On 24.01.19 16:34, Philippe Gerum wrote:
In timestamping mode, read() returns the timestamp of the latest event
receipt on the pin based on CLOCK_MONOTONIC, along with the pin
state. This is an optional pin readout mode controlled by the
GPIO_RTIOC_TS request, e.g.:
struct rtdm_gpio_readout rdo;
int ret, on, val;
on = 1;
ret = ioctl(pinfd, GPIO_RTIOC_TS, &on);
ret = read(pinfd, &rdo, sizeof(rdo));
/* pin state changed to rdo.value at time rdo.timestamp */
on = 0;
ret = ioctl(pinfd, GPIO_RTIOC_TS, &on);
ret = read(pinfd, &val, sizeof(val));
/* pin state changed to value (time of change unspecified) */
By default, timestamping mode is disabled, which corresponds to the
original behavior.
Signed-off-by: Philippe Gerum <[email protected]>
---
include/cobalt/kernel/rtdm/gpio.h | 1 +
include/rtdm/uapi/gpio.h | 18 +++++++----
kernel/drivers/gpio/gpio-core.c | 54 +++++++++++++++++++++++--------
3 files changed, 54 insertions(+), 19 deletions(-)
diff --git a/include/cobalt/kernel/rtdm/gpio.h
b/include/cobalt/kernel/rtdm/gpio.h
index cdb472f8a..00055ec0a 100644
--- a/include/cobalt/kernel/rtdm/gpio.h
+++ b/include/cobalt/kernel/rtdm/gpio.h
@@ -33,6 +33,7 @@ struct rtdm_gpio_pin {
rtdm_event_t event;
char *name;
struct gpio_desc *desc;
+ nanosecs_abs_t timestamp;
};
struct rtdm_gpio_chip {
diff --git a/include/rtdm/uapi/gpio.h b/include/rtdm/uapi/gpio.h
index b745f156c..ac14be66c 100644
--- a/include/rtdm/uapi/gpio.h
+++ b/include/rtdm/uapi/gpio.h
@@ -18,12 +18,18 @@
#ifndef _RTDM_UAPI_GPIO_H
#define _RTDM_UAPI_GPIO_H
-#define GPIO_RTIOC_DIR_OUT _IOW(RTDM_CLASS_GPIO, 0, int)
-#define GPIO_RTIOC_DIR_IN _IO(RTDM_CLASS_GPIO, 1)
-#define GPIO_RTIOC_IRQEN _IOW(RTDM_CLASS_GPIO, 2, int) /* GPIO
trigger */
-#define GPIO_RTIOC_IRQDIS _IO(RTDM_CLASS_GPIO, 3)
-#define GPIO_RTIOC_REQS _IO(RTDM_CLASS_GPIO, 4)
-#define GPIO_RTIOC_RELS _IO(RTDM_CLASS_GPIO, 5)
+struct rtdm_gpio_readout {
+ __u64 timestamp;
nanosecs_abs_t - we use this type also in to userspace interface.
