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Commit 5cbc7ca9 authored by Matthias Brugger's avatar Matthias Brugger Committed by Mark Brown
Browse files

spi: spi-omap2-mcspi.c: Toggle CS after each word 



This patch allows the board code to define SPI devices which needs to
toggle the chip select after every word send. This is needed to get a
better resolution reading e.g. an ADC data stream.
Apart from that, as in the normal code CS is controlled by software,
a transfer is done much faster.

Signed-off-by: default avatarMatthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent 18dd6199

drivers/spi/spi-omap2-mcspi.c

+18 −0
Original line number Diff line number Diff line
@@ -927,6 +927,7 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m) 


	struct spi_device		*spi;

	struct spi_transfer		*t = NULL;

	struct spi_master		*master;

	int				cs_active = 0;

	struct omap2_mcspi_cs		*cs;

	struct omap2_mcspi_device_config *cd;
@@ -935,6 +936,7 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m) 
	u32				chconf;



	spi = m->spi;

	master = spi->master;

	cs = spi->controller_state;

	cd = spi->controller_data;
@@ -952,6 +954,14 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m) 
			if (!t->speed_hz && !t->bits_per_word)

				par_override = 0;

		}

		if (cd && cd->cs_per_word) {

			chconf = mcspi->ctx.modulctrl;

			chconf &= ~OMAP2_MCSPI_MODULCTRL_SINGLE;

			mcspi_write_reg(master, OMAP2_MCSPI_MODULCTRL, chconf);

			mcspi->ctx.modulctrl =

				mcspi_read_cs_reg(spi, OMAP2_MCSPI_MODULCTRL);

		}





		if (!cs_active) {

			omap2_mcspi_force_cs(spi, 1);
@@ -1013,6 +1023,14 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m) 
	if (cs_active)

		omap2_mcspi_force_cs(spi, 0);



	if (cd && cd->cs_per_word) {

		chconf = mcspi->ctx.modulctrl;

		chconf |= OMAP2_MCSPI_MODULCTRL_SINGLE;

		mcspi_write_reg(master, OMAP2_MCSPI_MODULCTRL, chconf);

		mcspi->ctx.modulctrl =

			mcspi_read_cs_reg(spi, OMAP2_MCSPI_MODULCTRL);

	}



	omap2_mcspi_set_enable(spi, 0);



	m->status = status;

include/linux/platform_data/spi-omap2-mcspi.h

+3 −0
Original line number Diff line number Diff line
@@ -22,6 +22,9 @@ struct omap2_mcspi_dev_attr { 


struct omap2_mcspi_device_config {

	unsigned turbo_mode:1;



	/* toggle chip select after every word */

	unsigned cs_per_word:1;

};



#endif