i2c: davinci: Add cpufreq support

Add cpufreq support for DaVinci I2C driver.
Tested on DA850/OMAP-L138 EVM.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 7afeb28d6d76..352b4e7bdd9e 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -36,6 +36,7 @@
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/slab.h>
+#include <linux/cpufreq.h>
 
 #include <mach/hardware.h>
 #include <mach/i2c.h>
@@ -107,6 +108,10 @@ struct davinci_i2c_dev {
         int                     stop;
         u8                      terminate;
         struct i2c_adapter      adapter;
+#ifdef CONFIG_CPU_FREQ
+        struct completion       xfr_complete;
+        struct notifier_block   freq_transition;
+#endif
 };
 
 /* default platform data to use if not supplied in the platform_device */
@@ -391,6 +396,11 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
                 if (ret < 0)
                         return ret;
         }
+
+#ifdef CONFIG_CPU_FREQ
+        complete(&dev->xfr_complete);
+#endif
+
         return num;
 }
 
@@ -523,6 +533,48 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
         return count ? IRQ_HANDLED : IRQ_NONE;
 }
 
+#ifdef CONFIG_CPU_FREQ
+static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
+                                     unsigned long val, void *data)
+{
+        struct davinci_i2c_dev *dev;
+
+        dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
+        if (val == CPUFREQ_PRECHANGE) {
+                wait_for_completion(&dev->xfr_complete);
+                davinci_i2c_reset_ctrl(dev, 0);
+        } else if (val == CPUFREQ_POSTCHANGE) {
+                i2c_davinci_calc_clk_dividers(dev);
+                davinci_i2c_reset_ctrl(dev, 1);
+        }
+
+        return 0;
+}
+
+static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
+{
+        dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
+
+        return cpufreq_register_notifier(&dev->freq_transition,
+                                         CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
+{
+        cpufreq_unregister_notifier(&dev->freq_transition,
+                                    CPUFREQ_TRANSITION_NOTIFIER);
+}
+#else
+static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
+{
+        return 0;
+}
+
+static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
+{
+}
+#endif
+
 static struct i2c_algorithm i2c_davinci_algo = {
         .master_xfer    = i2c_davinci_xfer,
         .functionality  = i2c_davinci_func,
@@ -562,6 +614,9 @@ static int davinci_i2c_probe(struct platform_device *pdev)
         }
 
         init_completion(&dev->cmd_complete);
+#ifdef CONFIG_CPU_FREQ
+        init_completion(&dev->xfr_complete);
+#endif
         dev->dev = get_device(&pdev->dev);
         dev->irq = irq->start;
         platform_set_drvdata(pdev, dev);
@@ -587,6 +642,12 @@ static int davinci_i2c_probe(struct platform_device *pdev)
                 goto err_unuse_clocks;
         }
 
+        r = i2c_davinci_cpufreq_register(dev);
+        if (r) {
+                dev_err(&pdev->dev, "failed to register cpufreq\n");
+                goto err_free_irq;
+        }
+
         adap = &dev->adapter;
         i2c_set_adapdata(adap, dev);
         adap->owner = THIS_MODULE;
@@ -628,6 +689,8 @@ static int davinci_i2c_remove(struct platform_device *pdev)
         struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
         struct resource *mem;
 
+        i2c_davinci_cpufreq_deregister(dev);
+
         platform_set_drvdata(pdev, NULL);
         i2c_del_adapter(&dev->adapter);
         put_device(&pdev->dev);