diff mbox series

[LINUX,V3,7/9] gpio: gpio-xilinx: Add support for suspend and resume

Message ID 1605201148-4508-8-git-send-email-srinivas.neeli@xilinx.com (mailing list archive)
State New, archived
Headers show
Series gpio-xilinx: Update on xilinx gpio driver | expand

Commit Message

Srinivas Neeli Nov. 12, 2020, 5:12 p.m. UTC 
Add support for suspend and resume, pm runtime suspend and resume.
Added free and request calls.

Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
---
Changes in V3:
-Created new patch for suspend and resume.
---
 drivers/gpio/gpio-xilinx.c | 89 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 87 insertions(+), 2 deletions(-)

Comments

Linus Walleij Nov. 18, 2020, 12:38 a.m. UTC | #1 
Hi Srinivas,

On Thu, Nov 12, 2020 at 6:13 PM Srinivas Neeli
<srinivas.neeli@xilinx.com> wrote:

> Add support for suspend and resume, pm runtime suspend and resume.
> Added free and request calls.
>
> Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com>
> ---
> Changes in V3:
> -Created new patch for suspend and resume.

(...)

I'm following the idea here I think.

> @@ -544,6 +618,8 @@ static int xgpio_probe(struct platform_device *pdev)

> +       pm_runtime_enable(&pdev->dev);
> +       status = pm_runtime_get_sync(&pdev->dev);
> +       if (status < 0)
> +               goto err_unprepare_clk;

Now the clock is enabled a second time. Because
runtime PM kicks in.

Do this instead:
pm_runtime_get_noresume()
pm_runtime_set_active()
pm_runtime_enable()

Now runtime PM knows it is active and will not call
runtime resume and enable the clock a second time.

> +       pm_runtime_put(&pdev->dev);
>         return 0;

This is right, now pm runtime will gate the clock
until the first GPIO is requested.

> +err_pm_put:
> +       pm_runtime_put_sync(&pdev->dev);
>  err_unprepare_clk:
> +       pm_runtime_disable(&pdev->dev);
>         clk_disable_unprepare(chip->clk);
>         return status;

Use this on the errorpath instead:
pm_runtime_put_noidle()
pm_runtime_disable()
clk_disable_unprepare();

Now the code will not call runtime suspend to
gate the clock a second time.

Double-check the references to the clock and check
in debugfs that the clock really gets disabled if you're
not using any GPIOs.

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
index 9abef56eca32..48f2a6c894f5 100644
--- a/drivers/gpio/gpio-xilinx.c
+++ b/drivers/gpio/gpio-xilinx.c
@@ -17,6 +17,7 @@ 
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>
 #include <linux/of_platform.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
 /* Register Offset Definitions */
@@ -275,6 +276,39 @@  static void xgpio_save_regs(struct xgpio_instance *chip)
 		       chip->gpio_dir[1]);
 }
 
+static int xgpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+	int ret;
+
+	ret = pm_runtime_get_sync(chip->parent);
+	/*
+	 * If the device is already active pm_runtime_get() will return 1 on
+	 * success, but gpio_request still needs to return 0.
+	 */
+	return ret < 0 ? ret : 0;
+}
+
+static void xgpio_free(struct gpio_chip *chip, unsigned int offset)
+{
+	pm_runtime_put(chip->parent);
+}
+
+static int __maybe_unused xgpio_suspend(struct device *dev)
+{
+	struct xgpio_instance *gpio = dev_get_drvdata(dev);
+	struct irq_data *data = irq_get_irq_data(gpio->irq);
+
+	if (!data) {
+		dev_err(dev, "irq_get_irq_data() failed\n");
+		return -EINVAL;
+	}
+
+	if (!irqd_is_wakeup_set(data))
+		return pm_runtime_force_suspend(dev);
+
+	return 0;
+}
+
 /**
  * xgpio_irq_ack - Acknowledge a child GPIO interrupt.
  * @irq_data: per IRQ and chip data passed down to chip functions
@@ -285,6 +319,46 @@  static void xgpio_irq_ack(struct irq_data *irq_data)
 {
 }
 
+static int __maybe_unused xgpio_resume(struct device *dev)
+{
+	struct xgpio_instance *gpio = dev_get_drvdata(dev);
+	struct irq_data *data = irq_get_irq_data(gpio->irq);
+
+	if (!data) {
+		dev_err(dev, "irq_get_irq_data() failed\n");
+		return -EINVAL;
+	}
+
+	if (!irqd_is_wakeup_set(data))
+		return pm_runtime_force_resume(dev);
+
+	return 0;
+}
+
+static int __maybe_unused xgpio_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct xgpio_instance *gpio = platform_get_drvdata(pdev);
+
+	clk_disable(gpio->clk);
+
+	return 0;
+}
+
+static int __maybe_unused xgpio_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct xgpio_instance *gpio = platform_get_drvdata(pdev);
+
+	return clk_enable(gpio->clk);
+}
+
+static const struct dev_pm_ops xgpio_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(xgpio_suspend, xgpio_resume)
+	SET_RUNTIME_PM_OPS(xgpio_runtime_suspend,
+			   xgpio_runtime_resume, NULL)
+};
+
 /**
  * xgpio_irq_mask - Write the specified signal of the GPIO device.
  * @irq_data: per IRQ and chip data passed down to chip functions
@@ -544,6 +618,8 @@  static int xgpio_probe(struct platform_device *pdev)
 	chip->gc.of_gpio_n_cells = cells;
 	chip->gc.get = xgpio_get;
 	chip->gc.set = xgpio_set;
+	chip->gc.request = xgpio_request;
+	chip->gc.free = xgpio_free;
 	chip->gc.set_multiple = xgpio_set_multiple;
 
 	chip->gc.label = dev_name(&pdev->dev);
@@ -566,6 +642,10 @@  static int xgpio_probe(struct platform_device *pdev)
 		dev_err(&pdev->dev, "Failed to prepare clk\n");
 		return status;
 	}
+	pm_runtime_enable(&pdev->dev);
+	status = pm_runtime_get_sync(&pdev->dev);
+	if (status < 0)
+		goto err_unprepare_clk;
 
 	xgpio_save_regs(chip);
 
@@ -590,7 +670,7 @@  static int xgpio_probe(struct platform_device *pdev)
 				     GFP_KERNEL);
 	if (!girq->parents) {
 		status = -ENOMEM;
-		goto err_unprepare_clk;
+		goto err_pm_put;
 	}
 	girq->parents[0] = chip->irq;
 	girq->default_type = IRQ_TYPE_NONE;
@@ -600,12 +680,16 @@  static int xgpio_probe(struct platform_device *pdev)
 	status = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);
 	if (status) {
 		dev_err(&pdev->dev, "failed to add GPIO chip\n");
-		goto err_unprepare_clk;
+		goto err_pm_put;
 	}
 
+	pm_runtime_put(&pdev->dev);
 	return 0;
 
+err_pm_put:
+	pm_runtime_put_sync(&pdev->dev);
 err_unprepare_clk:
+	pm_runtime_disable(&pdev->dev);
 	clk_disable_unprepare(chip->clk);
 	return status;
 }
@@ -623,6 +707,7 @@  static struct platform_driver xgpio_plat_driver = {
 	.driver		= {
 			.name = "gpio-xilinx",
 			.of_match_table	= xgpio_of_match,
+			.pm = &xgpio_dev_pm_ops,
 	},
 };