[U-Boot] [PATCH 0/2] arm nomadik: gpio and i2c

[Heiko Schocher]

Hello Alessandro,

Alessandro Rubini wrote:
> This adds gpio and i2c support for the Nomadik evaluation kit. They
> are needed to turn on the LCD backlight in order to later add LCD
> support.
> 
> I have one doubt and some questions on gpio:
> 
> To use soft_i2c I need to define some macros in the config file.
> Instead of writing hard numbers there I called the gpio functions, but
> the config file is inluded from asm sources as well.  I don't think my
> approach is beautiful at all (both #ifndef __ASSEMBLY__ and #include
> "../board/"), but I didn't find a better solution.

Yes, thats a problem ... if we had a GPIO Framework it would be solved
by including gpio.h ...

Or, maybe, we can make a soft_i2c.h which which gets only included
if saying CONFIG_I2C_SOFT_INCLUDE is defined. soft_i2c.h defines for
example:

#define I2C_SDA(x)	i2c_soft_sda(bit)

void i2c_soft_sda(int pin);

and you can define this function i2c_soft_sda(int pin) in your board
specific code ... maybe a cleaner option?

to speak in c, I tried the following patch on the suen3 plattform,
where I have actually a similiar problem, and this worked fine :-)

[PATCH] i2c, soft: added soft_i2c.h

In case you must define functions for the I2C_XXX
defines, it is necessary to have a soft_i2c.h, which
defines functions for this macros. This functions can
then be programmed in board specific code. To activate
this it must be CONFIG_I2C_SOFT_INCLUDE defined in the
board config file.

Signed-off-by: Heiko Schocher <hs at denx.de>
---
 drivers/i2c/soft_i2c.c |    3 +++
 include/soft_i2c.h     |   16 ++++++++++++++++
 2 files changed, 19 insertions(+), 0 deletions(-)
 create mode 100644 include/soft_i2c.h

diff --git a/drivers/i2c/soft_i2c.c b/drivers/i2c/soft_i2c.c
index 59883a5..30e24f3 100644
--- a/drivers/i2c/soft_i2c.c
+++ b/drivers/i2c/soft_i2c.c
@@ -43,6 +43,9 @@
 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
 #include <asm/io.h>
 #endif
+#if defined(CONFIG_SOFT_I2C_INCLUDE)
+#include <soft_i2c.h>
+#endif
 #include <i2c.h>

 /* #define	DEBUG_I2C	*/
diff --git a/include/soft_i2c.h b/include/soft_i2c.h
new file mode 100644
index 0000000..39f9a35
--- /dev/null
+++ b/include/soft_i2c.h
@@ -0,0 +1,16 @@
+#ifndef _CONFIG_SOFT_I2C
+#define _CONFIG_SOFT_I2C
+#define I2C_ACTIVE	i2c_soft_active();
+#define I2C_TRISTATE	i2c_soft_tristate();
+#define I2C_READ	i2c_soft_read();
+#define I2C_SDA(bit)	i2c_soft_sda(bit);
+#define I2C_SCL(bit)	i2c_soft_scl(bit);
+#define	I2C_DELAY	i2c_soft_delay();
+
+void	i2c_soft_active(void);
+void	i2c_soft_tristate(void);
+int	i2c_soft_read(void);
+void	i2c_soft_sda(int value);
+void	i2c_soft_scl(int value);
+void	i2c_soft_delay(void);
+#endif
-- 
1.6.0.GIT

Maybe you can try it too?

> I would like to add a gpio command, and I've found no generic gpio
> stuff.  Only one board (cm-bf527) has a gpio commands, but quite a few
> have similar commands to set leds or other bits.  Is time ripe for a
> generic gpio driver with board-specific limits and operations? Would
> that be interesting for u-boot-next?  Should I process with a board-specific
> gpio command by now?

I vote for making a gpio framework, but that will take a while I think ...
Hmm.. maybe we use my proposal for such a soft_i2c.h, so I think, it is
okay for such a board specific gpio (unless we have a gpio framework).

bye
Heiko
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