@@ -20,6 +20,7 @@
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/stringify.h>
+#include <linux/pm_runtime.h>
#define DRIVER_NAME "uio_pdrv_genirq"
@@ -27,8 +28,27 @@ struct uio_pdrv_genirq_platdata {
struct uio_info *uioinfo;
spinlock_t lock;
unsigned long flags;
+ struct platform_device *pdev;
};
+static int uio_pdrv_genirq_open(struct uio_info *info, struct inode *inode)
+{
+ struct uio_pdrv_genirq_platdata *priv = info->priv;
+
+ /* Wait until the Runtime PM code has woken up the device */
+ pm_runtime_get_sync(&priv->pdev->dev);
+ return 0;
+}
+
+static int uio_pdrv_genirq_release(struct uio_info *info, struct inode *inode)
+{
+ struct uio_pdrv_genirq_platdata *priv = info->priv;
+
+ /* Tell the Runtime PM code that the device has become idle */
+ pm_runtime_put_sync(&priv->pdev->dev);
+ return 0;
+}
+
static irqreturn_t uio_pdrv_genirq_handler(int irq, struct uio_info *dev_info)
{
struct uio_pdrv_genirq_platdata *priv = dev_info->priv;
@@ -97,6 +117,7 @@ static int uio_pdrv_genirq_probe(struct
priv->uioinfo = uioinfo;
spin_lock_init(&priv->lock);
priv->flags = 0; /* interrupt is enabled to begin with */
+ priv->pdev = pdev;
uiomem = &uioinfo->mem[0];
@@ -136,8 +157,17 @@ static int uio_pdrv_genirq_probe(struct
uioinfo->irq_flags |= IRQF_DISABLED;
uioinfo->handler = uio_pdrv_genirq_handler;
uioinfo->irqcontrol = uio_pdrv_genirq_irqcontrol;
+ uioinfo->open = uio_pdrv_genirq_open;
+ uioinfo->release = uio_pdrv_genirq_release;
uioinfo->priv = priv;
+ /* Enable Runtime PM for this device:
+ * The device starts in suspended state to allow the hardware to be
+ * turned off by default. The Runtime PM bus code should power on the
+ * hardware and enable clocks at open().
+ */
+ pm_runtime_enable(&pdev->dev);
+
ret = uio_register_device(&pdev->dev, priv->uioinfo);
if (ret) {
dev_err(&pdev->dev, "unable to register uio device\n");
@@ -157,16 +187,40 @@ static int uio_pdrv_genirq_remove(struct
struct uio_pdrv_genirq_platdata *priv = platform_get_drvdata(pdev);
uio_unregister_device(priv->uioinfo);
+ pm_runtime_disable(&pdev->dev);
kfree(priv);
return 0;
}
+static int uio_pdrv_genirq_runtime_nop(struct device *dev)
+{
+ /* Runtime PM callback shared between ->runtime_suspend()
+ * and ->runtime_resume(). Simply returns success.
+ *
+ * In this driver pm_runtime_get_sync() and pm_runtime_put_sync()
+ * are used at open() and release() time. This allows the
+ * Runtime PM code to turn off power to the device while the
+ * device is unused, ie before open() and after release().
+ *
+ * This Runtime PM callback does not need to save or restore
+ * any registers since user space is responsbile for hardware
+ * register reinitialization after open().
+ */
+ return 0;
+}
+
+static struct dev_pm_ops uio_pdrv_genirq_dev_pm_ops = {
+ .runtime_suspend = uio_pdrv_genirq_runtime_nop,
+ .runtime_resume = uio_pdrv_genirq_runtime_nop,
+};
+
static struct platform_driver uio_pdrv_genirq = {
.probe = uio_pdrv_genirq_probe,
.remove = uio_pdrv_genirq_remove,
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
+ .pm = &uio_pdrv_genirq_dev_pm_ops,
},
};