Applied "spi: cadence: Correct initialisation of runtime PM" to the spi tree

[Mark Brown <broonie@xxxxxxxxxx>]

The patch

   spi: cadence: Correct initialisation of runtime PM

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 734882a8bf984c2ac8a57d8ac3ee53230bd0bed8 Mon Sep 17 00:00:00 2001
From: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 4 Jan 2019 18:08:09 +0000
Subject: [PATCH] spi: cadence: Correct initialisation of runtime PM

Currently the driver calls pm_runtime_put_autosuspend but without ever
having done a pm_runtime_get, this causes the reference count in the pm
runtime core to become -1. The bad reference count causes the core to
sometimes suspend whilst an active SPI transfer is in progress.

arizona spi0.1: SPI transfer timed out
spi_master spi0: failed to transfer one message from queue

The correct proceedure is to do all the initialisation that requires the
hardware to be powered up before enabling the PM runtime, then enable
the PM runtime having called pm_runtime_set_active to inform it that the
hardware is currently powered up. The core will then power it down at
it's leisure and no explicit pm_runtime_put is required.

Fixes: d36ccd9f7ea4 ("spi: cadence: Runtime pm adaptation")
Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/spi/spi-cadence.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-cadence.c b/drivers/spi/spi-cadence.c
index e332d173dbf9..5036d89f46bb 100644
--- a/drivers/spi/spi-cadence.c
+++ b/drivers/spi/spi-cadence.c
@@ -522,11 +522,6 @@ static int cdns_spi_probe(struct platform_device *pdev)
 		goto clk_dis_apb;
 	}
 
-	pm_runtime_use_autosuspend(&pdev->dev);
-	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
-	pm_runtime_set_active(&pdev->dev);
-	pm_runtime_enable(&pdev->dev);
-
 	ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
 	if (ret < 0)
 		master->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS;
@@ -541,8 +536,10 @@ static int cdns_spi_probe(struct platform_device *pdev)
 	/* SPI controller initializations */
 	cdns_spi_init_hw(xspi);
 
-	pm_runtime_mark_last_busy(&pdev->dev);
-	pm_runtime_put_autosuspend(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq <= 0) {
-- 
2.20.1