Re: [PATCH v2] input/imx_keypad: add pm suspend and resume functions

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, Oct 26, 2011 at 04:41:41PM +0800, Hui Wang wrote:
> Sascha Hauer wrote:
> >On Thu, Oct 13, 2011 at 10:13:33AM +0800, Hui Wang wrote:
> >>The imx_keypad driver is set wake capable in the imx_keypad_probe(),
> >>but it doesn't implement suspend and reusme callback interface.
> >>
> >>From the i.MX series MCU Reference Manual, the kpp (keypad port) is
> >>a major wake up source which can detect any key press even in low
> >>power modes and even when there is no clock.
> >>
> >>Now add suspend and resume callback functions for this driver.
> >>
> >>Signed-off-by: Hui Wang <jason77.wang@gmail.com>
> >>---
> >>
> >>Sorry for resending this patch, the previous sent patch with [v2]
> >>as a prefix, i am afraid that patch was filtered out from mailing list.
> >>Now resending this patch with [PATCH v2] as a prefix.
> >>
> >>In the V2:
> >>1) add a check for input->users before disable clock.
> >>2) add mutex_lock/unlock to protect input->users checking.
> >>3) use SIMPLE_DEV_PM_OPS.
> >>
> >> drivers/input/keyboard/imx_keypad.c |   46 +++++++++++++++++++++++++++++++++++
> >> 1 files changed, 46 insertions(+), 0 deletions(-)
> >>
> >>diff --git a/drivers/input/keyboard/imx_keypad.c b/drivers/input/keyboard/imx_keypad.c
> >>index d92c15c..c43fa97 100644
> >>--- a/drivers/input/keyboard/imx_keypad.c
> >>+++ b/drivers/input/keyboard/imx_keypad.c
> >>@@ -567,10 +567,56 @@ static int __devexit imx_keypad_remove(struct platform_device *pdev)
> >> 	return 0;
> >> }
> >>+#ifdef CONFIG_PM
> >>+static int imx_kbd_suspend(struct device *dev)
> >>+{
> >>+	struct platform_device *pdev = to_platform_device(dev);
> >>+	struct imx_keypad *kbd = platform_get_drvdata(pdev);
> >>+	struct input_dev *input_dev = kbd->input_dev;
> >>+
> >>+	/* imx kbd can wake up system even clock is disabled */
> >>+	mutex_lock(&input_dev->mutex);
> >>+
> >>+	if (input_dev->users)
> >>+		clk_disable(kbd->clk);
> >>+
> >>+	mutex_unlock(&input_dev->mutex);
> >>+
> >>+	if (device_may_wakeup(&pdev->dev))
> >>+		enable_irq_wake(kbd->irq);
> >
> >enable_irq_wake can fail. More specifically it *will* fail on all non
> >tzic i.MX boards as this function is not yet implemented for the avic
> >irq controller.
> >You should check the return value.
> >
> Hi Sascha,
> 
> I have sent a patch to change plat-mxc/avic.c to use generic irq
> chip, in this patch, two lines to handle wakeup_set issues:
> 
> gc->wake_enabled = IRQ_MSK(32);
> ct->chip.irq_set_wake = irq_gc_set_wake;
> 
> These two lines will make enable_irq_wake successful unconditionally.
> 
> And i recall you have sent this patch to Arnd through a pull request.

Ok, so currently this function can't fail, but this a very bad excuse for
not checking error values.

Sascha


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