Messages in this thread Patch in this message | | | Date | Mon, 18 Feb 2008 12:42:37 +0100 | From | Haavard Skinnemoen <> | Subject | Re: atmel_spi clock polarity |
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On Sat, 16 Feb 2008 22:32:52 +0900 (JST) Atsushi Nemoto <anemo@mba.ocn.ne.jp> wrote:
> Here is my quick workaround for this problem. It makes all CSRn.CPOL > match for the transfer before activating chipselect. I'm not quite > sure my analysis is correct, and there might be better solution. > Could you give me any comments?
I'm not sure if I fully understand what problem you're seeing. Is the clock state wrong when the chip select is activated? If so, does the patch below help?
Haavard
diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c index 293b7ca..4f19b82 100644 --- a/drivers/spi/atmel_spi.c +++ b/drivers/spi/atmel_spi.c @@ -90,6 +90,7 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi) mr = spi_readl(as, MR); mr = SPI_BFINS(PCS, ~(1 << spi->chip_select), mr); + spi_writel(as, MR, mr); dev_dbg(&spi->dev, "activate %u%s, mr %08x\n", gpio, active ? " (high)" : "", @@ -97,7 +98,6 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi) if (!(cpu_is_at91rm9200() && spi->chip_select == 0)) gpio_set_value(gpio, active); - spi_writel(as, MR, mr); } static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
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