[PATCH v2 1/2] wifi: ath12k: support calibration-variant from device tree

[Andrew LaMarche <andrewjlamarche@gmail.com>]

ath10k and ath11k support reading calibration variants from the device
tree to locate the correct Board Description File (BDF). The ath12k-wsi
binding already describes using qcom,calibration-variant but it is not
implemented in the driver.

Many ath12k designs expose all the radios under a single phy, each of
which typically require a separate BDF. Without this, the radios may not
come up or will not be calibrated correctly.

Fix this by parsing the device tree for the generation-agnostic
qcom,calibration-variant. This allows the driver to properly select,
read and apply the correct BDF.

Signed-off-by: Andrew LaMarche <andrewjlamarche@gmail.com>
---
Changes in v2:
- Drop ath12k-specific binding qcom,ath12k-calibration-variant in favor
  of generation agnostic qcom,calibration-variant.
- Link to v1: https://lore.kernel.org/all/20260131003222.2011259-1-andrewjlamarche@gmail.com
---
 drivers/net/wireless/ath/ath12k/core.c | 22 ++++++++++++++++++++++
 drivers/net/wireless/ath/ath12k/qmi.c  |  4 ++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
index 742d4fd1b598..52c28864c63c 100644
--- a/drivers/net/wireless/ath/ath12k/core.c
+++ b/drivers/net/wireless/ath/ath12k/core.c
@@ -812,6 +812,28 @@ int ath12k_core_check_smbios(struct ath12k_base *ab)
 	return 0;
 }
 
+int ath12k_core_check_dt(struct ath12k_base *ab)
+{
+	size_t max_len = sizeof(ab->qmi.target.bdf_ext);
+	const char *variant = NULL;
+	struct device_node *node;
+
+	node = ab->dev->of_node;
+	if (!node)
+		return -ENOENT;
+
+	of_property_read_string(node, "qcom,calibration-variant",
+			&variant);
+	if (!variant)
+		return -ENODATA;
+
+	if (strscpy(ab->qmi.target.bdf_ext, variant, max_len) < 0)
+		ath12k_dbg(ab, ATH12K_DBG_BOOT,
+				"bdf variant string is longer than the buffer can accommodate (variant: %s)\n", variant);
+
+	return 0;
+}
+
 static int ath12k_core_soc_create(struct ath12k_base *ab)
 {
 	int ret;
diff --git a/drivers/net/wireless/ath/ath12k/qmi.c b/drivers/net/wireless/ath/ath12k/qmi.c
index fd762b5d7bb5..3cf39ae06fd3 100644
--- a/drivers/net/wireless/ath/ath12k/qmi.c
+++ b/drivers/net/wireless/ath/ath12k/qmi.c
@@ -2945,6 +2945,10 @@ int ath12k_qmi_request_target_cap(struct ath12k_base *ab)
 	if (r)
 		ath12k_dbg(ab, ATH12K_DBG_QMI, "SMBIOS bdf variant name not set.\n");
 
+	r = ath12k_core_check_dt(ab);
+	if (r)
+		ath12k_dbg(ab, ATH12K_DBG_QMI, "DT bdf variant name not set.\n");
+
 	r = ath12k_acpi_start(ab);
 	if (r)
 		/* ACPI is optional so continue in case of an error */
-- 
2.43.0