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gpio: rcar: Fine-grained Runtime PM support 

Currently gpio modules are runtime-resumed at probe time. This means the
gpio module will be active all the time (except during system suspend,
if not configured as a wake-up source).

While an R-Car Gen2 gpio module retains pins configured for output at
the requested level while put in standby mode, gpio registercannot be
accessed while suspended.  Unfortunately pm_runtime_get_sync() cannot be
called from all contexts where gpio register access is needed. Hence
move the Runtime PM handling from probe/remove time to gpio request/free
time, which is probably the best we can do.

On r8a7791/koelsch, gpio modules 0, 1, 3, and 4 are now suspended during
normal use (gpio2 is used for LEDs and regulators, gpio5 for keys, gpio6
for SD-Card CD & WP, gpio7 for keys and regulators).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
hifive-unleashed-5.1
Geert Uytterhoeven 2015-06-25 16:45:57 +02:00 committed by Linus Walleij
parent 527b397a7a
commit 65194cb174
1 changed files with 16 additions and 4 deletions
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20
drivers/gpio/gpio-rcar.c
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@ -251,17 +251,32 @@ static void gpio_rcar_config_general_input_output_mode(struct gpio_chip *chip,
static int gpio_rcar_request(struct gpio_chip *chip, unsigned offset)
{
return pinctrl_request_gpio(chip->base + offset);
struct gpio_rcar_priv *p = gpio_to_priv(chip);
int error;
error = pm_runtime_get_sync(&p->pdev->dev);
if (error < 0)
return error;
error = pinctrl_request_gpio(chip->base + offset);
if (error)
pm_runtime_put(&p->pdev->dev);
return error;
}
static void gpio_rcar_free(struct gpio_chip *chip, unsigned offset)
{
struct gpio_rcar_priv *p = gpio_to_priv(chip);
pinctrl_free_gpio(chip->base + offset);
/* Set the GPIO as an input to ensure that the next GPIO request won't
* drive the GPIO pin as an output.
*/
gpio_rcar_config_general_input_output_mode(chip, offset, false);
pm_runtime_put(&p->pdev->dev);
}
static int gpio_rcar_direction_input(struct gpio_chip *chip, unsigned offset)
@ -405,7 +420,6 @@ static int gpio_rcar_probe(struct platform_device *pdev)
}
pm_runtime_enable(dev);
pm_runtime_get_sync(dev);
io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
@ -487,7 +501,6 @@ static int gpio_rcar_probe(struct platform_device *pdev)
err1:
gpiochip_remove(gpio_chip);
err0:
pm_runtime_put(dev);
pm_runtime_disable(dev);
return ret;
}
@ -498,7 +511,6 @@ static int gpio_rcar_remove(struct platform_device *pdev)
gpiochip_remove(&p->gpio_chip);
pm_runtime_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);
return 0;
}