[PATCH 1/2] ASoC: Intel: bytcr_rt5640: Add support for non ACPI instantiated codec

[Hans de Goede <hdegoede@redhat.com>]

On some x86 Bay Trail tablets which shipped with Android as factory OS,
the DSDT is so broken that the codec needs to be manually instantatiated
by the special x86-android-tablets.ko "fixup" driver for cases like this.

This means that the codec-dev cannot be retrieved through its ACPI fwnode,
add support to the bytcr_rt5640 machine driver for such manually
instantiated rt5640 i2c_clients.

An example of a tablet which needs this is the Vexia EDU ATLA 10 tablet,
which has been distributed to schools in the Spanish Andalucía region.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 sound/soc/intel/boards/bytcr_rt5640.c | 33 ++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)

diff --git a/sound/soc/intel/boards/bytcr_rt5640.c b/sound/soc/intel/boards/bytcr_rt5640.c
index 2ed49acb4e36..8dfd91cc3668 100644
--- a/sound/soc/intel/boards/bytcr_rt5640.c
+++ b/sound/soc/intel/boards/bytcr_rt5640.c
@@ -17,6 +17,7 @@
 #include <linux/acpi.h>
 #include <linux/clk.h>
 #include <linux/device.h>
+#include <linux/device/bus.h>
 #include <linux/dmi.h>
 #include <linux/gpio/consumer.h>
 #include <linux/gpio/machine.h>
@@ -32,6 +33,8 @@
 #include "../atom/sst-atom-controls.h"
 #include "../common/soc-intel-quirks.h"
 
+#define BYT_RT5640_FALLBACK_CODEC_DEV_NAME	"i2c-rt5640"
+
 enum {
 	BYT_RT5640_DMIC1_MAP,
 	BYT_RT5640_DMIC2_MAP,
@@ -1698,9 +1701,33 @@ static int snd_byt_rt5640_mc_probe(struct platform_device *pdev)
 
 	codec_dev = acpi_get_first_physical_node(adev);
 	acpi_dev_put(adev);
-	if (!codec_dev)
-		return -EPROBE_DEFER;
-	priv->codec_dev = get_device(codec_dev);
+
+	if (codec_dev) {
+		priv->codec_dev = get_device(codec_dev);
+	} else {
+		/*
+		 * Special case for Android tablets where the codec i2c_client
+		 * has been manually instantiated by x86_android_tablets.ko due
+		 * to a broken DSDT.
+		 */
+		codec_dev = bus_find_device_by_name(&i2c_bus_type, NULL,
+					BYT_RT5640_FALLBACK_CODEC_DEV_NAME);
+		if (!codec_dev)
+			return -EPROBE_DEFER;
+
+		if (!i2c_verify_client(codec_dev)) {
+			dev_err(dev, "Error '%s' is not an i2c_client\n",
+				BYT_RT5640_FALLBACK_CODEC_DEV_NAME);
+			put_device(codec_dev);
+		}
+
+		/* fixup codec name */
+		strscpy(byt_rt5640_codec_name, BYT_RT5640_FALLBACK_CODEC_DEV_NAME,
+			sizeof(byt_rt5640_codec_name));
+
+		/* bus_find_device() returns a reference no need to get() */
+		priv->codec_dev = codec_dev;
+	}
 
 	/*
 	 * swap SSP0 if bytcr is detected
-- 
2.47.0