[media] exynos4-is: Clear isp-i2c adapter power.ignore_children flag

Since commit 04f59143b571161d25315dd52d7a2ecc022cb71a
("i2c: let I2C masters ignore their children for PM")
the power.ignore_children flag is set when registering an I2C
adapter.  Since I2C transfers are not managed by the fimc-isp-i2c
driver its clients use pm_runtime_* calls directly to communicate
required power state of the bus controller.

However, when the power.ignore_children flag is set that doesn't
work, so clear that flag back after registering the adapter.
While at it drop pm_runtime_enable() call on the i2c_adapter
as it is already done by the I2C subsystem when registering
I2C adapter.

This patch is meant as a minimal change to fix the regression,
eventually the I2C_ISPx clock handling will be moved to the
top level fimc-is driver and whole runtime PM code is going to
be dropped from the fimc-is-i2c module.

Cc: <stable@vger.kernel.org> # 4.7+
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/platform/exynos4-is/fimc-is-i2c.c

@@ -55,23 +55,33 @@ static int fimc_is_i2c_probe(struct platform_device *pdev)
 	i2c_adap->algo = &fimc_is_i2c_algorithm;
 	i2c_adap->class = I2C_CLASS_SPD;
 
-	ret = i2c_add_adapter(i2c_adap);
-	if (ret < 0)
-		return ret;
-
 	platform_set_drvdata(pdev, isp_i2c);
-
 	pm_runtime_enable(&pdev->dev);
-	pm_runtime_enable(&i2c_adap->dev);
 
+	ret = i2c_add_adapter(i2c_adap);
+	if (ret < 0)
+		goto err_pm_dis;
+	/*
+	 * Client drivers of this adapter don't do any I2C transfers as that
+	 * is handled by the ISP firmware.  But we rely on the runtime PM
+	 * state propagation from the clients up to the adapter driver so
+	 * clear the ignore_children flags here.  PM rutnime calls are not
+	 * used in probe() handler of clients of this adapter so there is
+	 * no issues with clearing the flag right after registering the I2C
+	 * adapter.
+	 */
+	pm_suspend_ignore_children(&i2c_adap->dev, false);
 	return 0;
+
+err_pm_dis:
+	pm_runtime_disable(&pdev->dev);
+	return ret;
 }
 
 static int fimc_is_i2c_remove(struct platform_device *pdev)
 {
 	struct fimc_is_i2c *isp_i2c = platform_get_drvdata(pdev);
 
-	pm_runtime_disable(&isp_i2c->adapter.dev);
 	pm_runtime_disable(&pdev->dev);
 	i2c_del_adapter(&isp_i2c->adapter);