linux-kernel - Re: [PATCH 2a/3] mmc: core: Allow host driver to provide isr for card-detect interrupts.

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Date:	Tue, 23 Dec 2014 12:37:52 +0100
From:	Ulf Hansson <ulf.hansson@...aro.org>
To:	NeilBrown <neilb@...e.de>
Cc:	Chris Ball <chris@...ntf.net>,
	GTA04 owners <gta04-owner@...delico.com>,
	linux-omap <linux-omap@...r.kernel.org>,
	linux-mmc <linux-mmc@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2a/3] mmc: core: Allow host driver to provide isr for
 card-detect interrupts.

On 23 December 2014 at 09:48, NeilBrown <neilb@...e.de> wrote:
> On Mon, 22 Dec 2014 16:35:40 +0100 Ulf Hansson <ulf.hansson@...aro.org> wrote:
>
>> On 20 December 2014 at 00:07, NeilBrown <neilb@...e.de> wrote:
>> > One of the reasons omap_hsmmc doesn't use the slot-gpio library
>> > is that it has some non-standard functionality in the card-detect
>> > interrupt service routine.
>> >
>> > To make it possible for omap_hsmmc (and maybe others) to be converted
>> > to use slot-gpio, add 'mmc_gpio_request_cd_isr' which provide an
>> > alternate isr to be register by the slot-gpio code.
>> >
>> > Signed-off-by: NeilBrown <neilb@...e.de>
>> > ---
>> >  drivers/mmc/core/slot-gpio.c  |   24 +++++++++++++++++++++++-
>> >  include/linux/mmc/slot-gpio.h |    2 ++
>> >  2 files changed, 25 insertions(+), 1 deletion(-)
>> >
>> > This and following are the result of splitting the previous
>> > '2/3' into to patches: core and omap_hsmmc as requested.
>> >
>> > NeilBrown
>> >
>> >
>> > diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c
>> > index 69bbf2adb329..f56323f5a996 100644
>> > --- a/drivers/mmc/core/slot-gpio.c
>> > +++ b/drivers/mmc/core/slot-gpio.c
>> > @@ -23,6 +23,7 @@ struct mmc_gpio {
>> >         struct gpio_desc *cd_gpio;
>> >         bool override_ro_active_level;
>> >         bool override_cd_active_level;
>> > +       irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id);
>> >         char *ro_label;
>> >         char cd_label[0];
>> >  };
>> > @@ -156,8 +157,10 @@ void mmc_gpiod_request_cd_irq(struct mmc_host *host)
>> >                 irq = -EINVAL;
>> >
>> >         if (irq >= 0) {
>> > +               if (ctx->cd_gpio_isr == NULL)
>>
>> Please change to:
>> if (!ctx->cd_gpio_isr)
>
> will do (though I personally prefer the explicit "NULL" :-).
>
>>
>> > +                       ctx->cd_gpio_isr = mmc_gpio_cd_irqt;
>> >                 ret = devm_request_threaded_irq(&host->class_dev, irq,
>> > -                       NULL, mmc_gpio_cd_irqt,
>> > +                       NULL, ctx->cd_gpio_isr,
>> >                         IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>> >                         ctx->cd_label, host);
>> >                 if (ret < 0)
>> > @@ -171,6 +174,25 @@ void mmc_gpiod_request_cd_irq(struct mmc_host *host)
>> >  }
>> >  EXPORT_SYMBOL(mmc_gpiod_request_cd_irq);
>> >
>> > +/* Register an alternate interrupt service routine for
>> > + * the card-detect GPIO.
>> > + */
>> > +int mmc_gpio_request_cd_isr(struct mmc_host *host,
>> > +                           irqreturn_t (*isr)(int irq, void *dev_id))
>> > +{
>> > +       struct mmc_gpio *ctx;
>> > +       int ret;
>> > +
>> > +       ret = mmc_gpio_alloc(host);
>> > +       if (ret < 0)
>> > +               return ret;
>> > +       ctx = host->slot.handler_priv;
>> > +       if (ctx->cd_gpio_isr)
>> > +               return -EBUSY;
>> > +       ctx->cd_gpio_isr = isr;
>> > +       return 0;
>> > +}
>>
>> I decided to queue those patchsets I recently posted which simplifies
>> the slot-gpio API. Please re-base this patch on top of my next branch.
>
> OK.
>
>>
>> Moreover, I actually wonder whether we need to add this API at all.
>> After my changes, all you need to do from your host driver ->probe(),
>> is to assign your isr routine to ctx->cd_gpio_isr.
>
> 'struct mmc_gpio' is local to slot-gpio.c, so code in other files cannot
> access the members directly.

You are right. I don't think they should.

Let's add the API instead, but rename it to something like
mmc_gpio_set_cd_isr().

Kind regards
Uffe

>
> If you want to move it to include/linux/mmc/host.h and change
>   void *handler_priv;
> to
>   struct mmc_gpio *gpios;
>
> or similar, then I'll happily update it directly.
> What do you think?
>
> NeilBrown
>
>
>>
>> > +
>> >  /**
>> >   * mmc_gpio_request_cd - request a gpio for card-detection
>> >   * @host: mmc host
>> > diff --git a/include/linux/mmc/slot-gpio.h b/include/linux/mmc/slot-gpio.h
>> > index e56fa24c9322..9e55db60deb0 100644
>> > --- a/include/linux/mmc/slot-gpio.h
>> > +++ b/include/linux/mmc/slot-gpio.h
>> > @@ -28,6 +28,8 @@ int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id,
>> >  int mmc_gpiod_request_ro(struct mmc_host *host, const char *con_id,
>> >                          unsigned int idx, bool override_active_level,
>> >                          unsigned int debounce, bool *gpio_invert);
>> > +int mmc_gpio_request_cd_isr(struct mmc_host *host,
>> > +                           irqreturn_t (*isr)(int irq, void *dev_id));
>> >  void mmc_gpiod_free_cd(struct mmc_host *host);
>> >  void mmc_gpiod_request_cd_irq(struct mmc_host *host);
>> >
>> >
>> >
>>
>> Kind regards
>> Uffe
>
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