i2c-designware: Add runtime power management support

Add runtime power management to the PCI driver.

Signed-off-by: Dirk Brandewie <dirk.brandewie@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

3 files changed, 98 insertions, 2 deletions

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index b9f18ddaaa76..df8799241009 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -31,6 +31,7 @@
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/pm_runtime.h>
 #include <linux/delay.h>
 #include "i2c-designware-core.h"
 
@@ -501,6 +502,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
         dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
 
         mutex_lock(&dev->lock);
+        pm_runtime_get_sync(dev->dev);
 
         INIT_COMPLETION(dev->cmd_complete);
         dev->msgs = msgs;
@@ -550,6 +552,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
         ret = -EIO;
 
 done:
+        pm_runtime_put(dev->dev);
         mutex_unlock(&dev->lock);
 
         return ret;
@@ -671,10 +674,13 @@ void i2c_dw_enable(struct dw_i2c_dev *dev)
         dw_writel(dev, 1, DW_IC_ENABLE);
 }
 
-void i2c_dw_disable(struct dw_i2c_dev *dev)
+u32 i2c_dw_is_enabled(struct dw_i2c_dev *dev)
 {
-        int ret;
+        return dw_readl(dev, DW_IC_ENABLE);
+}
 
+void i2c_dw_disable(struct dw_i2c_dev *dev)
+{
         /* Disable controller */
         dw_writel(dev, 0, DW_IC_ENABLE);
 
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 601dd67a6c27..02d1a2ddd853 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -98,6 +98,7 @@ extern int i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 extern u32 i2c_dw_func(struct i2c_adapter *adap);
 extern irqreturn_t i2c_dw_isr(int this_irq, void *dev_id);
 extern void i2c_dw_enable(struct dw_i2c_dev *dev);
+extern u32 i2c_dw_is_enabled(struct dw_i2c_dev *dev);
 extern void i2c_dw_disable(struct dw_i2c_dev *dev);
 extern void i2c_dw_clear_int(struct dw_i2c_dev *dev);
 extern void i2c_dw_disable_int(struct dw_i2c_dev *dev);
diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
index 83307ef3b41f..d2223b5f922b 100644
--- a/drivers/i2c/busses/i2c-designware-pcidrv.c
+++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
@@ -38,6 +38,7 @@
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
+#include <linux/pm_runtime.h>
 #include "i2c-designware-core.h"
 
 #define DRIVER_NAME "i2c-designware-pci"
@@ -137,6 +138,82 @@ static struct i2c_algorithm i2c_dw_algo = {
         .functionality  = i2c_dw_func,
 };
 
+static int i2c_dw_pci_suspend(struct pci_dev *pdev, pm_message_t mesg)
+{
+        struct dw_i2c_dev *i2c = pci_get_drvdata(pdev);
+        int err;
+
+
+        i2c_dw_disable(i2c);
+
+        err = pci_save_state(pdev);
+        if (err) {
+                dev_err(&pdev->dev, "pci_save_state failed\n");
+                return err;
+        }
+
+        err = pci_set_power_state(pdev, PCI_D3hot);
+        if (err) {
+                dev_err(&pdev->dev, "pci_set_power_state failed\n");
+                return err;
+        }
+
+        return 0;
+}
+
+static int i2c_dw_pci_runtime_suspend(struct device *dev)
+{
+        struct pci_dev *pdev = to_pci_dev(dev);
+        dev_dbg(dev, "PCI suspend called\n");
+        return i2c_dw_pci_suspend(pdev, PMSG_SUSPEND);
+}
+
+static int i2c_dw_pci_resume(struct pci_dev *pdev)
+{
+        struct dw_i2c_dev *i2c = pci_get_drvdata(pdev);
+        int err;
+        u32 enabled;
+
+        enabled = i2c_dw_is_enabled(i2c);
+        if (enabled)
+                return 0;
+
+        err = pci_set_power_state(pdev, PCI_D0);
+        if (err) {
+                dev_err(&pdev->dev, "pci_set_power_state() failed\n");
+                return err;
+        }
+
+        pci_restore_state(pdev);
+
+        i2c_dw_init(i2c);
+        i2c_dw_enable(i2c);
+        return 0;
+}
+
+static int i2c_dw_pci_runtime_resume(struct device *dev)
+{
+        struct pci_dev *pdev = to_pci_dev(dev);
+        dev_dbg(dev, "runtime_resume called\n");
+        return i2c_dw_pci_resume(pdev);
+}
+
+static int i2c_dw_pci_runtime_idle(struct device *dev)
+{
+        int err = pm_schedule_suspend(dev, 500);
+        dev_dbg(dev, "runtime_idle called\n");
+
+        if (err != 0)
+                return 0;
+        return -EBUSY;
+}
+
+static const struct dev_pm_ops i2c_dw_pm_ops = {
+        .runtime_suspend = i2c_dw_pci_runtime_suspend,
+        .runtime_resume = i2c_dw_pci_runtime_resume,
+        .runtime_idle = i2c_dw_pci_runtime_idle,
+};
+
 static u32 i2c_dw_get_clk_rate_khz(struct dw_i2c_dev *dev)
 {
         return dev->controller->clk_khz;
@@ -245,6 +322,9 @@ const struct pci_device_id *id)
                 goto err_free_irq;
         }
 
+        pm_runtime_put_noidle(&pdev->dev);
+        pm_runtime_allow(&pdev->dev);
+
         return 0;
 
 err_free_irq:
@@ -264,6 +344,10 @@ static void __devexit i2c_dw_pci_remove(struct pci_dev *pdev)
 {
         struct dw_i2c_dev *dev = pci_get_drvdata(pdev);
 
+        i2c_dw_disable(dev);
+        pm_runtime_forbid(&pdev->dev);
+        pm_runtime_get_noresume(&pdev->dev);
+
         pci_set_drvdata(pdev, NULL);
         i2c_del_adapter(&dev->adapter);
         put_device(&pdev->dev);
@@ -297,6 +381,11 @@ static struct pci_driver dw_i2c_driver = {
         .id_table       = i2_designware_pci_ids,
         .probe          = i2c_dw_pci_probe,
         .remove         = __devexit_p(i2c_dw_pci_remove),
+        .resume         = i2c_dw_pci_resume,
+        .suspend        = i2c_dw_pci_suspend,
+        .driver         = {
+                .pm     = &i2c_dw_pm_ops,
+        },
 };
 
 static int __init dw_i2c_init_driver(void)