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From: Mohd Ayaan Anwar <mohd.anwar@oss.qualcomm.com>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Alex Elder <elder@riscstar.com>,
	Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>,
	andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@kernel.org,
	kuba@kernel.org, pabeni@redhat.com, robh@kernel.org,
	krzk+dt@kernel.org, conor+dt@kernel.org, hkallweit1@gmail.com,
	linux@armlinux.org.uk, Daniel Thompson <daniel@riscstar.com>,
	ansuelsmth@gmail.com, donggeunyoo.kernel@gmail.com,
	devicetree@vger.kernel.org, netdev@vger.kernel.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v2 2/2] net: phy: qcom: qca808x: Add regulator management
Date: Thu, 15 Oct 2026 22:07:17 +0530	[thread overview]
Message-ID: <atEBPbpMtlmG+Mxe@oss.qualcomm.com> (raw)
In-Reply-To: <1af4e7a8-adb9-41bd-8841-61180b284470@lunn.ch>

On Thu, Oct 15, 2026 at 06:27:01PM +0200, Andrew Lunn wrote:
> On Thu, Oct 15, 2026 at 11:01:43AM -0500, Alex Elder wrote:
> > On 10/15/26 10:40 AM, Lorenzo Bianconi wrote:
> > > > +	if (count)
> > > > +		fsleep(phydev->mdio.reset_assert_delay);
> > > nit: should we check reset_assert_delay field is actually set?
> > 
> > Are you saying there should be an alternative delay used
> > if it is not set?  Do you have a suggestion for what to
> > use in that case?
> 
> Does the binding require the value is set?
> 
> What happens it if is 0? I think fsleep() is happy to delay for 0 uS,
> but does the hardware still work? Does the datasheet say anything
> about power on delays?
> 

I was going to share a text version of the power-up diagram given in
this PHY's datasheet. This might help.

Power-Up Sequence

1. DVDD asserted
   |
   |<-------- 10 ms -------->|   (required for external power)
   |
2. DVDD18 / AVDD18 asserted

3. VDD1P25 asserted
   |
   |<-------- 0.2 ms ------->|   (required for LDO to settle)
   |
4. VDD_LDO asserted

5. AVDD asserted
   |
   |<--------- 2 ms -------->|   (required for XTL to oscillate)
   |
6. Crystal 50 MHz starts oscillating

7. PAD reset deasserted
   |
   |<------- 10 ms --------->|   (deglitch time)


So, maybe just fsleep(22200) or something a bit higher?

	Ayaan


      reply	other threads:[~2026-10-15 16:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-15 14:38 [PATCH net-next v2 0/2] net: phy: qcom: add qca808x support Alex Elder
2026-10-15 14:38 ` [PATCH net-next v2 1/2] dt-bindings: net: qca,qca808x: Add regulator properties Alex Elder
2026-10-15 14:38 ` [PATCH net-next v2 2/2] net: phy: qcom: qca808x: Add regulator management Alex Elder
2026-10-15 15:16   ` Maxime Chevallier
2026-10-15 15:40   ` Lorenzo Bianconi
2026-10-15 16:01     ` Alex Elder
2026-10-15 16:27       ` Andrew Lunn
2026-10-15 16:37         ` Mohd Ayaan Anwar [this message]

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