[PATCH v6 06/14] ALSA: hda: cs35l41: Support reading subsystem id from ACPI

From: Vitaly Rodionov
Date: Tue Jun 21 2022 - 17:39:47 EST


From: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>

On some laptop models, the ACPI contains the unique
Subsystem ID, and this value should be preferred
over the value from the HDA driver.

Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Vitaly Rodionov <vitalyr@xxxxxxxxxxxxxxxxxxxxx>
---
sound/pci/hda/cs35l41_hda.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)

diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c
index 7f0132694774..5f89a0462eb6 100644
--- a/sound/pci/hda/cs35l41_hda.c
+++ b/sound/pci/hda/cs35l41_hda.c
@@ -545,6 +545,36 @@ static int cs35l41_hda_apply_properties(struct cs35l41_hda *cs35l41)
return cs35l41_hda_channel_map(cs35l41->dev, 0, NULL, 1, &hw_cfg->spk_pos);
}

+static int cs35l41_get_acpi_sub_string(struct device *dev, struct acpi_device *adev,
+ const char **subsysid)
+{
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+ acpi_status status;
+ int ret = 0;
+
+ status = acpi_evaluate_object(adev->handle, "_SUB", NULL, &buffer);
+ if (ACPI_SUCCESS(status)) {
+ obj = buffer.pointer;
+ if (obj->type == ACPI_TYPE_STRING) {
+ *subsysid = devm_kstrdup(dev, obj->string.pointer, GFP_KERNEL);
+ if (*subsysid == NULL) {
+ dev_err(dev, "Cannot allocate Subsystem ID");
+ ret = -ENOMEM;
+ }
+ } else {
+ dev_warn(dev, "Warning ACPI _SUB did not return a string\n");
+ ret = -ENODEV;
+ }
+ acpi_os_free(buffer.pointer);
+ } else {
+ dev_dbg(dev, "Warning ACPI _SUB failed: %#x\n", status);
+ ret = -ENODEV;
+ }
+
+ return ret;
+}
+
static int cs35l41_hda_read_acpi(struct cs35l41_hda *cs35l41, const char *hid, int id)
{
struct cs35l41_hw_cfg *hw_cfg = &cs35l41->hw_cfg;
@@ -564,6 +594,12 @@ static int cs35l41_hda_read_acpi(struct cs35l41_hda *cs35l41, const char *hid, i
physdev = get_device(acpi_get_first_physical_node(adev));
acpi_dev_put(adev);

+ ret = cs35l41_get_acpi_sub_string(cs35l41->dev, adev, &cs35l41->acpi_subsystem_id);
+ if (ret)
+ dev_info(cs35l41->dev, "No Subsystem ID found in ACPI: %d", ret);
+ else
+ dev_dbg(cs35l41->dev, "Subsystem ID %s found", cs35l41->acpi_subsystem_id);
+
property = "cirrus,dev-index";
ret = device_property_count_u32(physdev, property);
if (ret <= 0)
--
2.34.1