[3/4] mmc: omap_hsmmc: Remux pins to support SDIO interrupt and PM runtime
diff mbox

Message ID 20130607214957.18581.90624.stgit@localhost
State New, archived
Headers show

Commit Message

Tony Lindgren June 7, 2013, 9:49 p.m. UTC
On some omaps we need to remux MMC pins for PM, and for some omaps
we need to remux the SDIO IRQ pin.

Based on an earlier patch by Andreas Fenkart <afenkart@gmail.com>.

Cc: Andreas Fenkart <afenkart@gmail.com>
Cc: Balaji T K <balajitk@ti.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/mmc/host/omap_hsmmc.c |   93 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 84 insertions(+), 9 deletions(-)


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Comments

Linus Walleij June 10, 2013, 4:03 p.m. UTC | #1
On Fri, Jun 7, 2013 at 11:49 PM, Tony Lindgren <tony@atomide.com> wrote:

> On some omaps we need to remux MMC pins for PM, and for some omaps
> we need to remux the SDIO IRQ pin.
>
> Based on an earlier patch by Andreas Fenkart <afenkart@gmail.com>.
(...)
> +       host->pinctrl = devm_pinctrl_get(host->dev);
> +       if (IS_ERR(host->pinctrl)) {
> +               dev_dbg(host->dev, "no pinctrl handle\n");
> +               ret = 0;
> +               goto out;
> +       }
> +
> +       host->fixed = pinctrl_lookup_state(host->pinctrl,
> +                                          PINCTRL_STATE_DEFAULT);
> +       if (IS_ERR(host->fixed)) {
> +               dev_dbg(host->dev,
> +                        "pins are not configured from the driver\n");
> +               host->fixed = NULL;
> +               ret = 0;
> +               goto out;
> +       }
> +
> +       ret = pinctrl_select_state(host->pinctrl, host->fixed);
> +       if (ret < 0)
> +               goto err;
> +
> +       /* For most cases we don't have wake-ups, and exit after this */
> +       host->active = pinctrl_lookup_state(host->pinctrl, "active");
> +       if (IS_ERR(host->active)) {
> +               ret = PTR_ERR(host->active);
> +               host->active = NULL;
> +               return 0;
> +       }
> +
> +       host->idle = pinctrl_lookup_state(host->pinctrl,
> +                                         PINCTRL_STATE_IDLE);
> +       if (IS_ERR(host->idle)) {
> +               ret = PTR_ERR(host->idle);
> +               host->idle = NULL;
> +               goto err;
> +       }

You can use the new infrastructure to make the core select:

pinctrl_pm_select_default_state(host->dev);
pinctrl_pm_select_idle_state(host->dev);

What is the semantic difference between "default" and "active"?

If this is something very generic that a lot of platforms will want
to have, why not add it to include/linux/pinctrl/pinctrl-state.h
and augment the core to cache and handle this too?

However in this case I *suspect* that what you really want
to do it to rename the state called "default" to "sleep"
(it appears the default state is sleepy) and then rename
the "active" state to "default" (as this is the defined semantic
meaning of "default" from <linux/pinctrl/pinctrl-state.h>.

But maybe I'm not quite getting the subtle difference between
"default" and "active" here so enlighten me.

Yours,
Linus Walleij
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Tony Lindgren June 10, 2013, 4:23 p.m. UTC | #2
* Linus Walleij <linus.walleij@linaro.org> [130610 09:09]:
> 
> You can use the new infrastructure to make the core select:
> 
> pinctrl_pm_select_default_state(host->dev);
> pinctrl_pm_select_idle_state(host->dev);

OK great.
 
> What is the semantic difference between "default" and "active"?

We only should remux the pins that need remuxing as that's done
every time hitting idle. So I think we should have the following
default groups:

default		Static pins that don't change, no need to remux
		configured in consumer driver probe like we already
		do

active		Optional dynamic pins remuxed for runtime, can be
		configured and selected in consumer driver probe.
		The consumer driver may also want to select this
		state in PM runtime resume.

idle		Optional dynamic pins remuxed for idle. The consumer
		driver may also want to select this state in PM
		runtime suspend depending on device_can_wakeup()
		and driver specific needs.
 
