i2c-nomadik: dynamic clocking

This makes sure the Nomadik I2C bus driver silicon is only clocked
when really needed, saving some microamps here and there when
there is no I2C traffic.

Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Sundar R Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

drivers/i2c/busses/i2c-nomadik.c

@@ -250,6 +250,8 @@ static int init_hw(struct nmk_i2c_dev *dev)
 {
 	int stat;
 
+	clk_enable(dev->clk);
+
 	stat = flush_i2c_fifo(dev);
 	if (stat)
 		return stat;
@@ -263,6 +265,8 @@ static int init_hw(struct nmk_i2c_dev *dev)
 
 	dev->cli.operation = I2C_NO_OPERATION;
 
+	clk_disable(dev->clk);
+
 	return 0;
 }
 
@@ -558,6 +562,8 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
 	if (status)
 		return status;
 
+	clk_enable(dev->clk);
+
 	/* setup the i2c controller */
 	setup_i2c_controller(dev);
 
@@ -590,10 +596,13 @@ static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
 			dev_err(&dev->pdev->dev, "%s\n",
 				cause >= ARRAY_SIZE(abort_causes)
 				? "unknown reason" : abort_causes[cause]);
+			clk_disable(dev->clk);
 			return status;
 		}
 		mdelay(1);
 	}
+	clk_disable(dev->clk);
+
 	/* return the no. messages processed */
 	if (status)
 		return status;
@@ -857,8 +866,6 @@ static int __devinit nmk_i2c_probe(struct platform_device *pdev)
 		goto err_no_clk;
 	}
 
-	clk_enable(dev->clk);
-
 	adap = &dev->adap;
 	adap->dev.parent = &pdev->dev;
 	adap->owner	= THIS_MODULE;
@@ -895,7 +902,6 @@ static int __devinit nmk_i2c_probe(struct platform_device *pdev)
 	return 0;
 
  err_init_hw:
-	clk_disable(dev->clk);
  err_add_adap:
 	clk_put(dev->clk);
  err_no_clk:
@@ -928,7 +934,6 @@ static int __devexit nmk_i2c_remove(struct platform_device *pdev)
 	iounmap(dev->virtbase);
 	if (res)
 		release_mem_region(res->start, resource_size(res));
-	clk_disable(dev->clk);
 	clk_put(dev->clk);
 	platform_set_drvdata(pdev, NULL);
 	kfree(dev);