Re: [PATCH V2 4/5] drivers/rtc/rtc-ds1307.c: Support optional wakeup interrupt source

From: Nishanth Menon <nm@ti.com>
To: Grygorii Strashko <grygorii.strashko@ti.com>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>,
	Alessandro Zummo <a.zummo@towertech.it>
Cc: <linux-kernel@vger.kernel.org>, <rtc-linux@googlegroups.com>,
	<linux-omap@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>, <balbi@ti.com>
Subject: Re: [PATCH V2 4/5] drivers/rtc/rtc-ds1307.c: Support optional wakeup interrupt source
Date: Wed, 24 Jun 2015 11:26:54 -0500	[thread overview]
Message-ID: <20150624162654.GA29259@kahuna> (raw)
In-Reply-To: <558AD5B1.8030406@ti.com>

On 11:07-20150624, Nishanth Menon wrote:
> On 06/24/2015 10:36 AM, Grygorii Strashko wrote:
> > On 06/23/2015 07:15 PM, Nishanth Menon wrote:
> [...]
> 
> >> +		ds1307->wakeirq = of_irq_get(node, 1);
> >> +		if (ds1307->wakeirq <= 0) {
> >> +			if (ds1307->wakeirq == -EPROBE_DEFER) {
> >> +				err = ds1307->wakeirq;
> >> +				goto exit;
> >> +			}
> >> +			ds1307->wakeirq = 0;
> >> +			goto no_irq;
> >> +		}
> > 
> > Might be above code could be done a little bit simpler?
> > 
> > 		err = of_irq_get(node, 1);
> > 		if (err <= 0) {
> > 			if (err == -EPROBE_DEFER)
> > 				goto exit;
> > 			goto no_irq;
> 
> I had considered it, but problem with this approach is that is err
> does not get reset back to 0 and probe will fail as it flows through
> the rest of the code.. which is not our intent.

I am wrong here - code just returns 0 and ignores err. So, how about
the following patch instead: (Alexandre, please do let me know if the
entire series needs to be reposted):
 - improvement as suggested
 - Picked up previous acks
 - cleanup in probe does not need dev_pm_clear_wake_irq.
-->8<---
>From 12367f8edffc25613f6f920d9bd7b69dfed57ce1 Mon Sep 17 00:00:00 2001
From: Nishanth Menon <nm@ti.com>
Date: Mon, 22 Jun 2015 14:13:19 -0500
Subject: [PATCH V3] drivers/rtc/rtc-ds1307.c: Support optional wakeup interrupt
 source

With the recent pinctrl-single changes, SoCs such as Texas
Instrument's OMAP processors can treat wake-up events from deeper idle
states as interrupts.

Let's add support for the optional second interrupt for wake-up using
the generic wakeirq support added in commit 4990d4fe327b ("PM /
Wakeirq: Add automated device wake IRQ handling")

Finally, to pass the wake-up interrupt in the dts file,
interrupts-extended property needs to be passed.

This is similar in approach to commit 2a0b965cfb6e ("serial: omap: Add
support for optional wake-up") + ee83bd3b6483 ("serial: omap: Switch
wake-up interrupt to generic wakeirq")

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
---
 drivers/rtc/rtc-ds1307.c |   36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index b03880fc32b5..e16989c48a90 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -15,6 +15,9 @@
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/pm_wakeirq.h>
 #include <linux/rtc/ds1307.h>
 #include <linux/rtc.h>
 #include <linux/slab.h>
@@ -114,6 +117,7 @@ struct ds1307 {
 #define HAS_ALARM	1		/* bit 1 == irq claimed */
 	struct i2c_client	*client;
 	struct rtc_device	*rtc;
+	int			wakeirq;
 	s32 (*read_block_data)(const struct i2c_client *client, u8 command,
 			       u8 length, u8 *values);
 	s32 (*write_block_data)(const struct i2c_client *client, u8 command,
@@ -1156,6 +1160,8 @@ read_rtc:
 	}
 
 	if (want_irq) {
+		struct device_node *node = client->dev.of_node;
+
 		err = devm_request_threaded_irq(&client->dev,
 						client->irq, NULL, irq_handler,
 						IRQF_SHARED | IRQF_ONESHOT,
@@ -1163,13 +1169,34 @@ read_rtc:
 		if (err) {
 			client->irq = 0;
 			dev_err(&client->dev, "unable to request IRQ!\n");
-		} else {
+			goto no_irq;
+		}
 
-			set_bit(HAS_ALARM, &ds1307->flags);
-			dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
+		set_bit(HAS_ALARM, &ds1307->flags);
+		dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
+
+		/* Currently supported by OF code only! */
+		if (!node)
+			goto no_irq;
+
+		err = of_irq_get(node, 1);
+		if (err <= 0) {
+			if (err == -EPROBE_DEFER)
+				goto exit;
+			goto no_irq;
+		}
+		ds1307->wakeirq = err;
+
+		err = dev_pm_set_dedicated_wake_irq(&client->dev,
+						    ds1307->wakeirq);
+		if (err) {
+			dev_err(&client->dev, "unable to setup wakeIRQ %d!\n",
+				err);
+			goto exit;
 		}
 	}
 
+no_irq:
 	if (chip->nvram_size) {
 
 		ds1307->nvram = devm_kzalloc(&client->dev,
@@ -1213,6 +1240,9 @@ static int ds1307_remove(struct i2c_client *client)
 {
 	struct ds1307 *ds1307 = i2c_get_clientdata(client);
 
+	if (ds1307->wakeirq)
+		dev_pm_clear_wake_irq(&client->dev);
+
 	if (test_and_clear_bit(HAS_NVRAM, &ds1307->flags))
 		sysfs_remove_bin_file(&client->dev.kobj, ds1307->nvram);
 
-- 
1.7.9.5

-- 
Regards,
Nishanth Menon
