staging: fbtft: fix 9-bit SPI support detection

Since the result of the setup function isn't adequate to check
9-bit SPI support, we better check bits_per_word_mask. Btw this
change avoids a NULL pointer dereference with master drivers
without a separate setup function.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 23392eb6799ec0e946f238b42b9d02c0673e92d8..7f5fa3d1cab049fecfeca3bc221536a6c218524b 100644 (file)
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -1436,15 +1436,11 @@ int fbtft_probe_common(struct fbtft_display *display,
 
        /* 9-bit SPI setup */
        if (par->spi && display->buswidth == 9) {
-               par->spi->bits_per_word = 9;
-               ret = par->spi->master->setup(par->spi);
-               if (ret) {
+               if (par->spi->master->bits_per_word_mask & SPI_BPW_MASK(9)) {
+                       par->spi->bits_per_word = 9;
+               } else {
                        dev_warn(&par->spi->dev,
                                "9-bit SPI not available, emulating using 8-bit.\n");
-                       par->spi->bits_per_word = 8;
-                       ret = par->spi->master->setup(par->spi);
-                       if (ret)
-                               goto out_release;
                        /* allocate buffer with room for dc bits */
                        par->extra = devm_kzalloc(par->info->device,
                                par->txbuf.len + (par->txbuf.len / 8) + 8,

diff --git a/drivers/staging/fbtft/flexfb.c b/drivers/staging/fbtft/flexfb.c
index c763efc5de7dc468708945845b22154860b00869..3f380a0086c3d191b21e5f6889232bf23f190413 100644 (file)
--- a/drivers/staging/fbtft/flexfb.c
+++ b/drivers/staging/fbtft/flexfb.c
@@ -463,15 +463,12 @@ static int flexfb_probe_common(struct spi_device *sdev,
                        }
                        par->fbtftops.write_register = fbtft_write_reg8_bus9;
                        par->fbtftops.write_vmem = fbtft_write_vmem16_bus9;
-                       sdev->bits_per_word = 9;
-                       ret = sdev->master->setup(sdev);
-                       if (ret) {
+                       if (par->spi->master->bits_per_word_mask
+                           & SPI_BPW_MASK(9)) {
+                               par->spi->bits_per_word = 9;
+                       } else {
                                dev_warn(dev,
                                        "9-bit SPI not available, emulating using 8-bit.\n");
-                               sdev->bits_per_word = 8;
-                               ret = sdev->master->setup(sdev);
-                               if (ret)
-                                       goto out_release;
                                /* allocate buffer with room for dc bits */
                                par->extra = devm_kzalloc(par->info->device,
                                                par->txbuf.len + (par->txbuf.len / 8) + 8,