serial: mxs-auart: add interrupts for modem control lines

Handle CTS/DSR/RI/DCD GPIO interrupts in mxs-auart.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 5922cb435a87ccf10959bbe46d669b479a8e8aac..088f1e17b33e19035ff3a519b7aba7a8e8b095e3 100644 (file)
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -42,7 +42,10 @@
 
 #include <asm/cacheflush.h>
 
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/err.h>
+#include <linux/irq.h>
 #include "serial_mctrl_gpio.h"
 
 #define MXS_AUART_PORTS 5
@@ -146,6 +149,7 @@ struct mxs_auart_port {
 #define MXS_AUART_DMA_RX_READY 3  /* bit 3 */
 #define MXS_AUART_RTSCTS       4  /* bit 4 */
        unsigned long flags;
+       unsigned int mctrl_prev;
        enum mxs_auart_type devtype;
 
        unsigned int irq;
@@ -163,6 +167,8 @@ struct mxs_auart_port {
        void *rx_dma_buf;
 
        struct mctrl_gpios      *gpios;
+       int                     gpio_irq[UART_GPIO_MAX];
+       bool                    ms_irq_enabled;
 };
 
 static struct platform_device_id mxs_auart_devtype[] = {
@@ -427,6 +433,29 @@ static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl)
        mctrl_gpio_set(s->gpios, mctrl);
 }
 
+#define MCTRL_ANY_DELTA        (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
+static u32 mxs_auart_modem_status(struct mxs_auart_port *s, u32 mctrl)
+{
+       u32 mctrl_diff;
+
+       mctrl_diff = mctrl ^ s->mctrl_prev;
+       s->mctrl_prev = mctrl;
+       if (mctrl_diff & MCTRL_ANY_DELTA && s->ms_irq_enabled &&
+                                               s->port.state != NULL) {
+               if (mctrl_diff & TIOCM_RI)
+                       s->port.icount.rng++;
+               if (mctrl_diff & TIOCM_DSR)
+                       s->port.icount.dsr++;
+               if (mctrl_diff & TIOCM_CD)
+                       uart_handle_dcd_change(&s->port, mctrl & TIOCM_CD);
+               if (mctrl_diff & TIOCM_CTS)
+                       uart_handle_cts_change(&s->port, mctrl & TIOCM_CTS);
+
+               wake_up_interruptible(&s->port.state->port.delta_msr_wait);
+       }
+       return mctrl;
+}
+
 static u32 mxs_auart_get_mctrl(struct uart_port *u)
 {
        struct mxs_auart_port *s = to_auart_port(u);
@@ -439,6 +468,64 @@ static u32 mxs_auart_get_mctrl(struct uart_port *u)
        return mctrl_gpio_get(s->gpios, &mctrl);
 }
 
