From: shawnguo@kernel.org (Shawn Guo)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] spi: imx: set correct chip_select in platform setup
Date: Mon, 20 Mar 2017 15:38:16 +0800 [thread overview]
Message-ID: <20170320073815.GD3443@dragon> (raw)
In-Reply-To: <1489726983-17706-2-git-send-email-gerg@linux-m68k.org>
On Fri, Mar 17, 2017 at 03:03:02PM +1000, Greg Ungerer wrote:
> Some platform based configuration setup of spi-imx SPI devices does
> not set the "chip_select" to the actual hardware chip select used.
> This works because the cs_gpio mapping that is associated with this
> platform setup maps the chip_select offset used to the appropriate
> hardware chip select. The spi-imx driver uses the chip_select as an
> index into the cs_gpio array and ultimately gets the correct hardware
> chip select for its hardware setup.
>
> The motivation is to be able to eventually modify the spi-imx code to
> use the "chip_select" directly for harwdare setup instead of indirectly
> via the cs_gpio mapping array.
>
> This change only affects platforms using the hardware chip select
> addressing method for their SPI devices (sometimes called native chip
> select). The majority of devices using the spi-imx driver use the GPIO
> addressing method.
>
> The change to use the correct "chip_select" is strait forward. But the
> cs_gpio mapping arrary also needs to be modifed to match that change. In
> simple terms the cs_gpio mapping should always have the hardware chip
> select number at its same index offset.
>
> There is no functional change with these patches. The three affected
> platforms should work exactly as before. However I don't have any of
> these platforms (or access to them) and so I can't test them. So this
> patch is compile tested only.
>
> Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
The subject prefix should be 'ARM: imx: ...'.
Since the patch can go independently, I fix up the prefix and applied
the patch. Thanks.
Shawn
next prev parent reply other threads:[~2017-03-20 7:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-17 5:03 [PATCH 0/2] spi: imx: native chip selects and devicetree Greg Ungerer
2017-03-17 5:03 ` [PATCH 1/2] spi: imx: set correct chip_select in platform setup Greg Ungerer
2017-03-20 7:38 ` Shawn Guo [this message]
2017-03-20 11:52 ` Greg Ungerer
2017-03-17 5:03 ` [PATCH 2/2] spi: imx: fix use of native chip-selects with devicetree Greg Ungerer
2017-03-20 7:39 ` Shawn Guo
2017-03-20 13:22 ` Vladimir Zapolskiy
2017-03-21 2:05 ` Greg Ungerer
2017-03-21 8:05 ` Uwe Kleine-König
2017-03-21 11:53 ` Greg Ungerer
2017-03-21 12:11 ` Uwe Kleine-König
2017-03-21 13:22 ` Greg Ungerer
2017-03-21 19:23 ` Uwe Kleine-König
2017-03-21 20:15 ` Geert Uytterhoeven
2017-03-22 0:50 ` Greg Ungerer
2017-03-22 7:09 ` Geert Uytterhoeven
2017-09-04 12:47 ` Applied "spi: imx: fix use of native chip-selects with devicetree" to the spi tree Mark Brown
2017-10-10 20:38 ` [2/2] spi: imx: fix use of native chip-selects with devicetree Trent Piepho
2017-10-12 6:26 ` Greg Ungerer
2017-10-12 20:41 ` Trent Piepho
2017-03-20 7:35 ` [PATCH 0/2] spi: imx: native chip selects and devicetree Shawn Guo
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