From: Stefan Wahren <info@lategoodbye.de>
To: linux-rpi-kernel <linux-rpi-kernel@lists.infradead.org>,
linux-i2c@vger.kernel.org
Subject: i2c-bcm2835: Unable to read from i2c0
Date: Thu, 28 Jan 2016 22:43:17 +0100 [thread overview]
Message-ID: <56AA8B75.9060801@lategoodbye.de> (raw)
Hi,
i'm using a Raspberry Pi B (rev 1) and Linux kernel 4.5rc-1. I have
connected a PiGlow (SN3218 at address 0x54) to the P1 Header. The I2C
bus clock is set to 100 kHz. Every time i want to read data from i2c0
the following error appear:
[ 94.343612] i2c-bcm2835 20205000.i2c: i2c transfer failed: 100
According to the BCM2835 datasheet this should be an ERR ACK (Slave has
not acknowledged its address).
> i2cdetect -y 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
> i2cdetect -q -y 0
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- 54 -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
Strangly writing data to the SN3218 works.
Does anyone have an explanation for this error?
Regards
Stefan
next reply other threads:[~2016-01-28 21:43 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-28 21:43 Stefan Wahren [this message]
[not found] ` <56AA8B75.9060801-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
2016-01-28 22:49 ` i2c-bcm2835: Unable to read from i2c0 Phil
[not found] ` <7de3fd0b-7973-476c-a009-e9a1fb032a80-2ueSQiBKiTY7tOexoI0I+QC/G2K4zDHf@public.gmane.org>
2016-01-29 18:16 ` Stefan Wahren
[not found] ` <56ABAC83.4000402-saaNCTdWVBT7BZbvpMY5sg@public.gmane.org>
2016-01-29 18:47 ` Phil
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