Linux USB
 help / color / mirror / Atom feed
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>



             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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260820-fsa4480-wait-for-power-v1-1-d13aa1bfac51@altlinux.org \
    --to=devnull+neko.altlinux.org@kernel.org \
    --cc=danila@mainlining.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=heikki.krogerus@linux.intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=neko@altlinux.org \
    --cc=phone-devel@vger.kernel.org \
    --cc=~postmarketos/upstreaming@lists.sr.ht \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox