[v3,3/3] gpio: rcar: Use wakeup_path i.s.o. explicit clock handling

Message ID 1518443713-1835-4-git-send-email-geert+renesas@glider.be
State New
Headers show
Series
  • renesas: irqchip: Use wakeup_path i.s.o. explicit clock handling
Related show

Commit Message

Geert Uytterhoeven Feb. 12, 2018, 1:55 p.m.
Since commit ab82fa7da4dce5c7 ("gpio: rcar: Prevent module clock disable
when wake-up is enabled"), when a GPIO is used for wakeup, the GPIO
block's module clock (if exists) is manually kept running during system
suspend, to make sure the device stays active.

However, this explicit clock handling is merely a workaround for a
failure to properly communicate wakeup information to the device core.

Instead, set the device's power.wakeup_path field, to indicate this
device is part of the wakeup path.  Depending on the PM Domain's
active_wakeup configuration, the genpd core code will keep the device
enabled (and the clock running) during system suspend when needed.
This allows for the removal of all explicit clock handling code from the
driver.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
v3:
  - Revert to v1, as WAKEUP_PATH didn't make it,
  - Use an atomic_t instead of a boolean flag, as the latter tracked
    only the status of the last configured GPIO, while multiple GPIOs on
    the same GPIO controller may be involved with wake-up,
  - Use new helper device_set_wakeup_path(),
  - Drop checks for CONFIG_PM_SLEEP, as device_set_wakeup_path() is
    always available, unlike dev_pm_info.wakeup_path,
  - Mark gpio_rcar_suspend() __maybe_unused,
  - Drop RFC state, now the dependencies are upstream.

v2 (sent by Ulf Hanson):
  - Convert to use the WAKEUP_PATH driver PM flag (Ulf).
---
 drivers/gpio/gpio-rcar.c | 38 ++++++++++++++++----------------------
 1 file changed, 16 insertions(+), 22 deletions(-)

Comments

Linus Walleij Feb. 22, 2018, 2:23 p.m. | #1
On Mon, Feb 12, 2018 at 2:55 PM, Geert Uytterhoeven
<geert+renesas@glider.be> wrote:

> Since commit ab82fa7da4dce5c7 ("gpio: rcar: Prevent module clock disable
> when wake-up is enabled"), when a GPIO is used for wakeup, the GPIO
> block's module clock (if exists) is manually kept running during system
> suspend, to make sure the device stays active.
>
> However, this explicit clock handling is merely a workaround for a
> failure to properly communicate wakeup information to the device core.
>
> Instead, set the device's power.wakeup_path field, to indicate this
> device is part of the wakeup path.  Depending on the PM Domain's
> active_wakeup configuration, the genpd core code will keep the device
> enabled (and the clock running) during system suspend when needed.
> This allows for the removal of all explicit clock handling code from the
> driver.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Acked-by: Linus Walleij <linus.walleij@linaro.org>

Can I apply this and only this patch to GPIO?

Should it be applied for fixes, next?

Else please funnel this through the irqchip tree with my
ACK.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Geert Uytterhoeven Feb. 22, 2018, 2:44 p.m. | #2
Hi Linus,

On Thu, Feb 22, 2018 at 3:23 PM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Mon, Feb 12, 2018 at 2:55 PM, Geert Uytterhoeven
> <geert+renesas@glider.be> wrote:
>
>> Since commit ab82fa7da4dce5c7 ("gpio: rcar: Prevent module clock disable
>> when wake-up is enabled"), when a GPIO is used for wakeup, the GPIO
>> block's module clock (if exists) is manually kept running during system
>> suspend, to make sure the device stays active.
>>
>> However, this explicit clock handling is merely a workaround for a
>> failure to properly communicate wakeup information to the device core.
>>
>> Instead, set the device's power.wakeup_path field, to indicate this
>> device is part of the wakeup path.  Depending on the PM Domain's
>> active_wakeup configuration, the genpd core code will keep the device
>> enabled (and the clock running) during system suspend when needed.
>> This allows for the removal of all explicit clock handling code from the
>> driver.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
>
> Acked-by: Linus Walleij <linus.walleij@linaro.org>
>
> Can I apply this and only this patch to GPIO?

