From: Aisheng Dong <aisheng.d...@nxp.com>

Flexcan will be disabled during suspend if no wakeup function required and
enabled after resume accordingly. During this period, we could explicitly
disable clocks.

Implement Runtime PM which will:
1) Keep device in suspend state (clocks disabled) if it's not openned.
2) Make Power Domain framework be able to shutdown the corresponding power
   domain of this device.

Signed-off-by: Aisheng Dong <aisheng.d...@nxp.com>
Signed-off-by: Joakim Zhang <qiangqing.zh...@nxp.com>
---
ChangeLog:
V1->V2:
        *rebased on patch "can: flexcan: add self wakeup support".
        *add check when to do flexcan_clks_disable/enable() during
         Runtime PM.
---
 drivers/net/can/flexcan.c | 119 ++++++++++++++++++++++++--------------
 1 file changed, 77 insertions(+), 42 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index d12b2f7d2834..130a2cb04827 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -24,6 +24,7 @@
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <linux/regmap.h>
 
@@ -277,6 +278,7 @@ struct flexcan_priv {
        u32 reg_imask1_default;
        u32 reg_imask2_default;
 
+       struct device *dev;
        struct clk *clk_ipg;
        struct clk *clk_per;
        const struct flexcan_devtype_data *devtype_data;
@@ -444,6 +446,27 @@ static inline void flexcan_error_irq_disable(const struct 
flexcan_priv *priv)
        priv->write(reg_ctrl, &regs->ctrl);
 }
 
+static int flexcan_clks_enable(const struct flexcan_priv *priv)
+{
+       int err;
+
+       err = clk_prepare_enable(priv->clk_ipg);
+       if (err)
+               return err;
+
+       err = clk_prepare_enable(priv->clk_per);
+       if (err)
+               clk_disable_unprepare(priv->clk_ipg);
+
+       return err;
+}
+
+static void flexcan_clks_disable(const struct flexcan_priv *priv)
+{
+       clk_disable_unprepare(priv->clk_ipg);
+       clk_disable_unprepare(priv->clk_per);
+}
+
 static inline int flexcan_transceiver_enable(const struct flexcan_priv *priv)
 {
        if (!priv->reg_xceiver)
@@ -570,19 +593,11 @@ static int flexcan_get_berr_counter(const struct 
net_device *dev,
        const struct flexcan_priv *priv = netdev_priv(dev);
        int err;
 
-       err = clk_prepare_enable(priv->clk_ipg);
-       if (err)
-               return err;
-
-       err = clk_prepare_enable(priv->clk_per);
-       if (err)
-               goto out_disable_ipg;
+       pm_runtime_get_sync(priv->dev);
 
        err = __flexcan_get_berr_counter(dev, bec);
 
-       clk_disable_unprepare(priv->clk_per);
- out_disable_ipg:
-       clk_disable_unprepare(priv->clk_ipg);
+       pm_runtime_put(priv->dev);
 
        return err;
 }
@@ -1215,17 +1230,13 @@ static int flexcan_open(struct net_device *dev)
        struct flexcan_priv *priv = netdev_priv(dev);
        int err;
 
-       err = clk_prepare_enable(priv->clk_ipg);
+       err = pm_runtime_get_sync(priv->dev);
        if (err)
                return err;
 
-       err = clk_prepare_enable(priv->clk_per);
-       if (err)
-               goto out_disable_ipg;
-
        err = open_candev(dev);
        if (err)
-               goto out_disable_per;
+               goto out_pm_runtime;
 
        err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev);
        if (err)
@@ -1288,10 +1299,8 @@ static int flexcan_open(struct net_device *dev)
        free_irq(dev->irq, dev);
  out_close:
        close_candev(dev);
- out_disable_per:
-       clk_disable_unprepare(priv->clk_per);
- out_disable_ipg:
-       clk_disable_unprepare(priv->clk_ipg);
+ out_pm_runtime:
+       pm_runtime_put(priv->dev);
 
        return err;
 }
@@ -1306,11 +1315,11 @@ static int flexcan_close(struct net_device *dev)
 
        can_rx_offload_del(&priv->offload);
        free_irq(dev->irq, dev);
-       clk_disable_unprepare(priv->clk_per);
-       clk_disable_unprepare(priv->clk_ipg);
 
        close_candev(dev);
 
+       pm_runtime_put(priv->dev);
+
        can_led_event(dev, CAN_LED_EVENT_STOP);
 
        return 0;
@@ -1349,18 +1358,10 @@ static int register_flexcandev(struct net_device *dev)
        struct flexcan_regs __iomem *regs = priv->regs;
        u32 reg, err;
 
-       err = clk_prepare_enable(priv->clk_ipg);
-       if (err)
-               return err;
-
-       err = clk_prepare_enable(priv->clk_per);
-       if (err)
-               goto out_disable_ipg;
-
        /* select "bus clock", chip must be disabled */
        err = flexcan_chip_disable(priv);
        if (err)
-               goto out_disable_per;
+               return err;
        reg = priv->read(&regs->ctrl);
        reg |= FLEXCAN_CTRL_CLK_SRC;
        priv->write(reg, &regs->ctrl);
@@ -1389,13 +1390,8 @@ static int register_flexcandev(struct net_device *dev)
 
        err = register_candev(dev);
 
