From: Philipp Zabel <p.zabel@pengutronix.de>
To: Phil Edworthy <phil.edworthy@renesas.com>,
Rob Herring <robh@kernel.org>,
Krzysztof Kozlowski <krzk@kernel.org>
Cc: Wolfram Sang <wsa@kernel.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Jarkko Nikula <jarkko.nikula@linux.intel.com>,
Sam Protsenko <semen.protsenko@linaro.org>,
Sven Peter <sven@svenpeter.dev>, Jan Dabros <jsd@semihalf.com>,
Lukas Bulwahn <lukas.bulwahn@gmail.com>,
Tyrone Ting <kfting@nuvoton.com>, Arnd Bergmann <arnd@arndb.de>,
Olof Johansson <olof@lixom.net>,
Biju Das <biju.das.jz@bp.renesas.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
devicetree@vger.kernel.org, linux-i2c@vger.kernel.org,
linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH v2 0/2] i2c: Add new driver for Renesas RZ/V2M controller
Date: Wed, 29 Jun 2022 18:20:55 +0200 [thread overview]
Message-ID: <c168df990e1187bf44a5c46be53aa6b20d30d14d.camel@pengutronix.de> (raw)
In-Reply-To: <20220628194526.111501-1-phil.edworthy@renesas.com>
Hi Phil,
On Di, 2022-06-28 at 20:45 +0100, Phil Edworthy wrote:
> Hi,
>
> The Renesas RZ/V2M SoC (r9a09g011) has a new i2c controller. This series
> add the driver. One annoying problem is that the SoC uses a single reset
> line for two i2c controllers, and unfortunately one of the controllers
> is managed by some firmware, not by Linux. Therefore, the driver just
> deasserts the reset.
This sounds scary. If the driver is never loaded, and the reset is
never deasserted, what happens to the firmware trying to access the
other i2c controller? Does it hang? Or write to the reset controller
registers to deassert the reset? If so, is there any protection against
concurrent access from firmware and reset controller driver?
regards
Philipp
next prev parent reply other threads:[~2022-06-29 16:21 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-28 19:45 [PATCH v2 0/2] i2c: Add new driver for Renesas RZ/V2M controller Phil Edworthy
2022-06-28 19:45 ` [PATCH v2 1/2] dt-bindings: i2c: Document RZ/V2M I2C controller Phil Edworthy
2022-06-29 2:09 ` Rob Herring
2022-06-29 6:53 ` Geert Uytterhoeven
2022-06-29 8:15 ` Krzysztof Kozlowski
2022-06-29 13:50 ` Rob Herring
2022-06-29 8:22 ` Krzysztof Kozlowski
2022-06-30 11:43 ` Phil Edworthy
2022-06-28 19:45 ` [PATCH v2 2/2] i2c: Add Renesas RZ/V2M controller Phil Edworthy
2022-06-28 21:08 ` Andy Shevchenko
2022-06-29 6:52 ` Geert Uytterhoeven
2022-06-29 10:43 ` Andy Shevchenko
2022-06-29 15:58 ` Geert Uytterhoeven
2022-06-29 16:10 ` Andy Shevchenko
2022-06-30 9:41 ` Phil Edworthy
2022-06-30 9:54 ` Andy Shevchenko
2022-06-29 16:26 ` Philipp Zabel
2022-06-29 16:20 ` Philipp Zabel [this message]
2022-06-29 17:18 ` [PATCH v2 0/2] i2c: Add new driver for " Geert Uytterhoeven
2022-06-30 13:43 ` Phil Edworthy
2022-06-30 14:45 ` Philipp Zabel
2022-06-30 15:16 ` Phil Edworthy
2022-07-01 15:40 ` Philipp Zabel
2022-07-01 16:18 ` Phil Edworthy
2022-07-01 15:40 ` Philipp Zabel
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