Re: [PATCH 2/2] ARM: mach-imx: CAN clock fix for i.MX53

Marc Kleine-Budde
2012-10-26T14:05:48Z

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On 10/26/2012 03:52 PM, Roland Stigge wrote:
> On 10/26/2012 01:05 PM, Roland Stigge wrote:
>> On 10/26/2012 12:30 PM, Marc Kleine-Budde wrote:
>>>>>> + clk[can1_serial_gate] = imx_clk_gate2("can1_serial_gate",
>>>>>> "can_sel", MXC_CCM_CCGR4, 6); + clk[can1_ipg_gate] =
>>>>>> imx_clk_gate2("can1_ipg_gate", "ipg", MXC_CCM_CCGR4, 8); +
>>>>>> clk[can2_serial_gate] = imx_clk_gate2("can2_serial_gate",
>>>>>> "can_sel", MXC_CCM_CCGR4, 6); + clk[can2_ipg_gate] =
>>>>>> imx_clk_gate2("can2_ipg_gate", "ipg", MXC_CCM_CCGR4, 8);
>>>>>
>>>>> This doesn't.
>>>>
>>>> This may be right, but unfortunately, since the introduction of
>>>> your can1 + can2 clocking change, the first block stopped working
>>>> for me.
>>>
>>> You are effectively using can2's clock for can1. Are you sure you
>>> haven't mixed up can1 and can2?
>>
>> Just using the above patch and patch 1/2 from this series (missing can
>> pinmuxing), doing like this in custom .dts:
>>
>> + can1: can@53fc8000 {
>> + pinctrl-names = "default";
>> + pinctrl-0 = <&pinctrl_can1_1>;
>> + clock-frequency = <66500000>;
>
> That was the problem, since in flexcan.c probe():
>
>
> if (pdev->dev.of_node)
> of_property_read_u32(pdev->dev.of_node,
> "clock-frequency", &clock_freq);
>
> if (!clock_freq) {
> clk_ipg = devm_clk_get(&pdev->dev, "ipg");
> if (IS_ERR(clk_ipg)) {
> dev_err(&pdev->dev, "no ipg clock defined\n");
> err = PTR_ERR(clk_ipg);
> goto failed_clock;
> }
> clock_freq = clk_get_rate(clk_ipg);
>
> clk_per = devm_clk_get(&pdev->dev, "per");
> if (IS_ERR(clk_per)) {
> dev_err(&pdev->dev, "no per clock defined\n");
> err = PTR_ERR(clk_per);
> goto failed_clock;
> }
> }
>
> Sorry for the noise.

We have the possibility to specify the clock frequency in the device
tree as the power pc has no support for generic clock yet.

Marc
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