[RFC PATCH] genirq: implement read_irq_line for interrupt lines
adharmap at codeaurora.org
Fri Apr 15 18:17:32 EDT 2011
David Daney wrote:
> On 04/15/2011 11:42 AM, Abhijeet Dharmapurikar wrote:
>> + * irq_read_line - read the value on an irq line
>> + * @irq: Interrupt number representing a hardware line
>> + *
>> + * This function may be called from IRQ context only when
>> + * desc->chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
> What does it return? I can see that -EINVAL is returned if it isn't
> applicable to this irq. But what if chip->irq_read_line is implemented?
It returns the logical state of that line (0 when it is low or 1 when it
is high). Will add the return type in the comment.
>> + */
>> +int irq_read_line(unsigned int irq)
>> + struct irq_desc *desc = irq_to_desc(irq);
>> + unsigned long flags;
>> + int val;
>> + if (!desc || !desc->irq_data.chip->irq_read_line)
>> + return -EINVAL;
It returns -EINVAL is irq_read_line is not implemented.
>> + chip_bus_lock(desc);
>> + raw_spin_lock_irqsave(&desc->lock, flags);
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