[PATCH 5/6] mfd/ab8500: support of hierachical interrupt

[PATCH 5/6] mfd/ab8500: support of hierachical interrupt

[Linus Walleij]

From: Michel JAOUEN <michel.jaouen@stericsson.com>

Hierarchical interrupt is supported since ab8500 V2.
However, it is not implemented in ab8500-core driver.
With curent implementation, when an ab9540 interrupt occurs,
17 Latch registers are read through i2c. With hierarchical
interrupt implementation, there is only 4 i2c accesses.

Signed-off-by: Maxime Coquelin <maxime.coquelin@stericsson.com>
Tested-by: Michel Jaouen <michel.jaouen@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/mfd/ab8500-core.c |   85 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 82 insertions(+), 3 deletions(-)

diff --git a/drivers/mfd/ab8500-core.c b/drivers/mfd/ab8500-core.c
index 9781e1e..8e56fd1 100644
--- a/drivers/mfd/ab8500-core.c
+++ b/drivers/mfd/ab8500-core.c
@@ -91,6 +91,15 @@
 #define AB8500_IT_MASK23_REG		0x56
 #define AB8500_IT_MASK24_REG		0x57
 
+/*
+ * latch hierarchy registers
+ */
+#define AB8500_IT_LATCHHIER1_REG	0x60
+#define AB8500_IT_LATCHHIER2_REG	0x61
+#define AB8500_IT_LATCHHIER3_REG	0x62
+
+#define AB8500_IT_LATCHHIER_NUM		3
+
 #define AB8500_REV_REG			0x80
 #define AB8500_IC_NAME_REG		0x82
 #define AB8500_SWITCH_OFF_STATUS	0x00
@@ -337,6 +346,67 @@ static struct irq_chip ab8500_irq_chip = {
 	.irq_unmask		= ab8500_irq_unmask,
 };
 
+static irqreturn_t ab8500_hierarchical_irq(int irq, void *dev)
+{
+	struct ab8500 *ab8500 = dev;
+	int i;
+
+	dev_vdbg(ab8500->dev, "interrupt\n");
+
+	/*  Hierarchical interrupt version */
+	for (i = 0; i < AB8500_IT_LATCHHIER_NUM; i++) {
+		int status;
+		u8 hier_val;
+
+		status = get_register_interruptible(ab8500, AB8500_INTERRUPT,
+			AB8500_IT_LATCHHIER1_REG + i, &hier_val);
+		if (status < 0 || hier_val == 0)
+			continue;
+
+		do {
+			int latch_bit = __ffs(hier_val);
+			u8 offset = i * 8 + latch_bit;
+			u8 latch_val;
+
+			/* Fix inconsistent ITFromLatch25 bit mapping... */
+			if (unlikely(offset == 17))
+				offset = 24;
+
+			status = get_register_interruptible(ab8500,
+					AB8500_INTERRUPT,
+					AB8500_IT_LATCH1_REG + offset,
+					&latch_val);
+			if (status < 0 || latch_val == 0)
+				goto discard;
+
+			do {
+				int int_bit = __ffs(latch_val);
+				int line;
+				int j;
+
+				for (j = 0; j < ab8500->mask_size; j++)
+					if (ab8500->irq_reg_offset[j] == offset)
+						break;
+
+				if (j >= ab8500->mask_size) {
+					dev_err(ab8500->dev,
+							"Register offset 0x%2x not declared\n",
+							offset);
+					return IRQ_HANDLED;
+				}
+
+				line = j * 8 + int_bit;
+
+				handle_nested_irq(ab8500->irq_base + line);
+				latch_val &= ~(1 << int_bit);
+			} while (latch_val);
+discard:
+			hier_val &= ~(1 << latch_bit);
+		} while (hier_val);
+	}
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t ab8500_irq(int irq, void *dev)
 {
 	struct ab8500 *ab8500 = dev;
@@ -1196,9 +1266,18 @@ int __devinit ab8500_init(struct ab8500 *ab8500, enum ab8500_version version)
 		if (ret)
 			goto out_freeoldmask;
 