> If this is something very generic that a lot of platforms will want
> to have, why not add it to include/linux/pinctrl/pinctrl-state.h
> and augment the core to cache and handle this too?

Yes we should do that assuming the above grouping makes sense
to you.
 
> However in this case I *suspect* that what you really want
> to do it to rename the state called "default" to "sleep"
> (it appears the default state is sleepy) and then rename
> the "active" state to "default" (as this is the defined semantic
> meaning of "default" from <linux/pinctrl/pinctrl-state.h>.

The idle state above could also be called sleep instead of idle
if you prefer that.

> But maybe I'm not quite getting the subtle difference between
> "default" and "active" here so enlighten me.

I think the confusion is caused by the fact that we need three
mux groups, not just two :) The toggling between active and idle
is the hotpath as that can potentially happen for multiple drivers
every time we enter and exit idle.

Regards,

Tony
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Linus Walleij June 11, 2013, 7:54 a.m. UTC | #3
On Mon, Jun 10, 2013 at 6:23 PM, Tony Lindgren <tony@atomide.com> wrote:

> We only should remux the pins that need remuxing as that's done
> every time hitting idle. So I think we should have the following
> default groups:
>
> default         Static pins that don't change, no need to remux
>                 configured in consumer driver probe like we already
>                 do
>
> active          Optional dynamic pins remuxed for runtime, can be
>                 configured and selected in consumer driver probe.
>                 The consumer driver may also want to select this
>                 state in PM runtime resume.
>
> idle            Optional dynamic pins remuxed for idle. The consumer
>                 driver may also want to select this state in PM
>                 runtime suspend depending on device_can_wakeup()
>                 and driver specific needs.

The one thing I don't understand is why a driver would select the
active state in probe(), unless it's a driver that does not support
runtime PM. (But maybe that's what you mean.)

Compare this to <linus/pinctrl/pinctrl-state.h>:

/**
 * @PINCTRL_STATE_DEFAULT: the state the pinctrl handle shall be put
 *      into as default, usually this means the pins are up and ready to
 *      be used by the device driver. This state is commonly used by
 *      hogs to configure muxing and pins at boot, and also as a state
 *      to go into when returning from sleep and idle in
 *      .pm_runtime_resume() or ordinary .resume() for example.
 * @PINCTRL_STATE_IDLE: the state the pinctrl handle shall be put into
 *      when the pins are idle. This is a state where the system is relaxed
 *      but not fully sleeping - some power may be on but clocks gated for
 *      example. Could typically be set from a pm_runtime_suspend() or
 *      pm_runtime_idle() operation.
 * @PINCTRL_STATE_SLEEP: the state the pinctrl handle shall be put into
 *      when the pins are sleeping. This is a state where the system is in
 *      its lowest sleep state. Could typically be set from an
 *      ordinary .suspend() function.
 */
#define PINCTRL_STATE_DEFAULT "default"
#define PINCTRL_STATE_IDLE "idle"
#define PINCTRL_STATE_SLEEP "sleep"

The way I currently use these in e.g.
drivers/spi/spi-pl022 is:

probe:
 -> default

runtime_suspend:
 -> idle

runtime_resume:
 -> default

suspend:
 -> sleep

resume:
  -> default
  -> idle

Notice that we go to default then idle on probe and
runtime resume. This is because the idle state is
optional (as is the sleep state).

So I guess if we should extend this terminology to match
what you are using for the OMAP it would rather be like
this:

probe:
 -> default

runtime_suspend:
 -> idle

runtime_resume:
 -> default
 -> active

suspend:
 -> sleep

resume:
  -> default
  -> idle

Just one more optional "active" state in runtime resume.
Correct?

If we can agree on this I will add the active state to the
state table and add a container in the core for this as well
as pinctrl_pm_select_active_state() so we can skip all the
pointless boilerplate also in the OMAP drivers, plus increase
the readability and portability quite a bit.

