))); } else { @@ -667,6 +726,7 @@ static int asc_init_port(struct asc_port *ascport, { struct uart_port *port = &ascport->port; struct resource *res; + int ret; port->iotype = UPIO_MEM; port->flags = UPF_BOOT_AUTOCONF; @@ -693,6 +753,27 @@ static int asc_init_port(struct asc_port *ascport, WARN_ON(ascport->port.uartclk == 0); clk_disable_unprepare(ascport->clk); + ascport->pinctrl = devm_pinctrl_get(&pdev->dev); + if (IS_ERR(ascport->pinctrl)) { + ret = PTR_ERR(ascport->pinctrl); + dev_err(&pdev->dev, "Failed to get Pinctrl: %d\n", ret); + } + + ascport->states[DEFAULT] = + pinctrl_lookup_state(ascport->pinctrl, "default"); + if (IS_ERR(ascport->states[DEFAULT])) { + ret = PTR_ERR(ascport->states[DEFAULT]); + dev_err(&pdev->dev, + "Failed to look up Pinctrl state 'default': %d\n", ret); + return ret; + } + + /* "no-hw-flowctrl" state is optional */ + ascport->states[NO_HW_FLOWCTRL] = + pinctrl_lookup_state(ascport->pinctrl, "no-hw-flowctrl"); + if (IS_ERR(ascport->states[NO_HW_FLOWCTRL])) + ascport->states[NO_HW_FLOWCTRL] = NULL; + return 0; } @@ -713,9 +794,11 @@ static struct asc_port *asc_of_get_asc_port(struct platform_device *pdev) return NULL; asc_ports[id].hw_flow_control = of_property_read_bool(np, - "st,hw-flow-control"); + "uart-has-rtscts"); asc_ports[id].force_m1 = of_property_read_bool(np, "st,force_m1"); asc_ports[id].port.line = id; + asc_ports[id].rts = NULL; + return &asc_ports[id]; } |