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spi: omap2-mcspi: Configure hardware when slave driver changes mode 

commit 97ca0d6cc118716840ea443e010cb3d5f2d25eaf upstream.

Commit id 2bd16e3e23d9df41592c6b257c59b6860a9cc3ea
(spi: omap2-mcspi: Do not configure the controller
on each transfer unless needed) does its job too
well so omap2_mcspi_setup_transfer() isn't called
even when an SPI slave driver changes 'spi->mode'.
The result is that the mode requested by the SPI
slave driver never takes effect.

Fix this by adding the 'mode' member to the
omap2_mcspi_cs structure which holds the mode
value that the hardware is configured for.
When the SPI slave driver changes 'spi->mode'
it will be different than the value of this new
member and the SPI master driver will know that
the hardware must be reconfigured (by calling
omap2_mcspi_setup_transfer()).

Fixes: 2bd16e3e23 (spi: omap2-mcspi: Do not configure the controller on each transfer unless needed)
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mark A. Greer 2014-07-01 20:28:32 -07:00 committed by Greg Kroah-Hartman
parent bd09037436
commit abcc94f839
1 changed files with 14 additions and 0 deletions
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14
drivers/spi/spi-omap2-mcspi.c
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@ -136,6 +136,7 @@ struct omap2_mcspi_cs {
void __iomem *base;
unsigned long phys;
int word_len;
u16 mode;
struct list_head node;
/* Context save and restore shadow register */
u32 chconf0;
@ -801,6 +802,8 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
mcspi_write_chconf0(spi, l);
cs->mode = spi->mode;
dev_dbg(&spi->dev, "setup: speed %d, sample %s edge, clk %s\n",
OMAP2_MCSPI_MAX_FREQ >> div,
(spi->mode & SPI_CPHA) ? "trailing" : "leading",
@ -871,6 +874,7 @@ static int omap2_mcspi_setup(struct spi_device *spi)
return -ENOMEM;
cs->base = mcspi->base + spi->chip_select * 0x14;
cs->phys = mcspi->phys + spi->chip_select * 0x14;
cs->mode = 0;
cs->chconf0 = 0;
spi->controller_state = cs;
/* Link this to context save list */
@ -1043,6 +1047,16 @@ static void omap2_mcspi_work(struct omap2_mcspi *mcspi, struct spi_message *m)
mcspi_read_cs_reg(spi, OMAP2_MCSPI_MODULCTRL);
}
/*
* The slave driver could have changed spi->mode in which case
* it will be different from cs->mode (the current hardware setup).
* If so, set par_override (even though its not a parity issue) so
* omap2_mcspi_setup_transfer will be called to configure the hardware
* with the correct mode on the first iteration of the loop below.
*/
if (spi->mode != cs->mode)
par_override = 1;
omap2_mcspi_set_enable(spi, 0);
m->status = status;