[PATCH] soc: imx: Register SoC device only on i.MX boards

[Peng Fan]

> Subject: [PATCH] soc: imx: Register SoC device only on i.MX boards
> 
> At the moment, using the ARM32 multi_v7_defconfig always results in two
> SoCs being exposed in sysfs. This is wrong, as far as I'm aware the Qualcomm
> DragonBoard 410c does not actually make use of a i.MX SoC. :)
> 
>   qcom-db410c:/sys/devices/soc0$ grep . *
>   family:Freescale i.MX
>   machine:Qualcomm Technologies, Inc. APQ 8016 SBC
>   revision:0.0
>   serial_number:0000000000000000
>   soc_id:Unknown
> 
>   qcom-db410c:/sys/devices/soc1$ grep . *
>   family:Snapdragon
>   machine:APQ8016
>   ...
> 
> This happens because imx_soc_device_init() registers the soc device
> unconditionally, even when running on devices that do not make use of i.MX.
> Arnd already reported this more than a year ago and even suggested a fix
> similar to this commit, but for some reason it was never submitted.
> 
> Fix it by checking if the "__mxc_cpu_type" variable was actually initialized by
> earlier platform code. On devices without i.MX it will simply stay 0.
> 
> Cc: Peng Fan <peng.fan at nxp.com>
> Fixes: d2199b34871b ("ARM: imx: use device_initcall for
> imx_soc_device_init")
> Reported-by: Arnd Bergmann <arnd at arndb.de>
> Link:
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore.ke
> rnel.org%2Fr%2FCAK8P3a0hxO1TmK6oOMQ70AHSWJnP_CAq57YMOutrxkSY
> NjFeuw%40mail.gmail.com%2F&data=04%7C01%7Cpeng.fan%40nxp.co
> m%7Cba6334562b49404f88b708d9b8ad36b5%7C686ea1d3bc2b4c6fa92cd9
> 9c5c301635%7C0%7C0%7C637743876348146819%7CUnknown%7CTWFpbG
> Zsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6
> Mn0%3D%7C3000&sdata=mAeB%2FvXO4cUbcPPLBH14LkDzxMz2w5SLj
> iNEZhjgFuU%3D&reserved=0
> Signed-off-by: Stephan Gerhold <stephan at gerhold.net>

Reviewed-by: Peng Fan <peng.fan at nxp.com>

> ---
>  drivers/soc/imx/soc-imx.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/soc/imx/soc-imx.c b/drivers/soc/imx/soc-imx.c index
> ac6d856ba228..77bc12039c3d 100644
> --- a/drivers/soc/imx/soc-imx.c
> +++ b/drivers/soc/imx/soc-imx.c
> @@ -36,6 +36,10 @@ static int __init imx_soc_device_init(void)
>  	int ret;
>  	int i;
> 
> +	/* Return early if this is running on devices with different SoCs */
> +	if (!__mxc_cpu_type)
> +		return 0;
> +
>  	if (of_machine_is_compatible("fsl,ls1021a"))
>  		return 0;
> 
> --
> 2.34.1