[PATCH 5/7] smc911x: improve detection handle

[Sascha Hauer]

On Wed, Aug 29, 2012 at 07:06:16AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote:
> detect if the bus is swapped and report a 32bit drivers is used on a 16bit bus
> 
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
> ---
>  drivers/net/smc911x.c |   20 +++++++++++++++++++-
>  drivers/net/smc911x.h |    2 ++
>  2 files changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/smc911x.c b/drivers/net/smc911x.c
> index 75a332e..17f365d 100644
> --- a/drivers/net/smc911x.c
> +++ b/drivers/net/smc911x.c
> @@ -470,9 +470,27 @@ static int smc911x_probe(struct device_d *dev)
>  	}
>  
>  	val = smc911x_reg_read(priv, BYTE_TEST);
> -	if(val != 0x87654321) {
> +	if (val == 0x43218765) {
> +		dev_info(dev, "BYTE_TEST looks swapped, "
> +			   "applying WORD_SWAP");

dev_dbg please. Users shouldn't be interested in this.

> +		smc911x_reg_write(priv, WORD_SWAP, 0xffffffff);
> +
> +		/* 1 dummy read of BYTE_TEST is needed after a write to
> +		 * WORD_SWAP before its contents are valid */
> +		val = smc911x_reg_read(priv, BYTE_TEST);
> +
> +		val = smc911x_reg_read(priv, BYTE_TEST);
> +	}
> +
> +	if (val != 0x87654321) {
>  		dev_err(dev, "no smc911x found on 0x%p (byte_test=0x%08x)\n",
>  			priv->base, val);
> +		if (((val >> 16) & 0xFFFF) == (val & 0xFFFF)) {
> +			dev_err(dev, "top 16 bits equal to bottom 16 bits\n");
> +			dev_err(dev,
> +				   "This may mean the chip is set "
> +				   "for 32 bit while the bus is reading 16 bit\n");

Please replace the second dev_err with a comment in the source code.
This is developer information only; developers will grep for the source
of the message anyway.

Sascha

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