[PATCH RESEND] i2c/nomadik: runtime PM support

* [PATCH RESEND] i2c/nomadik: runtime PM support
@ 2012-03-08 13:30 Linus Walleij
       [not found] ` <1331213407-10135-1-git-send-email-linus.walleij-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org>
  0 siblings, 1 reply; 17+ messages in thread
From: Linus Walleij @ 2012-03-08 13:30 UTC (permalink / raw)
  To: Ben Dooks, linux-i2c-u79uwXL29TY76Z2rM5mHXA
  Cc: Jonas Aaberg, Magnus Damm, Rafael J. Wysocki, Mark Brown, Linus Walleij

From: Jonas Aaberg <jonas.aberg-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org>

Turn off the clock and regulator to the I2C block using runtime
PM.

Cc: Magnus Damm <magnus.damm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Rafael J. Wysocki <rjw-KKrjLPT3xs0@public.gmane.org>
Cc: Mark Brown <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
Signed-off-by: Jonas Aaberg <jonas.aberg-0IS4wlFg1OjSUeElwK9/Pw@public.gmane.org>
Signed-off-by: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
So I'm resending this, after discussion with Mark Brown and others
I can only conclude that the question of whether to handle
clocks and/or regulators centrally in say
drivers/base/power/clock_ops.c or distributed in drivers is not
simple to determine.

When I discussed the matter with Mark I think we concluded that
the approach for his systems will be to add calls in the drivers
to begin with, then consolidate to the system-wide handlers
when/if it makes sense.

The key reason is that we have hardware blocks with different
characteristics on the order to do things, whereas in some other
systems (like shmobile I guess) every IP block shall be twisted
the same way. We have a mixed legacy of ARM PrimeCells and IP
blocks from different corners of the world and just cannot do
it in one single way. ARM PrimeCells already have some
centralized runtime PM callbacks.
---
 drivers/i2c/busses/i2c-nomadik.c |   53 ++++++++++++++++++++++++++++----------
 1 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index 5267ab9..3c9803d 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -628,12 +628,8 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
 
 	dev->busy = true;
 
-	if (dev->regulator)
-		regulator_enable(dev->regulator);
 	pm_runtime_get_sync(&dev->pdev->dev);
 
-	clk_enable(dev->clk);
-
 	status = init_hw(dev);
 	if (status)
 		goto out;
@@ -666,10 +662,8 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
 	}
 
 out:
-	clk_disable(dev->clk);
-	pm_runtime_put_sync(&dev->pdev->dev);
-	if (dev->regulator)
-		regulator_disable(dev->regulator);
+
+	pm_runtime_put(&dev->pdev->dev);
 
 	dev->busy = false;
 
@@ -859,9 +853,9 @@ static irqreturn_t i2c_irq_handler(int irq, void *arg)
 
 
 #ifdef CONFIG_PM
-static int nmk_i2c_suspend(struct device *dev)
+
+static int nmk_i2c_suspend(struct platform_device *pdev, pm_message_t state)
 {
-	struct platform_device *pdev = to_platform_device(dev);
 	struct nmk_i2c_dev *nmk_i2c = platform_get_drvdata(pdev);
 
 	if (nmk_i2c->busy)
@@ -870,23 +864,53 @@ static int nmk_i2c_suspend(struct device *dev)
 	return 0;
 }
 
-static int nmk_i2c_resume(struct device *dev)
+static int nmk_i2c_suspend_noirq(struct device *dev)
 {
+	struct nmk_i2c_dev *nmk_i2c =
+		platform_get_drvdata(to_platform_device(dev));
+
+	if (nmk_i2c->busy)
+		return -EBUSY;
+
 	return 0;
 }
+
 #else
 #define nmk_i2c_suspend	NULL
-#define nmk_i2c_resume	NULL
+#define nmk_i2c_suspend_noirq NULL
 #endif
 
+static int nmk_i2c_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct nmk_i2c_dev *nmk_i2c = platform_get_drvdata(pdev);
+
+	clk_disable(nmk_i2c->clk);
+	if (nmk_i2c->regulator)
+		regulator_disable(nmk_i2c->regulator);
+	return 0;
+}
+
+static int nmk_i2c_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct nmk_i2c_dev *nmk_i2c = platform_get_drvdata(pdev);
+
+	if (nmk_i2c->regulator)
+		regulator_enable(nmk_i2c->regulator);
+	clk_enable(nmk_i2c->clk);
+	return 0;
+}
+
 /*
  * We use noirq so that we suspend late and resume before the wakeup interrupt
  * to ensure that we do the !pm_runtime_suspended() check in resume before
  * there has been a regular pm runtime resume (via pm_runtime_get_sync()).
  */
 static const struct dev_pm_ops nmk_i2c_pm = {
-	.suspend_noirq	= nmk_i2c_suspend,
-	.resume_noirq	= nmk_i2c_resume,
+	SET_RUNTIME_PM_OPS(nmk_i2c_runtime_suspend, nmk_i2c_runtime_resume,
+			   NULL)
+	.suspend_noirq	= nmk_i2c_suspend_noirq,
 };
 
 static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap)
@@ -1047,6 +1071,7 @@ static struct platform_driver nmk_i2c_driver = {
 	},
 	.probe = nmk_i2c_probe,
 	.remove = __devexit_p(nmk_i2c_remove),
+	.suspend = nmk_i2c_suspend,
 };
 
 static int __init nmk_i2c_init(void)
-- 
1.7.8

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