From: Girish KS <girishks2000@gmail.com>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: spi-devel-general@lists.sourceforge.net,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 3/4] spi: s3c64xx: add gpio quirk for controller
Date: Thu, 7 Feb 2013 10:54:01 -0800 [thread overview]
Message-ID: <CAKrE-KfrWdOxm+DJyWqZn1Ye509E_LjzmDb5FMq55SF9-Sua0A@mail.gmail.com> (raw)
In-Reply-To: <20130207115546.GA3801@sirena.org.uk>
On Thu, Feb 7, 2013 at 3:55 AM, Mark Brown
<broonie@opensource.wolfsonmicro.com> wrote:
> On Tue, Feb 05, 2013 at 03:09:43PM -0800, Girish K S wrote:
>> This patch adds support for spi controllers with
>> dedicated clk/miso/mosi/cs pins. It skips the gpio
>> parsing and initialization for controllers that
>> have dedicated pins.
>
>> if (sdd->tgl_spi != spi) { /* if last mssg on diff device */
>> /* Deselect the last toggled device */
>> cs = sdd->tgl_spi->controller_data;
>> - gpio_set_value(cs->line,
>> - spi->mode & SPI_CS_HIGH ? 0 : 1);
>> + if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_GPIO))
>> + gpio_set_value(cs->line,
>> + spi->mode & SPI_CS_HIGH ? 0 : 1);
>> }
>
> This isn't going to work with system designs which ignore the /CS line
> the controller has and just use a GPIO instead. This is very common,
> for example when connecting multiple devices to the same SPI bus.
As per grant's comment i would remove the quirk option and check for
"cs-gpio" property
to handle /CS. When multiple devices are connected to the same spi
bus, "cs-gpio" entry would exist in the dts
file, and works with /CS gpio lines.
>
> It seems like there's really two changes here. One change is making the
> provision of pinmux information optional, the other is allowing the user
> to use the controller /CS management rather than using GPIO.
As suggested i would make two changes.
1. would parse the "gpios" property and make decision whether to use
gpios/dedicated pins for miso/miso/clk.
2.would parse "cs-gpio" property from dts node to handle the chip select
correct me if my understanding is wrong
WARNING: multiple messages have this Message-ID (diff)
From: Girish KS <girishks2000-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Mark Brown
<broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH 3/4] spi: s3c64xx: add gpio quirk for controller
Date: Thu, 7 Feb 2013 10:54:01 -0800 [thread overview]
Message-ID: <CAKrE-KfrWdOxm+DJyWqZn1Ye509E_LjzmDb5FMq55SF9-Sua0A@mail.gmail.com> (raw)
In-Reply-To: <20130207115546.GA3801-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
On Thu, Feb 7, 2013 at 3:55 AM, Mark Brown
<broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org> wrote:
> On Tue, Feb 05, 2013 at 03:09:43PM -0800, Girish K S wrote:
>> This patch adds support for spi controllers with
>> dedicated clk/miso/mosi/cs pins. It skips the gpio
>> parsing and initialization for controllers that
>> have dedicated pins.
>
>> if (sdd->tgl_spi != spi) { /* if last mssg on diff device */
>> /* Deselect the last toggled device */
>> cs = sdd->tgl_spi->controller_data;
>> - gpio_set_value(cs->line,
>> - spi->mode & SPI_CS_HIGH ? 0 : 1);
>> + if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_GPIO))
>> + gpio_set_value(cs->line,
>> + spi->mode & SPI_CS_HIGH ? 0 : 1);
>> }
>
> This isn't going to work with system designs which ignore the /CS line
> the controller has and just use a GPIO instead. This is very common,
> for example when connecting multiple devices to the same SPI bus.
As per grant's comment i would remove the quirk option and check for
"cs-gpio" property
to handle /CS. When multiple devices are connected to the same spi
bus, "cs-gpio" entry would exist in the dts
file, and works with /CS gpio lines.
>
> It seems like there's really two changes here. One change is making the
> provision of pinmux information optional, the other is allowing the user
> to use the controller /CS management rather than using GPIO.
As suggested i would make two changes.
1. would parse the "gpios" property and make decision whether to use
gpios/dedicated pins for miso/miso/clk.
2.would parse "cs-gpio" property from dts node to handle the chip select
correct me if my understanding is wrong
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WARNING: multiple messages have this Message-ID (diff)
From: girishks2000@gmail.com (Girish KS)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/4] spi: s3c64xx: add gpio quirk for controller
Date: Thu, 7 Feb 2013 10:54:01 -0800 [thread overview]
Message-ID: <CAKrE-KfrWdOxm+DJyWqZn1Ye509E_LjzmDb5FMq55SF9-Sua0A@mail.gmail.com> (raw)
In-Reply-To: <20130207115546.GA3801@sirena.org.uk>
On Thu, Feb 7, 2013 at 3:55 AM, Mark Brown
<broonie@opensource.wolfsonmicro.com> wrote:
> On Tue, Feb 05, 2013 at 03:09:43PM -0800, Girish K S wrote:
>> This patch adds support for spi controllers with
>> dedicated clk/miso/mosi/cs pins. It skips the gpio
>> parsing and initialization for controllers that
>> have dedicated pins.
