From: Mark Brown <broonie@kernel.org>
To: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc: agross@kernel.org, bjorn.andersson@linaro.org,
lgirdwood@gmail.com, wcheng@codeaurora.org,
linux-arm-msm@vger.kernel.org, dmitry.baryshkov@linaro.org
Subject: Re: [PATCH] regulator: Fix current limit for QCOM PMIC VBUS
Date: Fri, 23 Apr 2021 17:32:03 +0100 [thread overview]
Message-ID: <20210423163203.GF5507@sirena.org.uk> (raw)
In-Reply-To: <20210423160658.1542090-1-bryan.odonoghue@linaro.org>
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On Fri, Apr 23, 2021 at 05:06:58PM +0100, Bryan O'Donoghue wrote:
> + /* Set OTG current limit to 3000mA up from bootloader set 2000mA */
> + regmap_update_bits(regmap, base + OTG_CURRENT_LIMIT_CFG,
> + OTG_CURRENT_LIMIT_MASK, OTG_CURRENT_LIMIT_3000MA);
This seems like something that needs to be configured per system, the
system may not be physically capable of delivering an additional amp
(150% of the current defaults) safely. It's going to be better to be
out of spec for high current USB devices than to exceed safe physical
limits, there's a good solid reason why the regulator API never touches
the hardware without explicit constraints allowing it to do so.
I also thought there was support in the USB specs for negotiating how
much power is drawn (not that everything will DTRT there but still)?
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next prev parent reply other threads:[~2021-04-23 16:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-23 16:06 [PATCH] regulator: Fix current limit for QCOM PMIC VBUS Bryan O'Donoghue
2021-04-23 16:32 ` Mark Brown [this message]
2021-04-23 20:24 ` Bryan O'Donoghue
2021-04-23 20:38 ` Bryan O'Donoghue
2021-04-26 11:55 ` Mark Brown
2021-04-26 12:03 ` Bryan O'Donoghue
2021-04-26 12:12 ` Mark Brown
2021-04-26 12:50 ` Bryan O'Donoghue
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