Re: [PATCH v3 1/1] OMAP2: Spi: Force CS to be in inactive state after off-mode transition

[Kevin Hilman <khilman@deeprootsystems.com>]

Gregory CLEMENT <gregory.clement@free-electrons.com> writes:

> When SPI wake up from OFF mode, CS is in the wrong state: force it to
> the inactive state.
>
> During the system life, I monitored the CS behavior using a
> oscilloscope. I also activated debug in omap2_mcspi, so I saw when
> driver disable the clocks and
> Each time the CS was in the correct state.
> It was only when system was put suspend to ram with off-mode activated
> that on resume the CS was in wrong state( ie activated).
>
> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

Lots of whitespace issues in this patch, please run through checkpatch.

> ---
>  drivers/spi/omap2_mcspi.c |   29 +++++++++++++++++++++++++++++
>  1 files changed, 29 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
> index 2a651e6..708990e 100644
> --- a/drivers/spi/omap2_mcspi.c
> +++ b/drivers/spi/omap2_mcspi.c
> @@ -1305,11 +1305,40 @@ static int __exit omap2_mcspi_remove(struct
> platform_device *pdev)
>  /* work with hotplug and coldplug */
>  MODULE_ALIAS("platform:omap2_mcspi");
>  +#ifdef	CONFIG_PM
> +/* When SPI wake up, CS is in wrong state: force it to unactive state*/

This comment should be more specific that only this condition happens
only on off-mode wakeups

> +static int omap2_mcspi_resume(struct platform_device *pdev)
> +{
> +	struct spi_master	*master;
> +	struct omap2_mcspi	*mcspi;
> +	struct omap2_mcspi_cs *cs;
> +
> +	master = dev_get_drvdata(&pdev->dev);
> +	mcspi = spi_master_get_devdata(master);
> +	omap2_mcspi_enable_clocks(master);

insert blank line here

> +	/* We need to togle CS state for OMAP take this chang in account*/
> +

remove blank line here

> +	list_for_each_entry(cs, &omap2_mcspi_ctx[master->bus_num - 1].cs,
> +			    node)
> +    {

this '{' belongs on like above 

> +        MOD_REG_BIT(cs->chconf0, OMAP2_MCSPI_CHCONF_FORCE, 1);
> +		__raw_writel(cs->chconf0, cs->base + OMAP2_MCSPI_CHCONF0);
> +        MOD_REG_BIT(cs->chconf0, OMAP2_MCSPI_CHCONF_FORCE, 0);
> +		__raw_writel(cs->chconf0, cs->base + OMAP2_MCSPI_CHCONF0);
> +    }

Rather than force the state to a hard-coded value, it seems better if
the driver instead restore the previous state, which could be saved
during suspend.

> +	omap2_mcspi_disable_clocks(master);
> +    return 0;
> +}
> +#else
> +#define	omap2_mcspi_resume	NULL
> +#endif
> +
>  static struct platform_driver omap2_mcspi_driver = {
>  	.driver = {
>  		.name =		"omap2_mcspi",
>  		.owner =	THIS_MODULE,
>  	},
> +	.resume =	omap2_mcspi_resume,
>  	.remove =	__exit_p(omap2_mcspi_remove),
>  };
>  -- 1.7.0.4

Kevin