>
>> if (sdd->tgl_spi != spi) { /* if last mssg on diff device */
>> /* Deselect the last toggled device */
>> cs = sdd->tgl_spi->controller_data;
>> - gpio_set_value(cs->line,
>> - spi->mode & SPI_CS_HIGH ? 0 : 1);
>> + if (!(sdd->port_conf->quirks & S3C64XX_SPI_QUIRK_GPIO))
>> + gpio_set_value(cs->line,
>> + spi->mode & SPI_CS_HIGH ? 0 : 1);
>> }
>
> This isn't going to work with system designs which ignore the /CS line
> the controller has and just use a GPIO instead. This is very common,
> for example when connecting multiple devices to the same SPI bus.
As per grant's comment i would remove the quirk option and check for
"cs-gpio" property
to handle /CS. When multiple devices are connected to the same spi
bus, "cs-gpio" entry would exist in the dts
file, and works with /CS gpio lines.
>
> It seems like there's really two changes here. One change is making the
> provision of pinmux information optional, the other is allowing the user
> to use the controller /CS management rather than using GPIO.
As suggested i would make two changes.
1. would parse the "gpios" property and make decision whether to use
gpios/dedicated pins for miso/miso/clk.
2.would parse "cs-gpio" property from dts node to handle the chip select
correct me if my understanding is wrong
next prev parent reply other threads:[~2013-02-07 18:54 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-05 23:09 [PATCH 0/4] Add polling support for 64xx spi controller Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-05 23:09 ` [PATCH 1/4] spi: s3c64xx: modified error interrupt handling and init Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-06 10:26 ` Grant Likely
2013-02-06 10:26 ` Grant Likely
2013-02-06 10:26 ` Grant Likely
2013-02-06 20:12 ` Girish KS
2013-02-06 20:12 ` Girish KS
2013-02-06 20:12 ` Girish KS
2013-02-06 23:48 ` Grant Likely
2013-02-06 23:48 ` Grant Likely
2013-02-06 23:48 ` Grant Likely
2013-02-07 0:33 ` Girish KS
2013-02-07 0:33 ` Girish KS
2013-02-07 0:33 ` Girish KS
2013-02-08 1:04 ` Girish KS
2013-02-08 1:04 ` Girish KS
2013-02-08 1:04 ` Girish KS
2013-02-08 8:16 ` Girish KS
2013-02-08 8:16 ` Girish KS
2013-02-08 8:16 ` Girish KS
2013-02-07 11:09 ` Tomasz Figa
2013-02-07 11:09 ` Tomasz Figa
2013-02-07 17:46 ` Girish KS
2013-02-07 17:46 ` Girish KS
2013-02-07 17:46 ` Girish KS
2013-02-08 8:33 ` Tomasz Figa
2013-02-08 8:33 ` Tomasz Figa
2013-02-08 8:33 ` Tomasz Figa
2013-02-08 8:58 ` Girish KS
2013-02-08 8:58 ` Girish KS
2013-02-08 8:58 ` Girish KS
2013-02-08 9:26 ` Girish KS
2013-02-08 9:26 ` Girish KS
2013-02-08 9:26 ` Girish KS
2013-02-05 23:09 ` [PATCH 2/4] spi: s3c64xx: added support for polling mode Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-06 10:35 ` Grant Likely
2013-02-06 10:35 ` Grant Likely
2013-02-06 10:35 ` Grant Likely
2013-02-06 22:04 ` Girish KS
2013-02-06 22:04 ` Girish KS
2013-02-06 22:04 ` Girish KS
2013-02-05 23:09 ` [PATCH 3/4] spi: s3c64xx: add gpio quirk for controller Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-06 10:40 ` Grant Likely
2013-02-06 10:40 ` Grant Likely
2013-02-06 10:40 ` Grant Likely
2013-02-06 22:38 ` Girish KS
2013-02-06 22:38 ` Girish KS
2013-02-06 22:38 ` Girish KS
2013-02-07 11:55 ` Mark Brown
2013-02-07 11:55 ` Mark Brown
2013-02-07 11:55 ` Mark Brown
2013-02-07 18:54 ` Girish KS [this message]
2013-02-07 18:54 ` Girish KS
2013-02-07 18:54 ` Girish KS
2013-02-08 13:17 ` Mark Brown
2013-02-08 13:17 ` Mark Brown
2013-02-05 23:09 ` [PATCH 4/4] spi: s3c64xx: add support for exynos5440 spi Girish K S
2013-02-05 23:09 ` Girish K S
2013-02-05 23:09 ` Girish K S
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