>> However in this case I *suspect* that what you really want
>> to do it to rename the state called "default" to "sleep"
>> (it appears the default state is sleepy) and then rename
>> the "active" state to "default" (as this is the defined semantic
>> meaning of "default" from <linux/pinctrl/pinctrl-state.h>.
>
> The idle state above could also be called sleep instead of idle
> if you prefer that.

No I think we should reserve that name for the pin state
associated with suspend(). Let's leave it like this.

> I think the confusion is caused by the fact that we need three
> mux groups, not just two :) The toggling between active and idle
> is the hotpath as that can potentially happen for multiple drivers
> every time we enter and exit idle.

Actually we have the same thing, it's just that our "default"
and "active" are the same thing. But it seems we need to
add your granularity to this.

Yours,
Linus Walleij
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Tony Lindgren June 12, 2013, 1:21 p.m. UTC | #4
* Linus Walleij <linus.walleij@linaro.org> [130611 01:00]:
> On Mon, Jun 10, 2013 at 6:23 PM, Tony Lindgren <tony@atomide.com> wrote:
> 
> > We only should remux the pins that need remuxing as that's done
> > every time hitting idle. So I think we should have the following
> > default groups:
> >
> > default         Static pins that don't change, no need to remux
> >                 configured in consumer driver probe like we already
> >                 do
> >
> > active          Optional dynamic pins remuxed for runtime, can be
> >                 configured and selected in consumer driver probe.
> >                 The consumer driver may also want to select this
> >                 state in PM runtime resume.
> >
> > idle            Optional dynamic pins remuxed for idle. The consumer
> >                 driver may also want to select this state in PM
> >                 runtime suspend depending on device_can_wakeup()
> >                 and driver specific needs.
> 
> The one thing I don't understand is why a driver would select the
> active state in probe(), unless it's a driver that does not support
> runtime PM. (But maybe that's what you mean.)

Yes you're right, there should not be any need to select active state
in probe, that should be selected by PM runtime.
 
> Compare this to <linus/pinctrl/pinctrl-state.h>:
> 
> /**
>  * @PINCTRL_STATE_DEFAULT: the state the pinctrl handle shall be put
>  *      into as default, usually this means the pins are up and ready to
>  *      be used by the device driver. This state is commonly used by
>  *      hogs to configure muxing and pins at boot, and also as a state
>  *      to go into when returning from sleep and idle in
>  *      .pm_runtime_resume() or ordinary .resume() for example.
>  * @PINCTRL_STATE_IDLE: the state the pinctrl handle shall be put into
>  *      when the pins are idle. This is a state where the system is relaxed
>  *      but not fully sleeping - some power may be on but clocks gated for
>  *      example. Could typically be set from a pm_runtime_suspend() or
>  *      pm_runtime_idle() operation.
>  * @PINCTRL_STATE_SLEEP: the state the pinctrl handle shall be put into
>  *      when the pins are sleeping. This is a state where the system is in
>  *      its lowest sleep state. Could typically be set from an
>  *      ordinary .suspend() function.
>  */
> #define PINCTRL_STATE_DEFAULT "default"
> #define PINCTRL_STATE_IDLE "idle"
> #define PINCTRL_STATE_SLEEP "sleep"
> 
> The way I currently use these in e.g.
> drivers/spi/spi-pl022 is:
> 
> probe:
>  -> default
> 
> runtime_suspend:
>  -> idle
> 
> runtime_resume:
>  -> default
> 
> suspend:
>  -> sleep
> 
> resume:
>   -> default
>   -> idle
> 
> Notice that we go to default then idle on probe and
> runtime resume. This is because the idle state is
> optional (as is the sleep state).
> 
> So I guess if we should extend this terminology to match
> what you are using for the OMAP it would rather be like
> this:
> 
> probe:
>  -> default
> 
> runtime_suspend:
>  -> idle
> 
> runtime_resume:
>  -> default
>  -> active

At least for omaps, there's no need to select default in
runtime_resume as the default pins stay that way.
 
> suspend:
>  -> sleep

For omaps, we would just select idle pins again in the
suspend case.
 
