linux-kernel - [PATCH v2 3/3] gpio: rcar: Use WAKEUP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1514554304-18989-4-git-send-email-ulf.hansson@linaro.org>
Date:   Fri, 29 Dec 2017 14:31:44 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     "Rafael J . Wysocki" <rjw@...ysocki.net>, linux-pm@...r.kernel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Simon Horman <horms@...ge.net.au>,
        Niklas Soderlund <niklas.soderlund+renesas@...natech.se>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        linux-renesas-soc@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 3/3] gpio: rcar: Use WAKEUP_PATH driver PM flag

From: Geert Uytterhoeven <geert+renesas@...der.be>

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 PM core. Instead, set the
WAKEUP_PATH driver PM flag to indicate that the device is part of the
wakeup path, which further also enables middle-layers and PM domains (like
genpd) to act on this.

In case the device is attached to genpd and depending on if it has an
active wakeup configuration, genpd will keep the device active (the clock
running) during system suspend when needed. This enables us to remove all
explicit clock handling code from the driver, so let's do that as well.

Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
[Ulf: Converted to use the WAKEUP_PATH driver PM flag]
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
---
 drivers/gpio/gpio-rcar.c | 40 +++++++++++++++-------------------------
 1 file changed, 15 insertions(+), 25 deletions(-)

diff --git a/drivers/gpio/gpio-rcar.c b/drivers/gpio/gpio-rcar.c
index e76de57..d414511 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;
 	bool has_both_edge_trigger;
-	bool needs_clk;
+	bool wakeup_path;
 };
 
 #define IOINTSEL 0x00	/* General IO/Interrupt Switching Register */
@@ -186,14 +184,7 @@ 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);
-	else
-		clk_disable(p->clk);
-
+	p->wakeup_path = on;
 	return 0;
 }
 
@@ -330,17 +321,14 @@ 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 +391,6 @@ 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,
@@ -415,6 +402,18 @@ static int gpio_rcar_parse_dt(struct gpio_rcar_priv *p, unsigned int *npins)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int gpio_rcar_suspend(struct device *dev)
+{
+	struct gpio_rcar_priv *p = dev_get_drvdata(dev);
+
+	dev_pm_set_driver_flags(dev, p->wakeup_path ? DPM_FLAG_WAKEUP_PATH : 0);
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(gpio_rcar_pm_ops, gpio_rcar_suspend, NULL);
+
 static int gpio_rcar_probe(struct platform_device *pdev)
 {
 	struct gpio_rcar_priv *p;
@@ -440,16 +439,6 @@ 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);
@@ -536,6 +525,7 @@ static struct platform_driver gpio_rcar_device_driver = {
 	.remove		= gpio_rcar_remove,
 	.driver		= {
 		.name	= "gpio_rcar",
+		.pm     = &gpio_rcar_pm_ops,
 		.of_match_table = of_match_ptr(gpio_rcar_of_table),
 	}
 };
-- 
2.7.4