Linux Device Drivers 3 examples

1 files changed, 46 insertions, 0 deletions

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+/*
+ * Useful info describing the parallel port device.
+ *
+ * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
+ * Copyright (C) 2001 O'Reilly & Associates
+ *
+ * The source code in this file can be freely used, adapted,
+ * and redistributed in source or binary form, so long as an
+ * acknowledgment appears in derived source files.  The citation
+ * should list that the code comes from the book "Linux Device
+ * Drivers" by Alessandro Rubini and Jonathan Corbet, published
+ * by O'Reilly & Associates.   No warranty is attached;
+ * we cannot take responsibility for errors or fitness for use.
+ *
+ */
+
+/*
+ * Register offsets
+ */
+#define SP_DATA    0x00
+#define SP_STATUS  0x01
+#define SP_CONTROL 0x02
+#define SP_NPORTS     3
+
+/*
+ * Status register bits.
+ */
+#define SP_SR_BUSY 	0x80
+#define SP_SR_ACK	0x40
+#define SP_SR_PAPER	0x20
+#define SP_SR_ONLINE	0x10
+#define SP_SR_ERR	0x08
+
+/*
+ * Control register.
+ */
+#define SP_CR_IRQ	0x10
+#define SP_CR_SELECT	0x08
+#define SP_CR_INIT	0x04
+#define SP_CR_AUTOLF	0x02
+#define SP_CR_STROBE	0x01
+
+/*
+ * Minimum space before waking up a writer.
+ */
+#define SP_MIN_SPACE	PAGE_SIZE/2