Instead of enabling/disabling clocks at several locations in the driver,
use the runtime_pm framework. This consolidates the actions for
runtime PM in the appropriate callbacks and makes the driver more
readable and mantainable.

Signed-off-by: Soren Brinkmann <soren.brinkm...@xilinx.com>
Signed-off-by: Kedareswara rao Appana <appa...@xilinx.com>
---
Changes for v3:
  - Converted the driver to use runtime_pm.
Changes for v2:
  - Removed the struct platform_device* from suspend/resume
    as suggest by Lothar.

 drivers/net/can/xilinx_can.c |  119 +++++++++++++++++++++++++----------------
 1 files changed, 72 insertions(+), 47 deletions(-)

diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
index 8a998e3..1be28ed 100644
--- a/drivers/net/can/xilinx_can.c
+++ b/drivers/net/can/xilinx_can.c
@@ -32,6 +32,7 @@
 #include <linux/can/dev.h>
 #include <linux/can/error.h>
 #include <linux/can/led.h>
+#include <linux/pm_runtime.h>
 
 #define DRIVER_NAME    "xilinx_can"
 
@@ -138,7 +139,7 @@ struct xcan_priv {
        u32 (*read_reg)(const struct xcan_priv *priv, enum xcan_reg reg);
        void (*write_reg)(const struct xcan_priv *priv, enum xcan_reg reg,
                        u32 val);
-       struct net_device *dev;
+       struct device *dev;
        void __iomem *reg_base;
        unsigned long irq_flags;
        struct clk *bus_clk;
@@ -842,6 +843,13 @@ static int xcan_open(struct net_device *ndev)
        struct xcan_priv *priv = netdev_priv(ndev);
        int ret;
 
+       ret = pm_runtime_get_sync(priv->dev);
+       if (ret < 0) {
+               netdev_err(ndev, "%s: runtime CAN resume failed(%d)\n\r",
+                               __func__, ret);
+               return ret;
+       }
+
        ret = request_irq(ndev->irq, xcan_interrupt, priv->irq_flags,
                        ndev->name, ndev);
        if (ret < 0) {
@@ -849,29 +857,17 @@ static int xcan_open(struct net_device *ndev)
                goto err;
        }
 
-       ret = clk_prepare_enable(priv->can_clk);
-       if (ret) {
-               netdev_err(ndev, "unable to enable device clock\n");
-               goto err_irq;
-       }
-
-       ret = clk_prepare_enable(priv->bus_clk);
-       if (ret) {
-               netdev_err(ndev, "unable to enable bus clock\n");
-               goto err_can_clk;
-       }
-
        /* Set chip into reset mode */
        ret = set_reset_mode(ndev);
        if (ret < 0) {
                netdev_err(ndev, "mode resetting failed!\n");
-               goto err_bus_clk;
+               goto err_irq;
        }
 
        /* Common open */
        ret = open_candev(ndev);
        if (ret)
-               goto err_bus_clk;
+               goto err_irq;
 
        ret = xcan_chip_start(ndev);
        if (ret < 0) {
@@ -887,13 +883,11 @@ static int xcan_open(struct net_device *ndev)
 
 err_candev:
        close_candev(ndev);
-err_bus_clk:
-       clk_disable_unprepare(priv->bus_clk);
-err_can_clk:
-       clk_disable_unprepare(priv->can_clk);
 err_irq:
        free_irq(ndev->irq, ndev);
 err:
+       pm_runtime_put(priv->dev);
+
        return ret;
 }
 
@@ -910,12 +904,11 @@ static int xcan_close(struct net_device *ndev)
        netif_stop_queue(ndev);
        napi_disable(&priv->napi);
        xcan_chip_stop(ndev);
-       clk_disable_unprepare(priv->bus_clk);
-       clk_disable_unprepare(priv->can_clk);
        free_irq(ndev->irq, ndev);
        close_candev(ndev);
 
        can_led_event(ndev, CAN_LED_EVENT_STOP);
+       pm_runtime_put(priv->dev);
 
        return 0;
 }
@@ -934,27 +927,21 @@ static int xcan_get_berr_counter(const struct net_device 
*ndev,
        struct xcan_priv *priv = netdev_priv(ndev);
        int ret;
 
-       ret = clk_prepare_enable(priv->can_clk);
-       if (ret)
-               goto err;
+       ret = pm_runtime_get_sync(priv->dev);
+       if (ret < 0) {
+               netdev_err(ndev, "%s: runtime resume failed(%d)\n\r",
+                               __func__, ret);
+               return ret;
+       }
 
-       ret = clk_prepare_enable(priv->bus_clk);
-       if (ret)
-               goto err_clk;
 
        bec->txerr = priv->read_reg(priv, XCAN_ECR_OFFSET) & XCAN_ECR_TEC_MASK;
        bec->rxerr = ((priv->read_reg(priv, XCAN_ECR_OFFSET) &
                        XCAN_ECR_REC_MASK) >> XCAN_ESR_REC_SHIFT);
 
