Re: [PATCH 3/3 v2] cyber2000fb: add I2C support

Add I2C support for the DDC bus to cyber2000fb driver. This is only bus
support, driver does not use EDID.
Tested on two different CyberPro 2000 cards with i2cdetect and decode-edid.

Signed-off-by: Ondrej Zary <redacted>
---
This is v2 with added locking and ddc things properly named.

diff -urp linux-2.6.35-rc3-/drivers/video/cyber2000fb.c linux-2.6.35-rc3/drivers/video/cyber2000fb.c

--- linux-2.6.35-rc3-/drivers/video/cyber2000fb.c	2010-07-31 21:58:35.000000000 +0200
+++ linux-2.6.35-rc3/drivers/video/cyber2000fb.c	2010-08-01 00:02:59.000000000 +0200

@@ -48,6 +48,10 @@
 #include <linux/init.h>
 #include <linux/io.h>
 
+#include <linux/i2c.h>
+#include <linux/i2c-id.h>
+#include <linux/i2c-algo-bit.h>
+
 #include <asm/pgtable.h>
 #include <asm/system.h>
 

@@ -88,6 +92,12 @@ struct cfb_info {
 	u_char			ramdac_powerdown;
 
 	u32			pseudo_palette[16];
+#ifdef CONFIG_FB_CYBER2000_I2C

+	bool			ddc_registered;
+	struct i2c_adapter	ddc_adapter;
+	struct i2c_algo_bit_data	ddc_algo;
+	struct mutex		reg_b0_lock;

+static void cyber2000fb_enable_ddc(struct cfb_info *cfb)
+{
+	mutex_lock(&cfb->reg_b0_lock);
+	cyber2000fb_writew(0x1bf, 0x3ce, cfb);
+}
+
+static void cyber2000fb_disable_ddc(struct cfb_info *cfb)
+{
+	cyber2000fb_writew(0x0bf, 0x3ce, cfb);
+	mutex_unlock(&cfb->reg_b0_lock);
+}
+
+
+static void cyber2000fb_setscl(void *data, int val)

+{
+	struct cfb_info *cfb = data;
+	unsigned char reg;
+
+	cyber2000fb_enable_ddc(cfb);
+	reg = cyber2000_grphr(DDC_REG, cfb);
+	if (!val)	/* bit is inverted */
+		reg |= DDC_SCL_OUT;
+	else
+		reg &= ~DDC_SCL_OUT;
+	cyber2000_grphw(DDC_REG, reg, cfb);
+	cyber2000fb_disable_ddc(cfb);
+}
+
+static void cyber2000fb_setsda(void *data, int val)

+{
+	struct cfb_info *cfb = data;
+	unsigned char reg;
+
+	cyber2000fb_enable_ddc(cfb);
+	reg = cyber2000_grphr(DDC_REG, cfb);
+	if (!val)	/* bit is inverted */
+		reg |= DDC_SDA_OUT;
+	else
+		reg &= ~DDC_SDA_OUT;
+	cyber2000_grphw(DDC_REG, reg, cfb);
+	cyber2000fb_disable_ddc(cfb);
+}
+
+static int cyber2000fb_getscl(void *data)

+{
+	struct cfb_info *cfb = data;
+	int retval;
+
+	cyber2000fb_enable_ddc(cfb);
+	retval = !!(cyber2000_grphr(DDC_REG, cfb) & DDC_SCL_IN);
+	cyber2000fb_disable_ddc(cfb);
+
+	return retval;
+}
+
+static int cyber2000fb_getsda(void *data)