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SubjectRe: [PATCH] can: Fix bug in suspend/resume
On 11/13/2014 07:58 AM, Kedareswara rao Appana wrote:
> When accessing the priv structure use container_of instead of dev_get_drvdata.

Why?

> Enable the clocks in the suspend before accessing the registers of the CAN.
>
> Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
> ---
> drivers/net/can/xilinx_can.c | 20 ++++++++++++++++++--
> 1 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/can/xilinx_can.c b/drivers/net/can/xilinx_can.c
> index 5e8b560..63ef645 100644
> --- a/drivers/net/can/xilinx_can.c
> +++ b/drivers/net/can/xilinx_can.c
> @@ -972,15 +972,30 @@ static const struct net_device_ops xcan_netdev_ops = {
> */
> static int __maybe_unused xcan_suspend(struct device *dev)
> {
> - struct platform_device *pdev = dev_get_drvdata(dev);
> + struct platform_device *pdev = container_of(dev,
> + struct platform_device, dev);
> struct net_device *ndev = platform_get_drvdata(pdev);
> struct xcan_priv *priv = netdev_priv(ndev);
> + int ret;
>
> if (netif_running(ndev)) {
> netif_stop_queue(ndev);
> netif_device_detach(ndev);
> }
>
> + ret = clk_prepare_enable(priv->can_clk);
> + if (ret) {
> + dev_err(dev, "unable to enable device clock\n");
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(priv->bus_clk);
> + if (ret) {
> + dev_err(dev, "unable to enable bus clock\n");
> + clk_disable_unprepare(priv->can_clk);
> + return ret;
> + }

Now you have clock imbalance. Per suspend/resume cycle the clocks are
enabled twice, but disabled only once.

> +
> priv->write_reg(priv, XCAN_MSR_OFFSET, XCAN_MSR_SLEEP_MASK);
> priv->can.state = CAN_STATE_SLEEPING;
>
> @@ -999,7 +1014,8 @@ static int __maybe_unused xcan_suspend(struct device *dev)
> */
> static int __maybe_unused xcan_resume(struct device *dev)
> {
> - struct platform_device *pdev = dev_get_drvdata(dev);
> + struct platform_device *pdev = container_of(dev,
> + struct platform_device, dev);
> struct net_device *ndev = platform_get_drvdata(pdev);
> struct xcan_priv *priv = netdev_priv(ndev);
> int ret;
>

Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |

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