[PATCH/RFC] gpio: rcar: Add clock support

[PATCH/RFC] gpio: rcar: Add clock support

[Yoshihiro Kaneko]

From: Koji Matsuoka <koji.matsuoka.xm@renesas.com>

The clock of GPIO is an initial value of enable. However,
since correction which sets the clock to disable was added
by the boot loader, the clock control was added.

Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
---

This patch is based on for-next branch of Linus Walleij's gpio tree.

 drivers/gpio/gpio-rcar.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c
index c49522e..6d4a0bc 100644
--- a/drivers/gpio/gpio-rcar.c
+++ b/drivers/gpio/gpio-rcar.c
@@ -14,6 +14,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/gpio.h>
 #include <linux/init.h>
@@ -37,6 +38,7 @@ struct gpio_rcar_priv {
 	struct platform_device *pdev;
 	struct gpio_chip gpio_chip;
 	struct irq_chip irq_chip;
+	struct clk *clk;
 };
 
 #define IOINTSEL 0x00
@@ -367,6 +369,13 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, p);
 
+	p->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(p->clk)) {
+		dev_err(&pdev->dev, "failed to get access to GPIO clock\n");
+		return PTR_ERR(p->clk);
+	}
+	clk_prepare_enable(p->clk);
+
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 
@@ -449,6 +458,7 @@ static int gpio_rcar_probe(struct platform_device *pdev)
 err1:
 	gpiochip_remove(&p->gpio_chip);
 err0:
+	clk_disable_unprepare(p->clk);
 	pm_runtime_put(dev);
 	pm_runtime_disable(dev);
 	return ret;
@@ -460,6 +470,7 @@ static int gpio_rcar_remove(struct platform_device *pdev)
 
 	gpiochip_remove(&p->gpio_chip);
 
+	clk_disable_unprepare(p->clk);
 	pm_runtime_put(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 	return 0;
-- 
1.9.1

Re: [PATCH/RFC] gpio: rcar: Add clock support

[Geert Uytterhoeven]

Hi Kaneko-san, Matsuoka-san,

On Sun, Feb 15, 2015 at 4:46 PM, Yoshihiro Kaneko <ykaneko0929@gmail.com> wrote:
> From: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
>
> The clock of GPIO is an initial value of enable. However,
> since correction which sets the clock to disable was added
> by the boot loader, the clock control was added.

Thanks for your patch!

Are you sure you this is really needed to enable the GPIO module clocks?

While I'm still using the original U-Boot that doesn't disable (almost) all
MSTP clocks, I do use my own early startup code that disables (almost) all
MSTP clocks to make sure I don't miss enabling any clocks, and the GPIO
clocks are enabled by the call to pm_runtime_get_sync() in gpio_rcar_probe(),
added in commit df0c6c80232f ("gpio: rcar: Add minimal runtime PM support").

> diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c
> index c49522e..6d4a0bc 100644
> --- a/drivers/gpio/gpio-rcar.c
> +++ b/drivers/gpio/gpio-rcar.c

> @@ -367,6 +369,13 @@ static int gpio_rcar_probe(struct platform_device *pdev)
>
>         platform_set_drvdata(pdev, p);
>
> +       p->clk = devm_clk_get(&pdev->dev, NULL);
> +       if (IS_ERR(p->clk)) {
> +               dev_err(&pdev->dev, "failed to get access to GPIO clock\n");
> +               return PTR_ERR(p->clk);
> +       }
> +       clk_prepare_enable(p->clk);
> +
>         pm_runtime_enable(dev);
>         pm_runtime_get_sync(dev);

With some extra debugging code on Koelsch:

    gpio_rcar_probe:370
--> MSTP gpio0 ON
    gpio_rcar_probe:373
    gpiochip_find_base: found new base at 992
    GPIO chip e6050000.gpio: created GPIO range 0->31 ==> e6060000.pfc PIN 0->31
    gpiochip_add: registered GPIOs 992 to 1023 on device: e6050000.gpio
    gpio_rcar e6050000.gpio: driving 32 GPIOs

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

Re: [PATCH/RFC] gpio: rcar: Add clock support

[Yoshihiro Kaneko]

Hi Geert-san,

2015-02-16 17:48 GMT+09:00 Geert Uytterhoeven <geert@linux-m68k.org>:
> Hi Kaneko-san, Matsuoka-san,
>
> On Sun, Feb 15, 2015 at 4:46 PM, Yoshihiro Kaneko <ykaneko0929@gmail.com> wrote:
>> From: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
>>
>> The clock of GPIO is an initial value of enable. However,
>> since correction which sets the clock to disable was added
>> by the boot loader, the clock control was added.
>
> Thanks for your patch!
>
> Are you sure you this is really needed to enable the GPIO module clocks?
>
> While I'm still using the original U-Boot that doesn't disable (almost) all
> MSTP clocks, I do use my own early startup code that disables (almost) all
> MSTP clocks to make sure I don't miss enabling any clocks, and the GPIO
> clocks are enabled by the call to pm_runtime_get_sync() in gpio_rcar_probe(),
> added in commit df0c6c80232f ("gpio: rcar: Add minimal runtime PM support").

Thanks, with that in mind I'd like to withdraw this patch.

Kaneko

>
>> diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c
>> index c49522e..6d4a0bc 100644
>> --- a/drivers/gpio/gpio-rcar.c
>> +++ b/drivers/gpio/gpio-rcar.c
>
>> @@ -367,6 +369,13 @@ static int gpio_rcar_probe(struct platform_device *pdev)
>>
>>         platform_set_drvdata(pdev, p);
>>
>> +       p->clk = devm_clk_get(&pdev->dev, NULL);
>> +       if (IS_ERR(p->clk)) {
>> +               dev_err(&pdev->dev, "failed to get access to GPIO clock\n");
>> +               return PTR_ERR(p->clk);
>> +       }
>> +       clk_prepare_enable(p->clk);
>> +
>>         pm_runtime_enable(dev);
>>         pm_runtime_get_sync(dev);
>
> With some extra debugging code on Koelsch:
>
>     gpio_rcar_probe:370
> --> MSTP gpio0 ON
>     gpio_rcar_probe:373
>     gpiochip_find_base: found new base at 992
>     GPIO chip e6050000.gpio: created GPIO range 0->31 ==> e6060000.pfc PIN 0->31
>     gpiochip_add: registered GPIOs 992 to 1023 on device: e6050000.gpio
>     gpio_rcar e6050000.gpio: driving 32 GPIOs
>
> 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