From: Mark Brown <broonie@kernel.org>
To: Jon Lin <jon.lin@rock-chips.com>
Cc: heiko@sntech.de, linux-spi@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/6] spi: rockchip: Preset cs-high and clk polarity in setup progress
Date: Tue, 15 Feb 2022 12:36:40 +0000 [thread overview]
Message-ID: <YgueWHKur2w55s+0@sirena.org.uk> (raw)
In-Reply-To: <e0f0ca0d-40df-cf86-9471-9272bcc171f9@rock-chips.com>
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On Tue, Feb 15, 2022 at 11:00:54AM +0800, Jon Lin wrote:
> 在 2022/2/14 20:49, Mark Brown 写道:
> > As covered in the documentation setup() for one device may run while
> > another is active, therefore if multiple devices are configured in the
> > same register you should use a lock to ensure there can't be multiple
> > writes. Note that the above appears to not just be setting the mode but
> > also the chip select so if you've got two SPI_CS_HIGH devices then
> > they'll both be going in and separately setting cr0.
> Is the io_mutex in function spi_setup is good enough?
It's not supposed to be for that but looking at the code quickly I
*think* setup() is never called with io_mutex held so it might well be
fine - you should double check though. If not you'd need to add another
lock in your driver data.
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WARNING: multiple messages have this Message-ID (diff)
From: Mark Brown <broonie@kernel.org>
To: Jon Lin <jon.lin@rock-chips.com>
Cc: heiko@sntech.de, linux-spi@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/6] spi: rockchip: Preset cs-high and clk polarity in setup progress
Date: Tue, 15 Feb 2022 12:36:40 +0000 [thread overview]
Message-ID: <YgueWHKur2w55s+0@sirena.org.uk> (raw)
In-Reply-To: <e0f0ca0d-40df-cf86-9471-9272bcc171f9@rock-chips.com>
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On Tue, Feb 15, 2022 at 11:00:54AM +0800, Jon Lin wrote:
> 在 2022/2/14 20:49, Mark Brown 写道:
> > As covered in the documentation setup() for one device may run while
> > another is active, therefore if multiple devices are configured in the
> > same register you should use a lock to ensure there can't be multiple
> > writes. Note that the above appears to not just be setting the mode but
> > also the chip select so if you've got two SPI_CS_HIGH devices then
> > they'll both be going in and separately setting cr0.
> Is the io_mutex in function spi_setup is good enough?
It's not supposed to be for that but looking at the code quickly I
*think* setup() is never called with io_mutex held so it might well be
fine - you should double check though. If not you'd need to add another
lock in your driver data.
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http://lists.infradead.org/mailman/listinfo/linux-rockchip
WARNING: multiple messages have this Message-ID (diff)
From: Mark Brown <broonie@kernel.org>
To: Jon Lin <jon.lin@rock-chips.com>
Cc: heiko@sntech.de, linux-spi@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/6] spi: rockchip: Preset cs-high and clk polarity in setup progress
Date: Tue, 15 Feb 2022 12:36:40 +0000 [thread overview]
Message-ID: <YgueWHKur2w55s+0@sirena.org.uk> (raw)
In-Reply-To: <e0f0ca0d-40df-cf86-9471-9272bcc171f9@rock-chips.com>
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On Tue, Feb 15, 2022 at 11:00:54AM +0800, Jon Lin wrote:
> 在 2022/2/14 20:49, Mark Brown 写道:
> > As covered in the documentation setup() for one device may run while
> > another is active, therefore if multiple devices are configured in the
> > same register you should use a lock to ensure there can't be multiple
> > writes. Note that the above appears to not just be setting the mode but
> > also the chip select so if you've got two SPI_CS_HIGH devices then
> > they'll both be going in and separately setting cr0.
> Is the io_mutex in function spi_setup is good enough?
It's not supposed to be for that but looking at the code quickly I
*think* setup() is never called with io_mutex held so it might well be
fine - you should double check though. If not you'd need to add another
lock in your driver data.
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_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-02-15 12:36 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-11 3:43 [PATCH 1/6] spi: rockchip: Stop spi slave dma receiver when cs inactive Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` [PATCH 2/6] spi: rockchip: Preset cs-high and clk polarity in setup progress Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 11:24 ` Mark Brown
2022-02-11 11:24 ` Mark Brown
2022-02-11 11:24 ` Mark Brown
[not found] ` <4222ce7d-a1e3-1728-fec2-976946b06ba9@rock-chips.com>
2022-02-14 12:49 ` Mark Brown
2022-02-14 12:49 ` Mark Brown
2022-02-14 12:49 ` Mark Brown
[not found] ` <e0f0ca0d-40df-cf86-9471-9272bcc171f9@rock-chips.com>
2022-02-15 12:36 ` Mark Brown [this message]
2022-02-15 12:36 ` Mark Brown
2022-02-15 12:36 ` Mark Brown
2022-02-16 1:23 ` Jon Lin
2022-02-16 1:23 ` Jon Lin
2022-02-16 1:23 ` Jon Lin
2022-02-11 3:43 ` [PATCH 3/6] spi: rockchip: Fix error in getting num-cs property Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 11:25 ` Mark Brown
2022-02-11 11:25 ` Mark Brown
2022-02-11 11:25 ` Mark Brown
2022-02-11 3:43 ` [PATCH 4/6] spi: rockchip: Suspend and resume the bus during NOIRQ_SYSTEM_SLEEP_PM ops Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` [PATCH v10 5/6] spi: rockchip: Support cs-gpio Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 11:48 ` Mark Brown
2022-02-11 11:48 ` Mark Brown
2022-02-11 11:48 ` Mark Brown
2022-02-11 3:43 ` [PATCH 5/6] spi: rockchip: terminate dma transmission when slave abort Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 11:49 ` Mark Brown
2022-02-11 11:49 ` Mark Brown
2022-02-11 11:49 ` Mark Brown
2022-02-11 3:43 ` [PATCH 6/6] spi: rockchip: clear interrupt status in error handler Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` [PATCH v10 6/6] spi: rockchip: Support SPI_CS_HIGH Jon Lin
2022-02-11 3:43 ` Jon Lin
2022-02-11 3:43 ` Jon Lin
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