From: Bryan O'Donoghue <bod@kernel.org>
To: Wenmeng Liu <wenmeng.liu@oss.qualcomm.com>,
Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: mchehab@kernel.org, linux-media@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] media: i2c: imx412: wait for NVM read (T7) before programming mode registers
Date: Mon, 12 Jan 2026 11:59:38 +0000 [thread overview]
Message-ID: <6126ae90-6f46-46f4-9a28-1b8d7ef69277@kernel.org> (raw)
In-Reply-To: <828597fc-ec02-488c-99e9-418a7ff266d3@oss.qualcomm.com>
On 12/01/2026 11:50, Wenmeng Liu wrote:
> -- if disable gpiod_set_value_cansleep(imx412->reset_gpio, 1); form
> imx412_power_off, the issue will not happen.
Yeah this is basically what I said in the last email.
The state transition diagram for starting the part will assume reset is
asserted.
So in power_on() - you need to assert reset prior to powering on and
clocking the part - which is the eqivalent logic to what you posted above.
The reason you should do this in power_on() is it doesn't assume
power_off has run first.
power_on should establish the initial conditions required to power on
the device, in this case, we've established you need to have reset
asserted first.
---
bod
prev parent reply other threads:[~2026-01-12 11:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <tjF2Z2nt6dR-T_d-5cSpzZqItgoMsUzNmUBQ-jucG9SMQ9Q4y9cCrW4aya-hRJR0dQG-q63OBmZajTWMbxfeUA==@protonmail.internalid>
2026-01-09 4:49 ` Wenmeng Liu
2026-01-09 12:32 ` Bryan O'Donoghue
2026-01-12 3:07 ` Wenmeng Liu
2026-01-12 9:06 ` Sakari Ailus
2026-01-12 10:09 ` Wenmeng Liu
2026-01-12 10:21 ` Bryan O'Donoghue
2026-01-12 11:50 ` Wenmeng Liu
2026-01-12 11:59 ` Bryan O'Donoghue [this message]
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