@@ -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 +195,9 @@ 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
+ * @tx_timer: Timer for tx
*/
struct cdns_uart {
struct uart_port *port;
@@ -203,10 +208,21 @@ 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 hrtimer 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)
@@ -312,6 +328,55 @@ 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)
+{
+ bool enable;
+
+ enable = cdns_uart->port->rs485.flags & SER_RS485_RTS_ON_SEND;
+ cdns_rts_gpio_enable(cdns_uart, enable);
+
+ 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)
+{
+ bool enable;
+
+ enable = cdns_uart->port->rs485.flags & SER_RS485_RTS_AFTER_SEND;
+ cdns_rts_gpio_enable(cdns_uart, enable);
+
+ cdns_uart->rs485_tx_started = false;
+}
+
/**
* cdns_uart_tx_empty - Check whether TX is empty
* @port: Handle to the uart port structure
@@ -327,6 +392,37 @@ static unsigned int cdns_uart_tx_empty(struct uart_port *port)
return (status == CDNS_UART_SR_TXEMPTY) ? TIOCSER_TEMT : 0;
}
+/**
+ * cdns_rs485_rx_callback - Timer rx callback handler for rs485.
+ * @t: Handle to the hrtimer structure
+ */
+static enum hrtimer_restart cdns_rs485_rx_callback(struct hrtimer *t)
+{
+ struct cdns_uart *cdns_uart = container_of(t, struct cdns_uart, tx_timer);
+
+ /*
+ * Default Rx should be setup, because Rx signaling path
+ * need to enable to receive data.
+ */
+ cdns_rs485_rx_setup(cdns_uart);
+
+ return HRTIMER_NORESTART;
+}
+
+/**
+ * cdns_calc_after_tx_delay - calculate delay required for after tx.
+ * @cdns_uart: Handle to the cdns_uart
+ */
+static u64 cdns_calc_after_tx_delay(struct cdns_uart *cdns_uart)
+{
+ /*
+ * Frame time + stop bit time + rs485.delay_rts_after_send
+ */
+ return cdns_uart->port->frame_time
+ + DIV_ROUND_UP(cdns_uart->port->frame_time, 7)
+ + (u64)cdns_uart->port->rs485.delay_rts_after_send * NSEC_PER_MSEC;
+}
+
/**
* cdns_uart_handle_tx - Handle the bytes to be transmitted.
* @dev_id: Id of the UART port
@@ -335,6 +431,7 @@ static unsigned int cdns_uart_tx_empty(struct uart_port *port)
static void cdns_uart_handle_tx(void *dev_id)
{
struct uart_port *port = (struct uart_port *)dev_id;
+ struct cdns_uart *cdns_uart = port->private_data;
unsigned int numbytes;
if (uart_circ_empty(&port->state->xmit) || uart_tx_stopped(port)) {
@@ -371,6 +468,16 @@ static void cdns_uart_handle_tx(void *dev_id)
&port->state->xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
}
+
+ /* Enable the TX Empty interrupt */
+ writel(CDNS_UART_IXR_TXEMPTY, cdns_uart->port->membase + CDNS_UART_IER);
+
+ if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED &&
+ (uart_circ_empty(&port->state->xmit) || uart_tx_stopped(port))) {
+ cdns_uart->tx_timer.function = &cdns_rs485_rx_callback;
+ hrtimer_start(&cdns_uart->tx_timer,
+ ns_to_ktime(cdns_calc_after_tx_delay(cdns_uart)), HRTIMER_MODE_REL);
+ }
}
/**
@@ -603,6 +710,21 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb,
}
#endif
+/**
+ * cdns_rs485_tx_callback - Timer tx callback handler for rs485.
+ * @t: Handle to the hrtimer structure
+ */
+static enum hrtimer_restart cdns_rs485_tx_callback(struct hrtimer *t)
+{
+ struct cdns_uart *cdns_uart = container_of(t, struct cdns_uart, tx_timer);
+
+ uart_port_lock(cdns_uart->port);
+ cdns_uart_handle_tx(cdns_uart->port);
+ uart_port_unlock(cdns_uart->port);
+
+ return HRTIMER_NORESTART;
+}
+
/**
* cdns_uart_start_tx - Start transmitting bytes
* @port: Handle to the uart port structure
@@ -610,6 +732,7 @@ 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;
@@ -629,10 +752,16 @@ static void cdns_uart_start_tx(struct uart_port *port)
/* Clear the TX Empty interrupt */
writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR);
+ if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED) {
+ if (!cdns_uart->rs485_tx_started) {
+ cdns_uart->tx_timer.function = &cdns_rs485_tx_callback;
+ cdns_rs485_tx_setup(cdns_uart);
+ return hrtimer_start(&cdns_uart->tx_timer,
+ ms_to_ktime(port->rs485.delay_rts_before_send),
+ HRTIMER_MODE_REL);
+ }
+ }
cdns_uart_handle_tx(port);
-
- /* Enable the TX Empty interrupt */
- writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER);
}
/**
@@ -642,6 +771,10 @@ 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;
+
+ if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED)
+ cdns_rs485_rx_setup(cdns_uart);
regval = readl(port->membase + CDNS_UART_CR);
regval |= CDNS_UART_CR_TX_DIS;
@@ -853,6 +986,9 @@ 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)
+ cdns_rs485_rx_setup(cdns_uart);
+
/*
* Clear the RX disable bit and then set the RX enable bit to enable
* the receiver.
@@ -912,6 +1048,10 @@ static void cdns_uart_shutdown(struct uart_port *port)
{
int status;
unsigned long flags;
+ struct cdns_uart *cdns_uart = port->private_data;
+
+ if (cdns_uart->port->rs485.flags & SER_RS485_ENABLED)
+ hrtimer_cancel(&cdns_uart->tx_timer);
spin_lock_irqsave(&port->lock, flags);
@@ -1057,6 +1197,8 @@ static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
if (mctrl & TIOCM_RTS)
val |= CDNS_UART_MODEMCR_RTS;
+ if (cdns_uart_data->gpiod_rts)
+ gpiod_set_value(cdns_uart_data->gpiod_rts, !(mctrl & TIOCM_RTS));
if (mctrl & TIOCM_DTR)
val |= CDNS_UART_MODEMCR_DTR;
if (mctrl & TIOCM_LOOP)
@@ -1537,6 +1679,39 @@ static int cdns_get_id(struct platform_device *pdev)
return id;
}
+/**
+ * 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;
+ struct cdns_uart *cdns_uart = port->private_data;
+
+ 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);
+
+ /* Timer setup */
+ hrtimer_init(&cdns_uart->tx_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ cdns_uart->tx_timer.function = &cdns_rs485_tx_callback;
+
+ /* Disable transmitter and make Rx setup*/
+ cdns_uart_stop_tx(port);
+ } else {
+ hrtimer_cancel(&cdns_uart->tx_timer);
+ }
+ return 0;
+}
+
/**
* cdns_uart_probe - Platform driver probe
* @pdev: Pointer to the platform device structure
@@ -1674,9 +1849,23 @@ 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);
@@ -1695,6 +1884,8 @@ 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) {
@@ -1723,6 +1914,7 @@ 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);