Subject: [PATCH] rtc: ds1307: fix kernel splat due to wakeup irq handling

From: [email-masked] (Tony Lindgren)
Date: Wed, 11 Nov 2015 08:47:10 -0800

* Felipe Balbi <[email-masked]> [151111 08:11]:
> Since commit 3fffd1283927 ("i2c: allow specifying
> separate wakeup interrupt in device tree") we have
> automatic wakeup irq support for i2c devices. That
> commit missed the fact that rtc-1307 had its own
> wakeup irq handling and ended up introducing a
> kernel splat for at least Beagle x15 boards.
> 
> Fix that by reverting original commit _and_ passing
> correct interrupt names on DTS so i2c-core can
> choose correct IRQ as wakeup.
> 
> Now that we have automatic wakeirq support, we can
> revert the original commit which did it manually.
> 
> Fixes the following warning:
> 
> [   10.346582] WARNING: CPU: 1 PID: 263 at linux/drivers/base/power/wakeirq.c:43 dev_pm_attach_wake_irq+0xbc/0xd4()
> [   10.359244] rtc-ds1307 2-006f: wake irq already initialized

Best to merge the dts change along with the driver fix in this case:

Acked-by: Tony Lindgren <[email-masked]>

> Cc: Nishanth Menon <[email-masked]>
> Signed-off-by: Felipe Balbi <[email-masked]>
> ---
>  arch/arm/boot/dts/am57xx-beagle-x15.dts |  1 +
>  drivers/rtc/rtc-ds1307.c                | 36 +++------------------------------
>  2 files changed, 4 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/am57xx-beagle-x15.dts b/arch/arm/boot/dts/am57xx-beagle-x15.dts
> index d9ba6b879fc1..00352e761b8c 100644
> --- a/arch/arm/boot/dts/am57xx-beagle-x15.dts
> +++ b/arch/arm/boot/dts/am57xx-beagle-x15.dts
> @@ -604,6 +604,7 @@
>  		reg = <0x6f>;
>  		interrupts-extended = <&crossbar_mpu GIC_SPI 2 IRQ_TYPE_EDGE_RISING>,
>  				      <&dra7_pmx_core 0x424>;
> +		interrupt-names = "irq", "wakeup";
>  
>  		pinctrl-names = "default";
>  		pinctrl-0 = <&mcp79410_pins_default>;
> diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
> index 188006c55ce0..325836818826 100644
> --- a/drivers/rtc/rtc-ds1307.c
> +++ b/drivers/rtc/rtc-ds1307.c
> @@ -15,9 +15,6 @@
>  #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>
> @@ -117,7 +114,6 @@ 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,
> @@ -1146,8 +1142,6 @@ 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,
> @@ -1155,34 +1149,13 @@ read_rtc:
>  		if (err) {
>  			client->irq = 0;
>  			dev_err(&client->dev, "unable to request IRQ!\n");
> -			goto no_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;
> +		} else {
>  
> -		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;
> +			set_bit(HAS_ALARM, &ds1307->flags);
> +			dev_dbg(&client->dev, "got IRQ %d\n", client->irq);
>  		}
>  	}
>  
> -no_irq:
>  	if (chip->nvram_size) {
>  
>  		ds1307->nvram = devm_kzalloc(&client->dev,
> @@ -1226,9 +1199,6 @@ 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);
>  
> -- 
> 2.6.2
>