i2c: nomadik: Fixup deployment of runtime PM

Since the runtime PM state is expected to be active according to the
amba bus, we must align our behaviour while probing to it.

Moreover, this is needed to be able to have the driver fully functional
without depending on CONFIG_RUNTIME_PM.

Since the device is active while a successful probe has been completed,
the reference counting for the clock will be screwed up and never reach
zero. We resolve this by implementing runtime PM callbacks and let them
handle the resources accordingly, including the clock.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[wsa: s/#if/#ifdef/]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index ce835e8..6319f44 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/drivers/i2c/busses/i2c-nomadik.c
@@ -666,7 +666,7 @@
 static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
 		struct i2c_msg msgs[], int num_msgs)
 {
-	int status;
+	int status = 0;
 	int i;
 	struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap);
 	int j;
@@ -675,19 +675,6 @@
 
 	pm_runtime_get_sync(&dev->adev->dev);
 
-	status = clk_prepare_enable(dev->clk);
-	if (status) {
-		dev_err(&dev->adev->dev, "can't prepare_enable clock\n");
-		goto out_clk;
-	}
-
-	/* Optionaly enable pins to be muxed in and configured */
-	pinctrl_pm_select_default_state(&dev->adev->dev);
-
-	status = init_hw(dev);
-	if (status)
-		goto out;
-
 	/* Attempt three times to send the message queue */
 	for (j = 0; j < 3; j++) {
 		/* setup the i2c controller */
@@ -708,12 +695,6 @@
 			break;
 	}
 
-out:
-	clk_disable_unprepare(dev->clk);
-out_clk:
-	/* Optionally let pins go into idle state */
-	pinctrl_pm_select_idle_state(&dev->adev->dev);
-
 	pm_runtime_put_sync(&dev->adev->dev);
 
 	dev->busy = false;
@@ -930,6 +911,41 @@
 #define nmk_i2c_resume	NULL
 #endif
 
+#ifdef CONFIG_PM
+static int nmk_i2c_runtime_suspend(struct device *dev)
+{
+	struct amba_device *adev = to_amba_device(dev);
+	struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev);
+
+	clk_disable_unprepare(nmk_i2c->clk);
+	pinctrl_pm_select_idle_state(dev);
+	return 0;
+}
+
+static int nmk_i2c_runtime_resume(struct device *dev)
+{
+	struct amba_device *adev = to_amba_device(dev);
+	struct nmk_i2c_dev *nmk_i2c = amba_get_drvdata(adev);
+	int ret;
+
+	ret = clk_prepare_enable(nmk_i2c->clk);
+	if (ret) {
+		dev_err(dev, "can't prepare_enable clock\n");
+		return ret;
+	}
+
+	pinctrl_pm_select_default_state(dev);
+
+	ret = init_hw(nmk_i2c);
+	if (ret) {
+		clk_disable_unprepare(nmk_i2c->clk);
+		pinctrl_pm_select_idle_state(dev);
+	}
+
+	return ret;
+}
+#endif
+
 /*
  * 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
@@ -938,6 +954,9 @@
 static const struct dev_pm_ops nmk_i2c_pm = {
 	.suspend_noirq	= nmk_i2c_suspend,
 	.resume_noirq	= nmk_i2c_resume,
+	SET_PM_RUNTIME_PM_OPS(nmk_i2c_runtime_suspend,
+			nmk_i2c_runtime_resume,
+			NULL)
 };
 
 static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap)
@@ -1001,11 +1020,6 @@
 
 	amba_set_drvdata(adev, dev);
 
-	/* Select default pin state */
-	pinctrl_pm_select_default_state(&adev->dev);
-	/* If possible, let's go to idle until the first transfer */
-	pinctrl_pm_select_idle_state(&adev->dev);
-
 	dev->virtbase = devm_ioremap(&adev->dev, adev->res.start,
 				resource_size(&adev->res));
 	if (IS_ERR(dev->virtbase)) {
@@ -1030,6 +1044,14 @@
 		goto err_no_mem;
 	}
 
+	ret = clk_prepare_enable(dev->clk);
+	if (ret) {
+		dev_err(&adev->dev, "can't prepare_enable clock\n");
+		goto err_no_mem;
+	}
+
+	init_hw(dev);
+
 	adap = &dev->adap;
 	adap->dev.of_node = np;
 	adap->dev.parent = &adev->dev;
@@ -1049,13 +1071,15 @@
 	ret = i2c_add_adapter(adap);
 	if (ret) {
 		dev_err(&adev->dev, "failed to add adapter\n");
-		goto err_no_mem;
+		goto err_no_adap;
 	}
 
 	pm_runtime_put(&adev->dev);
 
 	return 0;
 
+ err_no_adap:
+	clk_disable_unprepare(dev->clk);
  err_no_mem:
 
 	return ret;
@@ -1072,6 +1096,7 @@
 	clear_all_interrupts(dev);
 	/* disable the controller */
 	i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
+	clk_disable_unprepare(dev->clk);
 	if (res)
 		release_mem_region(res->start, resource_size(res));