This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / drivers / video / fb_ddc.c

diff --git a/drivers/video/fb_ddc.c b/drivers/video/fb_ddc.c
new file mode 100644 (file)
index 0000000..f836137
--- /dev/null
+++ b/drivers/video/fb_ddc.c
@@ -0,0 +1,116 @@
+/*
+ * driver/vide/fb_ddc.c - DDC/EDID read support.
+ *
+ *  Copyright (C) 2006 Dennis Munsie <dmunsie@cecropia.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fb.h>
+#include <linux/i2c-algo-bit.h>
+
+#include "edid.h"
+
+#define DDC_ADDR       0x50
+
+static unsigned char *fb_do_probe_ddc_edid(struct i2c_adapter *adapter)
+{
+       unsigned char start = 0x0;
+       unsigned char *buf = kmalloc(EDID_LENGTH, GFP_KERNEL);
+       struct i2c_msg msgs[] = {
+               {
+                       .addr   = DDC_ADDR,
+                       .flags  = 0,
+                       .len    = 1,
+                       .buf    = &start,
+               }, {
+                       .addr   = DDC_ADDR,
+                       .flags  = I2C_M_RD,
+                       .len    = EDID_LENGTH,
+                       .buf    = buf,
+               }
+       };
+
+       if (!buf) {
+               dev_warn(&adapter->dev, "unable to allocate memory for EDID "
+                        "block.\n");
+               return NULL;
+       }
+
+       if (i2c_transfer(adapter, msgs, 2) == 2)
+               return buf;
+
+       dev_warn(&adapter->dev, "unable to read EDID block.\n");
+       kfree(buf);
+       return NULL;
+}
+
+unsigned char *fb_ddc_read(struct i2c_adapter *adapter)
+{
+       struct i2c_algo_bit_data *algo_data = adapter->algo_data;
+       unsigned char *edid = NULL;
+       int i, j;
+
+       algo_data->setscl(algo_data->data, 1);
+       algo_data->setscl(algo_data->data, 0);
+
+       for (i = 0; i < 3; i++) {
+               /* For some old monitors we need the
+                * following process to initialize/stop DDC
+                */
+               algo_data->setsda(algo_data->data, 0);
+               msleep(13);
+
+               algo_data->setscl(algo_data->data, 1);
+               for (j = 0; j < 5; j++) {
+                       msleep(10);
+                       if (algo_data->getscl(algo_data->data))
+                               break;
+               }
+               if (j == 5)
+                       continue;
+
+               algo_data->setsda(algo_data->data, 0);
+               msleep(15);
+               algo_data->setscl(algo_data->data, 0);
+               msleep(15);
+               algo_data->setsda(algo_data->data, 1);
+               msleep(15);
+
+               /* Do the real work */
+               edid = fb_do_probe_ddc_edid(adapter);
+               algo_data->setsda(algo_data->data, 0);
+               algo_data->setscl(algo_data->data, 0);
+               msleep(15);
+
+               algo_data->setscl(algo_data->data, 1);
+               for (j = 0; j < 10; j++) {
+                       msleep(10);
+                       if (algo_data->getscl(algo_data->data))
+                               break;
+               }
+
+               algo_data->setsda(algo_data->data, 1);
+               msleep(15);
+               algo_data->setscl(algo_data->data, 0);
+               if (edid)
+                       break;
+       }
+       /* Release the DDC lines when done or the Apple Cinema HD display
+        * will switch off
+        */
+       algo_data->setsda(algo_data->data, 0);
+       algo_data->setscl(algo_data->data, 0);
+
+       return edid;
+}
+
+EXPORT_SYMBOL_GPL(fb_ddc_read);
+
+MODULE_AUTHOR("Dennis Munsie <dmunsie@cecropia.com>");
+MODULE_DESCRIPTION("DDC/EDID reading support");
+MODULE_LICENSE("GPL");