linux-kernel - [PATCH v4 1/2] usb: misc: onboard_dev: extend platform data to add power on delay field

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Message-ID: <1725192519-3867920-2-git-send-email-radhey.shyam.pandey@amd.com>
Date: Sun, 1 Sep 2024 17:38:38 +0530
From: Radhey Shyam Pandey <radhey.shyam.pandey@....com>
To: <gregkh@...uxfoundation.org>, <mka@...omium.org>,
	<sakari.ailus@...ux.intel.com>, <wentong.wu@...el.com>,
	<javier.carrasco@...fvision.net>, <stefan.eichenberger@...adex.com>,
	<francesco.dolcini@...adex.com>, <jbrunet@...libre.com>,
	<macpaul.lin@...iatek.com>, <frieder.schrempf@...tron.de>
CC: <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<git@....com>, Radhey Shyam Pandey <radhey.shyam.pandey@....com>
Subject: [PATCH v4 1/2] usb: misc: onboard_dev: extend platform data to add power on delay field

Introduce dedicated field 'power_on_delay_us' in onboard platform data
and update its delay for USB5744 configuration. Hub itself requires some
delay after reset to get to state where configuration data is going to
be accepted. Without delay upcoming support for configuration via SMBUS
is reporting a failure on the first SMBus write.

i2c 2-002d: error -ENXIO: BYPASS_UDC_SUSPEND bit configuration failed

Similar delay is likely also required for default configuration but
because there is enough time (code execution) between reset and usage
of the hub any issue is not visible but it doesn't mean delay shouldn't
be reflected.

Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@....com>
Suggested-by: Matthias Kaehlcke <mka@...omium.org>
---
Changes for v4:
- None

Changes for v3:
- Modified power_on_delay_us comment.

Changes for v2:
- New patch
---
 drivers/usb/misc/onboard_usb_dev.c | 1 +
 drivers/usb/misc/onboard_usb_dev.h | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/drivers/usb/misc/onboard_usb_dev.c b/drivers/usb/misc/onboard_usb_dev.c
index 56710e6b1653..da27c48fc11d 100644
--- a/drivers/usb/misc/onboard_usb_dev.c
+++ b/drivers/usb/misc/onboard_usb_dev.c
@@ -98,6 +98,7 @@ static int onboard_dev_power_on(struct onboard_dev *onboard_dev)
 
 	fsleep(onboard_dev->pdata->reset_us);
 	gpiod_set_value_cansleep(onboard_dev->reset_gpio, 0);
+	fsleep(onboard_dev->pdata->power_on_delay_us);
 
 	onboard_dev->is_powered_on = true;
 
diff --git a/drivers/usb/misc/onboard_usb_dev.h b/drivers/usb/misc/onboard_usb_dev.h
index fbba549c0f47..317b3eb99c02 100644
--- a/drivers/usb/misc/onboard_usb_dev.h
+++ b/drivers/usb/misc/onboard_usb_dev.h
@@ -10,6 +10,7 @@
 
 struct onboard_dev_pdata {
 	unsigned long reset_us;		/* reset pulse width in us */
+	unsigned long power_on_delay_us; /* power on delay in us */
 	unsigned int num_supplies;	/* number of supplies */
 	const char * const supply_names[MAX_SUPPLIES];
 	bool is_hub;
@@ -24,6 +25,7 @@ static const struct onboard_dev_pdata microchip_usb424_data = {
 
 static const struct onboard_dev_pdata microchip_usb5744_data = {
 	.reset_us = 0,
+	.power_on_delay_us = 10000,
 	.num_supplies = 2,
 	.supply_names = { "vdd", "vdd2" },
 	.is_hub = true,
-- 
2.34.1