[U-Boot] [RFC 0/2] Add cdns-i2c driver as drop in for zynq-i2c

Michal Simek michal.simek at xilinx.com
Thu Jan 7 09:13:07 CET 2016


On 7.1.2016 06:18, Moritz Fischer wrote:
> On Tue, Jan 5, 2016 at 11:53 PM, Michal Simek <michal.simek at xilinx.com> wrote:
>> On 5.1.2016 18:30, Moritz Fischer wrote:
>>> Hi Michal,
>>>
>>> On Tue, Jan 5, 2016 at 7:44 AM, Michal Simek <michal.simek at xilinx.com> wrote:
>>>
>>>> I have looked at these patches and I don't know why there is 100k
>>>> limitation in cdns_i2c_set_bus_speed. DTS is using 400k in Linux without
>>>> any problem.
>>>
>>> Well I could statically calculate the values for 400K, too but anyway that works
>>> only if your CPU_CLK_1X is 111MHz. Is there a way to figure out the CPU_CLK_1X
>>> frequency?
>>
>> Check the clock driver.
> 
> Wouldn't that nececitate dm capable clk drivers? Were you talking about
> arch/arm/mach-zynq/clk.c?

yes. clk dump shows that information. It means you should be able to get
that information. Probably we will need to create clk driver.

Thanks,
Michal


=> clk dump
clk		frequency
    armpll          1333333320
    ddrpll          1066666656
     iopll           999999990
 cpu_6or4x           666666660
 cpu_3or2x           333333330
    cpu_2x           222222220
    cpu_1x           111111110
    ddr_2x           355555552
    ddr_3x           533333328
       dci            10158730
     lqspi           199999998
       smc            22222222
      pcap           199999998
      gem0            25000000
      gem1            16666667
     fclk0            50000000
     fclk1            50000000
     fclk2            50000000
     fclk3            50000000
     sdio0            50000000
     sdio1            50000000
     uart0            50000000
     uart1            50000000
      spi0            15873016
      spi1            15873016
 usb0_aper           111111110
 usb1_aper           111111110
 gem0_aper           111111110
 gem1_aper           111111110
sdio0_aper           111111110
sdio1_aper           111111110
 spi0_aper           111111110
 spi1_aper           111111110
 can0_aper           111111110
 can1_aper           111111110
 i2c0_aper           111111110
 i2c1_aper           111111110
uart0_aper           111111110
uart1_aper           111111110
 gpio_aper           111111110
lqspi_aper           111111110
  smc_aper           111111110
   dbg_trc            66666666
   dbg_apb            66666666



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