Patch "mfd: arizona: Fix initialisation of the PM runtime" has been added to the 4.1-stable tree

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

mfd: arizona: Fix initialisation of the PM runtime

to the 4.1-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:
mfd-arizona-fix-initialisation-of-the-pm-runtime.patch
and it can be found in the queue-4.1 subdirectory.

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

From: Charles Keepax <[email protected]>
Date: Sun, 14 Jun 2015 15:41:50 +0100
Subject: mfd: arizona: Fix initialisation of the PM runtime

From: Charles Keepax <[email protected]>

commit 72e43164fd472f6c2659c8313b87da962322dbcf upstream.

The PM runtime core by default assumes a chip is suspended when runtime PM is enabled. Currently the arizona driver enables runtime PM when the chip is fully active and then disables the DCVDD regulator at the end of arizona_dev_init. This however has several problems, firstly the if we reach the end of arizona_dev_init, we did not properly follow all the proceedures for shutting down the chip, and most notably we never marked the chip as cache only so any writes occurring between then and the next PM runtime resume will be lost. Secondly, if we are already resumed when we reach the end of dev_init, then at best we get unbalanced regulator enable/disables at work we lose DCVDD whilst we need it.

Additionally, since the commit 4f0216409f7c ("mfd: arizona: Add better support for system suspend"), the PM runtime operations may disable/enable the IRQ, so the IRQs must now be enabled before we call any PM operations.

This patch adds a call to pm_runtime_set_active to inform the PM core that the device is starting up active and moves the PM enabling to around the IRQ initialisation to avoid any PM callbacks happening until the IRQs are initialised.

---
 drivers/mfd/arizona-core.c |   14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

@@ -912,10 +912,6 @@ int arizona_dev_init(struct arizona *ari
 			     arizona->pdata.gpio_defaults[i]);
 	}
 
-	pm_runtime_set_autosuspend_delay(arizona->dev, 100);
-	pm_runtime_use_autosuspend(arizona->dev);
-	pm_runtime_enable(arizona->dev);
-
 	/* Chip default */
 	if (!arizona->pdata.clk32k_src)
 		arizona->pdata.clk32k_src = ARIZONA_32KZ_MCLK2;

@@ -1012,11 +1008,17 @@ int arizona_dev_init(struct arizona *ari
 					   arizona->pdata.spk_fmt[i]);
 	}
 
+	pm_runtime_set_active(arizona->dev);
+	pm_runtime_enable(arizona->dev);
+
 	/* Set up for interrupts */
 	ret = arizona_irq_init(arizona);
 	if (ret != 0)
 		goto err_reset;
 
+	pm_runtime_set_autosuspend_delay(arizona->dev, 100);
+	pm_runtime_use_autosuspend(arizona->dev);
+
 	arizona_request_irq(arizona, ARIZONA_IRQ_CLKGEN_ERR, "CLKGEN error",
 			    arizona_clkgen_err, arizona);
 	arizona_request_irq(arizona, ARIZONA_IRQ_OVERCLOCKED, "Overclocked",

@@ -1045,10 +1047,6 @@ int arizona_dev_init(struct arizona *ari
 		goto err_irq;
 	}
 
-#ifdef CONFIG_PM
-	regulator_disable(arizona->dcvdd);
-#endif
-
 	return 0;
 
 err_irq:

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

queue-4.1/mfd-arizona-fix-initialisation-of-the-pm-runtime.patch