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>

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 86d2158946bbf3de879cc459e53aa00005e6768f..798729eb66894dce93764449c15e2c3e3fb85736 100644 (file)
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -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;