+ __s32 value;
+};
+
+#define GPIO_RTIOC_DIR_OUT _IOW(RTDM_CLASS_GPIO, 0, int)
+#define GPIO_RTIOC_DIR_IN _IO(RTDM_CLASS_GPIO, 1)
+#define GPIO_RTIOC_IRQEN _IOW(RTDM_CLASS_GPIO, 2, int) /* GPIO trigger */
+#define GPIO_RTIOC_IRQDIS _IO(RTDM_CLASS_GPIO, 3)
+#define GPIO_RTIOC_REQS _IO(RTDM_CLASS_GPIO, 4)
+#define GPIO_RTIOC_RELS _IO(RTDM_CLASS_GPIO, 5)
+#define GPIO_RTIOC_TS _IOR(RTDM_CLASS_GPIO, 7, int)
#define GPIO_TRIGGER_NONE 0x0 /* unspecified */
#define GPIO_TRIGGER_EDGE_RISING 0x1
diff --git a/kernel/drivers/gpio/gpio-core.c b/kernel/drivers/gpio/gpio-core.c
index 3ce73dbd5..81f9653f1 100644
--- a/kernel/drivers/gpio/gpio-core.c
+++ b/kernel/drivers/gpio/gpio-core.c
@@ -28,7 +28,8 @@ struct rtdm_gpio_chan {
int requested : 1,
has_direction : 1,
is_output : 1,
- is_interrupt : 1;
+ is_interrupt : 1,
+ want_timestamp : 1;
};
static LIST_HEAD(rtdm_gpio_chips);
@@ -41,6 +42,7 @@ static int gpio_pin_interrupt(rtdm_irq_t *irqh)
pin = rtdm_irq_get_arg(irqh, struct rtdm_gpio_pin);
+ pin->timestamp = rtdm_clock_read_monotonic();
rtdm_event_signal(&pin->event);
return RTDM_IRQ_HANDLED;
@@ -187,6 +189,12 @@ static int gpio_pin_ioctl_nrt(struct rtdm_fd *fd,
gpio_free(gpio);
chan->requested = false;
break;
+ case GPIO_RTIOC_TS:
+ ret = rtdm_safe_copy_from_user(fd, &val, arg, sizeof(val));
+ if (ret)
+ return ret;
+ chan->want_timestamp = !!val;
+ break;
default:
return -EINVAL;
}
@@ -199,11 +207,9 @@ static ssize_t gpio_pin_read_rt(struct rtdm_fd *fd,
{
struct rtdm_gpio_chan *chan = rtdm_fd_to_private(fd);
struct rtdm_device *dev = rtdm_fd_device(fd);
+ struct rtdm_gpio_readout rdo;
struct rtdm_gpio_pin *pin;
- int value, ret;
-
- if (len < sizeof(value))
- return -EINVAL;
+ int ret;
if (!chan->has_direction)
return -EAGAIN;
@@ -213,16 +219,37 @@ static ssize_t gpio_pin_read_rt(struct rtdm_fd *fd,
pin = container_of(dev, struct rtdm_gpio_pin, dev);
- if (!(fd->oflags & O_NONBLOCK)) {
- ret = rtdm_event_wait(&pin->event);
- if (ret)
- return ret;
- }
+ if (chan->want_timestamp) {
+ if (len < sizeof(rdo))
+ return -EINVAL;
+
+ if (!(fd->oflags & O_NONBLOCK)) {
+ ret = rtdm_event_wait(&pin->event);
+ if (ret)
+ return ret;
+ rdo.timestamp = pin->timestamp;
+ } else
+ rdo.timestamp = rtdm_clock_read_monotonic();
+
+ len = sizeof(rdo);
+ rdo.value = gpiod_get_raw_value(pin->desc);
+ ret = rtdm_safe_copy_to_user(fd, buf, &rdo, len);
+ } else {
+ if (len < sizeof(rdo.value))
+ return -EINVAL;
- value = gpiod_get_raw_value(pin->desc);
- ret = rtdm_safe_copy_to_user(fd, buf, &value, sizeof(value));
+ if (!(fd->oflags & O_NONBLOCK)) {
+ ret = rtdm_event_wait(&pin->event);
+ if (ret)
+ return ret;
+ }
+
+ len = sizeof(rdo.value);
+ rdo.value = gpiod_get_raw_value(pin->desc);
+ ret = rtdm_safe_copy_to_user(fd, buf, &rdo.value, len);
+ }
- return ret ?: sizeof(value);
+ return ret ?: len;
}
static ssize_t gpio_pin_write_rt(struct rtdm_fd *fd,
@@ -462,6 +489,7 @@ int rtdm_gpiochip_post_event(struct rtdm_gpio_chip *rgc,
return -EINVAL;
pin = rgc->pins + offset;
+ pin->timestamp = rtdm_clock_read_monotonic();
rtdm_event_signal(&pin->event);
return 0;
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
