[PATCH 2/2] serial: mxs-auart: add interrupts for modem control lines
Janusz Uzycki
j.uzycki at elproma.com.pl
Sat Sep 27 13:32:49 PDT 2014
Handle CTS/DSR/RI/DCD GPIO interrupts in mxs-auart.
Signed-off-by: Janusz Uzycki <j.uzycki at elproma.com.pl>
---
drivers/tty/serial/mxs-auart.c | 174 ++++++++++++++++++++++++++-
1 file changed, 172 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 46fb8a6..3977bd3 100644
--- 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;
@@ -1043,9 +1156,54 @@ static bool mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev)
if (!RTS_AT_AUART() || !CTS_AT_AUART())
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 =
@@ -1093,6 +1251,8 @@ 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);
@@ -1105,13 +1265,20 @@ 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",
@@ -1120,6 +1287,8 @@ 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);
@@ -1139,6 +1308,7 @@ 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);
--
1.7.11.3
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