Re: [PATCH v3] can: Convert to runtime_pm

From: SÃren Brinkmann
Date: Thu Nov 27 2014 - 13:24:14 EST


Hi Kedar,

On Thu, 2014-11-27 at 06:38PM +0530, 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",

There might be other issues than the resume that make this fail. It
should probably just say 'pm_runtime_get failed'.
The CAN in the string should not be needed, the netdev_err macro makes
sure the device name is printed.
Can we have a space between 'failed' and the error code?
There should not be a '\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);

As above.

SÃren
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