tty: uartclk value from serial_core exposed to sysfs

Added file /sys/devices/.../tty/ttySX/uartclk to allow reading
uartclk value in struct uart_port in serial_core via sysfs.

tty_register_device() has been generalized and refactored in order
to add support for setting drvdata and attribute_group to the device.

Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 59 insertions, 10 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index d3bf91a..dcb30d5 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3041,9 +3041,39 @@ static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
 struct device *tty_register_device(struct tty_driver *driver, unsigned index,
 				   struct device *device)
 {
-	struct device *ret;
+	return tty_register_device_attr(driver, index, device, NULL, NULL);
+}
+EXPORT_SYMBOL(tty_register_device);
+
+/**
+ *	tty_register_device_attr - register a tty device
+ *	@driver: the tty driver that describes the tty device
+ *	@index: the index in the tty driver for this tty device
+ *	@device: a struct device that is associated with this tty device.
+ *		This field is optional, if there is no known struct device
+ *		for this tty device it can be set to NULL safely.
+ *	@drvdata: Driver data to be set to device.
+ *	@attr_grp: Attribute group to be set on device.
+ *
+ *	Returns a pointer to the struct device for this tty device
+ *	(or ERR_PTR(-EFOO) on error).
+ *
+ *	This call is required to be made to register an individual tty device
+ *	if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set.  If
+ *	that bit is not set, this function should not be called by a tty
+ *	driver.
+ *
+ *	Locking: ??
+ */
+struct device *tty_register_device_attr(struct tty_driver *driver,
+				   unsigned index, struct device *device,
+				   void *drvdata,
+				   const struct attribute_group **attr_grp)
+{
 	char name[64];
-	dev_t dev = MKDEV(driver->major, driver->minor_start) + index;
+	dev_t devt = MKDEV(driver->major, driver->minor_start) + index;
+	struct device *dev = NULL;
+	int retval = -ENODEV;
 	bool cdev = false;
 
 	if (index >= driver->num) {
@@ -3058,19 +3088,38 @@ struct device *tty_register_device(struct tty_driver *driver, unsigned index,
 		tty_line_name(driver, index, name);
 
 	if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
-		int error = tty_cdev_add(driver, dev, index, 1);
-		if (error)
-			return ERR_PTR(error);
+		retval = tty_cdev_add(driver, devt, index, 1);
+		if (retval)
+			goto error;
 		cdev = true;
 	}
 
-	ret = device_create(tty_class, device, dev, NULL, name);
-	if (IS_ERR(ret) && cdev)
-		cdev_del(&driver->cdevs[index]);
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev) {
+		retval = -ENOMEM;
+		goto error;
+	}
 
-	return ret;
+	dev->devt = devt;
+	dev->class = tty_class;
+	dev->parent = device;
+	dev_set_name(dev, "%s", name);
+	dev->groups = attr_grp;
+	dev_set_drvdata(dev, drvdata);
+
+	retval = device_register(dev);
+	if (retval)
+		goto error;
+
+	return dev;
+
+error:
+	put_device(dev);
+	if (cdev)
+		cdev_del(&driver->cdevs[index]);
+	return ERR_PTR(retval);
 }
-EXPORT_SYMBOL(tty_register_device);
+EXPORT_SYMBOL_GPL(tty_register_device_attr);
 
 /**
  * 	tty_unregister_device - unregister a tty device