[U-Boot] [PATCH 3/3] spi: mxc_spi: Fix spi mode communication where clock is inverted

Peng Fan peng.fan at nxp.com
Sun Jun 24 11:44:20 UTC 2018



> -----Original Message-----
> From: Michael Trimarchi [mailto:michael at amarulasolutions.com]
> Sent: 2018年6月21日 4:51
> To: Jagan Teki <jagan at openedev.com>
> Cc: Stefano Babic <sbabic at denx.de>; Peng Fan <peng.fan at nxp.com>;
> shyam.saini at amarulasolutions.com; u-boot at lists.denx.de
> Subject: [PATCH 3/3] spi: mxc_spi: Fix spi mode communication where clock is
> inverted
> 
> During spi initialization logic creates a glitch on the clock and if this is followed
> by the chip select this can be interpretated as clock. Add a delay let the glitch
> out of chip select

I did not see issue. What issue do you see and which platform? Adding a delay here seems hacky which
forces all SoC using this driver needs a delay.
 
> 
> Signed-off-by: Michael Trimarchi <michael at amarulasolutions.com>
> ---
>  drivers/spi/mxc_spi.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c index 0dccc38..d450f16
> 100644
> --- a/drivers/spi/mxc_spi.c
> +++ b/drivers/spi/mxc_spi.c
> @@ -387,6 +387,7 @@ static int mxc_spi_claim_bus_internal(struct
> mxc_spi_slave *mxcs, int cs)
>  	}
>  	reg_write(&regs->period, MXC_CSPIPERIOD_32KHZ);
>  	reg_write(&regs->intr, 0);
> +	udelay(50);
> 
>  	return 0;
>  }
> --
> 2.7.4



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