[PATCH 1/2] ASoC: Intel: sst: Fallback to BYT-CR if IRQ 5 is missing

Stephan Gerhold
2018-12-22T14:52:02Z

Some devices detected as BYT-T by the PMIC-type based detection
have only a single IRQ listed in the 80860F28 ACPI device. This
causes -ENXIO later when attempting to get the IRQ at index 5.
It turns out these devices behave more like BYT-CR devices,
and using the IRQ at index 0 makes sound work correctly.

This patch adds a fallback for these devices to is_byt_cr():
If there is no IRQ resource at index 5, treating the device
as BYT-T is guaranteed to fail later, so we can safely treat
these devices as BYT-CR without breaking any working device.

Link: http://mailman.alsa-project.org/pipermail/alsa-devel/2018-December/143176.html
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
---
Moved the "Detected Baytrail-CR platform" message to is_byt_cr()
so we can log a different message if the fallback is used.

Tested this on my device as-is, and simulated a "normal"
BYT-T and BYT-CR device (copied their IRQs to a custom DSDT).

sound/soc/intel/atom/sst/sst_acpi.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/sound/soc/intel/atom/sst/sst_acpi.c b/sound/soc/intel/atom/sst/sst_acpi.c
index 3a95ebbfc45d..755a396121ff 100644
--- a/sound/soc/intel/atom/sst/sst_acpi.c
+++ b/sound/soc/intel/atom/sst/sst_acpi.c
@@ -255,10 +255,22 @@ static int is_byt(void)
return status;
}

-static int is_byt_cr(struct device *dev, bool *bytcr)
+static int is_byt_cr(struct platform_device *pdev, bool *bytcr)
{
+ struct device *dev = &pdev->dev;
int status = 0;

+ if (platform_get_resource(pdev, IORESOURCE_IRQ, 5) == NULL) {
+ /*
+ * Some devices detected as BYT-T have only a single IRQ listed,
+ * causing platform_get_irq with index 5 to return -ENXIO.
+ * The correct IRQ in this case is at index 0, as used on BYT-CR.
+ */
+ dev_info(dev, "Falling back to Baytrail-CR platform\n");
+ *bytcr = true;
+ return status;
+ }
+
if (IS_ENABLED(CONFIG_IOSF_MBI)) {
u32 bios_status;

@@ -278,10 +290,12 @@ static int is_byt_cr(struct device *dev, bool *bytcr)
/* bits 26:27 mirror PMIC options */
bios_status = (bios_status >> 26) & 3;

- if ((bios_status == 1) || (bios_status == 3))
+ if ((bios_status == 1) || (bios_status == 3)) {
+ dev_info(dev, "Detected Baytrail-CR platform\n");
*bytcr = true;
- else
+ } else {
dev_info(dev, "BYT-CR not detected\n");
+ }
}
} else {
dev_info(dev, "IOSF_MBI not enabled, no BYT-CR detection\n");
@@ -333,10 +347,8 @@ static int sst_acpi_probe(struct platform_device *pdev)
if (ret < 0)
return ret;

- ret = is_byt_cr(dev, &bytcr);
+ ret = is_byt_cr(pdev, &bytcr);
if (!(ret < 0 || !bytcr)) {
- dev_info(dev, "Detected Baytrail-CR platform\n");
-
/* override resource info */
byt_rvp_platform_data.res_info = &bytcr_res_info;
}
--
2.20.1