From 3e7e45216912bc0e50100e86006796383807e507 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Thu, 7 Mar 2019 14:30:56 +0000
Subject: [PATCH] dev: add generic lp driver

---
 Kernel/dev/lpgeneric.c | 74 ++++++++++++++++++++++++++++++++++++++++++
 Kernel/dev/lpgeneric.h |  8 +++++
 2 files changed, 82 insertions(+)
 create mode 100644 Kernel/dev/lpgeneric.c
 create mode 100644 Kernel/dev/lpgeneric.h

diff --git a/Kernel/dev/lpgeneric.c b/Kernel/dev/lpgeneric.c
new file mode 100644
index 00000000..cad1e735
--- /dev/null
+++ b/Kernel/dev/lpgeneric.c
@@ -0,0 +1,74 @@
+/*
+ *	Generic printer interface
+ *
+ *	The caller needs to define the following in the config (and they can
+ *	be defined to variables if needed)
+ *
+ *	CONFIG_LP_GENERIC
+ *	LP_DATA
+ *	LP_STATUS
+ *	LP_IS_BUSY		- eg to (lpstate & 0x80)
+ *	LP_STROBE		- these may be null for auto-strobe
+ *				- delays need to be in the macro
+ *				- may reference lpdata if needed
+ */
+#include <kernel.h>
+#include <version.h>
+#include <kdata.h>
+#include <lpgeneric.h>
+
+#ifdef CONFIG_LP_GENERIC
+
+__sfr __banked __at LP_STATUS lpstat;
+__sfr __banked __at LP_DATA lpdata;
+
+int lpr_open(uint8_t minor, uint16_t flag)
+{
+    used(flag);
+
+    if (minor) {
+        udata.u_error = ENODEV;
+        return -1;
+    }
+    return 0;
+}
+
+int lpr_close(uint8_t minor)
+{
+    used(minor);
+    return 0;
+}
+
+static uint8_t iopoll(void)
+{
+	/* Ought to be a core helper for this lot ? */
+	if (need_reschedule())
+		_sched_yield();
+	if (chksigs()) {
+		if (!udata.u_done) {
+			udata.u_error = EINTR;
+			udata.u_done = (usize_t)-1;
+                }
+                return 1;
+	}
+	return 0;
+}
+
+int lpr_write(uint8_t minor, uint8_t rawflag, uint8_t flag)
+{
+    char *p = udata.u_base;
+    minor; rawflag; flag; // shut up compiler
+
+    while(udata.u_done < udata.u_count) {
+        while (LP_IS_BUSY) {
+            if (iopoll())
+                return udata.u_done;
+        }
+        lpdata = ugetc(p++);
+        LP_STROBE;
+        udata.u_done++;
+    }
+    return udata.u_done;
+}
+
+#endif
diff --git a/Kernel/dev/lpgeneric.h b/Kernel/dev/lpgeneric.h
new file mode 100644
index 00000000..7765c187
--- /dev/null
+++ b/Kernel/dev/lpgeneric.h
@@ -0,0 +1,8 @@
+#ifndef __DEVLPR_DOT_H__
+#define __DEVLPR_DOT_H__
+
+int lpr_open(uint8_t minor, uint16_t flag);
+int lpr_close(uint8_t minor);
+int lpr_write(uint8_t minor, uint8_t rawflag, uint8_t flag);
+
+#endif
-- 
2.34.1