From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Mark Brown <broonie@kernel.org>, Daniel Mack <daniel@zonque.org>,
Haojian Zhuang <haojian.zhuang@gmail.com>,
Robert Jarzmik <robert.jarzmik@free.fr>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
linux-spi <linux-spi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH RFC 2/2] spi: pxa2xx: Only claim CS GPIOs when the slave device is created
Date: Fri, 4 Aug 2017 13:29:29 +0300 [thread overview]
Message-ID: <20170804102929.GY2369@lahna.fi.intel.com> (raw)
In-Reply-To: <5a691263ccf9d61134d6184861b37eaf37b13b77.1501760433.git.jan.kiszka@siemens.com>
On Thu, Aug 03, 2017 at 01:40:33PM +0200, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
>
> Avoid hogging chip select GPIOs just because they are listed for the
> master. They might be mulitplexed and, if no slave device is attached,
> used for different purposes. Moreover, this strategy avoids having to
> allocate a cs_gpiods structure.
>
> Tested on the IOT2000 where the second SPI bus is connected to an
> Arduino-compatible connector and multiplexed between SPI, GPIO and PWM
> usage.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
WARNING: multiple messages have this Message-ID (diff)
From: Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
To: Jan Kiszka <jan.kiszka-kv7WeFo6aLtBDgjK7y7TUQ@public.gmane.org>
Cc: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Daniel Mack <daniel-cYrQPVfZoowdnm+yROfE0A@public.gmane.org>,
Haojian Zhuang
<haojian.zhuang-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Robert Jarzmik <robert.jarzmik-GANU6spQydw@public.gmane.org>,
Andy Shevchenko
<andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
linux-spi <linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Linux Kernel Mailing List
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-arm-kernel
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH RFC 2/2] spi: pxa2xx: Only claim CS GPIOs when the slave device is created
Date: Fri, 4 Aug 2017 13:29:29 +0300 [thread overview]
Message-ID: <20170804102929.GY2369@lahna.fi.intel.com> (raw)
In-Reply-To: <5a691263ccf9d61134d6184861b37eaf37b13b77.1501760433.git.jan.kiszka-kv7WeFo6aLtBDgjK7y7TUQ@public.gmane.org>
On Thu, Aug 03, 2017 at 01:40:33PM +0200, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka-kv7WeFo6aLtBDgjK7y7TUQ@public.gmane.org>
>
> Avoid hogging chip select GPIOs just because they are listed for the
> master. They might be mulitplexed and, if no slave device is attached,
> used for different purposes. Moreover, this strategy avoids having to
> allocate a cs_gpiods structure.
>
> Tested on the IOT2000 where the second SPI bus is connected to an
> Arduino-compatible connector and multiplexed between SPI, GPIO and PWM
> usage.
>
> Signed-off-by: Jan Kiszka <jan.kiszka-kv7WeFo6aLtBDgjK7y7TUQ@public.gmane.org>
Acked-by: Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
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WARNING: multiple messages have this Message-ID (diff)
From: mika.westerberg@linux.intel.com (Mika Westerberg)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH RFC 2/2] spi: pxa2xx: Only claim CS GPIOs when the slave device is created
Date: Fri, 4 Aug 2017 13:29:29 +0300 [thread overview]
Message-ID: <20170804102929.GY2369@lahna.fi.intel.com> (raw)
In-Reply-To: <5a691263ccf9d61134d6184861b37eaf37b13b77.1501760433.git.jan.kiszka@siemens.com>
On Thu, Aug 03, 2017 at 01:40:33PM +0200, Jan Kiszka wrote:
> From: Jan Kiszka <jan.kiszka@siemens.com>
>
> Avoid hogging chip select GPIOs just because they are listed for the
> master. They might be mulitplexed and, if no slave device is attached,
> used for different purposes. Moreover, this strategy avoids having to
> allocate a cs_gpiods structure.
>
> Tested on the IOT2000 where the second SPI bus is connected to an
> Arduino-compatible connector and multiplexed between SPI, GPIO and PWM
> usage.
>
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
next prev parent reply other threads:[~2017-08-04 10:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-03 11:40 [PATCH RFC 0/2] spi: pxa2xx: gpiod cleanups and late CS GPIO allocation Jan Kiszka
2017-08-03 11:40 ` Jan Kiszka
2017-08-03 11:40 ` [PATCH RFC 1/2] spi: pxa2xx: Convert to GPIO descriptor API where possible Jan Kiszka
2017-08-03 11:40 ` Jan Kiszka
2017-08-03 11:40 ` Jan Kiszka
2017-08-04 10:10 ` Mika Westerberg
2017-08-04 10:10 ` Mika Westerberg
2017-08-04 10:10 ` Mika Westerberg
2017-08-04 10:18 ` Jan Kiszka
2017-08-04 10:18 ` Jan Kiszka
2017-08-04 10:18 ` Jan Kiszka
2017-08-04 10:24 ` Mika Westerberg
2017-08-04 10:24 ` Mika Westerberg
2017-08-04 10:24 ` Mika Westerberg
2017-08-04 11:43 ` Mark Brown
2017-08-04 11:43 ` Mark Brown
2017-08-04 11:43 ` Mark Brown
2017-08-04 11:44 ` Applied "spi: pxa2xx: Convert to GPIO descriptor API where possible" to the spi tree Mark Brown
2017-08-04 11:44 ` Mark Brown
2017-08-04 11:44 ` Mark Brown
2017-08-03 11:40 ` [PATCH RFC 2/2] spi: pxa2xx: Only claim CS GPIOs when the slave device is created Jan Kiszka
2017-08-03 11:40 ` Jan Kiszka
2017-08-03 11:40 ` Jan Kiszka
2017-08-04 10:29 ` Mika Westerberg [this message]
2017-08-04 10:29 ` Mika Westerberg
2017-08-04 10:29 ` Mika Westerberg
2017-08-04 11:43 ` Mark Brown
2017-08-04 11:43 ` Mark Brown
2017-08-04 11:43 ` Mark Brown
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