Date: Sun, 4 Dec 2011 10:19:53 -0700 From: Warner Losh <imp@bsdimp.com> To: Stefan Bethke <stb@lassitu.de> Cc: freebsd-embedded@FreeBSD.org Subject: Re: ar71xx_gpio.c touches SPI_CS1 and 2? Message-ID: <2B6F6CAC-F4EF-4958-A435-579A69862AE5@bsdimp.com> In-Reply-To: <A78C6CC2-A6C9-42CC-B128-871C34C201CD@lassitu.de> References: <A78C6CC2-A6C9-42CC-B128-871C34C201CD@lassitu.de>
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On Dec 4, 2011, at 5:14 AM, Stefan Bethke wrote: > I was looking into why I can't manipulate the USB led on my TL-WR1043ND, and came across the SPI chip selects, which share GPIO 0 and 1, respectively. The USB led is hooked up to GPIO 1. > > sys/mips/atheros/ar71xx_gpio.c:ar71xx_gpio_attach(device_t dev) enables both chip selects, and detach disables them again. > > Two points: > > - how can we express different uses for those two pins on a per-board config? > > - disabling the function is not correct for the gpio driver, I would think. If you load and unload it as a module, I expect losing access to the flash. When I was looking into this question for the Atmel chips, I was torn. On the one hand, it would be nice if there was a pin mux device. On the other hand, it didn't map well into the device model. I finally settled on having per-board functions that setup the pins. This is also the model followed by linux. Either the boot loader or the board-dependent code would do the setup. Warnerhelp
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