On Wed, Oct 10, 2012 at 10:36:59PM +0200, Carlo Caione wrote: > > On Oct 9, 2012, at 1:31 PM, Jean-Christophe PLAGNIOL-VILLARD <plagnioj@xxxxxxxxxxxx> wrote: > [cut] > > > you should add one bank pre gpio_chip > >> + struct bcm2835_gpio_chip *bcmgpio = container_of(chip, struct bcm2835_gpio_chip, chip); > >> + void __iomem *base = bcmgpio->base; > >> + unsigned gpiodir; > >> + unsigned gpio_bank = gpio / 10; > >> + unsigned gpio_field_offset = (gpio - 10 * gpio_bank) * 3; > > so this will be dropped > >> + > >> + gpiodir = readl(base + GPIOFSEL(gpio_bank)); > >> + gpiodir &= ~(7 << gpio_field_offset); > >> + gpiodir |= function << gpio_field_offset; > >> + writel(gpiodir, base + GPIOFSEL(gpio_bank)); > >> + gpiodir = readl(base + GPIOFSEL(gpio_bank)); > >> + > >> + return 0; > >> +} > >> + > > Uhm, this could be not convenient since the two banks in BCM2835 are > not really separated, there are not exclusive registers for one bank > or for the other. The registers used for GPIOs configuration manage > both the two banks (see for example GPFSELx). If I add one bank I can > avoid calculating the bank offset for GPCLRx and GPSETx but not for > GPFSELx and viceversa (in fact in the code I select the bank for > GPCLRx and GPSETx with gpio_bank = gpio / 32 whereas for GPIOFSEL with > gpio_bank = gpio / 10). Yay, confusing … I sometimes wonder if hardware designers know what pains they cause... Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