+/*
+ * Enable modem status interrupts
+ */
+static void mxs_auart_enable_ms(struct uart_port *port)
+{
+       struct mxs_auart_port *s = to_auart_port(port);
+
+       /*
+        * Interrupt should not be enabled twice
+        */
+       if (s->ms_irq_enabled)
+               return;
+
+       s->ms_irq_enabled = true;
+
+       if (s->gpio_irq[UART_GPIO_CTS] >= 0)
+               enable_irq(s->gpio_irq[UART_GPIO_CTS]);
+       /* TODO: enable AUART_INTR_CTSMIEN otherwise */
+
+       if (s->gpio_irq[UART_GPIO_DSR] >= 0)
+               enable_irq(s->gpio_irq[UART_GPIO_DSR]);
+
+       if (s->gpio_irq[UART_GPIO_RI] >= 0)
+               enable_irq(s->gpio_irq[UART_GPIO_RI]);
+
+       if (s->gpio_irq[UART_GPIO_DCD] >= 0)
+               enable_irq(s->gpio_irq[UART_GPIO_DCD]);
+}
+
+/*
+ * Disable modem status interrupts
+ */
+static void mxs_auart_disable_ms(struct uart_port *port)
+{
+       struct mxs_auart_port *s = to_auart_port(port);
+
+       /*
+        * Interrupt should not be disabled twice
+        */
+       if (!s->ms_irq_enabled)
+               return;
+
+       s->ms_irq_enabled = false;
+
+       if (s->gpio_irq[UART_GPIO_CTS] >= 0)
+               disable_irq(s->gpio_irq[UART_GPIO_CTS]);
+       /* TODO: disable AUART_INTR_CTSMIEN otherwise */
+
+       if (s->gpio_irq[UART_GPIO_DSR] >= 0)
+               disable_irq(s->gpio_irq[UART_GPIO_DSR]);
+
+       if (s->gpio_irq[UART_GPIO_RI] >= 0)
+               disable_irq(s->gpio_irq[UART_GPIO_RI]);
+
+       if (s->gpio_irq[UART_GPIO_DCD] >= 0)
+               disable_irq(s->gpio_irq[UART_GPIO_DCD]);
+}
+
 static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s);
 static void dma_rx_callback(void *arg)
 {
@@ -689,6 +776,12 @@ static void mxs_auart_settermios(struct uart_port *u,
                        dev_err(s->dev, "We can not start up the DMA.\n");
                }
        }
+
+       /* CTS flow-control and modem-status interrupts */
+       if (UART_ENABLE_MS(u, termios->c_cflag))
+               mxs_auart_enable_ms(u);
+       else
+               mxs_auart_disable_ms(u);
 }
 
 static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
@@ -706,8 +799,18 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
                | AUART_INTR_CTSMIS),
                        s->port.membase + AUART_INTR_CLR);
 
+       /*
+        * Dealing with GPIO interrupt
+        */
+       if (irq == s->gpio_irq[UART_GPIO_CTS] ||
+           irq == s->gpio_irq[UART_GPIO_DCD] ||
+           irq == s->gpio_irq[UART_GPIO_DSR] ||
+           irq == s->gpio_irq[UART_GPIO_RI])
+               mxs_auart_modem_status(s,
+                               mctrl_gpio_get(s->gpios, &s->mctrl_prev));
+
        if (istat & AUART_INTR_CTSMIS) {
-               if (CTS_AT_AUART())
+               if (CTS_AT_AUART() && s->ms_irq_enabled)
                        uart_handle_cts_change(&s->port,
                                        stat & AUART_STAT_CTS);
                writel(AUART_INTR_CTSMIS,
@@ -770,6 +873,10 @@ static int mxs_auart_startup(struct uart_port *u)
         */
        writel(AUART_LINECTRL_FEN, u->membase + AUART_LINECTRL_SET);
 
+       /* get initial status of modem lines */
+       mctrl_gpio_get(s->gpios, &s->mctrl_prev);
+
+       s->ms_irq_enabled = false;
        return 0;
 }
 
@@ -777,6 +884,8 @@ static void mxs_auart_shutdown(struct uart_port *u)
 {
        struct mxs_auart_port *s = to_auart_port(u);
 
+       mxs_auart_disable_ms(u);
+
        if (auart_dma_enabled(s))
                mxs_auart_dma_exit(s);
 
@@ -833,6 +942,7 @@ static struct uart_ops mxs_auart_ops = {
        .start_tx       = mxs_auart_start_tx,
        .stop_tx        = mxs_auart_stop_tx,
        .stop_rx        = mxs_auart_stop_rx,
+       .enable_ms      = mxs_auart_enable_ms,
        .break_ctl      = mxs_auart_break_ctl,
        .set_mctrl      = mxs_auart_set_mctrl,
        .get_mctrl      = mxs_auart_get_mctrl,
@@ -1035,6 +1145,9 @@ static int serial_mxs_probe_dt(struct mxs_auart_port *s,
 
 static bool mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev)
 {
+       enum mctrl_gpio_idx i;
+       struct gpio_desc *gpiod;
+
        s->gpios = mctrl_gpio_init(dev, 0);
        if (IS_ERR_OR_NULL(s->gpios))
                return false;
@@ -1047,9 +1160,54 @@ static bool mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev)
                clear_bit(MXS_AUART_RTSCTS, &s->flags);
        }
 
