Subject: Re: [PATCH] net, can, ti_hecc: add DT support for the ti,hecc controller

From: Marc Kleine-Budde <[email-masked]>
Date: Mon, 19 Oct 2015 08:58:25 +0200

On 10/19/2015 08:39 AM, Heiko Schocher wrote:
> add DT support for the ti hecc controller, used on
> am3517 SoCs.

A similar patch was posted a few days ago, see
http://comments.gmane.org/gmane.linux.can/8616 and my comments.

Please coordinate with Anton Glukhov (Cc'ed) and/or pick up his patches
as they are in better shape.

Marc
> 
> Signed-off-by: Heiko Schocher <[email-masked]>
> ---
> 
>  .../devicetree/bindings/net/can/ti_hecc-can.txt    | 20 ++++++++++
>  arch/arm/boot/dts/am3517.dtsi                      | 13 +++++++
>  drivers/net/can/ti_hecc.c                          | 45 +++++++++++++++++++++-
>  3 files changed, 76 insertions(+), 2 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/net/can/ti_hecc-can.txt
> 
> diff --git a/Documentation/devicetree/bindings/net/can/ti_hecc-can.txt b/Documentation/devicetree/bindings/net/can/ti_hecc-can.txt
> new file mode 100644
> index 0000000..09fab59
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/net/can/ti_hecc-can.txt
> @@ -0,0 +1,20 @@
> +* TI HECC CAN *
> +
> +Required properties:
> +  - compatible: Should be "ti,hecc"

We usually put the name of the first SoC this IP core appears in to the
compatible.

> +  - reg: Should contain CAN controller registers location and length
> +  - interrupts: Should contain IRQ line for the CAN controller

I'm missing the description of the ti,* properties. I think they are
required, too. Although the code doesn't enforce it.

> +
> +Example:
> +
> +	can0: hecc@5c050000 {
> +		compatible = "ti,hecc";
> +		reg = <0x5c050000 0x4000>;
> +		interrupts = <24>;
> +		ti,hecc_scc_offset = <0>;
> +		ti,hecc_scc_ram_offset = <0x3000>;
> +		ti,hecc_ram_offset = <0x3000>;
> +		ti,hecc_mbx_offset = <0x2000>;
> +		ti,hecc_int_line = <0>;
> +		ti,hecc_version = <1>;

Versioning in the OF world is done via the compatible. Are the offsets a
per SoC parameter? I'm not sure if it's better to put
the offsets into the driver.

> +	};
> diff --git a/arch/arm/boot/dts/am3517.dtsi b/arch/arm/boot/dts/am3517.dtsi
> index 5e3f5e8..47bc429 100644
> --- a/arch/arm/boot/dts/am3517.dtsi
> +++ b/arch/arm/boot/dts/am3517.dtsi
> @@ -25,6 +25,19 @@
>  			interrupt-names = "mc";
>  		};
>  
> +		can0: hecc@5c050000 {
> +			compatible = "ti,hecc";
> +			reg = <0x5c050000 0x4000>;
> +			interrupts = <24>;
> +			ti,hecc_scc_offset = <0>;
> +			ti,hecc_scc_ram_offset = <0x3000>;
> +			ti,hecc_ram_offset = <0x3000>;
> +			ti,hecc_mbx_offset = <0x2000>;
> +			ti,hecc_int_line = <0>;
> +			ti,hecc_version = <1>;
> +			status = "disabled";
> +		};
> +
>  		davinci_emac: ethernet@0x5c000000 {
>  			compatible = "ti,am3517-emac";
>  			ti,hwmods = "davinci_emac";
> diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
> index c08e8ea..f1705d5 100644
> --- a/drivers/net/can/ti_hecc.c
> +++ b/drivers/net/can/ti_hecc.c
> @@ -875,16 +875,56 @@ static const struct net_device_ops ti_hecc_netdev_ops = {
>  	.ndo_change_mtu		= can_change_mtu,
>  };
>  
> +#if defined(CONFIG_OF)
> +static const struct of_device_id ti_hecc_can_dt_ids[] = {
> +	{
> +		.compatible = "ti,hecc",
> +	}, {
> +		/* sentinel */
> +	}
> +};
> +MODULE_DEVICE_TABLE(of, ti_hecc_can_dt_ids);
> +#endif

Please remove the ifdef, use __maybe_unused instead.

> +
> +static const struct ti_hecc_platform_data
> +*ti_hecc_can_get_driver_data(struct platform_device *pdev)
> +{
> +	if (pdev->dev.of_node) {
> +		struct ti_hecc_platform_data *data;
> +		struct device_node *np = pdev->dev.of_node;
> +
> +		data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +		if (!data)
> +			return NULL;
> +
> +		of_property_read_u32(np, "ti,hecc_scc_offset",
> +				     &data->scc_hecc_offset);
> +		of_property_read_u32(np, "ti,hecc_scc_ram_offset",
> +				     &data->scc_ram_offset);
> +		of_property_read_u32(np, "ti,hecc_ram_offset",
> +				     &data->hecc_ram_offset);
> +		of_property_read_u32(np, "ti,hecc_mbx_offset",
> +				     &data->mbx_offset);
> +		of_property_read_u32(np, "ti,hecc_int_line",
> +				     &data->int_line);
> +		of_property_read_u32(np, "ti,hecc_version",
> +				     &data->version);

I'm missing error handling here.

> +		return data;
> +	}
> +	return (const struct ti_hecc_platform_data *)
> +		dev_get_platdata(&pdev->dev);

Is this cast needed?

> +}
> +
>  static int ti_hecc_probe(struct platform_device *pdev)
>  {
>  	struct net_device *ndev = (struct net_device *)0;
>  	struct ti_hecc_priv *priv;
> -	struct ti_hecc_platform_data *pdata;
> +	const struct ti_hecc_platform_data *pdata;
>  	struct resource *mem, *irq;
>  	void __iomem *addr;
>  	int err = -ENODEV;
>  
> -	pdata = dev_get_platdata(&pdev->dev);
> +	pdata = ti_hecc_can_get_driver_data(pdev);
>  	if (!pdata) {
>  		dev_err(&pdev->dev, "No platform data\n");
>  		goto probe_exit;
> @@ -1040,6 +1080,7 @@ static int ti_hecc_resume(struct platform_device *pdev)
>  static struct platform_driver ti_hecc_driver = {
>  	.driver = {
>  		.name    = DRV_NAME,
> +		.of_match_table = of_match_ptr(ti_hecc_can_dt_ids),
>  	},
>  	.probe = ti_hecc_probe,
>  	.remove = ti_hecc_remove,
> 

Marc

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