-		ret = request_threaded_irq(ab8500->irq, NULL, ab8500_irq,
-					   IRQF_ONESHOT | IRQF_NO_SUSPEND,
-					   "ab8500", ab8500);
+		/*  Activate this feature only in ab9540 */
+		/*  till tests are done on ab8500 1p2 or later*/
+		if (is_ab9540(ab8500))
+			ret = request_threaded_irq(ab8500->irq, NULL,
+					ab8500_hierarchical_irq,
+					IRQF_ONESHOT | IRQF_NO_SUSPEND,
+					"ab8500", ab8500);
+		else
+			ret = request_threaded_irq(ab8500->irq, NULL,
+					ab8500_irq,
+					IRQF_ONESHOT | IRQF_NO_SUSPEND,
+					"ab8500", ab8500);
 		if (ret)
 			goto out_removeirq;
 	}
-- 
1.7.9.2

Re: [PATCH 5/6] mfd/ab8500: support of hierachical interrupt

[Samuel Ortiz]

Hi Linus,

On Tue, Apr 17, 2012 at 09:30:49AM +0200, Linus Walleij wrote:
> +static irqreturn_t ab8500_hierarchical_irq(int irq, void *dev)
> +{
> +	struct ab8500 *ab8500 = dev;
> +	int i;
> +
> +	dev_vdbg(ab8500->dev, "interrupt\n");
> +
> +	/*  Hierarchical interrupt version */
> +	for (i = 0; i < AB8500_IT_LATCHHIER_NUM; i++) {
> +		int status;
> +		u8 hier_val;
> +
> +		status = get_register_interruptible(ab8500, AB8500_INTERRUPT,
> +			AB8500_IT_LATCHHIER1_REG + i, &hier_val);
> +		if (status < 0 || hier_val == 0)
> +			continue;
> +
> +		do {
> +			int latch_bit = __ffs(hier_val);
> +			u8 offset = i * 8 + latch_bit;
> +			u8 latch_val;
> +
> +			/* Fix inconsistent ITFromLatch25 bit mapping... */
> +			if (unlikely(offset == 17))
> +				offset = 24;
> +
> +			status = get_register_interruptible(ab8500,
> +					AB8500_INTERRUPT,
> +					AB8500_IT_LATCH1_REG + offset,
> +					&latch_val);
> +			if (status < 0 || latch_val == 0)
> +				goto discard;
> +
> +			do {
> +				int int_bit = __ffs(latch_val);
> +				int line;
> +				int j;
> +
> +				for (j = 0; j < ab8500->mask_size; j++)
> +					if (ab8500->irq_reg_offset[j] == offset)
> +						break;
> +
> +				if (j >= ab8500->mask_size) {
> +					dev_err(ab8500->dev,
> +							"Register offset 0x%2x not declared\n",
> +							offset);
> +					return IRQ_HANDLED;
> +				}
> +
> +				line = j * 8 + int_bit;
> +
> +				handle_nested_irq(ab8500->irq_base + line);
> +				latch_val &= ~(1 << int_bit);
> +			} while (latch_val);
> +discard:
> +			hier_val &= ~(1 << latch_bit);
> +		} while (hier_val);
> +	}
> +	return IRQ_HANDLED;
> +}
With 4 nested loops, this one is getting difficult to read. Have you
considered splitting the loops into separate routines ?

Cheers,
Samuel.

-- 
Intel Open Source Technology Centre
http://oss.intel.com/

Re: [PATCH 5/6] mfd/ab8500: support of hierachical interrupt

[Linus Walleij]

On Tue, May 1, 2012 at 1:31 PM, Samuel Ortiz <sameo@linux.intel.com> wrote:

> On Tue, Apr 17, 2012 at 09:30:49AM +0200, Linus Walleij wrote:
>> +static irqreturn_t ab8500_hierarchical_irq(int irq, void *dev)
>> +{

>> +     /*  Hierarchical interrupt version */
>> +     for (i = 0; i < AB8500_IT_LATCHHIER_NUM; i++) {
>> +             do {
>> +                     int latch_bit = __ffs(hier_val);
>> +                     do {
>> +                             int int_bit = __ffs(latch_val);
>> +                     } while (latch_val);
>> +             } while (hier_val);
>> +     }
>> +     return IRQ_HANDLED;
>> +}
>
> With 4 nested loops, this one is getting difficult to read. Have you
> considered splitting the loops into separate routines ?

I get the point :-D

Michel do you think this can be done?

Yours,
Linus Walleij