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From: Cyril Brulebois <cyril@debamax.com>
To: "Uwe Kleine-König" <uwe@kleine-koenig.org>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Stefan Wahren <stefan.wahren@i2se.com>,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	Maxime Ripard <maxime@cerno.tech>
Subject: Re: [PATCH v3] ARM: dts: bcm2711-rpi-cm4-io: Add rtc on a pinctrl-muxed i2c bus
Date: Sun, 2 Jan 2022 07:34:18 +0100	[thread overview]
Message-ID: <20220102063418.acneigxran2a6cpr@debamax.com> (raw)
In-Reply-To: <20220102043322.zv4r255yha5pvsp4@debamax.com>

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Cyril Brulebois <cyril@debamax.com> (2022-01-02):
> In passing, I'm seeing the RTC exclusively on (userspace) i2c-2 while
> I'm seeing the LED matrix on both (userspace) i2c-2 and i2c-3: […]

After a few more tests/reboots, checking the output of `i2cdetect -l`
gives the appropriate information, so that one can pick the right i2c-N
device, by looking at the *-mux entries and their channel IDs:

    …
    i2c-2	i2c       	bcm2835 (i2c@7e205000)          	I2C adapter
    …
    i2c-4	i2c       	i2c-2-mux (chan_id 0)           	I2C adapter
    i2c-5	i2c       	i2c-2-mux (chan_id 1)           	I2C adapter

And indeed, those channel IDs match what's been defined in the DTB, with
#0 set to i2c0_gpio0 (e.g. LED matrix on 40-pin header) and #1 set to
i2c0_gpio44 (e.g. RTC, fan control, etc.), which seem quite consistent
this time:

 - `i2cdetect -y 4` reports only 74 (the LED matrix);
 - `i2cdetect -y 5` reports 0c, 2f, and 51 as UU (the RTC).


Cheers,
-- 
Cyril Brulebois -- Debian Consultant @ DEBAMAX -- https://debamax.com/

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WARNING: multiple messages have this Message-ID (diff)
From: Cyril Brulebois <cyril@debamax.com>
To: "Uwe Kleine-König" <uwe@kleine-koenig.org>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	devicetree@vger.kernel.org,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Stefan Wahren <stefan.wahren@i2se.com>,
	Dave Stevenson <dave.stevenson@raspberrypi.com>,
	Maxime Ripard <maxime@cerno.tech>
Subject: Re: [PATCH v3] ARM: dts: bcm2711-rpi-cm4-io: Add rtc on a pinctrl-muxed i2c bus
Date: Sun, 2 Jan 2022 07:34:18 +0100	[thread overview]
Message-ID: <20220102063418.acneigxran2a6cpr@debamax.com> (raw)
In-Reply-To: <20220102043322.zv4r255yha5pvsp4@debamax.com>


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Cyril Brulebois <cyril@debamax.com> (2022-01-02):
> In passing, I'm seeing the RTC exclusively on (userspace) i2c-2 while
> I'm seeing the LED matrix on both (userspace) i2c-2 and i2c-3: […]

After a few more tests/reboots, checking the output of `i2cdetect -l`
gives the appropriate information, so that one can pick the right i2c-N
device, by looking at the *-mux entries and their channel IDs:

    …
    i2c-2	i2c       	bcm2835 (i2c@7e205000)          	I2C adapter
    …
    i2c-4	i2c       	i2c-2-mux (chan_id 0)           	I2C adapter
    i2c-5	i2c       	i2c-2-mux (chan_id 1)           	I2C adapter

And indeed, those channel IDs match what's been defined in the DTB, with
#0 set to i2c0_gpio0 (e.g. LED matrix on 40-pin header) and #1 set to
i2c0_gpio44 (e.g. RTC, fan control, etc.), which seem quite consistent
this time:

 - `i2cdetect -y 4` reports only 74 (the LED matrix);
 - `i2cdetect -y 5` reports 0c, 2f, and 51 as UU (the RTC).


Cheers,
-- 
Cyril Brulebois -- Debian Consultant @ DEBAMAX -- https://debamax.com/

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_______________________________________________
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linux-arm-kernel@lists.infradead.org
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  reply	other threads:[~2022-01-02  6:34 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-31 11:51 [PATCH v3] ARM: dts: bcm2711-rpi-cm4-io: Add rtc on a pinctrl-muxed i2c bus Uwe Kleine-König
2021-12-31 11:51 ` Uwe Kleine-König
2022-01-02  4:33 ` Cyril Brulebois
2022-01-02  4:33   ` Cyril Brulebois
2022-01-02  6:34   ` Cyril Brulebois [this message]
2022-01-02  6:34     ` Cyril Brulebois
2022-01-18 19:45 ` Jean-Michel Hautbois
2022-01-18 19:45   ` Jean-Michel Hautbois
2022-01-18 20:00   ` Florian Fainelli
2022-01-18 20:00     ` Florian Fainelli
2022-01-18 20:02     ` Jean-Michel Hautbois
2022-01-18 20:02       ` Jean-Michel Hautbois
2022-01-18 20:47     ` Laurent Pinchart
2022-01-18 20:47       ` Laurent Pinchart
2022-01-18 22:41       ` Uwe Kleine-König
2022-01-18 22:41         ` Uwe Kleine-König
2022-01-18 22:59         ` Laurent Pinchart
2022-01-18 22:59           ` Laurent Pinchart
2022-01-19  9:44           ` Dave Stevenson
2022-01-19  9:44             ` Dave Stevenson
2022-02-25  0:55             ` Florian Fainelli
2022-02-25  0:55               ` Florian Fainelli

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