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Subject: Re: [alsa-devel] [PATCH] ASoC: SOF: imx: fix reverse
 CONFIG_SND_SOC_SOF_OF dependency
To:     Arnd Bergmann <arnd@arndb.de>, Mark Brown <broonie@kernel.org>
Cc:     Hulk Robot <hulkci@huawei.com>, YueHaibing <yuehaibing@huawei.com>,
        Daniel Baluta <daniel.baluta@nxp.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>, Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        alsa-devel@alsa-project.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
References: <20191001142026.1124917-1-arnd@arndb.de>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Message-ID: <bb58c7cc-209d-7a2f-0e5b-95a9605ffe7b@linux.intel.com>
Date:   Tue, 1 Oct 2019 10:31:58 -0500
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On 10/1/19 9:20 AM, Arnd Bergmann wrote:
> CONFIG_SND_SOC_SOF_IMX depends on CONFIG_SND_SOC_SOF, but is in
> turn referenced by the sof-of-dev driver. This creates a reverse
> dependency that manifests in a link error when CONFIG_SND_SOC_SOF_OF
> is built-in but CONFIG_SND_SOC_SOF_IMX=m:
> 
> sound/soc/sof/sof-of-dev.o:(.data+0x118): undefined reference to `sof_imx8_ops'
> 
> Make the latter a 'bool' symbol and change the Makefile so the imx8
> driver is compiled the same way as the driver using it.
> 
> A nicer way would be to reverse the layering and move all
> the imx specific bits of sof-of-dev.c into the imx driver
> itself, which can then call into the common code. Doing this
> would need more testing and can be done if we add another
> driver like the first one.

Or use something like

config SND_SOC_SOF_IMX8_SUPPORT
	bool "SOF support for i.MX8"
    	depends on IMX_SCU
    	depends on IMX_DSP

config SND_SOC_SOF_IMX8
	tristate
	<i.mx selects>

config SND_SOC_SOF_OF
	depends on OF
	select SND_SOC_SOF_IMX8 if SND_SOC_SOF_IMX8_SUPPORT

That way you propagate the module/built-in information. That's how we 
fixed those issues for the Intel parts.

> 
> Fixes: f4df4e4042b0 ("ASoC: SOF: imx8: Fix COMPILE_TEST error")
> Fixes: 202acc565a1f ("ASoC: SOF: imx: Add i.MX8 HW support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   sound/soc/sof/imx/Kconfig  | 2 +-
>   sound/soc/sof/imx/Makefile | 4 +++-
>   2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/soc/sof/imx/Kconfig b/sound/soc/sof/imx/Kconfig
> index 5acae75f5750..a3891654a1fc 100644
> --- a/sound/soc/sof/imx/Kconfig
> +++ b/sound/soc/sof/imx/Kconfig
> @@ -12,7 +12,7 @@ config SND_SOC_SOF_IMX_TOPLEVEL
>   if SND_SOC_SOF_IMX_TOPLEVEL
>   
>   config SND_SOC_SOF_IMX8
> -	tristate "SOF support for i.MX8"
> +	bool "SOF support for i.MX8"
>   	depends on IMX_SCU
>   	depends on IMX_DSP
>   	help
> diff --git a/sound/soc/sof/imx/Makefile b/sound/soc/sof/imx/Makefile
> index 6ef908e8c807..9e8f35df0ff2 100644
> --- a/sound/soc/sof/imx/Makefile
> +++ b/sound/soc/sof/imx/Makefile
> @@ -1,4 +1,6 @@
>   # SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
>   snd-sof-imx8-objs := imx8.o
>   
> -obj-$(CONFIG_SND_SOC_SOF_IMX8) += snd-sof-imx8.o
> +ifdef CONFIG_SND_SOC_SOF_IMX8
> +obj-$(CONFIG_SND_SOC_SOF_OF) += snd-sof-imx8.o
> +endif
>