| Message ID | 20231213130023.606486-4-manikanta.guntupalli@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add rs485 support to uartps driver | expand |
On Wed, 13 Dec 2023, Manikanta Guntupalli wrote: > Add rs485 support to uartps driver. Use either rts-gpios or RTS > to control RS485 phy as driver or a receiver. > > Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com> > --- > Changes for V2: > Modify optional gpio name to xlnx,phy-ctrl-gpios. > Update commit description. > Add support for RTS, delay_rts_before_send and delay_rts_after_send in RS485 mode. > > Changes for V3: > Modify optional gpio name to rts-gpios. > Update commit description. > Move cdns_uart_tx_empty function to avoid prototype statement. > Remove assignment of struct serial_rs485 to port->rs485 as > serial core performs that. > Switch to native RTS in non GPIO case. > Handle rs485 during stop tx. > Remove explicit calls to configure gpio direction and value, > as devm_gpiod_get_optional performs that by using GPIOD_OUT_LOW argument. > Update implementation to support configuration of GPIO/RTS value > based on user configuration of SER_RS485_RTS_ON_SEND and > SER_RS485_RTS_AFTER_SEND. Move implementation to start_tx from handle_tx. > > Changes for V4: > Create separate patch for cdns_uart_tx_empty relocation. > Call cdns_rs485_rx_setup() before uart_add_one_port() in probe. > Update gpio descriptor name to gpiod_rts. > Instead of cdns_rs485_config_gpio_rts_high() and > cdns_rs485_config_gpio_rts_low() functions for RTS/GPIO value > configuration implement cdns_rts_gpio_enable(). > Disable auto rts and call cdns_uart_stop_tx() from cdns_rs485_config. > Use timer instead of mdelay for delay_rts_before_send and delay_rts_after_send. > Update cdns_uart_set_mctrl to support GPIO/RTS. > > Changes for V5: > None. > --- > drivers/tty/serial/xilinx_uartps.c | 214 +++++++++++++++++++++++++++-- > 1 file changed, 205 insertions(+), 9 deletions(-) > > diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c > index aafcc2179e0e..3e1045896812 100644 > --- a/drivers/tty/serial/xilinx_uartps.c > +++ b/drivers/tty/serial/xilinx_uartps.c > @@ -22,7 +22,9 @@ > #include <linux/of.h> > #include <linux/module.h> > #include <linux/pm_runtime.h> > -#include <linux/iopoll.h> > +#include <linux/gpio.h> > +#include <linux/gpio/consumer.h> > +#include <linux/delay.h> > > #define CDNS_UART_TTY_NAME "ttyPS" > #define CDNS_UART_NAME "xuartps" > @@ -193,6 +195,10 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); > * @clk_rate_change_nb: Notifier block for clock changes > * @quirks: Flags for RXBS support. > * @cts_override: Modem control state override > + * @gpiod_rts: Pointer to the gpio descriptor > + * @rs485_tx_started: RS485 tx state > + * @timer: Timer for tx and rx > + * @stop_tx_timer: Timer for stop tx > */ > struct cdns_uart { > struct uart_port *port; > @@ -203,10 +209,22 @@ struct cdns_uart { > struct notifier_block clk_rate_change_nb; > u32 quirks; > bool cts_override; > + struct gpio_desc *gpiod_rts; > + bool rs485_tx_started; > + struct timer_list timer; > + struct timer_list stop_tx_timer; > }; > struct cdns_platform_data { > u32 quirks; > }; > + > +struct serial_rs485 cdns_rs485_supported = { > + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | > + SER_RS485_RTS_AFTER_SEND, > + .delay_rts_before_send = 1, > + .delay_rts_after_send = 1, > +}; > + > #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \ > clk_rate_change_nb) > > @@ -305,6 +323,55 @@ static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus) > tty_flip_buffer_push(&port->state->port); > } > > +/** > + * cdns_rts_gpio_enable - Configure RTS/GPIO to high/low > + * @cdns_uart: Handle to the cdns_uart > + * @enable: Value to be set to RTS/GPIO > + */ > +static void cdns_rts_gpio_enable(struct cdns_uart *cdns_uart, bool enable) > +{ > + u32 val; > + > + if (cdns_uart->gpiod_rts) { > + gpiod_set_value(cdns_uart->gpiod_rts, enable); > + } else { > + val = readl(cdns_uart->port->membase + CDNS_UART_MODEMCR); > + if (enable) > + val &= ~CDNS_UART_MODEMCR_RTS; > + else > + val |= CDNS_UART_MODEMCR_RTS; > + writel(val, cdns_uart->port->membase + CDNS_UART_MODEMCR); > + } > +} > + > +/** > + * cdns_rs485_tx_setup - Tx setup specific to rs485 > + * @cdns_uart: Handle to the cdns_uart > + */ > +static void cdns_rs485_tx_setup(struct cdns_uart *cdns_uart) > +{ > + if (cdns_uart->port->rs485.flags & SER_RS485_RTS_ON_SEND) > + cdns_rts_gpio_enable(cdns_uart, 1); > + else > + cdns_rts_gpio_enable(cdns_uart, 0); > + > + cdns_uart->rs485_tx_started = true; > +} > + > +/** > + * cdns_rs485_rx_setup - Rx setup specific to rs485 > + * @cdns_uart: Handle to the cdns_uart > + */ > +static void cdns_rs485_rx_setup(struct cdns_uart *cdns_uart) > +{ > + if (cdns_uart->port->rs485.flags & SER_RS485_RTS_AFTER_SEND) > + cdns_rts_gpio_enable(cdns_uart, 1); > + else > + cdns_rts_gpio_enable(cdns_uart, 0); > + > + cdns_uart->rs485_tx_started = false; > +} > + > /** > * cdns_uart_tx_empty - Check whether TX is empty > * @port: Handle to the uart port structure > @@ -579,6 +646,42 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb, > } > #endif > > +/** > + * cdns_rs485_rx_callback - Timer rx callback handler for rs485. > + * @t: Handle to the timer list structure > + */ > +static void cdns_rs485_rx_callback(struct timer_list *t) > +{ > + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, timer); > + > + /* > + * Default Rx should be setup, because Rx signaling path > + * need to enable to receive data. > + */ > + cdns_rs485_rx_setup(cdns_uart); > +} > + > +/** > + * cdns_rs485_tx_callback - Timer tx callback handler for rs485. > + * @t: Handle to the timer list structure > + */ > +static void cdns_rs485_tx_callback(struct timer_list *t) > +{ > + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, timer); > + > + cdns_uart_handle_tx(cdns_uart->port); > + > + /* Enable the TX Empty interrupt */ > + writel(CDNS_UART_IXR_TXEMPTY, cdns_uart->port->membase + CDNS_UART_IER); > + > + if (uart_circ_empty(&cdns_uart->port->state->xmit) || > + uart_tx_stopped(cdns_uart->port)) { > + timer_setup(&cdns_uart->timer, cdns_rs485_rx_callback, 0); > + mod_timer(&cdns_uart->timer, jiffies + > + msecs_to_jiffies(cdns_uart->port->rs485.delay_rts_after_send)); > + } > +} > + > /** > * cdns_uart_start_tx - Start transmitting bytes > * @port: Handle to the uart port structure > @@ -586,6 +689,7 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb, > static void cdns_uart_start_tx(struct uart_port *port) > { > unsigned int status; > + struct cdns_uart *cdns_uart = port->private_data; > > if (uart_tx_stopped(port)) > return; > @@ -604,10 +708,40 @@ static void cdns_uart_start_tx(struct uart_port *port) > > writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR); > > - cdns_uart_handle_tx(port); > + if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) { > + if (!cdns_uart->rs485_tx_started) { > + timer_setup(&cdns_uart->timer, > + cdns_rs485_tx_callback, 0); > + cdns_rs485_tx_setup(cdns_uart); > + mod_timer(&cdns_uart->timer, jiffies + > + msecs_to_jiffies(port->rs485.delay_rts_before_send)); > + } else { > + if (!timer_pending(&cdns_uart->timer)) > + mod_timer(&cdns_uart->timer, jiffies); > + } > + } else { > + cdns_uart_handle_tx(port); > > - /* Enable the TX Empty interrupt */ > - writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER); > + /* Enable the TX Empty interrupt */ > + writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER); > + } > +} > + > +/** > + * cdns_rs485_stop_tx_callback - Timer stop tx callback handler for rs485. > + * @t: Handle to the timer list structure > + */ > +static void cdns_rs485_stop_tx_callback(struct timer_list *t) > +{ > + unsigned int regval; > + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, stop_tx_timer); > + > + cdns_rs485_rx_setup(cdns_uart); > + > + regval = readl(cdns_uart->port->membase + CDNS_UART_CR); > + regval |= CDNS_UART_CR_TX_DIS; > + /* Disable the transmitter */ > + writel(regval, cdns_uart->port->membase + CDNS_UART_CR); > } > > /** > @@ -617,11 +751,19 @@ static void cdns_uart_start_tx(struct uart_port *port) > static void cdns_uart_stop_tx(struct uart_port *port) > { > unsigned int regval; > + struct cdns_uart *cdns_uart = port->private_data; > > - regval = readl(port->membase + CDNS_UART_CR); > - regval |= CDNS_UART_CR_TX_DIS; > - /* Disable the transmitter */ > - writel(regval, port->membase + CDNS_UART_CR); > + if ((cdns_uart->port->rs485.flags & SER_RS485_ENABLED) && > + !timer_pending(&cdns_uart->stop_tx_timer) && > + cdns_uart->rs485_tx_started) { > + mod_timer(&cdns_uart->stop_tx_timer, jiffies + > + msecs_to_jiffies(cdns_uart->port->rs485.delay_rts_after_send)); > + } else { > + regval = readl(port->membase + CDNS_UART_CR); > + regval |= CDNS_UART_CR_TX_DIS; > + /* Disable the transmitter */ > + writel(regval, port->membase + CDNS_UART_CR); > + } > } > > /** > @@ -829,6 +971,12 @@ static int cdns_uart_startup(struct uart_port *port) > (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) > cpu_relax(); > > + if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) { > + timer_setup(&cdns_uart->stop_tx_timer, > + cdns_rs485_stop_tx_callback, 0); > + cdns_rs485_rx_setup(cdns_uart); > + } > + > /* > * Clear the RX disable bit and then set the RX enable bit to enable > * the receiver. > @@ -888,6 +1036,7 @@ static void cdns_uart_shutdown(struct uart_port *port) > { > int status; > unsigned long flags; > + struct cdns_uart *cdns_uart = port->private_data; > > uart_port_lock_irqsave(port, &flags); > > @@ -903,6 +1052,11 @@ static void cdns_uart_shutdown(struct uart_port *port) > uart_port_unlock_irqrestore(port, flags); > > free_irq(port->irq, port); > + > + if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) { > + del_timer_sync(&cdns_uart->timer); > + del_timer_sync(&cdns_uart->stop_tx_timer); > + } > } > > /** > @@ -1032,7 +1186,7 @@ static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) > mode_reg &= ~CDNS_UART_MR_CHMODE_MASK; > > if (mctrl & TIOCM_RTS) > - val |= CDNS_UART_MODEMCR_RTS; > + cdns_rts_gpio_enable(cdns_uart_data, 1); > if (mctrl & TIOCM_DTR) > val |= CDNS_UART_MODEMCR_DTR; > if (mctrl & TIOCM_LOOP) > @@ -1455,6 +1609,31 @@ MODULE_DEVICE_TABLE(of, cdns_uart_of_match); > /* Temporary variable for storing number of instances */ > static int instances; > > +/** > + * cdns_rs485_config - Called when an application calls TIOCSRS485 ioctl. > + * @port: Pointer to the uart_port structure > + * @termios: Pointer to the ktermios structure > + * @rs485: Pointer to the serial_rs485 