-       /* disable core and turn off clocks */
  out_chip_disable:
        flexcan_chip_disable(priv);
- out_disable_per:
-       clk_disable_unprepare(priv->clk_per);
- out_disable_ipg:
-       clk_disable_unprepare(priv->clk_ipg);
 
        return err;
 }
@@ -1556,6 +1552,7 @@ static int flexcan_probe(struct platform_device *pdev)
                priv->write = flexcan_write_le;
        }
 
+       priv->dev = &pdev->dev;
        priv->can.clock.freq = clock_freq;
        priv->can.bittiming_const = &flexcan_bittiming_const;
        priv->can.do_set_mode = flexcan_set_mode;
@@ -1569,14 +1566,23 @@ static int flexcan_probe(struct platform_device *pdev)
        priv->devtype_data = devtype_data;
        priv->reg_xceiver = reg_xceiver;
 
+       pm_runtime_enable(&pdev->dev);
+       err = pm_runtime_get_sync(&pdev->dev);
+       if (err < 0) {
+               dev_err(&pdev->dev, "pm_runtime_get failed(%d)\n", err);
+               goto failed_rpm_disable;
+       }
+
        err = register_flexcandev(dev);
        if (err) {
                dev_err(&pdev->dev, "registering netdev failed\n");
-               goto failed_register;
+               goto failed_rpm_put;
        }
 
        devm_can_led_init(dev);
 
+       pm_runtime_put(&pdev->dev);
+
        if (priv->devtype_data->quirks & FLEXCAN_QUIRK_SETUP_STOP_MODE) {
                err = flexcan_setup_stop_mode(pdev);
                if (err)
@@ -1588,8 +1594,11 @@ static int flexcan_probe(struct platform_device *pdev)
 
        return 0;
 
- failed_register:
+ failed_rpm_put:
+       pm_runtime_put(&pdev->dev);
        free_candev(dev);
+ failed_rpm_disable:
+       pm_runtime_disable(&pdev->dev);
        return err;
 }
 
@@ -1598,6 +1607,7 @@ static int flexcan_remove(struct platform_device *pdev)
        struct net_device *dev = platform_get_drvdata(pdev);
 
        unregister_flexcandev(dev);
+       pm_runtime_disable(&pdev->dev);
        free_candev(dev);
 
        return 0;
@@ -1607,7 +1617,7 @@ static int __maybe_unused flexcan_suspend(struct device 
*device)
 {
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);
-       int err;
+       int err = 0;
 
        if (netif_running(dev)) {
                /* if wakeup is enabled, enter stop mode
@@ -1620,20 +1630,21 @@ static int __maybe_unused flexcan_suspend(struct device 
*device)
                        err = flexcan_chip_disable(priv);
                        if (err)
                                return err;
+                       err = pm_runtime_force_suspend(device);
                }
                netif_stop_queue(dev);
                netif_device_detach(dev);
        }
        priv->can.state = CAN_STATE_SLEEPING;
 
-       return 0;
+       return err;
 }
 
 static int __maybe_unused flexcan_resume(struct device *device)
 {
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);
-       int err;
+       int err = 0;
 
        priv->can.state = CAN_STATE_ERROR_ACTIVE;
        if (netif_running(dev)) {
@@ -1642,11 +1653,34 @@ static int __maybe_unused flexcan_resume(struct device 
*device)
                if (device_may_wakeup(device)) {
                        disable_irq_wake(dev->irq);
                } else {
-                       err = flexcan_chip_enable(priv);
+                       err = pm_runtime_force_resume(device);
                        if (err)
                                return err;
+                       err = flexcan_chip_enable(priv);
                }
        }
+       return err;
+}
+
+static int __maybe_unused flexcan_runtime_suspend(struct device *device)
+{
+       struct net_device *dev = dev_get_drvdata(device);
+       struct flexcan_priv *priv = netdev_priv(dev);
+
+       if (netif_running(dev))
+               flexcan_clks_disable(priv);
+
+       return 0;
+}
+
+static int __maybe_unused flexcan_runtime_resume(struct device *device)
+{
+       struct net_device *dev = dev_get_drvdata(device);
+       struct flexcan_priv *priv = netdev_priv(dev);
+
+       if (!netif_running(dev))
+               flexcan_clks_enable(priv);
+
        return 0;
 }
 
@@ -1676,6 +1710,7 @@ static int __maybe_unused flexcan_noirq_resume(struct 
device *device)
 
 static const struct dev_pm_ops flexcan_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(flexcan_suspend, flexcan_resume)
+       SET_RUNTIME_PM_OPS(flexcan_runtime_suspend, flexcan_runtime_resume, 
NULL)
        SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(flexcan_noirq_suspend, 
flexcan_noirq_resume)
 };
 
-- 
2.17.1

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