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Patch "gpio: zynq: initialize clock even without CONFIG_PM" has been added to the 4.6-stable tree

PATCH [email protected] 1 participant 1 message Jun 22, 2016

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This is a note to let you know that I've just added the patch titled

gpio: zynq: initialize clock even without CONFIG_PM

to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
gpio-zynq-initialize-clock-even-without-config_pm.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 0f84f29ff30bdb1bca23017b118b4ea3999cac32 Mon Sep 17 00:00:00 2001

From: Helmut Grohne <[email protected]>
Date: Fri, 3 Jun 2016 14:15:32 +0200
Subject: gpio: zynq: initialize clock even without CONFIG_PM

From: Helmut Grohne <[email protected]>

commit 0f84f29ff30bdb1bca23017b118b4ea3999cac32 upstream.

When the PM initialization was moved in the commit referenced below, the code enabling the clock was removed from the probe function. On CONFIG_PM=y kernels, this is not a problem as the pm resume hook enables the clock, but when power management is disabled, all those pm_* functions are noops and the clock is never enabled resulting in a dysfunctional gpio controller.

Put the clock initialization back to support CONFIG_PM=n.

Fixes 3773c195d387 ("gpio: zynq: Do PM initialization earlier to support gpio hogs")
---
 drivers/gpio/gpio-zynq.c |    7 +++++++
 1 file changed, 7 insertions(+)
drivers/gpio/gpio-zynq.c +7 -0
@@ -709,7 +709,13 @@ static int zynq_gpio_probe(struct platfo
 		dev_err(&pdev->dev, "input clock not found.\n");
 		return PTR_ERR(gpio->clk);
 	}
+	ret = clk_prepare_enable(gpio->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to enable clock.\n");
+		return ret;
+	}
 
+	pm_runtime_set_active(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 	ret = pm_runtime_get_sync(&pdev->dev);
 	if (ret < 0)
@@ -747,6 +753,7 @@ err_pm_put:
 	pm_runtime_put(&pdev->dev);
 err_pm_dis:
 	pm_runtime_disable(&pdev->dev);
+	clk_disable_unprepare(gpio->clk);
 
 	return ret;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.6/gpio-zynq-fix-the-error-path.patch queue-4.6/gpio-zynq-initialize-clock-even-without-config_pm.patch