i2c: Tegra: Add DeviceTree support

This patch modifies the tegra i2c driver so that it can be initiailized
using the device tree along with the devices connected to the i2c bus.

Signed-off-by: John Bonesio <bones@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: OIof Johansson <olof@lixom.net>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 16 insertions, 1 deletions

diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index fb3b4f8f8152..2440b7411978 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/i2c-tegra.h>
+#include <linux/of_i2c.h>
 
 #include <asm/unaligned.h>
 
@@ -546,6 +547,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
         struct resource *iomem;
         struct clk *clk;
         struct clk *i2c_clk;
+        const unsigned int *prop;
         void *base;
         int irq;
         int ret = 0;
@@ -603,7 +605,17 @@ static int tegra_i2c_probe(struct platform_device *pdev)
         i2c_dev->irq = irq;
         i2c_dev->cont_id = pdev->id;
         i2c_dev->dev = &pdev->dev;
-        i2c_dev->bus_clk_rate = pdata ? pdata->bus_clk_rate : 100000;
+
+        i2c_dev->bus_clk_rate = 100000; /* default clock rate */
+        if (pdata) {
+                i2c_dev->bus_clk_rate = pdata->bus_clk_rate;
+
+        } else if (i2c_dev->dev->of_node) {    /* if there is a device tree node ... */
+                prop = of_get_property(i2c_dev->dev->of_node,
+                                "clock-frequency", NULL);
+                if (prop)
+                        i2c_dev->bus_clk_rate = be32_to_cpup(prop);
+        }
 
         if (pdev->id == 3)
                 i2c_dev->is_dvc = 1;
@@ -633,6 +645,7 @@ static int tegra_i2c_probe(struct platform_device *pdev)
         i2c_dev->adapter.algo = &tegra_i2c_algo;
         i2c_dev->adapter.dev.parent = &pdev->dev;
         i2c_dev->adapter.nr = pdev->id;
+        i2c_dev->adapter.dev.of_node = pdev->dev.of_node;
 
         ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
         if (ret) {
@@ -640,6 +653,8 @@ static int tegra_i2c_probe(struct platform_device *pdev)
                 goto err_free_irq;
         }
 
+        of_i2c_register_devices(&i2c_dev->adapter);
+
         return 0;
 err_free_irq:
         free_irq(i2c_dev->irq, i2c_dev);