[PATCH 1/1] 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 and
qcom,ath12k-calibration-variant, but it is not implemented in the code.

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 node or ath12k-specific
qcom,ath12k-calibration-variant node. This allows the driver to properly
select, read and apply the correct BDF.

Signed-off-by: Andrew LaMarche <andrewjlamarche@gmail.com>
---
 drivers/net/wireless/ath/ath12k/core.c | 25 +++++++++++++++++++++++++
 drivers/net/wireless/ath/ath12k/core.h |  2 +-
 drivers/net/wireless/ath/ath12k/qmi.c  |  4 ++++
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
index cc352eef1939..e45f76d81337 100644
--- a/drivers/net/wireless/ath/ath12k/core.c
+++ b/drivers/net/wireless/ath/ath12k/core.c
@@ -806,6 +806,31 @@ 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)
+		of_property_read_string(node, "qcom,ath12k-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/core.h b/drivers/net/wireless/ath/ath12k/core.h
index 3c1e0069be1e..39700a780ee2 100644
--- a/drivers/net/wireless/ath/ath12k/core.h
+++ b/drivers/net/wireless/ath/ath12k/core.h
@@ -1352,7 +1352,7 @@ int ath12k_core_fetch_bdf(struct ath12k_base *ath12k,
 			  struct ath12k_board_data *bd);
 void ath12k_core_free_bdf(struct ath12k_base *ab, struct ath12k_board_data *bd);
 int ath12k_core_fetch_regdb(struct ath12k_base *ab, struct ath12k_board_data *bd);
-int ath12k_core_check_dt(struct ath12k_base *ath12k);
+int ath12k_core_check_dt(struct ath12k_base *ab);
 int ath12k_core_check_smbios(struct ath12k_base *ab);
 void ath12k_core_halt(struct ath12k *ar);
 int ath12k_core_resume_early(struct ath12k_base *ab);
diff --git a/drivers/net/wireless/ath/ath12k/qmi.c b/drivers/net/wireless/ath/ath12k/qmi.c
index b7c48b6706df..22ef5aab871f 100644
--- a/drivers/net/wireless/ath/ath12k/qmi.c
+++ b/drivers/net/wireless/ath/ath12k/qmi.c
@@ -2903,6 +2903,10 @@ 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