fbdev: Add GXT4000P and GXT6500P support to the gxt4500 driver

I'm reviving an old patch from 2009 that adds support for GXT4000P and GXT6500P
adapter to the gxt4500 driver.

See threads at http://marc.info/?l=linux-fbdev-devel&m=124345080216952&w=2
and https://lists.ozlabs.org/pipermail/linuxppc-dev/2009-June/072672.html
for more details.

This patch adds support for GXT4000P and GXT6500P cards found on some
IBM pSeries machines.
GXT4000P/6000P and GXT4500P/6500P  couples are  identical from
software's point of view and are based on the same  Raster Engine
(RC1000), except for a different reference clock for the PLL.
GXT6x00P models are equipped with an additional Geometry Engine
(GT1000) but this driver doesn't use it.

Signed-off-by: Nico Macrionitis <acrux@cruxppc.org>
Signed-off-by: Giuseppe Coviello <cjg@cruxppc.org>
Tested-by: Dan Horák <dan@danny.cz>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/drivers/video/gxt4500.c b/drivers/video/gxt4500.c
index 0e9afa4..4bdea6e 100644
--- a/drivers/video/gxt4500.c
+++ b/drivers/video/gxt4500.c
@@ -1,5 +1,6 @@
 /*
- * Frame buffer device for IBM GXT4500P and GXT6000P display adaptors
+ * Frame buffer device for IBM GXT4500P/6500P and GXT4000P/6000P
+ * display adaptors
  *
  * Copyright (C) 2006 Paul Mackerras, IBM Corp. <paulus@samba.org>
  */
@@ -14,6 +15,8 @@
 #include <linux/string.h>
 
 #define PCI_DEVICE_ID_IBM_GXT4500P	0x21c
+#define PCI_DEVICE_ID_IBM_GXT6500P	0x21b
+#define PCI_DEVICE_ID_IBM_GXT4000P	0x16e
 #define PCI_DEVICE_ID_IBM_GXT6000P	0x170
 
 /* GXT4500P registers */
@@ -173,6 +176,8 @@
 /* List of supported cards */
 enum gxt_cards {
 	GXT4500P,
+	GXT6500P,
+	GXT4000P,
 	GXT6000P
 };
 
@@ -182,6 +187,8 @@
 	const char *cardname;
 } cardinfo[] = {
 	[GXT4500P] = { .refclk_ps = 9259, .cardname = "IBM GXT4500P" },
+	[GXT6500P] = { .refclk_ps = 9259, .cardname = "IBM GXT6500P" },
+	[GXT4000P] = { .refclk_ps = 40000, .cardname = "IBM GXT4000P" },
 	[GXT6000P] = { .refclk_ps = 40000, .cardname = "IBM GXT6000P" },
 };
 
@@ -736,6 +743,10 @@
 static const struct pci_device_id gxt4500_pci_tbl[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_GXT4500P),
 	  .driver_data = GXT4500P },
+	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_GXT6500P),
+	  .driver_data = GXT6500P },
+	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_GXT4000P),
+	  .driver_data = GXT4000P },
 	{ PCI_DEVICE(PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_GXT6000P),
 	  .driver_data = GXT6000P },
 	{ 0 }
@@ -768,7 +779,7 @@
 module_exit(gxt4500_exit);
 
 MODULE_AUTHOR("Paul Mackerras <paulus@samba.org>");
-MODULE_DESCRIPTION("FBDev driver for IBM GXT4500P/6000P");
+MODULE_DESCRIPTION("FBDev driver for IBM GXT4500P/6500P and GXT4000P/6000P");
 MODULE_LICENSE("GPL");
 module_param(mode_option, charp, 0);
 MODULE_PARM_DESC(mode_option, "Specify resolution as \"<xres>x<yres>[-<bpp>][@<refresh>]\"");