+       for (i = 0; i < UART_GPIO_MAX; i++) {
+               gpiod = mctrl_gpio_to_gpiod(s->gpios, i);
+               if (gpiod && (gpiod_get_direction(gpiod) == GPIOF_DIR_IN))
+                       s->gpio_irq[i] = gpiod_to_irq(gpiod);
+               else
+                       s->gpio_irq[i] = -EINVAL;
+       }
+
        return true;
 }
 
+static void mxs_auart_free_gpio_irq(struct mxs_auart_port *s)
+{
+       enum mctrl_gpio_idx i;
+
+       for (i = 0; i < UART_GPIO_MAX; i++)
+               if (s->gpio_irq[i] >= 0)
+                       free_irq(s->gpio_irq[i], s);
+}
+
+static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s)
+{
+       int *irq = s->gpio_irq;
+       enum mctrl_gpio_idx i;
+       int err = 0;
+
+       for (i = 0; (i < UART_GPIO_MAX) && !err; i++) {
+               if (irq[i] < 0)
+                       continue;
+
+               irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
+               err = request_irq(irq[i], mxs_auart_irq_handle,
+                               IRQ_TYPE_EDGE_BOTH, dev_name(s->dev), s);
+               if (err)
+                       dev_err(s->dev, "%s - Can't get %d irq\n",
+                               __func__, irq[i]);
+       }
+
+       /*
+        * If something went wrong, rollback.
+        */
+       while (err && (--i >= 0))
+               if (irq[i] >= 0)
+                       free_irq(irq[i], s);
+
+       return err;
+}
+
 static int mxs_auart_probe(struct platform_device *pdev)
 {
        const struct of_device_id *of_id =
@@ -1097,6 +1255,8 @@ static int mxs_auart_probe(struct platform_device *pdev)
        s->port.type = PORT_IMX;
        s->port.dev = s->dev = &pdev->dev;
 
+       s->mctrl_prev = 0;
+
        s->irq = platform_get_irq(pdev, 0);
        s->port.irq = s->irq;
        ret = request_irq(s->irq, mxs_auart_irq_handle, 0, dev_name(&pdev->dev), s);
@@ -1109,13 +1269,20 @@ static int mxs_auart_probe(struct platform_device *pdev)
                dev_err(&pdev->dev,
                        "Failed to initialize GPIOs. The serial port may not work as expected\n");
 
+       /*
+        * Get the GPIO lines IRQ
+        */
+       ret = mxs_auart_request_gpio_irq(s);
+       if (ret)
+               goto out_free_irq;
+
        auart_port[s->port.line] = s;
 
        mxs_auart_reset(&s->port);
 
        ret = uart_add_one_port(&auart_driver, &s->port);
        if (ret)
-               goto out_free_irq;
+               goto out_free_gpio_irq;
 
        version = readl(s->port.membase + AUART_VERSION);
        dev_info(&pdev->dev, "Found APPUART %d.%d.%d\n",
@@ -1124,6 +1291,8 @@ static int mxs_auart_probe(struct platform_device *pdev)
 
        return 0;
 
+out_free_gpio_irq:
+       mxs_auart_free_gpio_irq(s);
 out_free_irq:
        auart_port[pdev->id] = NULL;
        free_irq(s->irq, s);
@@ -1143,6 +1312,7 @@ static int mxs_auart_remove(struct platform_device *pdev)
 
        auart_port[pdev->id] = NULL;
 
+       mxs_auart_free_gpio_irq(s);
        clk_put(s->clk);
        free_irq(s->irq, s);
        kfree(s);