From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: linux-arm-kernel@lists.infradead.org,
Mark Brown <broonie@kernel.org>,
linux-spi@vger.kernel.org,
Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Subject: [BUG] vf610-zii-dev-rev-b SPI fails at boot
Date: Thu, 21 Feb 2019 15:24:59 +0000 [thread overview]
Message-ID: <20190221152459.axrjce7yqkjmedgl@shell.armlinux.org.uk> (raw)
While booting 4.20 on the ZII development revision B board, I notice
this in the kernel logs:
spi spi0.1: setup: unsupported mode bits 4
spi_gpio spi0: can't setup spi0.1, status -22
spi_master spi0: spi_device register error /spi0/at93c46d@1
spi_master spi0: Failed to create SPI device for /spi0/at93c46d@1
This is for the at93c46d@1 device attached to spi-gpio (see
arch/arm/boot/dts/vf610-zii-dev-rev-b.dts around line 330). This
is declared with "spi-cs-high;" in DT. It appears to be complaining
about the SPI_CS_HIGH flag.
It appears this warning comes from drivers/spi/spi.c around lines
2828-2847 due to:
bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD);
and it looks like spi-gpio sets:
master->mode_bits = SPI_3WIRE | SPI_CPHA | SPI_CPOL;
but then goes on to set:
spi_gpio->bitbang.flags = SPI_CS_HIGH;
However, this is ignored by bitbang if master->mode_bits has already
been set:
if (!master->mode_bits)
master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
It looks like this commit introduced for v4.19 broke the driver:
commit 4b859db2c60692560afbfef1b030d0ddef57b7ee
Author: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Date: Sat Jul 28 10:19:14 2018 +0200
by setting master->mode_bits - prior to this, bitbang would have set
the mode bits itself.
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
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next reply other threads:[~2019-02-21 15:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-21 15:24 Russell King - ARM Linux admin [this message]
2019-02-21 15:59 ` [PATCH] spi: spi-gpio: fix SPI_CS_HIGH capability Russell King
2019-02-21 16:14 ` Fabio Estevam
2019-02-21 19:21 ` Jonathan Neuschäfer
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