ASoC: fsl: fix snd-soc-imx-pcm module build

When building modules with CONFIG_SND_IMX_SOC=m in imx_v6_v7_defconfig,
we will see the following link error.

  LD [M]  sound/soc/fsl/snd-soc-fsl-ssi.o
  LD [M]  sound/soc/fsl/snd-soc-fsl-utils.o
  LD [M]  sound/soc/fsl/snd-soc-imx-ssi.o
  LD [M]  sound/soc/fsl/snd-soc-imx-audmux.o
  LD [M]  sound/soc/fsl/snd-soc-imx-pcm.o
sound/soc/fsl/imx-pcm-dma.o: In function `init_module':
imx-pcm-dma.c:(.init.text+0x0): multiple definition of `init_module'
sound/soc/fsl/imx-pcm-fiq.o:imx-pcm-fiq.c:(.init.text+0x0): first defined here
sound/soc/fsl/imx-pcm-dma.o: In function `cleanup_module':
imx-pcm-dma.c:(.exit.text+0x0): multiple definition of `cleanup_module'
sound/soc/fsl/imx-pcm-fiq.o:imx-pcm-fiq.c:(.exit.text+0x0): first defined here
make[4]: *** [sound/soc/fsl/snd-soc-imx-pcm.o] Error 1

The module snd-soc-imx-pcm is designed to link imx-pcm.o with
imx-pcm-dma.o or imx-pcm-fiq.o depending on if option SND_SOC_IMX_PCM_DMA
or SND_SOC_IMX_PCM_FIQ is enabled.  Both imx-pcm-dma and imx-pcm-fiq
register their own module_platform_driver.  However, these two options
are not mutually exclusive and can be enabled together.  And that's
why we see above multiple init_module definition error.

Instead of having both imx-pcm-dma and imx-pcm-fiq register their
own platform_driver, we should do only once in imx-pcm.c.  Using
platform_device_id to distinguish between imx-pcm-dma and imx-pcm-fiq,
we can run-time call imx-pcm-dma/fiq specific initialization in .probe
hook to have module snd-soc-imx-pcm work for both cases.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/fsl/imx-pcm-dma.c

@@ -154,26 +154,7 @@ static struct snd_soc_platform_driver imx_soc_platform_mx2 = {
 	.pcm_free	= imx_pcm_free,
 };
 
-static int imx_soc_platform_probe(struct platform_device *pdev)
+int imx_pcm_dma_init(struct platform_device *pdev)
 {
 	return snd_soc_register_platform(&pdev->dev, &imx_soc_platform_mx2);
 }
-
-static int imx_soc_platform_remove(struct platform_device *pdev)
-{
-	snd_soc_unregister_platform(&pdev->dev);
-	return 0;
-}
-
-static struct platform_driver imx_pcm_driver = {
-	.driver = {
-			.name = "imx-pcm-audio",
-			.owner = THIS_MODULE,
-	},
-	.probe = imx_soc_platform_probe,
-	.remove = imx_soc_platform_remove,
-};
-
-module_platform_driver(imx_pcm_driver);
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:imx-pcm-audio");

sound/soc/fsl/imx-pcm-fiq.c

@@ -281,7 +281,7 @@ static struct snd_soc_platform_driver imx_soc_platform_fiq = {
 	.pcm_free	= imx_pcm_fiq_free,
 };
 
-static int imx_soc_platform_probe(struct platform_device *pdev)
+int imx_pcm_fiq_init(struct platform_device *pdev)
 {
 	struct imx_ssi *ssi = platform_get_drvdata(pdev);
 	int ret;
@@ -314,23 +314,3 @@ failed_register:
 
 	return ret;
 }
-
-static int imx_soc_platform_remove(struct platform_device *pdev)
-{
-	snd_soc_unregister_platform(&pdev->dev);
-	return 0;
-}
-
-static struct platform_driver imx_pcm_driver = {
-	.driver = {
-			.name = "imx-fiq-pcm-audio",
-			.owner = THIS_MODULE,
-	},
-
-	.probe = imx_soc_platform_probe,
-	.remove = imx_soc_platform_remove,
-};
-
-module_platform_driver(imx_pcm_driver);
-
-MODULE_LICENSE("GPL");

sound/soc/fsl/imx-pcm.c

@@ -104,6 +104,38 @@ void imx_pcm_free(struct snd_pcm *pcm)
 }
 EXPORT_SYMBOL_GPL(imx_pcm_free);
 
+static int imx_pcm_probe(struct platform_device *pdev)
+{
+	if (strcmp(pdev->id_entry->name, "imx-fiq-pcm-audio") == 0)
+		return imx_pcm_fiq_init(pdev);
+
+	return imx_pcm_dma_init(pdev);
+}
+
+static int imx_pcm_remove(struct platform_device *pdev)
+{
+	snd_soc_unregister_platform(&pdev->dev);
+	return 0;
+}
+
+static struct platform_device_id imx_pcm_devtype[] = {
+	{ .name = "imx-pcm-audio", },
+	{ .name = "imx-fiq-pcm-audio", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, imx_pcm_devtype);
+
+static struct platform_driver imx_pcm_driver = {
+	.driver = {
+			.name = "imx-pcm",
+			.owner = THIS_MODULE,
+	},
+	.id_table = imx_pcm_devtype,
+	.probe = imx_pcm_probe,
+	.remove = imx_pcm_remove,
+};
+module_platform_driver(imx_pcm_driver);
+
 MODULE_DESCRIPTION("Freescale i.MX PCM driver");
 MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
 MODULE_LICENSE("GPL");

sound/soc/fsl/imx-pcm.h

@@ -30,4 +30,22 @@ int snd_imx_pcm_mmap(struct snd_pcm_substream *substream,
 int imx_pcm_new(struct snd_soc_pcm_runtime *rtd);
 void imx_pcm_free(struct snd_pcm *pcm);
 
+#ifdef CONFIG_SND_SOC_IMX_PCM_DMA
+int imx_pcm_dma_init(struct platform_device *pdev);
+#else
+static inline int imx_pcm_dma_init(struct platform_device *pdev)
+{
+	return -ENODEV;
+}
+#endif
+
+#ifdef CONFIG_SND_SOC_IMX_PCM_FIQ
+int imx_pcm_fiq_init(struct platform_device *pdev);
+#else
+static inline int imx_pcm_fiq_init(struct platform_device *pdev)
+{
+	return -ENODEV;
+}
+#endif
+
 #endif /* _IMX_PCM_H */