Subject: [PATCH] ARM: AM33XX: board-generic: Add of_dev_auxdata to fix dev_id for CAN module

From: [email-masked] (Rob Herring)
Date: Tue, 07 Aug 2012 10:19:48 -0500

On 08/07/2012 08:37 AM, Vaibhav Hiremath wrote:
> If the module requires only one clocksource to function, then
> driver can very well call clk_get() api with "con_id = NULL",
> 
>        clk = clk_get(dev, NULL);
> 
> And platform code should respect this and return valid clk handle.
> That means, now the clk_get() api would rely on dev_id, and platform
> code should either have clk node with matching dev_id (with con_id=NULL)
> or return dummy clk node.
> 
> With DT support, we can fix the dev_id for particular module
> using "struct of_dev_auxdata" to satisfy above clk framework requirement.
> 
> In case of AM33XX, we required this for the DCAN module, so this
> patch adds "of_dev_auxdata" for both DCAN_0/1 instances.
> 
> Signed-off-by: Vaibhav Hiremath <[email-masked]>
> Cc: Tony Lindgren <[email-masked]>
> Cc: Paul Walmsley <[email-masked]>
> Cc: Benoit Cousson <[email-masked]>
> Cc: Grant Likely <[email-masked]>
> ---
> This patch is boot tested on BeagleBone platform, and checked for
> clk_get() return value in d_can module driver.
> 
>  arch/arm/mach-omap2/board-generic.c |   18 +++++++++++++++++-
>  1 files changed, 17 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/board-generic.c b/arch/arm/mach-omap2/board-generic.c
> index 6f93a20..c9b7903 100644
> --- a/arch/arm/mach-omap2/board-generic.c
> +++ b/arch/arm/mach-omap2/board-generic.c
> @@ -37,11 +37,27 @@ static struct of_device_id omap_dt_match_table[] __initdata = {
>  	{ }
>  };
> 
> +/*
> + * Lookup table for attaching a specific name and platform_data pointer to
> + * devices as they get created by of_platform_populate(). Ideally this table
> + * would not exist, but the current clock implementation depends on some devices
> + * having a specific name OR to satisfy NULL con_id requirement from driver.
> + */
> +static const struct of_dev_auxdata am33xx_auxdata_lookup[] __initconst = {
> +	OF_DEV_AUXDATA("bosch,d_can", 0x481cc000, "d_can.0", NULL),
> +	OF_DEV_AUXDATA("bosch,d_can", 0x481d0000, "d_can.1", NULL),
> +	{ },
> +};

Adding an additional clkdev lookup accomplishes the same thing and is a
cleaner solution.

Rob

> +
>  static void __init omap_generic_init(void)
>  {
>  	omap_sdrc_init(NULL, NULL);
> 
> -	of_platform_populate(NULL, omap_dt_match_table, NULL, NULL);
> +	if (of_machine_is_compatible("ti,am33xx"))
> +		of_platform_populate(NULL, omap_dt_match_table,
> +				am33xx_auxdata_lookup, NULL);
> +	else
> +		of_platform_populate(NULL, omap_dt_match_table, NULL, NULL);
>  }
> 
>  #ifdef CONFIG_SOC_OMAP2420
> --
> 1.7.0.4
> 
> 
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