[PATCH v13 3/3] mmc: mediatek: add support for SDIO eint wakup IRQ
Axe Yang
axe.yang at mediatek.com
Fri Jul 22 00:53:30 PDT 2022
On Thu, 2022-07-21 at 12:58 +0200, Ulf Hansson wrote:
> + Linus Walleij
>
> On Tue, 19 Jul 2022 at 12:35, Axe Yang <axe.yang at mediatek.com> wrote:
> >
> > On Mon, 2022-07-18 at 14:21 +0200, Ulf Hansson wrote:
> > > On Thu, 23 Jun 2022 at 11:05, Axe Yang <axe.yang at mediatek.com>
> > > wrote:
> > > >
> > > > Add support for eint IRQ when MSDC is used as an SDIO host.
> > > > This
> > > > feature requires SDIO device support async IRQ function. With
> > > > this
> > > > feature, SDIO host can be awakened by SDIO card in suspend
> > > > state,
> > > > without additional pin.
> > > >
> > > > MSDC driver will time-share the SDIO DAT1 pin. During suspend,
> > > > MSDC
> > > > turn off clock and switch SDIO DAT1 pin to GPIO mode. And
> > > > during
> > > > resume, switch GPIO function back to DAT1 mode then turn on
> > > > clock.
> > > >
> > > > Some device tree property should be added or modified in MSDC
> > > > node
> > > > to support SDIO eint IRQ. Pinctrls "state_eint" is mandatory.
> > > > Since
> > > > this feature depends on asynchronous interrupts, "wakeup-
> > > > source",
> > > > "keep-power-in-suspend" and "cap-sdio-irq" flags are necessary,
> > > > and
> > > > the interrupts list should be extended(the interrupt named with
> > > > sdio_wakeup):
> > > > &mmcX {
> > > > ...
> > > > interrupt-names = "msdc", "sdio_wakeup";
> > > > interrupts-extended = <...>,
> > > > <&pio xxx
> > > > IRQ_TYPE_LEVEL_LOW>;
> > > > ...
> > > > pinctrl-names = "default", "state_uhs",
> > > > "state_eint";
> > > > ...
> > > > pinctrl-2 = <&mmc2_pins_eint>;
> > > > ...
> > > > cap-sdio-irq;
> > > > keep-power-in-suspend;
> > > > wakeup-source;
> > > > ...
> > > > };
> > > >
> > > > Co-developed-by: Yong Mao <yong.mao at mediatek.com>
> > > > Signed-off-by: Yong Mao <yong.mao at mediatek.com>
> > > > Signed-off-by: Axe Yang <axe.yang at mediatek.com>
> > >
> > > My apologies for the delay in reviewing this.
> >
> > It is okay. Glad to receive your reply.
> >
> > >
> > > > ---
> > > > drivers/mmc/host/mtk-sd.c | 84
> > > > ++++++++++++++++++++++++++++++++++++---
> > > > 1 file changed, 78 insertions(+), 6 deletions(-)
> > > >
> > > > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-
> > > > sd.c
> > > > index 195dc897188b..f907b96cfd87 100644
> > > > --- a/drivers/mmc/host/mtk-sd.c
> > > > +++ b/drivers/mmc/host/mtk-sd.c
> > > > @@ -1,6 +1,6 @@
> > > > // SPDX-License-Identifier: GPL-2.0-only
> > > > /*
> > > > - * Copyright (c) 2014-2015 MediaTek Inc.
> > > > + * Copyright (c) 2014-2015, 2022 MediaTek Inc.
> > > > * Author: Chaotian.Jing <chaotian.jing at mediatek.com>
> > > > */
> > > >
> > > > @@ -20,6 +20,7 @@
> > > > #include <linux/platform_device.h>
> > > > #include <linux/pm.h>
> > > > #include <linux/pm_runtime.h>
> > > > +#include <linux/pm_wakeirq.h>
> > > > #include <linux/regulator/consumer.h>
> > > > #include <linux/slab.h>
> > > > #include <linux/spinlock.h>
> > > > @@ -440,8 +441,10 @@ struct msdc_host {
> > > > struct pinctrl *pinctrl;
> > > > struct pinctrl_state *pins_default;
> > > > struct pinctrl_state *pins_uhs;
> > > > + struct pinctrl_state *pins_eint;
> > > > struct delayed_work req_timeout;
> > > > int irq; /* host interrupt */
> > > > + int eint_irq; /* interrupt from sdio device
> > > > for
> > > > waking up system */
> > > > struct reset_control *reset;
> > > >
> > > > struct clk *src_clk; /* msdc source clock */
> > > > @@ -1520,17 +1523,46 @@ static void
> > > > __msdc_enable_sdio_irq(struct
> > > > msdc_host *host, int enb)
> > > >
> > > > static void msdc_enable_sdio_irq(struct mmc_host *mmc, int
> > > > enb)
> > > > {
> > > > - unsigned long flags;
> > > > struct msdc_host *host = mmc_priv(mmc);
> > > > + unsigned long flags;
> > > > + int ret;
> > > >
> > > > spin_lock_irqsave(&host->lock, flags);
> > > > __msdc_enable_sdio_irq(host, enb);
> > > > spin_unlock_irqrestore(&host->lock, flags);
> > > >
> > > > - if (enb)
> > > > - pm_runtime_get_noresume(host->dev);
> > > > - else
> > > > - pm_runtime_put_noidle(host->dev);
> > > > + if (mmc_card_enable_async_irq(mmc->card) && host-
> > > > > pins_eint) {
> > > >
> > > > + if (enb) {
> > > > + /*
> > > > + * In
> > > > dev_pm_set_dedicated_wake_irq_reverse(), eint pin will be set
> > > > to
> > > > + * GPIO mode. We need to restore it to
> > > > SDIO
> > > > DAT1 mode after that.
