Messages in this thread | | | Date | Tue, 07 Feb 2006 11:50:08 +0000 | From | David Vrabel <> | Subject | Re: [PATCH] spi: Add PXA2xx SSP SPI Driver |
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stephen@streetfiresound.com wrote: > From: Stephen Street <stephen@streetfiresound.com> > > The driver turns a PXA2xx synchronous serial port (SSP) into a SPI master > controller (see Documentation/spi/spi_summary). The driver has the following > features:
I've not tested this on my PXA27x platform yet (I'll try and get this done this tomorrow) but a few comments.
> --- linux-2.6.16-rc2/drivers/spi/pxa2xx_spi.c 1969-12-31 16:00:00.000000000 -0800 > +++ linux-spi/drivers/spi/pxa2xx_spi.c 2006-02-06 18:39:45.339334630 -0800
> +#define CLOCK_SPEED_HZ 3686400
PXA27x has a clock speed of 13000000 Hz.
> + chip->cr0 = SSCR0_SerClkDiv((CLOCK_SPEED_HZ / spi->max_speed_hz) + 2)
Consider spi->max_speed_hz == CLOCK_SPEED_HZ which gives a divisor of 3 (when it should be 1).
You need SSCR0_SerClkDiv(CLOCK_SPEED_HZ / (spi->max_speed_hz + 1) + 1) for the correct divisor and for proper rounding.
> + /* Attach to IRQ */ > + irq = platform_get_irq(pdev, 0); > + if (irq == 0) { > + dev_err(&pdev->dev, "irq resource not defined\n"); > + status = -ENODEV; > + goto out_error_master_alloc; > + }
Greg K-H has a patch pending that makes platform_get_irq() return -ENXIO instead of 0 on error. This is required for SSP3 on the PXA27x which uses IRQ 0.
> + /* Release IRQ */ > + irq = platform_get_irq(pdev, 0); > + if (irq != 0) > + free_irq(irq, drv_data);
Similarly.
David Vrabel -- David Vrabel, Design Engineer
Arcom, Clifton Road Tel: +44 (0)1223 411200 ext. 3233 Cambridge CB1 7EA, UK Web: http://www.arcom.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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