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Subject[PATCH] can: flexcan: Implement CAN Runtime PM
Date
From: Dong Aisheng <aisheng.dong@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: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
---
drivers/net/can/flexcan.c | 125 +++++++++++++++++++++++++-------------
1 file changed, 82 insertions(+), 43 deletions(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 8e972ef08637..3813f6708201 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -23,6 +23,7 @@
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>

#define DRV_NAME "flexcan"
@@ -266,6 +267,7 @@ 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;
@@ -369,6 +371,27 @@ 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)
@@ -495,19 +518,11 @@ 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;
}
@@ -1096,17 +1111,13 @@ 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)
@@ -1128,10 +1139,8 @@ 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;
}
@@ -1145,11 +1154,11 @@ static int flexcan_close(struct net_device *dev)
flexcan_chip_stop(dev);

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;
@@ -1188,18 +1197,10 @@ 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);
@@ -1228,13 +1229,8 @@ 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;
}
@@ -1342,6 +1338,7 @@ 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;
@@ -1388,22 +1385,35 @@ static int flexcan_probe(struct platform_device *pdev)
if (err)
goto failed_offload;

+ 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);
+
dev_info(&pdev->dev, "device registered (reg_base=%p, irq=%d)\n",
priv->regs, dev->irq);

return 0;

+ failed_rpm_put:
+ pm_runtime_put(&pdev->dev);
+ failed_rpm_disable:
+ pm_runtime_disable(&pdev->dev);
failed_offload:
- failed_register:
free_candev(dev);
+
return err;
}

@@ -1413,6 +1423,7 @@ static int flexcan_remove(struct platform_device *pdev)
struct flexcan_priv *priv = netdev_priv(dev);

unregister_flexcandev(dev);
+ pm_runtime_disable(&pdev->dev);
can_rx_offload_del(&priv->offload);
free_candev(dev);

@@ -1423,38 +1434,66 @@ 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)) {
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)) {
netif_device_attach(dev);
netif_start_queue(dev);
- 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);
+
+ flexcan_clks_disable(priv);
+
return 0;
}

-static SIMPLE_DEV_PM_OPS(flexcan_pm_ops, flexcan_suspend, flexcan_resume);
+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);
+
+ flexcan_clks_enable(priv);
+
+ return 0;
+}
+
+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)
+};

static struct platform_driver flexcan_driver = {
.driver = {
--
2.17.1
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