From: Richard Leitner <richard.leitner@skidata.com>
To: Linus Walleij <linus.walleij@linaro.org>,
"Luca Porzio (lporzio)" <lporzio@micron.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
Bart Van Assche <bart.vanassche@sandisk.com>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Shawn Lin <shawn.lin@rock-chips.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Jaehoon Chung <jh80.chung@samsung.com>,
"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
Richard Leitner <dev@g0hl1n.net>
Subject: Re: [EXT] Re: [PATCH v2] mmc: core: add mmc-card hardware reset enable support
Date: Tue, 20 Jun 2017 12:24:14 +0200 [thread overview]
Message-ID: <dd844df4-ac50-daab-bc31-a636718227f5@skidata.com> (raw)
In-Reply-To: <CACRpkdb92scfO=tghucfC3RqQpi9K6YSuavte_b-AxH4hS87rQ@mail.gmail.com>
On 06/20/2017 11:45 AM, Linus Walleij wrote:
>> IMHO mmc-util is where the patch really stands: the enabling is OTP,
>> the programmer have to use mmc-util only once and the kernel
>> will behave accordingly.
>
> So we should not add it to the device tree.
>
>> Any platform vendor must check that the HW Reset pin is actually
>> Connected BEFORE enabling this feature otherwise the system may be
>> unstable. A DT Binding may be dangerous if this condition is not met
>> as well as the code execution at each MMC init is honestly redundant
>> for an OTP location of the extCSD.
>
> I agree. So the device should be configured during production, or
> a user who know exactly what they are doing may reconfigure it
> using the mmc-utils.
>
> Thus the kernel should just read what the device says and stay with
> that, no DT props or anything.
Ok. Thanks for that clarification to everybody involved!
Should we then add a warning/info message to the kernel if we have a
reset gpio configured in the DT, but the eMMC hasn't this OTP bit set?
Or should we just leave it as it is? (Due to the fact the reset-gpio
could be connected to an external reset chip?)
kind regards,
Richard.L
next prev parent reply other threads:[~2017-06-20 10:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-11 7:31 [PATCH v2] mmc: core: add mmc-card hardware reset enable support Richard Leitner
2017-04-11 8:17 ` Linus Walleij
2017-04-11 10:43 ` Ulf Hansson
2017-06-14 7:25 ` Richard Leitner
2017-06-14 16:12 ` [EXT] " Luca Porzio (lporzio)
2017-06-20 9:45 ` Linus Walleij
2017-06-20 10:24 ` Richard Leitner [this message]
2017-06-20 16:10 ` Linus Walleij
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