Hi Kevin,
yep, [1] is the same fix - thanks.
Hi Kalle,
i've applied these changes and PM runtime fix on top of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git (omap2plus_defconfig)
Could you check it with your use case, pls? (just to be sure that idea is right)
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index a0e49f6..cb09e20 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -586,6 +586,9 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
if (IS_ERR_VALUE(r))
goto out;
+ /* We have the bus, enable IRQ */
+ enable_irq(dev->irq);
+
r = omap_i2c_wait_for_bb(dev);
if (r < 0)
goto out;
@@ -606,6 +609,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
r = num;
omap_i2c_wait_for_bb(dev);
+ disable_irq(dev->irq);
out:
pm_runtime_put(dev->dev);
return r;
@@ -1060,6 +1064,9 @@ omap_i2c_probe(struct platform_device *pdev)
omap_i2c_isr;
r = request_irq(dev->irq, isr, IRQF_NO_SUSPEND, pdev->name, dev);
+ /* We enable IRQ only when request for I2C from master */
+ disable_irq(dev->irq);
+
if (r) {
dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
goto err_unuse_clocks;
@@ -1182,7 +1189,23 @@ static int omap_i2c_runtime_resume(struct device *dev)
}
#endif /* CONFIG_PM_RUNTIME */
+static int omap_i2c_suspend(struct device *dev)
+{
+ int ret;
+
+ /*
+ * Enable I2C device, so it will be accessible during
+ * later stages of suspending when device Runtime PM is disabled.
+ * I2C device will be turned off at "noirq" suspend stage.
+ */
+ ret = pm_runtime_resume(dev);
+ if (ret < 0)
+ return ret;
+ return 0;
+}
+
static struct dev_pm_ops omap_i2c_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(omap_i2c_suspend, NULL)
SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
omap_i2c_runtime_resume, NULL)
};
- Grygorii
________________________________________
From: Kevin Hilman [khilman@xxxxxxxxxxxxxxxxxxx]
Sent: Friday, October 12, 2012 5:34 PM
To: Strashko, Grygorii
Cc: Kalle Jokiniemi; linux-i2c@xxxxxxxxxxxxxxx; w.sang@xxxxxxxxxxxxxx; ben-linux@xxxxxxxxx; tony@xxxxxxxxxxx; linux-omap@xxxxxxxxxxxxxxx; Datta, Shubhrajyoti; Kankroliwala, Huzefa
Subject: Re: [PATCH v3] ARM: OMAP: i2c: fix interrupt flood during resume
"Strashko, Grygorii" <grygorii.strashko@xxxxxx> writes:
> Hi All,
>
> Sorry, for the late reply.
> + CC Huzefa Kankroliwala - who is I2C driver owner on Android Kernel 3.4.
Hi Grygorii, thanks for reviewing. I was hoping you would have some
ideas here as this was sounding familiar to something you had
mentioned elsewhere.
> Regarding this patch - from my point of view, it fixes corner case and not an issue in general.
> Let take a look on resume sequence:
> - platform resume
> - syscore resume
> - resume_noirq
> - enable IRQs - resume_device_irqs()
> |- at this point IRQ handler will be invoked if IRQ state is IRQS_PENDING.
> |- so, the I2C device IRQ handler may be called at time when I2C adapter IRQ is still disabled and, as result, the I2C device IRQ-handler may fail. (I2C device and I2C adapter may use different physical IRQ lines)
> - resume_late
> |- enable I2C bus IRQ
>
> Possibly, the better way is to enable/disable I2C bus IRQ when needed - in our case in omap_i2c_xfer().
> We use such approach in Android kernel 3.4
> (http://git.omapzoom.org/?p=kernel/omap.git;a=commitdiff;h=1445a4d3b587c164bd30d108b61760aaaa07365e)
I agree, that should work and cover the cases where I2C is used by other
processors also. Shubhrajyoti already posted something similar[1] but
it needed some rework (comments from Russell and myself.)
Huzefa, Shubhrajyoti, who can rework this idea for the upstream and/or
follow up with the earlier patch[1]?
Wolfram, I guess for now lets hold off on $SUBJECT patch. Seems we can
come up with a broader solution. Thanks.
Kevin
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2012-October/124427.html
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