Am 24.09.2012 13:05, schrieb Benoît Thébaudeau:
Hi Stefano, Matthias,
On Monday, September 24, 2012 11:45:33 AM, Stefano Babic wrote:
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 had the same issue a while ago. I have a fix for that. I will try to post it
tonight.
> 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.
Yes and no. The best would be to add a clock abstraction function
imx_get_i2cclk(), like what exists for UART. This is what I did.
What is the advantage of such a function over i2c_imx_get_clk(MXC_I2C_CLK)?
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.
That can be a good solution. What do you think about my imx_get_i2cclk()?
Also, note that there are some broken clocks for i.MX25. I²C is one of them. It
should be:
case MXC_I2C_CLK:
return imx_get_perclk(I2C_PER_CLK);
Why that? My understanding is that imx_get_perclk picks the right clock
as long as the 16 first entries of enum mxc_clock ar in the rigth order.
Regards
Matthias
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