* [BUG] vf610-zii-dev-rev-b SPI fails at boot
@ 2019-02-21 15:24 Russell King - ARM Linux admin
2019-02-21 15:59 ` [PATCH] spi: spi-gpio: fix SPI_CS_HIGH capability Russell King
0 siblings, 1 reply; 4+ messages in thread
From: Russell King - ARM Linux admin @ 2019-02-21 15:24 UTC (permalink / raw)
To: linux-arm-kernel, Mark Brown, linux-spi, Lorenzo Bianconi
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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^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] spi: spi-gpio: fix SPI_CS_HIGH capability
2019-02-21 15:24 [BUG] vf610-zii-dev-rev-b SPI fails at boot Russell King - ARM Linux admin
@ 2019-02-21 15:59 ` Russell King
2019-02-21 16:14 ` Fabio Estevam
0 siblings, 1 reply; 4+ messages in thread
From: Russell King @ 2019-02-21 15:59 UTC (permalink / raw)
To: Mark Brown, Lorenzo Bianconi; +Cc: linux-arm-kernel, linux-spi
spi-gpio is capable of dealing with active-high chip-selects.
Unfortunately, commit 4b859db2c606 ("spi: spi-gpio: add SPI_3WIRE
support") broke this by setting master->mode_bits, which overrides
the setting in the spi-bitbang code. Fix this.
Fixes: 4b859db2c606 ("spi: spi-gpio: add SPI_3WIRE support")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
Patch against 4.20
drivers/spi/spi-gpio.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c
index 45973ee3ae11..2d7cfe3c7732 100644
--- a/drivers/spi/spi-gpio.c
+++ b/drivers/spi/spi-gpio.c
@@ -410,7 +410,7 @@ static int spi_gpio_probe(struct platform_device *pdev)
return status;
master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
- master->mode_bits = SPI_3WIRE | SPI_CPHA | SPI_CPOL;
+ master->mode_bits = SPI_3WIRE | SPI_CPHA | SPI_CPOL | SPI_CS_HIGH;
master->flags = master_flags;
master->bus_num = pdev->id;
/* The master needs to think there is a chipselect even if not connected */
@@ -437,7 +437,6 @@ static int spi_gpio_probe(struct platform_device *pdev)
spi_gpio->bitbang.txrx_word[SPI_MODE_3] = spi_gpio_spec_txrx_word_mode3;
}
spi_gpio->bitbang.setup_transfer = spi_bitbang_setup_transfer;
- spi_gpio->bitbang.flags = SPI_CS_HIGH;
status = spi_bitbang_start(&spi_gpio->bitbang);
if (status)
--
2.7.4
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] spi: spi-gpio: fix SPI_CS_HIGH capability
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
0 siblings, 1 reply; 4+ messages in thread
From: Fabio Estevam @ 2019-02-21 16:14 UTC (permalink / raw)
To: Russell King, Jonathan Neuschäfer
Cc: Lorenzo Bianconi, Mark Brown,
moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE,
linux-spi
On Thu, Feb 21, 2019 at 1:00 PM Russell King <rmk+kernel@armlinux.org.uk> wrote:
>
> spi-gpio is capable of dealing with active-high chip-selects.
> Unfortunately, commit 4b859db2c606 ("spi: spi-gpio: add SPI_3WIRE
> support") broke this by setting master->mode_bits, which overrides
> the setting in the spi-bitbang code. Fix this.
>
> Fixes: 4b859db2c606 ("spi: spi-gpio: add SPI_3WIRE support")
> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> ---
> Patch against 4.20
Adding Jonathan who sent a similar fix recently:
https://patchwork.kernel.org/patch/10804855/
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] spi: spi-gpio: fix SPI_CS_HIGH capability
2019-02-21 16:14 ` Fabio Estevam
@ 2019-02-21 19:21 ` Jonathan Neuschäfer
0 siblings, 0 replies; 4+ messages in thread
From: Jonathan Neuschäfer @ 2019-02-21 19:21 UTC (permalink / raw)
To: Fabio Estevam
Cc: Jonathan Neuschäfer, linux-spi, Russell King, Mark Brown,
Lorenzo Bianconi,
moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE
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On Thu, Feb 21, 2019 at 01:14:04PM -0300, Fabio Estevam wrote:
> On Thu, Feb 21, 2019 at 1:00 PM Russell King <rmk+kernel@armlinux.org.uk> wrote:
> >
> > spi-gpio is capable of dealing with active-high chip-selects.
> > Unfortunately, commit 4b859db2c606 ("spi: spi-gpio: add SPI_3WIRE
> > support") broke this by setting master->mode_bits, which overrides
> > the setting in the spi-bitbang code. Fix this.
> >
> > Fixes: 4b859db2c606 ("spi: spi-gpio: add SPI_3WIRE support")
> > Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
> > ---
> > Patch against 4.20
>
> Adding Jonathan who sent a similar fix recently:
> https://patchwork.kernel.org/patch/10804855/
Hello Russel,
your patch looks better, and I think Mark Brown has already applied it.
Thanks.
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2019-02-21 15:24 [BUG] vf610-zii-dev-rev-b SPI fails at boot Russell King - ARM Linux admin
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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