> resume:
>   -> default
>   -> idle

And for omaps, there's no need to select default in resume
either. Just selecting active would do the trick for resume.

So for omaps, the sequence would be:

probe:
 -> default (typically all device pins except rx pin)

runtime_suspend:
suspend:
 -> idle (remux rx pin from device to gpio input for wake)
 
runtime_resume:
resume:
 -> active (remux rx pin from gpio input to device)
 
> Just one more optional "active" state in runtime resume.
> Correct?

Yes the "active" is needed, but "sleep" would be unused for
omaps.
 
> If we can agree on this I will add the active state to the
> state table and add a container in the core for this as well
> as pinctrl_pm_select_active_state() so we can skip all the
> pointless boilerplate also in the OMAP drivers, plus increase
> the readability and portability quite a bit.

Sounds good to me as long as we don't always need to select
the default pins over and over in PM runtime_resume.
 
> >> However in this case I *suspect* that what you really want
> >> to do it to rename the state called "default" to "sleep"
> >> (it appears the default state is sleepy) and then rename
> >> the "active" state to "default" (as this is the defined semantic
> >> meaning of "default" from <linux/pinctrl/pinctrl-state.h>.
> >
> > The idle state above could also be called sleep instead of idle
> > if you prefer that.
> 
> No I think we should reserve that name for the pin state
> associated with suspend(). Let's leave it like this.

OK
 
> > I think the confusion is caused by the fact that we need three
> > mux groups, not just two :) The toggling between active and idle
> > is the hotpath as that can potentially happen for multiple drivers
> > every time we enter and exit idle.
> 
> Actually we have the same thing, it's just that our "default"
> and "active" are the same thing. But it seems we need to
> add your granularity to this.

Well the difference seems to be that you need to remux all the
device pins for runtime_suspend and resume while in most of the
cases I know of only one device pins needs to be toggled and the
rest can be selected in driver probe.

Regards,

Tony
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Patch
diff mbox

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 7e28501..8ca08fb 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -185,6 +185,8 @@  struct omap_hsmmc_host {
 	int			req_in_progress;
 	struct omap_hsmmc_next	next_data;
 	bool			sdio_irq_en;
+	struct pinctrl		*pinctrl;
+	struct pinctrl_state	*fixed, *active, *idle;
 	bool			active_pinmux;
 	struct	omap_mmc_platform_data	*pdata;
 };
@@ -473,6 +475,67 @@  static void omap_hsmmc_gpio_free(struct omap_mmc_platform_data *pdata)
 		gpio_free(pdata->slots[0].gpio_cirq);
 }
 
+static int omap_hsmmc_pin_init(struct omap_hsmmc_host *host)
+{
+	int ret;
+
+	host->pinctrl = devm_pinctrl_get(host->dev);
+	if (IS_ERR(host->pinctrl)) {
+		dev_dbg(host->dev, "no pinctrl handle\n");
+		ret = 0;
+		goto out;
+	}
+
+	host->fixed = pinctrl_lookup_state(host->pinctrl,
+					   PINCTRL_STATE_DEFAULT);
+	if (IS_ERR(host->fixed)) {
+		dev_dbg(host->dev,
+			 "pins are not configured from the driver\n");
+		host->fixed = NULL;
+		ret = 0;
+		goto out;
+	}
+
+	ret = pinctrl_select_state(host->pinctrl, host->fixed);
+	if (ret < 0)
+		goto err;
+
+	/* For most cases we don't have wake-ups, and exit after this */
+	host->active = pinctrl_lookup_state(host->pinctrl, "active");
+	if (IS_ERR(host->active)) {
+		ret = PTR_ERR(host->active);
+		host->active = NULL;
+		return 0;
+	}
+
+	host->idle = pinctrl_lookup_state(host->pinctrl,
+					  PINCTRL_STATE_IDLE);
+	if (IS_ERR(host->idle)) {
+		ret = PTR_ERR(host->idle);
+		host->idle = NULL;
+		goto err;
+	}
+
+	/* Let's make sure the active and idle states work */
+	ret = pinctrl_select_state(host->pinctrl, host->idle);
+	if (ret < 0)
+		goto err;
+
+	ret = pinctrl_select_state(host->pinctrl, host->active);
+	if (ret < 0)
+		goto err;
+
+	dev_info(mmc_dev(host->mmc), "pins configured for wake-up events\n");
+
+	return 0;
+
+err:
+	dev_err(mmc_dev(host->mmc), "pins configuration error: %i\n", ret);
+
+out:
+	return ret;
+}
+
 /*
  * Start clock to the card
  */
@@ -1854,7 +1917,6 @@  static int omap_hsmmc_probe(struct platform_device *pdev)
 	const struct of_device_id *match;
 	dma_cap_mask_t mask;
 	unsigned tx_req, rx_req;
-	struct pinctrl *pinctrl;
 
