From: Vasiliy Doylov via B4 Relay <devnull+neko.altlinux.org@kernel.org>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
danila@mainlining.org, phone-devel@vger.kernel.org,
~postmarketos/upstreaming@lists.sr.ht,
Vasiliy Doylov <neko@altlinux.org>
Subject: [PATCH] usb: typec: mux: fsa4480: wait after enabling supply
Date: Thu, 20 Aug 2026 14:44:10 +0300 [thread overview]
Message-ID: <20260820-fsa4480-wait-for-power-v1-1-d13aa1bfac51@altlinux.org> (raw)
From: Vasiliy Doylov <neko@altlinux.org>
Add a 200 ms delay after enabling the optional vcc regulator in the
FSA4480 probe function. On some platforms (nothing-spacewar) the supply
needs time to stabilize before the chip is ready to respond to I2C reads.
Without this delay the initial DEVICE_ID read fails with -ENODEV.
Tested on: Nothing Phone (1) "sm7325-nothing-spacewar"
Signed-off-by: Vasiliy Doylov <neko@altlinux.org>
---
Add a 200 ms delay after enabling the optional vcc regulator in the
FSA4480 probe function. On some platforms (nothing-spacewar)
the supply needs time to stabilize before the chip is ready to respond
to I2C reads. Without this delay the initial DEVICE_ID read
intermittently fails with -ENODEV, preventing the driver from binding.
---
drivers/usb/typec/mux/fsa4480.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/typec/mux/fsa4480.c b/drivers/usb/typec/mux/fsa4480.c
index bea0c1deec94..4dab12c2b9d7 100644
--- a/drivers/usb/typec/mux/fsa4480.c
+++ b/drivers/usb/typec/mux/fsa4480.c
@@ -278,6 +278,8 @@ static int fsa4480_probe(struct i2c_client *client)
if (ret && ret != -ENODEV)
return dev_err_probe(dev, ret, "Failed to get regulator\n");
+ fsleep(200000);
+
ret = regmap_read(fsa->regmap, FSA4480_DEVICE_ID, &val);
if (ret)
return dev_err_probe(dev, -ENODEV, "FSA4480 not found\n");
---
base-commit: 6a746cd265aed59107ebdaa9ce039bb832922969
change-id: 20260820-fsa4480-wait-for-power-7ffdcd2bebbc
Best regards,
--
Vasiliy Doylov <neko@altlinux.org>
next reply other threads:[~2026-08-20 11:44 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-20 11:44 Vasiliy Doylov via B4 Relay [this message]
2026-08-24 0:09 ` [PATCH] usb: typec: mux: fsa4480: wait after enabling supply Danila Tikhonov
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