Re: [PATCH v3 1/8] ARM/dts: omap2: Add McBSP entries for OMAP2420 and OMAP2430 SoC

[Peter Ujfalusi <peter.ujfalusi@ti.com>]

Hi Benoit,

On 09/10/2012 11:07 AM, Benoit Cousson wrote:
> Hi Tony,
> 
> On 09/08/2012 12:29 AM, Tony Lindgren wrote:
>> * Peter Ujfalusi <peter.ujfalusi@ti.com> [120905 04:59]:
>>> +
>>> +	ocp {
>>> +		mcbsp1: mcbsp@48074000 {
>>> +			compatible = "ti,omap2420-mcbsp";
>>> +			reg = <0x48074000 0xff>;
>>> +			reg-names = "mpu";
>>> +			interrupts = <59>, /* TX interrupt */
>>> +				     <60>; /* RX interrupt */
>>> +			interrupt-names = "tx", "rx";
>>> +			interrupt-parent = <&intc>;
>>> +			ti,hwmods = "mcbsp1";
>>> +		};
>>> +
>>> +		mcbsp2: mcbsp@48076000 {
>>> +			compatible = "ti,omap2420-mcbsp";
>>> +			reg = <0x48076000 0xff>;
>>> +			reg-names = "mpu";
>>> +			interrupts = <62>, /* TX interrupt */
>>> +				     <63>; /* RX interrupt */
>>> +			interrupt-names = "tx", "rx";
>>> +			interrupt-parent = <&intc>;
>>> +			ti,hwmods = "mcbsp2";
>>> +		};
>>> +	};
>>
>> Hmm don't you need to specify the interrupt chip and offset for
>> the interrupts here?
> 
> Mmm, I'm not sure to get your question, there is the link to the
> interrupt-parent.
> 
> The interrupt number is relative to the parent interrupt domain. So even
> if the INTC IRQ offset start at 32 instead of 0, DT IRQ mechanism will
> convert that to the proper hwirq thanks to irqdomain.
> In that case we should always provide interrupt number relative to the
> interrupt controller HW number and not assuming any Linux IRQ number
> offset like before.
> 
> 
> And in fact the interrupt-parent is not even needed, by default if will
> look to the parent to get the interrupt-controller.

This is true, but it makes the 'code' a bit more readable if I (we) specify
the interrupt-parent.

> 
> Extract from [1]
> 
> interrupt-parent:
> "Because the hierarchy of the nodes in the interrupt tree might not
> match the device tree, the interrupt-parent property is available to
> make the definition of an interrupt parent explicit.
> The value is the phandle to the interrupt parent. If this property is
> missing from a device, its interrupt parent is assumed to be its device
> tree parent."
> 
> [1] http://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.0.pdf
> 
> Regards,
> Benoit
> 


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