[PATCH v1] power: sequencing: qcom-wcn: increase WCN7850 power-up delay

[Shuai Zhang]

When the WCN7850 is powered up from the Bluetooth side first, i.e.
BT_EN is asserted while WLAN_EN is still low, the chip starts from a
cold state and is not ready to accept the first HCI command 50 ms after
BT_EN goes high. The first command (0xfc00, read QCA version) is lost,
hci_qca does not resend it and fails after the 2 s command timeout:

  Bluetooth: hci0: Reading QCA version information failed (-110)

When WLAN is powered first, 50 ms is sufficient, so the failure only
shows up in the BT-first ordering. Measured on the affected board by
which enable pin rose first:

  pwup_delay_ms   BT-first boots   with -110
  50              9                9
  75              23               0
  100             21               0
  300             20               0

Raise the power-up delay of WCN7850 to 100 ms. The delay is shared by
the Bluetooth and WLAN targets, so WLAN power-up also waits 50 ms
longer.

Fixes: 2f1630f437df ("power: pwrseq: add a driver for the PMU module on the QCom WCN chipsets")
Signed-off-by: Cheng Jiang <cheng.jiang@xxxxxxxxxxxxxxxx>
Signed-off-by: Shuai Zhang <shuai.zhang@xxxxxxxxxxxxxxxx>
---
 drivers/power/sequencing/pwrseq-qcom-wcn.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/power/sequencing/pwrseq-qcom-wcn.c b/drivers/power/sequencing/pwrseq-qcom-wcn.c
index 636dd7e63..05ee1785e 100644
--- a/drivers/power/sequencing/pwrseq-qcom-wcn.c
+++ b/drivers/power/sequencing/pwrseq-qcom-wcn.c
@@ -427,7 +427,7 @@ static const char *const pwrseq_wcn7850_vregs[] = {
 static const struct pwrseq_qcom_wcn_pdata pwrseq_wcn7850_of_data = {
 	.vregs = pwrseq_wcn7850_vregs,
 	.num_vregs = ARRAY_SIZE(pwrseq_wcn7850_vregs),
-	.pwup_delay_ms = 50,
+	.pwup_delay_ms = 100,
 	.targets = pwrseq_qcom_wcn_targets,
 };
 
-- 
2.34.1