[U-Boot] I2C on iMX25

[Stefano Babic]

On 24/09/2012 11:32, Matthias Weißer wrote:
> Hi Stefano
> 

Hi Matthias,

> I am currently in the process of updating my zmx25 board support for a new
> hardware revision where I need I2C access. I2C on imx25 currently fails
> to build:
> 
> mxc_i2c.c: In function 'i2c_imx_get_clk':
> mxc_i2c.c:101:31: error: 'MXC_IPG_PERCLK' undeclared (first use in this
> function)

Ok, I see.

> 
> I can easily fix this by replacing MXC_IPG_PERCLK with MXC_I2C_CLK. But
> MXC_I2C_CLK is only defined for imx25. So, this change will break all other
> imx chips.

But this seems the right solution. The mxc_get_clk() gets as parameter
an enum representing a peripheral or a special clock name, valid for a
SOC. The driver should use the peripheral name.

> I can now add MXC_IPG_PERCLK to arch-mx25/clock.h and adopt
> generic.c accordingly but I don't think that this is the right way to go
> as the i2c clock can be different from perclk. Doing this
> #define MXC_IPG_PERCLK MXC_I2C_CLK
> in my config file is even more ugly.

This is wrong.

Really I think the right way is to add MXC_I2C_CLK to the other SOCs,
adding the case in their specific mxc_get_clock() implementation, for
example for mx6 something like this:

diff --git a/arch/arm/cpu/armv7/mx5/clock.c b/arch/arm/cpu/armv7/mx5/clock.c
index c67c3cf..8fa737a 100644
--- a/arch/arm/cpu/armv7/mx5/clock.c
+++ b/arch/arm/cpu/armv7/mx5/clock.c
@@ -482,6 +482,7 @@ unsigned int mxc_get_clock(enum mxc_clock clk)
        case MXC_IPG_CLK:
                return get_ipg_clk();
        case MXC_IPG_PERCLK:
+       case MXC_I2C_CLK:
                return get_ipg_per_clk();
        case MXC_UART_CLK:
                return get_uart_clk();


and updating the mxc_i2c driver to follow the same rule.

Best regards,
Stefano

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