On Tue, May 29, 2018 at 02:49:02PM +0300, Oleksandr Shamray wrote:

+static int jtag_release(struct inode *inode, struct file *file)
+{
+	return 0;
+}

If you do not do anything, then there is no need to have this callback
at all, right?

+/**
+ * enum jtag_endstate:
+ *
+ * @JTAG_STATE_IDLE: JTAG state machine IDLE state
+ * @JTAG_STATE_PAUSEIR: JTAG state machine PAUSE_IR state
+ * @JTAG_STATE_PAUSEDR: JTAG state machine PAUSE_DR state
+ */
+enum jtag_endstate {
+	JTAG_STATE_IDLE,
+	JTAG_STATE_PAUSEIR,
+	JTAG_STATE_PAUSEDR,

Be specific with these enums, set them to a value so you know all is
good.  Userspace C compilers can be funny at times.

Otherwise, looks really good, nice work.

greg k-h