Re: [RFC PATCH] genirq: implement read_irq_line for interrupt lines

From: Abhijeet Dharmapurikar
Date: Fri Apr 15 2011 - 18:17:40 EST

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);

Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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