serial: mctrl_gpio: implement interrupt handling
This allows to reduce the per-driver boiler plate considerably.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index c415b0e..379468e 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -439,11 +439,13 @@
Some helpers are provided in order to set/get modem control lines via GPIO.
-mctrl_gpio_init(dev, idx):
+mctrl_gpio_init(port, idx):
This will get the {cts,rts,...}-gpios from device tree if they are
present and request them, set direction etc, and return an
allocated structure. devm_* functions are used, so there's no need
to call mctrl_gpio_free().
+ As this sets up the irq handling make sure to not handle changes to the
+ gpio input lines in your driver, too.
mctrl_gpio_free(dev, gpios):
This will free the requested gpios in mctrl_gpio_init().
@@ -458,3 +460,9 @@
mctrl_gpio_get(gpios, mctrl):
This will update mctrl with the gpios values.
+
+mctrl_gpio_enable_ms(gpios):
+ Enables irqs and handling of changes to the ms lines.
+
+mctrl_gpio_disable_ms(gpios):
+ Disables irqs and handling of changes to the ms lines.
diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
index 1cdedd3..3eb57eb 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.c
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -12,18 +12,23 @@
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
- *
*/
#include <linux/err.h>
#include <linux/device.h>
+#include <linux/irq.h>
#include <linux/gpio/consumer.h>
#include <linux/termios.h>
+#include <linux/serial_core.h>
#include "serial_mctrl_gpio.h"
struct mctrl_gpios {
+ struct uart_port *port;
struct gpio_desc *gpio[UART_GPIO_MAX];
+ int irq[UART_GPIO_MAX];
+ unsigned int mctrl_prev;
+ bool mctrl_on;
};
static const struct {
@@ -112,13 +117,133 @@
}
EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
+#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
+static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
+{
+ struct mctrl_gpios *gpios = context;
+ struct uart_port *port = gpios->port;
+ u32 mctrl = gpios->mctrl_prev;
+ u32 mctrl_diff;
+
+ mctrl_gpio_get(gpios, &mctrl);
+
+ mctrl_diff = mctrl ^ gpios->mctrl_prev;
+ gpios->mctrl_prev = mctrl;
+
+ if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
+ if ((mctrl_diff & mctrl) & TIOCM_RI)
+ port->icount.rng++;
+
+ if ((mctrl_diff & mctrl) & TIOCM_DSR)
+ port->icount.dsr++;
+
+ if (mctrl_diff & TIOCM_CD)
+ uart_handle_dcd_change(port, mctrl & TIOCM_CD);
+
+ if (mctrl_diff & TIOCM_CTS)
+ uart_handle_cts_change(port, mctrl & TIOCM_CTS);
+
+ wake_up_interruptible(&port->state->port.delta_msr_wait);
+ }
+
+ return IRQ_HANDLED;
+}
+
+struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
+{
+ struct mctrl_gpios *gpios;
+ enum mctrl_gpio_idx i;
+
+ gpios = mctrl_gpio_init_noauto(port->dev, idx);
+ if (IS_ERR(gpios))
+ return gpios;
+
+ gpios->port = port;
+
+ for (i = 0; i < UART_GPIO_MAX; ++i) {
+ int ret;
+
+ if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
+ continue;
+
+ ret = gpiod_to_irq(gpios->gpio[i]);
+ if (ret <= 0) {
+ dev_err(port->dev,
+ "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
+ mctrl_gpios_desc[i].name, idx, ret);
+ return ERR_PTR(ret);
+ }
+ gpios->irq[i] = ret;
+
+ /* irqs should only be enabled in .enable_ms */
+ irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
+
+ ret = devm_request_irq(port->dev, gpios->irq[i],
+ mctrl_gpio_irq_handle,
+ IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
+ gpios);
+ if (ret) {
+ /* alternatively implement polling */
+ dev_err(port->dev,
+ "failed to request irq for %s (idx=%d, err=%d)\n",
+ mctrl_gpios_desc[i].name, idx, ret);
+ return ERR_PTR(ret);
+ }
+ }
+
+ return gpios;
+}
+
void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
{
enum mctrl_gpio_idx i;
- for (i = 0; i < UART_GPIO_MAX; i++)
+ for (i = 0; i < UART_GPIO_MAX; i++) {
+ if (gpios->irq[i])
+ devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
+
if (gpios->gpio[i])
devm_gpiod_put(dev, gpios->gpio[i]);
+ }
devm_kfree(dev, gpios);
}
EXPORT_SYMBOL_GPL(mctrl_gpio_free);
+
+void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
+{
+ enum mctrl_gpio_idx i;
+
+ /* .enable_ms may be called multiple times */
+ if (gpios->mctrl_on)
+ return;
+
+ gpios->mctrl_on = true;
+
+ /* get initial status of modem lines GPIOs */
+ mctrl_gpio_get(gpios, &gpios->mctrl_prev);
+
+ for (i = 0; i < UART_GPIO_MAX; ++i) {
+ if (!gpios->irq[i])
+ continue;
+
+ enable_irq(gpios->irq[i]);
+ }
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
+
+void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
+{
+ enum mctrl_gpio_idx i;
+
+ if (!gpios->mctrl_on)
+ return;
+
+ gpios->mctrl_on = false;
+
+ for (i = 0; i < UART_GPIO_MAX; ++i) {
+ if (!gpios->irq[i])
+ continue;
+
+ disable_irq(gpios->irq[i]);
+ }
+}
diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h
index 6d046fc..3c4ac9a 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.h
+++ b/drivers/tty/serial/serial_mctrl_gpio.h
@@ -22,6 +22,8 @@
#include <linux/device.h>
#include <linux/gpio/consumer.h>
+struct uart_port;
+
enum mctrl_gpio_idx {
UART_GPIO_CTS,
UART_GPIO_DSR,
@@ -60,6 +62,15 @@
enum mctrl_gpio_idx gidx);
/*
+ * Request and set direction of modem control lines GPIOs and sets up irq
+ * handling.
+ * devm_* functions are used, so there's no need to call mctrl_gpio_free().
+ * Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
+ * allocation error.
+ */
+struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx);
+
+/*
* Request and set direction of modem control lines GPIOs.
* devm_* functions are used, so there's no need to call mctrl_gpio_free().
* Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
@@ -75,6 +86,16 @@
*/
void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
+/*
+ * Enable gpio interrupts to report status line changes.
+ */
+void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
+
+/*
+ * Disable gpio interrupts to report status line changes.
+ */
+void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);
+
#else /* GPIOLIB */
static inline
@@ -96,6 +117,12 @@
}
static inline
+struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
+static inline
struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
{
return ERR_PTR(-ENOSYS);
@@ -106,6 +133,14 @@
{
}
+void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
+{
+}
+
+void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
+{
+}
+
#endif /* GPIOLIB */
#endif