[U-Boot] [PATCH V4] I2C: mxc_i2c rework

[Jason Hui]

Hi, Marek,

On Fri, Jul 29, 2011 at 5:32 PM, Marek Vasut <marek.vasut at gmail.com> wrote:
> Rewrite the mxc_i2c driver.
>  * This version is much closer to Linux implementation.
>  * Fixes IPG_PERCLK being incorrectly used as clock source
>  * Fixes behaviour of the driver on iMX51
>  * Clean up coding style a bit ;-)

I don't think you did the right thing by chaning IPG_PERCLK to IPG_CLK
As I said, the IPG_CLK is for IP register clock, while IPG_PERCLK is for
i2c function clock.

if you run clock command from mx51evk, you will get:
...
ipg clock     : 66500000Hz
ipg per clock : 665000000Hz
MX51EVK U-Boot >

It will give you that ipg per clock is 665M, which seems too big. It
is due to we configure
the pre-divider/pos-devider for perclk to zero, which leads to ipg_per
clock to be same as pll2 clock.
But I don't think this will have some issue.

BTW, I have applied your patch and test on mx53evk board, it seems the
i2c does not work correctly.
After apply your patch:
MX53EVK U-Boot > pmic dump  30
PMIC ID: 0x0000ffff [Rev: unknown]

0x00: 0001ffff 00ffffff 0039ffff 0000ffff 00ffffff 0000ffff 0000ffff 0000ffff
0x08: 0000ffff 0000ffff 0000ffff 0000ffff 0000ffff 0000ffff 0000ffff 0040ffff
0x10: 0000ffff 0000ffff 0000ffff 0000ffff 0000ffff 0001ffff 0000ffff 0000ffff
0x18: 0045ffff 0045ffff 0000ffff 0080ffff 0021ffff 0000ffff 0002ffff 0000ffff
0x20: 0004ffff 0000ffff 0021ffff 0000ffff 0000ffff 0000ffff 0000ffff 0000ffff
0x28: 0000ffff 0000ffff 0000ffff 0000ffff 0000ffff 0004ffff 0000ffff 00aeffff

The old:
MX53EVK U-Boot > pmic dump 30
PMIC ID: 0x000045d0 [Rev: 2.0]

0x00: 00015088 00ffffff 00395208 00000081 00fff7ff 0000401c 00000418 000045d0
0x08: 00000000 00000000 00000001 00000000 00000000 00000040 00000000 00400000
0x10: 00000000 00000000 00000000 00000000 00000011 0001ffff 00000000 00007fff
0x18: 00454a52 00456739 0000631a 0080739c 0021284a 00000a0a 00024fd0 000001d8
0x20: 00049208 00000000 00218000 00000000 00000000 00000000 00000000 00000000
0x28: 00000000 00000000 00000000 00008000 00000000 00046046 000001c0 00aeeaee

Jason