FAILED: patch "[PATCH] gpio: zynq: initialize clock even without CONFIG_PM" failed to apply to 4.6-stable tree

FAILED: patch "[PATCH] gpio: zynq: initialize clock even without CONFIG_PM" failed to apply to 4.6-stable tree

[gregkh]

The patch below does not apply to the 4.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 0f84f29ff30bdb1bca23017b118b4ea3999cac32 Mon Sep 17 00:00:00 2001
From: Helmut Grohne <h.grohne@intenta.de>
Date: Fri, 3 Jun 2016 14:15:32 +0200
Subject: [PATCH] gpio: zynq: initialize clock even without CONFIG_PM

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.

Cc: stable@vger.kernel.org
Signed-off-by: Helmut Grohne <h.grohne@intenta.de>
Fixes: 3773c195d387 ("gpio: zynq: Do PM initialization earlier to support gpio hogs")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-zynq.c b/drivers/gpio/gpio-zynq.c
index 75c6355b018d..e72794e463aa 100644
--- a/drivers/gpio/gpio-zynq.c
+++ b/drivers/gpio/gpio-zynq.c
@@ -709,7 +709,13 @@ static int zynq_gpio_probe(struct platform_device *pdev)
 		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;
 }

Re: FAILED: patch "[PATCH] gpio: zynq: initialize clock even without CONFIG_PM" failed to apply to 4.6-stable tree

[Helmut Grohne]

Hi greg,

On Sat, Jun 18, 2016 at 06:41:23PM +0200, gregkh@linuxfoundation.org wrote:
> The patch below does not apply to the 4.6-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

Thanks for considering the patch for stable. It seems though that my
notes concerning stable have been lost in transmission.

The first observation is that the regression was introduced in 4.4, so
no earlier stable trees are affected.

Then I had to rebase my patch, because it touches the same lines as
615d23f80efc ("gpio: zynq: Fix the error path"). My initial patch
posting[1] did not consider that patch, so there you go with a rebased
patch that applies to earlier kernel versions. I still use that patch
successfully for bisecting.

I do note however, that the mentioned "Fix the error path" commit also
looks like it should be included into a stable tree, because it fixes an
unbalanced pm_runtime_enable. Thus I recommend applying it to stable as
well. Then the patch that went into 4.7-rc3 just applies.

Helmut

[1] https://lkml.kernel.org/r/20160601110259.GA30501@laureti-dev

Re: FAILED: patch "[PATCH] gpio: zynq: initialize clock even without CONFIG_PM" failed to apply to 4.6-stable tree

[gregkh]

On Mon, Jun 20, 2016 at 08:22:00AM +0200, Helmut Grohne wrote:
> Hi greg,
> 
> On Sat, Jun 18, 2016 at 06:41:23PM +0200, gregkh@linuxfoundation.org wrote:
> > The patch below does not apply to the 4.6-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> 
> Thanks for considering the patch for stable. It seems though that my
> notes concerning stable have been lost in transmission.
> 
> The first observation is that the regression was introduced in 4.4, so
> no earlier stable trees are affected.
> 
> Then I had to rebase my patch, because it touches the same lines as
> 615d23f80efc ("gpio: zynq: Fix the error path"). My initial patch
> posting[1] did not consider that patch, so there you go with a rebased
> patch that applies to earlier kernel versions. I still use that patch
> successfully for bisecting.
> 
> I do note however, that the mentioned "Fix the error path" commit also
> looks like it should be included into a stable tree, because it fixes an
> unbalanced pm_runtime_enable. Thus I recommend applying it to stable as
> well. Then the patch that went into 4.7-rc3 just applies.

Thanks, I think I have it worked out now.

greg k-h