structure > + * > + * Return: 0 > + */ > +static int cdns_rs485_config(struct uart_port *port, struct ktermios *termios, > + struct serial_rs485 *rs485) > +{ > + u32 val; > + > + if (rs485->flags & SER_RS485_ENABLED) { > + dev_dbg(port->dev, "Setting UART to RS485\n"); > + /* Make sure auto RTS is disabled */ > + val = readl(port->membase + CDNS_UART_MODEMCR); > + val &= ~CDNS_UART_MODEMCR_FCM; > + writel(val, port->membase + CDNS_UART_MODEMCR); > + /* Disable transmitter and make Rx setup*/ Missing space. > + cdns_uart_stop_tx(port); > + } So you provide no way to disable RS485 after it once gets enable? Arguably that might not usually be a very useful thing to do in practice but API-wise this function is expected to be able to also turn RS485 off. I didn't do a full review but having to add a timer smells like you could reuse the existing em485 framework for timing, please check.
Hi, On 13.12.23 14:00, Manikanta Guntupalli wrote: > > +/** > + * cdns_rs485_rx_callback - Timer rx callback handler for rs485. > + * @t: Handle to the timer list structure > + */ > +static void cdns_rs485_rx_callback(struct timer_list *t) > +{ > + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, timer); > + > + /* > + * Default Rx should be setup, because Rx signaling path > + * need to enable to receive data. > + */ > + cdns_rs485_rx_setup(cdns_uart); > +} > + > +/** > + * cdns_rs485_tx_callback - Timer tx callback handler for rs485. > + * @t: Handle to the timer list structure > + */ > +static void cdns_rs485_tx_callback(struct timer_list *t) > +{ > + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, timer); > + > + cdns_uart_handle_tx(cdns_uart->port); This is called without holding the port lock now. Are you sure the lock is not needed? AFAIK the port lock is needed at least for accessing the circular buffer. > + > + /* Enable the TX Empty interrupt */ > + writel(CDNS_UART_IXR_TXEMPTY, cdns_uart->port->membase + CDNS_UART_IER); > + > + if (uart_circ_empty(&cdns_uart->port->state->xmit) || > + uart_tx_stopped(cdns_uart->port)) { > + timer_setup(&cdns_uart->timer, cdns_rs485_rx_callback, 0); > + mod_timer(&cdns_uart->timer, jiffies + > + msecs_to_jiffies(cdns_uart->port->rs485.delay_rts_after_send)); > + } > +} Regards, Lino
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c index aafcc2179e0e..3e1045896812 100644 --- a/drivers/tty/serial/xilinx_uartps.c +++ b/drivers/tty/serial/xilinx_uartps.c @@ -22,7 +22,9 @@ #include <linux/of.h> #include <linux/module.h> #include <linux/pm_runtime.h> -#include <linux/iopoll.h> +#include <linux/gpio.h> +#include <linux/gpio/consumer.h> +#include <linux/delay.h> #define CDNS_UART_TTY_NAME "ttyPS" #define CDNS_UART_NAME "xuartps" @@ -193,6 +195,10 @@ MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); * @clk_rate_change_nb: Notifier block for clock changes * @quirks: Flags for RXBS support. * @cts_override: Modem control state override + * @gpiod_rts: Pointer to the gpio descriptor + * @rs485_tx_started: RS485 tx state + * @timer: Timer for tx and rx + * @stop_tx_timer: Timer for stop tx */ struct cdns_uart { struct uart_port *port; @@ -203,10 +209,22 @@ struct cdns_uart { struct notifier_block clk_rate_change_nb; u32 quirks; bool cts_override; + struct gpio_desc *gpiod_rts; + bool rs485_tx_started; + struct timer_list timer; + struct timer_list stop_tx_timer; }; struct cdns_platform_data { u32 quirks; }; + +struct serial_rs485 cdns_rs485_supported = { + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | + SER_RS485_RTS_AFTER_SEND, + .delay_rts_before_send = 1, + .delay_rts_after_send = 1, +}; + #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \ clk_rate_change_nb) @@ -305,6 +323,55 @@ static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus) tty_flip_buffer_push(&port->state->port); } +/** + * cdns_rts_gpio_enable - Configure RTS/GPIO to high/low + * @cdns_uart: Handle to the cdns_uart + * @enable: Value to be set to RTS/GPIO + */ +static void cdns_rts_gpio_enable(struct cdns_uart *cdns_uart, bool enable) +{ + u32 val; + + if (cdns_uart->gpiod_rts) { + gpiod_set_value(cdns_uart->gpiod_rts, enable); + } else { + val = readl(cdns_uart->port->membase + CDNS_UART_MODEMCR); + if (enable) + val &= ~CDNS_UART_MODEMCR_RTS; + else + val |= CDNS_UART_MODEMCR_RTS; + writel(val, cdns_uart->port->membase + CDNS_UART_MODEMCR); + } +} + +/** + * cdns_rs485_tx_setup - Tx setup specific to rs485 + * @cdns_uart: Handle to the cdns_uart + */ +static void cdns_rs485_tx_setup(struct cdns_uart *cdns_uart) +{ + if (cdns_uart->port->rs485.flags & SER_RS485_RTS_ON_SEND) + cdns_rts_gpio_enable(cdns_uart, 1); + else + cdns_rts_gpio_enable(cdns_uart, 0); + + cdns_uart->rs485_tx_started = true; +} + +/** + * cdns_rs485_rx_setup - Rx setup specific to rs485 + * @cdns_uart: Handle to the cdns_uart + */ +static void cdns_rs485_rx_setup(struct cdns_uart *cdns_uart) +{ + if (cdns_uart->port->rs485.flags & SER_RS485_RTS_AFTER_SEND) + cdns_rts_gpio_enable(cdns_uart, 1); + else + cdns_rts_gpio_enable(cdns_uart, 0); + + cdns_uart->rs485_tx_started = false; +} + /** * cdns_uart_tx_empty - Check whether TX is empty * @port: Handle to the uart port structure @@ -579,6 +646,42 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb, } #endif +/** + * cdns_rs485_rx_callback - Timer rx callback handler for rs485. + * @t: Handle to the timer list structure + */ +static void cdns_rs485_rx_callback(struct timer_list *t) +{ + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, timer); + + /* + * Default Rx should be setup, because Rx signaling path + * need to enable to receive data. + */ + cdns_rs485_rx_setup(cdns_uart); +} + +/** + * cdns_rs485_tx_callback - Timer tx callback handler for rs485. + * @t: Handle to the timer list structure + */ +static void cdns_rs485_tx_callback(struct timer_list *t) +{ + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, timer); + + cdns_uart_handle_tx(cdns_uart->port); + + /* Enable the TX Empty interrupt */ + writel(CDNS_UART_IXR_TXEMPTY, cdns_uart->port->membase + CDNS_UART_IER); + + if (uart_circ_empty(&cdns_uart->port->state->xmit) || + uart_tx_stopped(cdns_uart->port)) { + timer_setup(&cdns_uart->timer, cdns_rs485_rx_callback, 0); + mod_timer(&cdns_uart->timer, jiffies + + msecs_to_jiffies(cdns_uart->port->rs485.delay_rts_after_send)); + } +} + /** * cdns_uart_start_tx - Start transmitting bytes * @port: Handle to the uart port structure @@ -586,6 +689,7 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb, static void cdns_uart_start_tx(struct uart_port *port) { unsigned int status; + struct cdns_uart *cdns_uart = port->private_data; if (uart_tx_stopped(port)) return; @@ -604,10 +708,40 @@ static void cdns_uart_start_tx(struct uart_port *port) writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR); - cdns_uart_handle_tx(port); + if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) { + if (!cdns_uart->rs485_tx_started) { + timer_setup(&cdns_uart->timer, + cdns_rs485_tx_callback, 0); + cdns_rs485_tx_setup(cdns_uart); + mod_timer(&cdns_uart->timer, jiffies + + msecs_to_jiffies(port->rs485.delay_rts_before_send)); + } else { + if (!timer_pending(&cdns_uart->timer)) + mod_timer(&cdns_uart->timer, jiffies); + } + } else { + cdns_uart_handle_tx(port); - /* Enable the TX Empty interrupt */ - writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER); + /* Enable the TX Empty interrupt */ + writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER); + } +} + +/** + * cdns_rs485_stop_tx_callback - Timer stop tx callback handler for rs485. + * @t: Handle to the timer list structure + */ +static void cdns_rs485_stop_tx_callback(struct timer_list *t) +{ + unsigned int regval; + struct cdns_uart *cdns_uart = from_timer(cdns_uart, t, stop_tx_timer); + + cdns_rs485_rx_setup(cdns_uart); + + regval = readl(cdns_uart->port->membase + CDNS_UART_CR); + regval |= CDNS_UART_CR_TX_DIS; + /* Disable the transmitter */ + writel(regval, cdns_uart->port->membase + CDNS_UART_CR); } /** @@ -617,11 +751,19 @@ static void cdns_uart_start_tx(struct uart_port *port) static void cdns_uart_stop_tx(struct uart_port *port) { unsigned int regval; + struct cdns_uart *cdns_uart = port->private_data; - regval = readl(port->membase + CDNS_UART_CR); - regval |= CDNS_UART_CR_TX_DIS; - /* Disable the transmitter */ - writel(regval, port->membase + CDNS_UART_CR); + if ((cdns_uart->port->rs485.flags & SER_RS485_ENABLED) && + !timer_pending(&cdns_uart->stop_tx_timer) && + cdns_uart->rs485_tx_started) { + mod_timer(&cdns_uart->stop_tx_timer, jiffies + + msecs_to_jiffies(cdns_uart->port->rs485.delay_rts_after_send)); + } else { + regval = readl(port->membase + CDNS_UART_CR); + regval |= CDNS_UART_CR_TX_DIS; + /* Disable the transmitter */ + writel(regval, port->membase + CDNS_UART_CR); + } } /** @@ -829,6 +971,12 @@ static int cdns_uart_startup(struct uart_port *port) (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) cpu_relax(); + if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) { + timer_setup(&cdns_uart->stop_tx_timer, + cdns_rs485_stop_tx_callback, 0); + cdns_rs485_rx_setup(cdns_uart); + } + /* * Clear the RX disable bit and then set the RX enable bit to enable * the receiver. @@ -888,6 +1036,7 @@ static void cdns_uart_shutdown(struct uart_port *port) { int status; unsigned long flags; + struct cdns_uart *cdns_uart = port->private_data; uart_port_lock_irqsave(port, &flags); @@ -903,6 +1052,11 @@ static void cdns_uart_shutdown(struct uart_port *port) uart_port_unlock_irqrestore(port, flags); free_irq(port->irq, port); + + if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) { + del_timer_sync(&cdns_uart->timer); + del_timer_sync(&cdns_uart->stop_tx_timer); + } } /** @@ -1032,7 +1186,7 @@ static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) mode_reg &= ~CDNS_UART_MR_CHMODE_MASK; if (mctrl & TIOCM_RTS) - val |= CDNS_UART_MODEMCR_RTS; + cdns_rts_gpio_enable(cdns_uart_data, 1); if (mctrl & TIOCM_DTR) val |= CDNS_UART_MODEMCR_DTR; if (mctrl & TIOCM_LOOP) @@ -1455,6 +1609,31 @@ MODULE_DEVICE_TABLE(of, cdns_uart_of_match); /* Temporary variable for storing number of instances */ static int instances; +/** + * cdns_rs485_config - Called when an application calls TIOCSRS485 ioctl. + * @port: Pointer to the uart_port structure + * @termios: Pointer to the ktermios structure + * @rs485: Pointer to the serial_rs485 structure + * + * Return: 0 + */ +static int cdns_rs485_config(struct uart_port *port, struct ktermios *termios, + struct serial_rs485 *rs485) +{ + u32 val; + + if (rs485->flags & SER_RS485_ENABLED) { + dev_dbg(port->dev, "Setting UART to