Yes please.

> Should it be applied for fixes, next?

No, as it depends on infrastructure (device_set_wakeup_path()) and fixes
(various "Keep wakeup sources active during system suspend") in v4.16-rc1.

Thanks!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Linus Walleij March 1, 2018, 4:06 p.m. | #3
On Mon, Feb 12, 2018 at 2:55 PM, Geert Uytterhoeven
<geert+renesas@glider.be> wrote:

> Since commit ab82fa7da4dce5c7 ("gpio: rcar: Prevent module clock disable
> when wake-up is enabled"), when a GPIO is used for wakeup, the GPIO
> block's module clock (if exists) is manually kept running during system
> suspend, to make sure the device stays active.
>
> However, this explicit clock handling is merely a workaround for a
> failure to properly communicate wakeup information to the device core.
>
> Instead, set the device's power.wakeup_path field, to indicate this
> device is part of the wakeup path.  Depending on the PM Domain's
> active_wakeup configuration, the genpd core code will keep the device
> enabled (and the clock running) during system suspend when needed.
> This allows for the removal of all explicit clock handling code from the
> driver.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> v3:

Patch applied for v4.16 fixes.

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Geert Uytterhoeven March 2, 2018, 8:20 a.m. | #4
Hi Linus,

On Thu, Mar 1, 2018 at 5:06 PM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Mon, Feb 12, 2018 at 2:55 PM, Geert Uytterhoeven
> <geert+renesas@glider.be> wrote:
>
>> Since commit ab82fa7da4dce5c7 ("gpio: rcar: Prevent module clock disable
>> when wake-up is enabled"), when a GPIO is used for wakeup, the GPIO
>> block's module clock (if exists) is manually kept running during system
>> suspend, to make sure the device stays active.
>>
>> However, this explicit clock handling is merely a workaround for a
>> failure to properly communicate wakeup information to the device core.
>>
>> Instead, set the device's power.wakeup_path field, to indicate this
>> device is part of the wakeup path.  Depending on the PM Domain's
>> active_wakeup configuration, the genpd core code will keep the device
>> enabled (and the clock running) during system suspend when needed.
>> This allows for the removal of all explicit clock handling code from the
>> driver.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
>> ---
>> v3:
>
> Patch applied for v4.16 fixes.

Are you aware this conflicts with commit 51750fb167a05468 ("gpio: gpio-rcar:
Support S2RAM") in gpio/for-next?

You can find the resolution in
https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git/tree/drivers/gpio/gpio-rcar.c?h=renesas-drivers-2018-02-28-v4.16-rc3

If there's anything else I can do, just ask!

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Linus Walleij March 2, 2018, 8:44 a.m. | #5
On Fri, Mar 2, 2018 at 9:20 AM, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> On Thu, Mar 1, 2018 at 5:06 PM, Linus Walleij <linus.walleij@linaro.org> wrote:
>> On Mon, Feb 12, 2018 at 2:55 PM, Geert Uytterhoeven
>> <geert+renesas@glider.be> wrote:
>>
>>> Since commit ab82fa7da4dce5c7 ("gpio: rcar: Prevent module clock disable
>>> when wake-up is enabled"), when a GPIO is used for wakeup, the GPIO
>>> block's module clock (if exists) is manually kept running during system
>>> suspend, to make sure the device stays active.
>>>
>>> However, this explicit clock handling is merely a workaround for a
>>> failure to properly communicate wakeup information to the device core.
>>>
>>> Instead, set the device's power.wakeup_path field, to indicate this
>>> device is part of the wakeup path.  Depending on the PM Domain's
>>> active_wakeup configuration, the genpd core code will keep the device
>>> enabled (and the clock running) during system suspend when needed.
>>> This allows for the removal of all explicit clock handling code from the
>>> driver.
>>>
>>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
>>> ---
>>> v3:
>>
>> Patch applied for v4.16 fixes.
>
> Are you aware this conflicts with commit 51750fb167a05468 ("gpio: gpio-rcar:
> Support S2RAM") in gpio/for-next?