> > > > + * Since the current pinstate is
> > > > pins_uhs,
> > > > to ensure pinctrl select take
> > > > + * affect successfully, we change the
> > > > pinstate to pins_eint firstly.
> > > > + */
> > > > + pinctrl_select_state(host->pinctrl,
> > > > host-
> > > > > pins_eint);
> > >
> > > I am sorry, but I don't understand what goes on here. Why do you
> > > need
> > > to change the pinctrl setting to "pins_eint" here?
> > >
> > > The bellow call to dev_pm_set_dedicated_wake_irq_reverse()
> > > doesn't
> > > change the pinctrl setting as the comment suggests above.
> > >
> >
> > Actually, the pinctrl setting is changed:
> > In dev_pm_set_dedicated_wake_irq_reverse() -> ... ->
> > request_threaded_irq() -> __setup_irq() -> irq_request_resources()
> > ->
> > mtk_eint_irq_request_resources()-> mtk_xt_set_gpio_as_eint(), the
> > SDIO
> > DAT1 pin will be force reset to GPIO mode:
>
> Aha. That looks a bit weird, but I get the problem now.
>
> I have looped in Linus (the pintctrl maintainer) to get his opinion
> on this.
>
Okay.
> >
> >
https://urldefense.com/v3/__https://elixir.bootlin.com/linux/latest/source/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c*L339__;Iw!!CTRNKA9wMg0ARbw!10fxyOdpvC-aCfRRWEGS5lXRPC6qJ0Z79tnrnTNbOu8VgamIxVATeM_wDz-obpEJ$
> >
> >
> > So, I have to call pinctrl_select_state() to restore SDIO DAT1 pin
> > mode(pins_uhs). But pinctrl_select_state() return directly because
> > MSDC
> > driver still wrongly thinks current DAT1 state is SDIO DAT1 mode:
> >
> >
https://urldefense.com/v3/__https://elixir.bootlin.com/linux/latest/source/drivers/pinctrl/core.c*L1344__;Iw!!CTRNKA9wMg0ARbw!10fxyOdpvC-aCfRRWEGS5lXRPC6qJ0Z79tnrnTNbOu8VgamIxVATeM_wD2q7InpM$
> >
> > , which means I have to call pinctrl_select_state() in pairs:
> > Change
> > pinctrl to another state(pins_eint), then change it back to
> > pins_uhs
> > mode.
>
> I see. So a call to pinctrl_select_state("pins_uhs") would not take
> effect, unless we call pinctrl_select_state("pins_eint") first. That
> sounds like the internal state of the pinctrl isn't maintained
> properly.
>
That is correct. The GPIO mode is modified in a very hidden way, by
pass pinctrl mechanism.
> Let's see what Linus thinks about this.
>
> Note that, I am happy to pick the patch as is around this, but I am
> worried we might be doing something at the mmc driver level, which
> should really be managed at the pinctrl layer.
>
Okay. I will release patch V14 after Linus replies.
> >
> >
> > > dev_pm_set_dedicated_wake_irq_reverse() will register the
> > > wakeirq,
> > > but
> > > more importantly, it should also leave the wakeirq disabled,
> > > right?
> >
> > Yes. wakeirq will be registered, and disabled. But SDIO DAT1 pin
> > mode
> > will be changed too.
> >
> > >
> > > > + ret =
> > > > dev_pm_set_dedicated_wake_irq_reverse(host->dev, host-
> > > > >eint_irq);
> > > > +
> > > > + if (ret) {
> > > > + dev_err(host->dev, "Failed to
> > > > register SDIO wakeup irq!\n");
> > > > + host->pins_eint = NULL;
> > > > + pm_runtime_get_noresume(host-
> > > > >dev);
> > > > + } else {
> > > > + dev_dbg(host->dev, "SDIO eint
> > > > irq:
> > > > %d!\n", host->eint_irq);
> > > > + }
> > > > +
> > > > + pinctrl_select_state(host->pinctrl,
> > > > host-
> > > > > pins_uhs);
> > >
> > > According to my comment above, I also don't understand why you
> > > need
> > > this. Why can't you just leave the pinctrl in the "pins_uhs"
> > > state?
> > >
> >
> > I have to call pinctrl_select_state() in pairs.
> >
> >
> > > > + } else {
> > > > + dev_pm_clear_wake_irq(host->dev);
> > > > + }
> > > > + } else {
> > > > + if (enb) {
> > > > + /* Ensure host->pins_eint is NULL */
> > > > + host->pins_eint = NULL;
> > > > + pm_runtime_get_noresume(host->dev);
> > > > + } else {
> > > > + pm_runtime_put_noidle(host->dev);
> > > > + }
> > > > + }
> > > > }
>
> [...]
>
>
Regards,
Axe
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