Re: [PATCH] spi: pl022: Allow request for higher frequency than maximum possible

[Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>]

On Thu, 19 Apr 2012 11:48:15 +0530, Viresh Kumar <viresh.kumar-qxv4g6HH51o@public.gmane.org> wrote:
> Currently, if we request for frequency greater than maximum possible, spi driver
> returns error.
> 
> For example, if the spi block src frequency is 333/4 MHz, i.e. 83.33.. MHz,
> maximum frequency programmable would be src/2. Which would come around 41.6...
> 
> It is difficult to pass frequency in these figures. We normally try to program
> in round figures, like 42 MHz and it should get programmed to <=
> requested_frequency, i.e. 41.6...
> 
> For this to happen, we must not return error even if requested freq is higher
> than max possible. But should program it to max possible.
> 
> Reported-by: Vinit Kamalaksha Shenoy <vinit.shenoy-qxv4g6HH51o@public.gmane.org>
> Signed-off-by: Viresh Kumar <viresh.kumar-qxv4g6HH51o@public.gmane.org>

Applied, thanks.

g.

> ---
>  drivers/spi/spi-pl022.c |   10 ++++++++--
>  1 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
> index 09c925a..99d5f6d 100644
> --- a/drivers/spi/spi-pl022.c
> +++ b/drivers/spi/spi-pl022.c
> @@ -1667,9 +1667,15 @@ static int calculate_effective_freq(struct pl022 *pl022, int freq, struct
>  	/* cpsdvsr = 254 & scr = 255 */
>  	min_tclk = spi_rate(rate, CPSDVR_MAX, SCR_MAX);
>  
> -	if (!((freq <= max_tclk) && (freq >= min_tclk))) {
> +	if (freq > max_tclk)
> +		dev_warn(&pl022->adev->dev,
> +			"Max speed that can be programmed is %d Hz, you requested %d\n",
> +			max_tclk, freq);
> +
> +	if (freq < min_tclk) {
>  		dev_err(&pl022->adev->dev,
> -			"controller data is incorrect: out of range frequency");
> +			"Requested frequency: %d Hz is less than minimum possible %d Hz\n",
> +			freq, min_tclk);
>  		return -EINVAL;
>  	}
>  
> -- 
> 1.7.9
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.

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