From: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public•gmane.org>
To: Michael Welling <mwelling-EkmVulN54Sk@public•gmane.org>
Cc: linux-omap-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public•gmane.org,
linux-next-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
linux-spi-u79uwXL29TY76Z2rM5mHXA@public•gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public•gmane.org
Subject: Re: [PATCH] spi: omap2-mcspi: Fix native cs with new set_cs
Date: Fri, 22 May 2015 13:25:44 +0100 [thread overview]
Message-ID: <20150522122544.GL21391@sirena.org.uk> (raw)
In-Reply-To: <20150521234832.GA1827@deathray>
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On Thu, May 21, 2015 at 06:48:33PM -0500, Michael Welling wrote:
> So after reverting this patch I found there is a issue in that it is difficult
> to determine when a transfer is complete to properly drive the chipselect from
> within the transfer_one function.
Is unprepare_message() a suitable place here? I've got a feeling the
answer is no...
> Then I figured that we could handle the case when GPIOs are being used with
> some conditional calls to omap2_mcspi_set_cs in the omap2_mcspi_work_one
> function.
>
> Near the beginning of the function I added:
> if (gpio_is_valid(spi->cs_gpio))
> omap2_mcspi_set_cs(spi, 0);
>
> Near the end of the function I added:
> if (gpio_is_valid(spi->cs_gpio))
> omap2_mcspi_set_cs(spi, 1);
>
> This makes GPIO chip select support work while leaving the native working
> as previous.
>
> Is this solution acceptible?
I think that's probably OK as well, it's not ideal though (and risky if
the chip select is routed somewhere...).
> In the process of reviewing the changes I found a few other things that
> should be changed as well.
Please send fixes for these as separate patches (ideally without any
dependency on your new work so we can send them to Linus as fixes).
> Here you will see a delay that is already handled by the core spi driver:
> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/tree/drivers/spi/spi-omap2-mcspi.c#n1166
I can't actually see that since I have no internet access right now!
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next prev parent reply other threads:[~2015-05-22 12:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-12 17:38 [PATCH] spi: omap2-mcspi: Fix native cs with new set_cs Michael Welling
2015-05-12 18:57 ` Nishanth Menon
[not found] ` <55524D20.2050203-l0cyMroinI0@public.gmane.org>
2015-05-12 19:19 ` Mark Brown
2015-05-12 19:21 ` Nishanth Menon
2015-05-12 19:17 ` Mark Brown
[not found] ` <20150512191758.GX3066-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2015-05-21 2:07 ` Michael Welling
2015-05-21 10:18 ` Mark Brown
2015-05-21 21:04 ` Michael Welling
2015-05-21 21:16 ` Mark Brown
2015-05-21 23:48 ` Michael Welling
2015-05-22 12:25 ` Mark Brown [this message]
2015-05-22 15:31 ` Michael Welling
2015-05-24 2:13 ` [PATCH 0/4] spi: omap2-mcspi: Fixes for recent updates Michael Welling
2015-05-24 2:13 ` [PATCH 1/4] spi: omap2-mcspi: Remove unnecessary delay Michael Welling
2015-05-24 2:13 ` [PATCH 2/4] spi: omap2-mcspi: Fix set_cs function for active high Michael Welling
2015-05-24 2:13 ` [PATCH 3/4] spi: omap2-mcspi: Fix GPIO chip select support Michael Welling
2015-05-24 2:13 ` [PATCH 4/4] spi: omap2-mcspi: Handle error on gpio_request Michael Welling
2015-05-24 8:13 ` Nicholas Mc Guire
2015-05-24 16:52 ` Michael Welling
[not found] ` <1432433625-23407-1-git-send-email-mwelling-EkmVulN54Sk@public.gmane.org>
2015-05-25 12:00 ` [PATCH 0/4] spi: omap2-mcspi: Fixes for recent updates Mark Brown
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