RS485\n"); + /* Make sure auto RTS is disabled */ + val = readl(port->membase + CDNS_UART_MODEMCR); + val &= ~CDNS_UART_MODEMCR_FCM; + writel(val, port->membase + CDNS_UART_MODEMCR); + /* Disable transmitter and make Rx setup*/ + cdns_uart_stop_tx(port); + } + return 0; +} + /** * cdns_uart_probe - Platform driver probe * @pdev: Pointer to the platform device structure @@ -1597,9 +1776,23 @@ static int cdns_uart_probe(struct platform_device *pdev) port->private_data = cdns_uart_data; port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG | CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT; + port->rs485_config = cdns_rs485_config; + port->rs485_supported = cdns_rs485_supported; cdns_uart_data->port = port; platform_set_drvdata(pdev, port); + rc = uart_get_rs485_mode(port); + if (rc) + goto err_out_clk_notifier; + + cdns_uart_data->gpiod_rts = devm_gpiod_get_optional(&pdev->dev, "rts", + GPIOD_OUT_LOW); + if (IS_ERR(cdns_uart_data->gpiod_rts)) { + rc = PTR_ERR(cdns_uart_data->gpiod_rts); + dev_err(port->dev, "xuartps: devm_gpiod_get_optional failed\n"); + goto err_out_clk_notifier; + } + pm_runtime_use_autosuspend(&pdev->dev); pm_runtime_set_autosuspend_delay(&pdev->dev, UART_AUTOSUSPEND_TIMEOUT); pm_runtime_set_active(&pdev->dev); @@ -1618,6 +1811,8 @@ static int cdns_uart_probe(struct platform_device *pdev) console_port = port; } #endif + if (cdns_uart_data->port->rs485.flags & SER_RS485_ENABLED) + cdns_rs485_rx_setup(cdns_uart_data); rc = uart_add_one_port(&cdns_uart_uart_driver, port); if (rc) { @@ -1646,6 +1841,7 @@ static int cdns_uart_probe(struct platform_device *pdev) pm_runtime_disable(&pdev->dev); pm_runtime_set_suspended(&pdev->dev); pm_runtime_dont_use_autosuspend(&pdev->dev); +err_out_clk_notifier: #ifdef CONFIG_COMMON_CLK clk_notifier_unregister(cdns_uart_data->uartclk, &cdns_uart_data->clk_rate_change_nb);
Add rs485 support to uartps driver. Use either rts-gpios or RTS to control RS485 phy as driver or a receiver. Signed-off-by: Manikanta Guntupalli <manikanta.guntupalli@amd.com> --- Changes for V2: Modify optional gpio name to xlnx,phy-ctrl-gpios. Update commit description. Add support for RTS, delay_rts_before_send and delay_rts_after_send in RS485 mode. Changes for V3: Modify optional gpio name to rts-gpios. Update commit description. Move cdns_uart_tx_empty function to avoid prototype statement. Remove assignment of struct serial_rs485 to port->rs485 as serial core performs that. Switch to native RTS in non GPIO case. Handle rs485 during stop tx. Remove explicit calls to configure gpio direction and value, as devm_gpiod_get_optional performs that by using GPIOD_OUT_LOW argument. Update implementation to support configuration of GPIO/RTS value based on user configuration of SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND. Move implementation to start_tx from handle_tx. Changes for V4: Create separate patch for cdns_uart_tx_empty relocation. Call cdns_rs485_rx_setup() before uart_add_one_port() in probe. Update gpio descriptor name to gpiod_rts. Instead of cdns_rs485_config_gpio_rts_high() and cdns_rs485_config_gpio_rts_low() functions for RTS/GPIO value configuration implement cdns_rts_gpio_enable(). Disable auto rts and call cdns_uart_stop_tx() from cdns_rs485_config. Use timer instead of mdelay for delay_rts_before_send and delay_rts_after_send. Update cdns_uart_set_mctrl to support GPIO/RTS. Changes for V5: None. --- drivers/tty/serial/xilinx_uartps.c | 214 +++++++++++++++++++++++++++-- 1 file changed, 205 insertions(+), 9 deletions(-)