mmc: spi: Toggle SPI polarity, do not hardcode it

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / drivers / mmc / host / mmc_spi.c

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 40a369c..b52489a 100644 (file)
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -1153,17 +1153,22 @@ static void mmc_spi_initsequence(struct mmc_spi_host *host)
         * SPI protocol.  Another is that when chipselect is released while
         * the card returns BUSY status, the clock must issue several cycles
         * with chipselect high before the card will stop driving its output.
+        *
+        * SPI_CS_HIGH means "asserted" here. In some cases like when using
+        * GPIOs for chip select, SPI_CS_HIGH is set but this will be logically
+        * inverted by gpiolib, so if we want to ascertain to drive it high
+        * we should toggle the default with an XOR as we do here.
         */
-       host->spi->mode |= SPI_CS_HIGH;
+       host->spi->mode ^= SPI_CS_HIGH;
        if (spi_setup(host->spi) != 0) {
                /* Just warn; most cards work without it. */
                dev_warn(&host->spi->dev,
                                "can't change chip-select polarity\n");
-               host->spi->mode &= ~SPI_CS_HIGH;
+               host->spi->mode ^= SPI_CS_HIGH;
        } else {
                mmc_spi_readbytes(host, 18);
 
-               host->spi->mode &= ~SPI_CS_HIGH;
+               host->spi->mode ^= SPI_CS_HIGH;
                if (spi_setup(host->spi) != 0) {
                        /* Wot, we can't get the same setup we had before? */
                        dev_err(&host->spi->dev,