[PATCH v4 07/14] mfd: Add driver for Maxim 77802 Power Management IC

Hello Doug,

On 06/26/2014 06:29 PM, Doug Anderson wrote:

Javier,

On Thu, Jun 26, 2014 at 9:18 AM, Javier Martinez Canillas
[off-list ref] wrote:

quoted

Hello Doug,

On 06/26/2014 06:12 PM, Doug Anderson wrote:

quoted

Javier,

On Thu, Jun 26, 2014 at 4:13 AM, Javier Martinez Canillas
[off-list ref] wrote:

quoted

quoted

quoted

+
+#ifdef CONFIG_PM_SLEEP
+static int max77802_suspend(struct device *dev)
+{
+    struct i2c_client *i2c = container_of(dev, struct i2c_client, dev);
+    struct max77802_dev *max77802 = i2c_get_clientdata(i2c);
+
+    if (device_may_wakeup(dev))
+            enable_irq_wake(max77802->irq);
+
+    disable_irq(max77802->irq);

Can you add short comment why this is needed? I know why but just for
future generations which will wonder: "why do we need to disable the IRQ
while suspending?" :). Especially that this is rather a workaround for
issue in other driver (I2C bus).

Good idea, I'll add a comment here on next version so code archaeologists can
figure out what what's going on here.

Is the disable_irq() needed if you have
<https://patchwork.kernel.org/patch/4421891/>?

Probably not but I added the following comment:

        /*
         * The IRQ must be disabled during suspend since due wakeup
         * ordering issues it may be possible that the I2C controller
         * is still suspended when the interrupt happens so the IRQ
         * handler will fail to read the I2C bus.
         */
        disable_irq(max77802->irq);

since in theory this PMIC can be used in other SoCs besides
Exynos5420/Exynos5800 and it may be possible that the I2C controller driver for
these other SoCs may not resume at noirq time.

But on a second thought, this PMIC seems to be designed specially for these two
Exynos SoCs so I guess it's safe to assume that it is not needed?

Right, there's a close coupling between PMICs and SoCs.  The PMIC has
special sequencing and default voltage levels that were tuned exactly
for this SoC.

Note: Wolfram has not actually responded to my patch much less
accepted it.  It's entirely possible that in another month or two
we'll hear back a big fat NAK.  In that case your solution will be the
best one I can think of.

Ok, in that case I'll leave as is for now and add the comment but later once/if
your patch is merged, this can be removed.

-Doug

Best regards,
Javier