[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <aec7e5c30810210540p6b50562ax50b0cdd9af9e12e7@mail.gmail.com>
Date: Tue, 21 Oct 2008 21:40:41 +0900
From: "Magnus Damm" <magnus.damm@...il.com>
To: "David Brownell" <david-b@...bell.net>
Cc: "Andrew Morton" <akpm@...ux-foundation.org>,
spi-devel-general@...ts.sourceforge.net,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [patch 2.6.27-git] spi_gpio driver
On Mon, Oct 20, 2008 at 1:24 PM, David Brownell <david-b@...bell.net> wrote:
> From: David Brownell <dbrownell@...rs.sourceforge.net>
>
> Generalize the old at91rm9200 "bootstrap" bitbanging SPI master driver
> as "spi_gpio", so it works with arbitrary GPIOs and can be configured
> through platform_data. Such SPI masters support:
>
> - any number of bus instances (bus_num is the platform_device.id)
> - any number of chipselects (one GPIO per spi_device)
> - all four SPI_MODE values, and SPI_CS_HIGH
> - i/o word sizes from 1 to 32 bits;
> - devices configured as with any other spi_master controller
>
> When configured using platform_data, this provides relatively low clock
> rates. On platforms that support inlined GPIO calls, significantly
> improved transfer speeds are also possible with a semi-custom driver.
> (It's still painful when accessing flash memory, but less so.)
>
> Sanity checked by using this version to replace both native controllers
> on a board with six different SPI slaves, relying on three different
> SPI_MODE_* values and both SPI_CS_HIGH settings for correct operation.
>
> Signed-off-by: David Brownell <dbrownell@...rs.sourceforge.net>
Works fine on SuperH together with the mmc_spi driver. Thanks!
Acked-by: Magnus Damm <damm@...l.co.jp>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists