linux-kernel - Re: [PATCH v4] pinctrl: mediatek: Implement wake handler and suspend resume

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Date:	Mon, 17 Aug 2015 21:25:53 +0800
From:	Yingjoe Chen <yingjoe.chen@...iatek.com>
To:	Daniel Kurtz <djkurtz@...omium.org>
CC:	maoguang meng <maoguang.meng@...iatek.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Hongzhou Yang <hongzhou.yang@...iatek.com>,
	<linux-gpio@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-mediatek@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4] pinctrl: mediatek: Implement wake handler and
 suspend resume

On Mon, 2015-08-17 at 17:09 +0800, Daniel Kurtz wrote:
> On Mon, Aug 17, 2015 at 3:52 PM, Yingjoe Chen <yingjoe.chen@...iatek.com> wrote:
> > On Fri, 2015-08-14 at 16:38 +0800, maoguang.meng@...iatek.com wrote:
> >> From: Maoguang Meng <maoguang.meng@...iatek.com>
> >>
> >> This patch implement irq_set_wake to get who is wakeup source and
> >> setup on suspend resume.
> >>
> >> Signed-off-by: Maoguang Meng <maoguang.meng@...iatek.com>
> >>
> >> ---
> >> changes since v3:
> >> -add a comment in mtk_eint_chip_read_mask.
> >> -delete ALIGN when allocate eint_offsets.ports.
> >> -fix unrelated change.
> >>
> >> changes since v2:
> >> -modify irq_wake to handle irq wakeup source.
> >> -allocate two buffers separately.
> >> -fix some codestyle.
> >>
> >> Changes since v1:
> >> -implement irq_wake handler.
> >> ---
> >>
> >>  drivers/pinctrl/mediatek/pinctrl-mt8173.c     |  1 +
> >>  drivers/pinctrl/mediatek/pinctrl-mtk-common.c | 91 ++++++++++++++++++++++++++-
> >>  drivers/pinctrl/mediatek/pinctrl-mtk-common.h |  4 ++
> >>  3 files changed, 95 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/pinctrl/mediatek/pinctrl-mt8173.c b/drivers/pinctrl/mediatek/pinctrl-mt8173.c
> >> index d0c811d..ad27184 100644
> >> --- a/drivers/pinctrl/mediatek/pinctrl-mt8173.c
> >> +++ b/drivers/pinctrl/mediatek/pinctrl-mt8173.c
> >> @@ -385,6 +385,7 @@ static struct platform_driver mtk_pinctrl_driver = {
> >>       .driver = {
> >>               .name = "mediatek-mt8173-pinctrl",
> >>               .of_match_table = mt8173_pctrl_match,
> >> +             .pm = &mtk_eint_pm_ops,
> >>       },
> >>  };
> >>
> >> diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
> >> index ad1ea16..fe34ce9 100644
> >> --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
> >> +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
> >> @@ -33,6 +33,7 @@
> >>  #include <linux/mfd/syscon.h>
> >>  #include <linux/delay.h>
> >>  #include <linux/interrupt.h>
> >> +#include <linux/pm.h>
> >>  #include <dt-bindings/pinctrl/mt65xx.h>
> >>
> >>  #include "../core.h"
> >> @@ -1062,6 +1063,77 @@ static int mtk_eint_set_type(struct irq_data *d,
> >>       return 0;
> >>  }
> >>
> >> +static int mtk_eint_irq_set_wake(struct irq_data *d, unsigned int on)
> >> +{
> >> +     struct mtk_pinctrl *pctl = irq_data_get_irq_chip_data(d);
> >> +     int shift = d->hwirq & 0x1f;
> >> +     int reg = d->hwirq >> 5;
> >> +
> >> +     if (on)
> >> +             pctl->wake_mask[reg] |= BIT(shift);
> >> +     else
> >> +             pctl->wake_mask[reg] &= ~BIT(shift);
> >> +
> >> +     return 0;
> >> +}
> >
> > Hi Maoguang,
> >
> > You changed from set_bit/clear_bit to this, but didn't add any locking.
> > Since this is basic read/modify/write, is it OK to do it without
> > locking?
> 
> I believe calling .irq_set_wake() concurrently with itself is
> protected by irq_get_desc_buslock():
> 
>  int irq_set_irq_wake(unsigned int irq, unsigned int on)
>  {
>          unsigned long flags;
>          struct irq_desc *desc = irq_get_desc_buslock(irq, &flags,
> IRQ_GET_DESC_CHECK_GLOBAL);
>          int ret = 0;
> ...
>                          ret = set_irq_wake_real(irq, on);
> ...
>          irq_put_desc_busunlock(desc, flags);
>          return ret;
>  }

Hi Dan,

You are right, irq_get_desc_buslock will acquire desc lock even when
irq_chip didn't provide irq_bus_lock callback. So this should be OK.
Sorry for the noise.

For this patch:

Acked-by: Yingjoe Chen <yingjoe.chen@...iatek.com>

Joe.C



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