 	match = of_match_device(of_match_ptr(omap_mmc_of_match), &pdev->dev);
 	if (match) {
@@ -2086,21 +2148,19 @@  static int omap_hsmmc_probe(struct platform_device *pdev)
 
 	omap_hsmmc_disable_irq(host);
 
-	pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
-	if (IS_ERR(pinctrl))
-		dev_warn(&pdev->dev,
-			"pins are not configured from the driver\n");
-
 	/*
-	 * For now, only support SDIO interrupt if we are doing
-	 * muxing of dat1 when booted with DT. This is because the
+	 * For now, only support SDIO interrupt if we are doing dynamic
+	 * remuxing of dat1 when booted with DT. This is because the
 	 * supposedly the wake-up events for CTPL don't work from deeper
 	 * idle states. And we don't want to add new legacy mux platform
 	 * init code callbacks any longer as we are moving to DT based
 	 * booting anyways.
 	 */
 	if (match) {
-		if (!IS_ERR(pinctrl) && mmc_slot(host).sdio_irq)
+		ret = omap_hsmmc_pin_init(host);
+		if (ret)
+			goto err_pinctrl_state;
+		else if (host->idle && mmc_slot(host).sdio_irq)
 			mmc->caps |= MMC_CAP_SDIO_IRQ;
 	}
 
@@ -2128,6 +2188,8 @@  static int omap_hsmmc_probe(struct platform_device *pdev)
 
 err_slot_name:
 	mmc_remove_host(mmc);
+err_pinctrl_state:
+	devm_pinctrl_put(host->pinctrl);
 	if ((mmc_slot(host).sdio_irq))
 		free_irq(mmc_slot(host).sdio_irq, host);
 err_irq_sdio:
@@ -2185,6 +2247,7 @@  static int omap_hsmmc_remove(struct platform_device *pdev)
 		dma_release_channel(host->tx_chan);
 	if (host->rx_chan)
 		dma_release_channel(host->rx_chan);
+	devm_pinctrl_put(host->pinctrl);
 
 	pm_runtime_put_sync(host->dev);
 	pm_runtime_disable(host->dev);
@@ -2320,6 +2383,12 @@  static int omap_hsmmc_runtime_suspend(struct device *dev)
 		OMAP_HSMMC_WRITE(host->base, STAT, STAT_CLEAR);
 		spin_unlock_irqrestore(&host->irq_lock, flags);
 
+		if (host->pinctrl && host->idle) {
+			ret = pinctrl_select_state(host->pinctrl, host->idle);
+			if (ret < 0)
+				dev_warn(mmc_dev(host->mmc), "Unable to select idle pinmux\n");
+		}
+
 		if (mmc_slot(host).sdio_irq)
 			enable_irq(mmc_slot(host).sdio_irq);
 	}
@@ -2343,6 +2412,12 @@  static int omap_hsmmc_runtime_resume(struct device *dev)
 		if (mmc_slot(host).sdio_irq)
 			disable_irq(mmc_slot(host).sdio_irq);
 
+		if (host->pinctrl && host->active) {
+			ret = pinctrl_select_state(host->pinctrl, host->active);
+			if (ret < 0)
+				dev_warn(mmc_dev(host->mmc), "Unable to select active pinmux\n");
+		}
+
 		spin_lock_irqsave(&host->irq_lock, flags);
 		host->active_pinmux = true;