[PATCH] spi/pxa2xx: fix incorrect SW mode chipselect setting for BayTrail LPSS SPI

Mark Brown broonie at kernel.org
Wed Jun 11 16:42:12 PDT 2014

On Wed, Jun 11, 2014 at 11:57:02PM +0800, Chew Chiau Ee wrote:

> It was observed that after module removal followed by insertion,
> the SW mode chipselect is not properly set. Thus causing transfer
> failure due to incorrect CS toggling.

> -	value &= ~SPI_CS_CONTROL_SW_MODE;
> +	orig = value &= ~SPI_CS_CONTROL_SW_MODE;
>  	writel(value, drv_data->ioaddr + offset + SPI_CS_CONTROL);
>  	value = readl(drv_data->ioaddr + offset + SPI_CS_CONTROL);
>  	if (value != orig) {

This is a *really* non-obvious fix, I'd have expected the original value
to be re-read from the hardware here rather than just tweaked, or at
least some comment explaining what's going on.  Possibly also saving to
a differently named temporary variable would do it but whatever I had to
go look at the context to figure out what was happening and even there I
was unclear.
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