[U-Boot] [RFC] [PATCH] DaVinci/i2c: allow multiple buses

[Jérôme Carretero]

Hi Tom,

I'm requesting comments on the following (untested) patch.
It adds support for multiple i2c buses on davinci_i2c, without altering one line of code.
What I don't like is that I'm doing a bit of macro black magic to transform constants into variables.
But I don't know whether refactoring the code would be accepted, so this is a first shot.

Regards,

-- 
cJ


commit 53d99d331dc7fc4bf3384a59bbca564bf1b85f6b
Author: Jerome Carretero <cJ-uboot at zougloub.eu>
Date:   Thu Dec 22 00:26:13 2011 -0500

    DaVinci/i2c: Support for multiple buses

diff --git a/arch/arm/include/asm/arch-davinci/i2c_defs.h b/arch/arm/include/asm/arch-davinci/i2c_defs.h
index 24cd268..1d24fbf 100644
--- a/arch/arm/include/asm/arch-davinci/i2c_defs.h
+++ b/arch/arm/include/asm/arch-davinci/i2c_defs.h
@@ -25,13 +25,18 @@
 #ifndef _DAVINCI_I2C_H_
 #define _DAVINCI_I2C_H_
 
+#include <asm/arch/hardware.h>
+
 #define I2C_WRITE		0
 #define I2C_READ		1
 
 #ifndef CONFIG_SOC_DA8XX
-#define I2C_BASE		0x01c21000
+# define I2C_BASE		DAVINCI_I2C_BASE
+# define I2C_DEFAULT_BASE I2C_BASE
 #else
-#define I2C_BASE		0x01c22000
+# define I2C_BASE0		DAVINCI_I2C0_BASE
+# define I2C_BASE1		DAVINCI_I2C1_BASE
+# define I2C_DEFAULT_BASE I2C_BASE0
 #endif
 
 #define	I2C_OA			(I2C_BASE + 0x00)
diff --git a/drivers/i2c/davinci_i2c.c b/drivers/i2c/davinci_i2c.c
index 2abddfb..be7fb7a 100644
--- a/drivers/i2c/davinci_i2c.c
+++ b/drivers/i2c/davinci_i2c.c
@@ -29,6 +29,44 @@
 #include <asm/arch/hardware.h>
 #include <asm/arch/i2c_defs.h>
 
+#if defined(CONFIG_I2C_MULTI_BUS)
+
+static unsigned int bus_initialized[I2C_BUS_MAX];
+static unsigned int current_bus;
+static unsigned long i2c_base = I2C_DEFAULT_BASE;
+
+#ifndef I2C_BASE
+# define I2C_BASE i2c_base
+#else
+# error CONFIG_I2C_MULTI_BUS *and* I2C_BASE defined !
+#endif
+
+int i2c_set_bus_num(unsigned int bus)
+{
+	if ((bus < 0) || (bus >= I2C_BUS_MAX)) { // TODO where to put I2C_BUS_MAX ?
+		printf("Bad bus: %d\n", bus);
+		return -1;
+	}
+
+	if (bus == 1)
+		i2c_base = I2C_BASE1;
+	else
+		i2c_base = I2C_BASE0;
+
+	current_bus = bus;
+
+	if (!bus_initialized[current_bus])
+		i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
+		return 0;
+}
+
+unsigned int i2c_get_bus_num(void)
+{
+	return current_bus;
+}
+
+#endif
+
 #define CHECK_NACK() \
 	do {\
 		if (tmp & (I2C_TIMEOUT | I2C_STAT_NACK)) {\