Subject: Re: [PATCH] spi: omap2-mcspi: Fix native cs with new set_cs

From: Nishanth Menon <[email-masked]>
Date: Tue, 12 May 2015 13:57:36 -0500

On 05/12/2015 12:38 PM, Michael Welling wrote:
> GPIO chip select patch series appears to have broken the native chip select
> support. This patch pulls the manual native chip select toggling out of
> the transfer_one routine and adds a set_cs routine.
> 
> Tested natively on AM3354 with SPI serial flash on spi0cs0.
> 
> Signed-off-by: Michael Welling <[email-masked]>
> ---
>  drivers/spi/spi-omap2-mcspi.c |   33 +++++++++++----------------------
>  1 file changed, 11 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 90cf7e7..a7d85c5 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -243,17 +243,20 @@ static void omap2_mcspi_set_enable(const struct spi_device *spi, int enable)
>  	mcspi_read_cs_reg(spi, OMAP2_MCSPI_CHCTRL0);
>  }
>  
> -static void omap2_mcspi_force_cs(struct spi_device *spi, int cs_active)
> +static void omap2_mcspi_set_cs(struct spi_device *spi, bool enable)
>  {
>  	u32 l;
>  
> -	l = mcspi_cached_chconf0(spi);
> -	if (cs_active)
> -		l |= OMAP2_MCSPI_CHCONF_FORCE;
> -	else
> -		l &= ~OMAP2_MCSPI_CHCONF_FORCE;
> +	if (spi->controller_state) {
> +		l = mcspi_cached_chconf0(spi);
>  
> -	mcspi_write_chconf0(spi, l);
> +		if (enable)
> +			l &= ~OMAP2_MCSPI_CHCONF_FORCE;
> +		else
> +			l |= OMAP2_MCSPI_CHCONF_FORCE;
> +
> +		mcspi_write_chconf0(spi, l);
> +	}
>  }
>  
>  static void omap2_mcspi_set_master_mode(struct spi_master *master)
> @@ -1075,7 +1078,6 @@ static int omap2_mcspi_work_one(struct omap2_mcspi *mcspi,
>  
>  	struct spi_master		*master;
>  	struct omap2_mcspi_dma		*mcspi_dma;
> -	int				cs_active = 0;
>  	struct omap2_mcspi_cs		*cs;
>  	struct omap2_mcspi_device_config *cd;
>  	int				par_override = 0;
> @@ -1118,11 +1120,6 @@ static int omap2_mcspi_work_one(struct omap2_mcspi *mcspi,
>  			mcspi_read_cs_reg(spi, OMAP2_MCSPI_MODULCTRL);
>  	}
>  
> -	if (!cs_active) {
> -		omap2_mcspi_force_cs(spi, 1);
> -		cs_active = 1;
> -	}
> -
>  	chconf = mcspi_cached_chconf0(spi);
>  	chconf &= ~OMAP2_MCSPI_CHCONF_TRM_MASK;
>  	chconf &= ~OMAP2_MCSPI_CHCONF_TURBO;
> @@ -1169,12 +1166,6 @@ static int omap2_mcspi_work_one(struct omap2_mcspi *mcspi,
>  	if (t->delay_usecs)
>  		udelay(t->delay_usecs);
>  
> -	/* ignore the "leave it on after last xfer" hint */
> -	if (t->cs_change) {
> -		omap2_mcspi_force_cs(spi, 0);
> -		cs_active = 0;
> -	}
> -
>  	omap2_mcspi_set_enable(spi, 0);
>  
>  	if (mcspi->fifo_depth > 0)
> @@ -1187,9 +1178,6 @@ out:
>  		status = omap2_mcspi_setup_transfer(spi, NULL);
>  	}
>  
> -	if (cs_active)
> -		omap2_mcspi_force_cs(spi, 0);
> -
>  	if (cd && cd->cs_per_word) {
>  		chconf = mcspi->ctx.modulctrl;
>  		chconf |= OMAP2_MCSPI_MODULCTRL_SINGLE;
> @@ -1334,6 +1322,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
>  	master->setup = omap2_mcspi_setup;
>  	master->auto_runtime_pm = true;
>  	master->transfer_one = omap2_mcspi_transfer_one;
> +	master->set_cs = omap2_mcspi_set_cs;
>  	master->cleanup = omap2_mcspi_cleanup;
>  	master->dev.of_node = node;
>  	master->max_speed_hz = OMAP2_MCSPI_MAX_FREQ;
> 

Tested on next-20150512
http://paste.ubuntu.org.cn/2600748
Since the original issue was reported by me in
http://marc.info/?t=143136312900001&r=1&w=2
Reported-by: Nishanth Menon <[email-masked]>

Tested-by: Nishanth Menon <[email-masked]>

-- 
Regards,
Nishanth Menon