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>

1 files changed, 9 insertions, 4 deletions

diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c
index a73c057f63fd..b2dbf7c468af 100644
--- a/drivers/i2c/busses/i2c-nomadik.c
+++ b/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);