serdev: Add serdev_device_write subroutine
Add serdev_device_write() a blocking call allowing to transfer
arbitraty amount of data (potentially exceeding amount that
serdev_device_write_buf can process in a single call)
To support that, also add serdev_device_write_wakeup().
Drivers wanting to use full extent of serdev_device_write
functionality are expected to provide serdev_device_write_wakeup() as
a sole handler of .write_wakeup event or call it as a part of driver's
custom .write_wakeup code.
Because serdev_device_write() subroutine is a superset of
serdev_device_write_buf() the patch re-impelements latter is terms of
the former. For drivers wanting to just use serdev_device_write_buf()
.write_wakeup handler is optional.
Cc: cphealy@gmail.com
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index f4c6c90..6701d10 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -116,17 +116,41 @@ void serdev_device_close(struct serdev_device *serdev)
}
EXPORT_SYMBOL_GPL(serdev_device_close);
-int serdev_device_write_buf(struct serdev_device *serdev,
- const unsigned char *buf, size_t count)
+void serdev_device_write_wakeup(struct serdev_device *serdev)
+{
+ complete(&serdev->write_comp);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
+
+int serdev_device_write(struct serdev_device *serdev,
+ const unsigned char *buf, size_t count,
+ unsigned long timeout)
{
struct serdev_controller *ctrl = serdev->ctrl;
+ int ret;
- if (!ctrl || !ctrl->ops->write_buf)
+ if (!ctrl || !ctrl->ops->write_buf ||
+ (timeout && !serdev->ops->write_wakeup))
return -EINVAL;
- return ctrl->ops->write_buf(ctrl, buf, count);
+ mutex_lock(&serdev->write_lock);
+ do {
+ reinit_completion(&serdev->write_comp);
+
+ ret = ctrl->ops->write_buf(ctrl, buf, count);
+ if (ret < 0)
+ break;
+
+ buf += ret;
+ count -= ret;
+
+ } while (count &&
+ (timeout = wait_for_completion_timeout(&serdev->write_comp,
+ timeout)));
+ mutex_unlock(&serdev->write_lock);
+ return ret < 0 ? ret : (count ? -ETIMEDOUT : 0);
}
-EXPORT_SYMBOL_GPL(serdev_device_write_buf);
+EXPORT_SYMBOL_GPL(serdev_device_write);
void serdev_device_write_flush(struct serdev_device *serdev)
{
@@ -232,6 +256,8 @@ struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
serdev->dev.parent = &ctrl->dev;
serdev->dev.bus = &serdev_bus_type;
serdev->dev.type = &serdev_device_type;
+ init_completion(&serdev->write_comp);
+ mutex_init(&serdev->write_lock);
return serdev;
}
EXPORT_SYMBOL_GPL(serdev_device_alloc);