On 11/24/2017 02:22 PM, Pankaj Bansal wrote:
> The FlexCAN driver assumed that FlexCAN controller is big endian for
> powerpc architecture and little endian for other architectures.
>
> But this may not be the case. FlexCAN controller can be little or big
> endian on any architecture. For e.g. NXP LS1021A ARM based SOC has big
> endian FlexCAN controller.
>
> Therefore, the driver has been modified to add a provision for both
> types of controllers using an additional device tree property. On a
> "fsl,p1010-flexcan" device BE is default, on all other devices LE is.
>
> Big Endian controllers should have "big-endian" set in the device tree.
> check "Documentation/devicetree/bindings/net/can/fsl-flexcan.txt" for
> usage.
>
> This is the standard practice followed in linux. for more info check:
> Documentation/devicetree/bindings/common-properties.txt
>
> Signed-off-by: Pankaj Bansal <pankaj.bansal@xxxxxxx>
> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@xxxxxxxxxxxxx>
> Signed-off-by: Sakar Arora <Sakar.Arora@xxxxxxxxxxxxx>
> Reviewed-by: Zhengxiong Jin <Jason.Jin@xxxxxxxxxxxxx>
> Reviewed-by: Poonam Aggrwal <poonam.aggrwal@xxxxxxx>
> ---
> Changes in v4:
> - Merged device tree changes and driver changes in one series
> Changes in v3:
> - Added fsl,imx25-flexcan, fsl,imx35-flexcan and fsl,imx53-flexcan
> support to the driver.
> - Modified patch deciption to state default endianness followed and
> to include fsl-flexcan.txt referance.
> Changes in v2:
> - Modified patch deciption to include common-properties.txt reference.
> - Reorder the LE/BE read/write APIs for better readability of code
> - Added an exception to force BE API selection, for powerpc based platform
> P1010. This ensures that new linux kernel works with old P1010
> device-tree, while future powerpc platforms that use big endian
> FlexCAN controller need to specify big-endian in device tree in
> FlexCAN node.
> - Tested on P1010 after backporting to freescale sdk 1.4 linux, without
> any change in device-tree.
> - Tested on NXP LS1021A arm based platform.
>
> drivers/net/can/flexcan.c | 233 ++++++++++++++++++++----------------
> 1 file changed, 131 insertions(+), 102 deletions(-)
>
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
> index a13a489..4c873fb 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
[...]
I think this will select LE for non DT devices, right?
> + if (of_property_read_bool(pdev->dev.of_node, "big-endian")) {
> + priv->read = flexcan_read_be;
> + priv->write = flexcan_write_be;
> + } else {
> + if (of_device_is_compatible(pdev->dev.of_node,
> + "fsl,p1010-flexcan")) {
> + priv->read = flexcan_read_be;
> + priv->write = flexcan_write_be;
> + } else {
> + priv->read = flexcan_read_le;
> + priv->write = flexcan_write_le;
> + }
> + }
> +
> priv->can.clock.freq = clock_freq;
> priv->can.bittiming_const = &flexcan_bittiming_const;
> priv->can.do_set_mode = flexcan_set_mode;
>
Marc
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