-       clk_disable_unprepare(priv->bus_clk);
-       clk_disable_unprepare(priv->can_clk);
+       pm_runtime_put(priv->dev);
 
        return 0;
-
-err_clk:
-       clk_disable_unprepare(priv->can_clk);
-err:
-       return ret;
 }
 
 
@@ -967,15 +954,45 @@ static const struct net_device_ops xcan_netdev_ops = {
 
 /**
  * xcan_suspend - Suspend method for the driver
- * @dev:       Address of the platform_device structure
+ * @dev:       Address of the net_device structure
  *
  * Put the driver into low power mode.
- * Return: 0 always
+ * Return: 0 on success and failure value on error
  */
 static int __maybe_unused xcan_suspend(struct device *dev)
 {
-       struct platform_device *pdev = dev_get_drvdata(dev);
-       struct net_device *ndev = platform_get_drvdata(pdev);
+       if (!device_may_wakeup(dev))
+               return pm_runtime_force_suspend(dev);
+
+       return 0;
+}
+
+/**
+ * xcan_resume - Resume from suspend
+ * @dev:       Address of the net_device structure
+ *
+ * Resume operation after suspend.
+ * Return: 0 on success and failure value on error
+ */
+static int __maybe_unused xcan_resume(struct device *dev)
+{
+       if (!device_may_wakeup(dev))
+               return pm_runtime_force_resume(dev);
+
+       return 0;
+
+}
+
+/**
+ * xcan_runtime_suspend - Runtime suspend method for the driver
+ * @dev:       Address of the net_device structure
+ *
+ * Put the driver into low power mode.
+ * Return: 0 always
+ */
+static int __maybe_unused xcan_runtime_suspend(struct device *dev)
+{
+       struct net_device *ndev = dev_get_drvdata(dev);
        struct xcan_priv *priv = netdev_priv(ndev);
 
        if (netif_running(ndev)) {
@@ -993,16 +1010,15 @@ static int __maybe_unused xcan_suspend(struct device 
*dev)
 }
 
 /**
- * xcan_resume - Resume from suspend
- * @dev:       Address of the platformdevice structure
+ * xcan_runtime_resume - Runtime resume from suspend
+ * @dev:       Address of the net_device structure
  *
  * Resume operation after suspend.
  * Return: 0 on success and failure value on error
  */
-static int __maybe_unused xcan_resume(struct device *dev)
+static int __maybe_unused xcan_runtime_resume(struct device *dev)
 {
-       struct platform_device *pdev = dev_get_drvdata(dev);
-       struct net_device *ndev = platform_get_drvdata(pdev);
+       struct net_device *ndev = dev_get_drvdata(dev);
        struct xcan_priv *priv = netdev_priv(ndev);
        int ret;
 
@@ -1030,7 +1046,10 @@ static int __maybe_unused xcan_resume(struct device *dev)
        return 0;
 }
 
-static SIMPLE_DEV_PM_OPS(xcan_dev_pm_ops, xcan_suspend, xcan_resume);
+static const struct dev_pm_ops xcan_dev_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(xcan_suspend, xcan_resume)
+       SET_PM_RUNTIME_PM_OPS(xcan_runtime_suspend, xcan_runtime_resume, NULL)
+};
 
 /**
  * xcan_probe - Platform registration call
@@ -1071,7 +1090,7 @@ static int xcan_probe(struct platform_device *pdev)
                return -ENOMEM;
 
        priv = netdev_priv(ndev);
-       priv->dev = ndev;
+       priv->dev = &pdev->dev;
        priv->can.bittiming_const = &xcan_bittiming_const;
        priv->can.do_set_mode = xcan_do_set_mode;
        priv->can.do_get_berr_counter = xcan_get_berr_counter;
@@ -1137,6 +1156,11 @@ static int xcan_probe(struct platform_device *pdev)
 
        netif_napi_add(ndev, &priv->napi, xcan_rx_poll, rx_max);
 
+       pm_runtime_set_active(&pdev->dev);
+       pm_runtime_irq_safe(&pdev->dev);
+       pm_runtime_enable(&pdev->dev);
+       pm_runtime_get_sync(&pdev->dev);
+
        ret = register_candev(ndev);
        if (ret) {
                dev_err(&pdev->dev, "fail to register failed (err=%d)\n", ret);
@@ -1144,8 +1168,9 @@ static int xcan_probe(struct platform_device *pdev)
        }
 
        devm_can_led_init(ndev);
-       clk_disable_unprepare(priv->bus_clk);
-       clk_disable_unprepare(priv->can_clk);
+
+       pm_runtime_put(&pdev->dev);
+
        netdev_dbg(ndev, "reg_base=0x%p irq=%d clock=%d, tx fifo depth:%d\n",
                        priv->reg_base, ndev->irq, priv->can.clock.freq,
                        priv->tx_max);
-- 
1.7.4

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