RE: [PATCH v3] can: Convert to runtime_pm

[Appana Durga Kedareswara Rao]

Hi Michal,

-----Original Message-----
From: Michal Simek [mailto:michal.simek@xxxxxxxxxx]
Sent: Thursday, November 27, 2014 8:17 PM
To: Appana Durga Kedareswara Rao; wg@xxxxxxxxxxxxxx; mkl@xxxxxxxxxxxxxx; Michal Simek; Soren Brinkmann; grant.likely@xxxxxxxxxx; robh+dt@xxxxxxxxxx
Cc: linux-can@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; Appana Durga Kedareswara Rao
Subject: Re: [PATCH v3] can: Convert to runtime_pm

On 11/27/2014 02:08 PM, Kedareswara rao Appana wrote:
> 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.brinkmann@xxxxxxxxxx>
> Signed-off-by: Kedareswara rao Appana <appanad@xxxxxxxxxx>
> ---
> 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

This is just the device structure.

K will modify in the next version of the patch .

>   *
>   * 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

ditto

K will modify in the next version of the patch .

> + *
> + * 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

ditto.
K will modify in the next version of the patch .
> + *
> + * 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

ditto.
K will modify in the next version of the patch .

Regards,
Kedar.
Thanks,
Michal


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