No but I guess I will become aware.

I have not yet mixed the fixes and devel branches for next.

> You can find the resolution in
> https://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git/tree/drivers/gpio/gpio-rcar.c?h=renesas-drivers-2018-02-28-v4.16-rc3

Thanks!

Yours,
Linus Walleij
--
To unsubscribe from this list: send the line "unsubscribe linux-gpio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c
index e76de57dd617d7e2..ebaea8b1594b7fc4 100644
--- a/drivers/gpio/gpio-rcar.c
+++ b/drivers/gpio/gpio-rcar.c
@@ -14,7 +14,6 @@ 
  * GNU General Public License for more details.
  */
 
-#include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/gpio.h>
 #include <linux/init.h>
@@ -37,10 +36,9 @@  struct gpio_rcar_priv {
 	struct platform_device *pdev;
 	struct gpio_chip gpio_chip;
 	struct irq_chip irq_chip;
-	struct clk *clk;
 	unsigned int irq_parent;
+	atomic_t wakeup_path;
 	bool has_both_edge_trigger;
-	bool needs_clk;
 };
 
 #define IOINTSEL 0x00	/* General IO/Interrupt Switching Register */
@@ -186,13 +184,10 @@  static int gpio_rcar_irq_set_wake(struct irq_data *d, unsigned int on)
 		}
 	}
 
-	if (!p->clk)
-		return 0;
-
 	if (on)
-		clk_enable(p->clk);
+		atomic_inc(&p->wakeup_path);
 	else
-		clk_disable(p->clk);
+		atomic_dec(&p->wakeup_path);
 
 	return 0;
 }
@@ -330,17 +325,14 @@  static int gpio_rcar_direction_output(struct gpio_chip *chip, unsigned offset,
 
 struct gpio_rcar_info {
 	bool has_both_edge_trigger;
-	bool needs_clk;
 };
 
 static const struct gpio_rcar_info gpio_rcar_info_gen1 = {
 	.has_both_edge_trigger = false,
-	.needs_clk = false,
 };
 
 static const struct gpio_rcar_info gpio_rcar_info_gen2 = {
 	.has_both_edge_trigger = true,
-	.needs_clk = true,
 };
 
 static const struct of_device_id gpio_rcar_of_table[] = {
@@ -403,7 +395,6 @@  static int gpio_rcar_parse_dt(struct gpio_rcar_priv *p, unsigned int *npins)
 	ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 0, &args);
 	*npins = ret == 0 ? args.args[2] : RCAR_MAX_GPIO_PER_BANK;
 	p->has_both_edge_trigger = info->has_both_edge_trigger;
-	p->needs_clk = info->needs_clk;
 
 	if (*npins == 0 || *npins > RCAR_MAX_GPIO_PER_BANK) {
 		dev_warn(&p->pdev->dev,
@@ -440,16 +431,6 @@  static int gpio_rcar_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, p);
 
-	p->clk = devm_clk_get(dev, NULL);
-	if (IS_ERR(p->clk)) {
-		if (p->needs_clk) {
-			dev_err(dev, "unable to get clock\n");
-			ret = PTR_ERR(p->clk);
-			goto err0;
-		}
-		p->clk = NULL;
-	}
-
 	pm_runtime_enable(dev);
 
 	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
@@ -531,11 +512,24 @@  static int gpio_rcar_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static int __maybe_unused gpio_rcar_suspend(struct device *dev)
+{
+	struct gpio_rcar_priv *p = dev_get_drvdata(dev);
+
+	if (atomic_read(&p->wakeup_path))
+		device_set_wakeup_path(dev);
+
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(gpio_rcar_pm_ops, gpio_rcar_suspend, NULL);
+
 static struct platform_driver gpio_rcar_device_driver = {
 	.probe		= gpio_rcar_probe,
 	.remove		= gpio_rcar_remove,
 	.driver		= {
 		.name	= "gpio_rcar",
+		.pm     = &gpio_rcar_pm_ops,
 		.of_match_table = of_match_ptr(gpio_rcar_of_table),
 	}
 };