linux-kernel - [PATCH v2 23/47] power/reset: gpio-poweroff: Register with kernel poweroff handler

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Message-Id: <1413864783-3271-24-git-send-email-linux@roeck-us.net>
Date:	Mon, 20 Oct 2014 21:12:39 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	linux-kernel@...r.kernel.org
Cc:	linux-pm@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>
Subject: [PATCH v2 23/47] power/reset: gpio-poweroff: Register with kernel poweroff handler

Register with kernel poweroff handler instead of setting pm_power_off
directly. Register with low priority to reflect that the original code
only sets pm_power_off if it was not already set.

Other changes:

Drop note that there can not be an additional instance of this driver.
The original reason no longer applies, it should be obvious that there
can only be one instance of the driver if static variables are used to
reflect its state, and support for multiple instances can now be added
easily if needed by avoiding static variables.

Do not create an error message if another poweroff handler has already
been registered. This is perfectly normal and acceptable.

Drop remove function since it is no longer needed.

Cc: Sebastian Reichel <sre@...nel.org>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@...il.com>
Cc: David Woodhouse <dwmw2@...radead.org>
Acked-by: Andrew Lunn <andrew@...n.ch>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
v2;
- Use define to specify poweroff handler priority
- Use devm_register_power_off_handler
- Drop remove function as it is no longer needed

 drivers/power/reset/gpio-poweroff.c | 40 ++++++++++++++++---------------------
 1 file changed, 17 insertions(+), 23 deletions(-)

diff --git a/drivers/power/reset/gpio-poweroff.c b/drivers/power/reset/gpio-poweroff.c
index ce849bc..5d35f13 100644
--- a/drivers/power/reset/gpio-poweroff.c
+++ b/drivers/power/reset/gpio-poweroff.c
@@ -14,18 +14,18 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/delay.h>
+#include <linux/notifier.h>
+#include <linux/pm.h>
 #include <linux/platform_device.h>
 #include <linux/gpio/consumer.h>
 #include <linux/of_platform.h>
 #include <linux/module.h>
 
-/*
- * Hold configuration here, cannot be more than one instance of the driver
- * since pm_power_off itself is global.
- */
 static struct gpio_desc *reset_gpio;
 
-static void gpio_poweroff_do_poweroff(void)
+static int gpio_poweroff_do_poweroff(struct notifier_block *this,
+				     unsigned long unused1, void *unused2)
+
 {
 	BUG_ON(!reset_gpio);
 
@@ -43,19 +43,19 @@ static void gpio_poweroff_do_poweroff(void)
 	mdelay(3000);
 
 	WARN_ON(1);
+
+	return NOTIFY_DONE;
 }
 
+static struct notifier_block gpio_poweroff_nb = {
+	.notifier_call = gpio_poweroff_do_poweroff,
+	.priority = POWEROFF_PRIORITY_LOW,
+};
+
 static int gpio_poweroff_probe(struct platform_device *pdev)
 {
 	bool input = false;
-
-	/* If a pm_power_off function has already been added, leave it alone */
-	if (pm_power_off != NULL) {
-		dev_err(&pdev->dev,
-			"%s: pm_power_off function already registered",
-		       __func__);
-		return -EBUSY;
-	}
+	int err;
 
 	reset_gpio = devm_gpiod_get(&pdev->dev, NULL);
 	if (IS_ERR(reset_gpio))
@@ -77,16 +77,11 @@ static int gpio_poweroff_probe(struct platform_device *pdev)
 		}
 	}
 
-	pm_power_off = &gpio_poweroff_do_poweroff;
-	return 0;
-}
-
-static int gpio_poweroff_remove(struct platform_device *pdev)
-{
-	if (pm_power_off == &gpio_poweroff_do_poweroff)
-		pm_power_off = NULL;
+	err = devm_register_power_off_handler(&pdev->dev, &gpio_poweroff_nb);
+	if (err)
+		dev_err(&pdev->dev, "Failed to register poweroff handler\n");
 
-	return 0;
+	return err;
 }
 
 static const struct of_device_id of_gpio_poweroff_match[] = {
@@ -96,7 +91,6 @@ static const struct of_device_id of_gpio_poweroff_match[] = {
 
 static struct platform_driver gpio_poweroff_driver = {
 	.probe = gpio_poweroff_probe,
-	.remove = gpio_poweroff_remove,
 	.driver = {
 		.name = "poweroff-gpio",
 		.owner = THIS_MODULE,
-- 
1.9.1

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