From: Patrick Menschel <menschel.p@posteo.de>
To: Thomas.Kopp@microchip.com, mkl@pengutronix.de, drew@beagleboard.org
Cc: socketcan@hartkopp.net, linux-can@vger.kernel.org, josh@macchina.cc
Subject: Re: mcp251xfd on RPi 5.4 downstream
Date: Mon, 2 Nov 2020 20:32:24 +0100 [thread overview]
Message-ID: <27b696e7-2c05-e8f3-ca3e-d30ceb11a818@posteo.de> (raw)
In-Reply-To: <DM6PR11MB4283DF81AFCFEBB886559B5AFB100@DM6PR11MB4283.namprd11.prod.outlook.com>
>> It may be a blunt guess, but according to page 99
>>
>> https://www.raspberrypi.org/documentation/hardware/raspberrypi/bcm27
>> 11/rpi_DATA_2711_1p0.pdf
>>
>> Pin 26 is pulldown. So it works if it remains unused because the pin is
>> input with pulldown thus the chip is selected by default.
>>
>> I don't know if the CE pin can actually work if there is no matching alt
>> function in pinselect register.
>>
>> --
>> Patrick
> Do you suggest that the communication works with a permanent low on CS/CE?
> Without the CS/CE pin having edges you will not be able to send multiple
> commands. The driver is writing/reading multiple times when bringing up the
> chip. If you have a permanent low that will fail. So somehow the CS does
> generate the right edges.
>
> Thomas
>
As mentioned it's a blunt guess. If there is more to CE functionality
then just enabling the recipient to listen, then I'm obviously wrong.
--
Patrick
next prev parent reply other threads:[~2020-11-02 19:32 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-22 3:10 mcp251xfd on RPi 5.4 downstream Drew Fustini
2020-10-22 6:00 ` Drew Fustini
2020-10-22 6:33 ` Marc Kleine-Budde
2020-10-22 18:42 ` Drew Fustini
2020-10-25 4:30 ` Drew Fustini
2020-10-25 8:49 ` Oliver Hartkopp
2020-10-25 10:58 ` Marc Kleine-Budde
2020-10-25 17:43 ` Patrick Menschel
2020-10-25 18:14 ` Marc Kleine-Budde
2020-10-25 18:42 ` Patrick Menschel
2020-10-26 1:59 ` Drew Fustini
2020-10-26 2:50 ` Drew Fustini
2020-10-26 5:16 ` Patrick Menschel
2020-10-26 7:45 ` Marc Kleine-Budde
2020-10-26 9:40 ` Marc Kleine-Budde
2020-10-26 16:51 ` Patrick Menschel
2020-10-26 17:00 ` Marc Kleine-Budde
2020-10-27 2:22 ` Drew Fustini
2020-10-27 6:35 ` Drew Fustini
2020-10-27 7:06 ` Marc Kleine-Budde
2020-10-27 18:18 ` Patrick Menschel
2020-10-27 18:22 ` Marc Kleine-Budde
2020-10-28 1:57 ` Drew Fustini
2020-10-28 3:47 ` Drew Fustini
2020-10-28 7:57 ` Marc Kleine-Budde
2020-10-31 12:27 ` Drew Fustini
2020-10-31 15:14 ` Patrick Menschel
2020-10-31 15:35 ` Patrick Menschel
2020-10-31 21:57 ` Drew Fustini
2020-11-01 22:49 ` Drew Fustini
2020-11-02 7:25 ` Marc Kleine-Budde
2020-11-02 8:18 ` Marc Kleine-Budde
[not found] ` <CAPgEAj7LcX3cb+syhtR1i3Uo1XkYYFQ_wDPV8GniaA-YwPk2Hg@mail.gmail.com>
2020-11-02 11:00 ` Marc Kleine-Budde
[not found] ` <CAPgEAj7BTJyiBg4QkKuekYH0zyrA-10dby3Lgb5qj2uiD4ZOYQ@mail.gmail.com>
2020-11-02 14:22 ` mcp251xfd: loopback test on waveshare canfd hat Marc Kleine-Budde
2020-11-02 14:35 ` Drew Fustini
2020-11-02 14:38 ` Marc Kleine-Budde
2020-11-02 17:34 ` mcp251xfd on RPi 5.4 downstream Patrick Menschel
2020-11-02 18:47 ` Patrick Menschel
2020-11-02 18:57 ` Thomas.Kopp
2020-11-02 19:32 ` Patrick Menschel [this message]
2020-11-04 18:48 ` Patrick Menschel
2020-11-05 7:15 ` Marc Kleine-Budde
2020-11-05 18:11 ` Patrick Menschel
2020-11-06 9:00 ` Marc Kleine-Budde
2020-11-06 11:31 ` Patrick Menschel
2020-11-06 11:36 ` Marc Kleine-Budde
2020-11-06 11:46 ` Patrick Menschel
2020-11-05 8:08 ` Marc Kleine-Budde
2020-11-05 8:07 ` Marc Kleine-Budde
2020-11-02 7:55 ` Marc Kleine-Budde
2020-11-02 7:26 ` Marc Kleine-Budde
2020-10-26 7:43 ` Marc Kleine-Budde
2020-11-20 12:32 ` Marc Kleine-Budde
[not found] ` <CAEf4M_B68X2T0rkaq0tqahBFPc+Gbvac7-+G0j5jd-g4j+j01g@mail.gmail.com>
2020-11-20 13:16 ` Marc Kleine-Budde
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