SPI controller drivers: check for unsupported modes

Minor SPI controller driver updates: make the setup() methods reject
spi->mode bits they don't support, by masking aginst the inverse of bits
they *do* support.  This insures against misbehavior later when new mode
bits get added.

Most controllers can't support SPI_LSB_FIRST; more handle SPI_CS_HIGH.
Support for all four SPI clock/transfer modes is routine.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

10 files changed, 66 insertions, 21 deletions

diff --git a/drivers/spi/atmel_spi.c b/drivers/spi/atmel_spi.c
index 8b2601de3630..7524a84bdd50 100644
--- a/drivers/spi/atmel_spi.c
+++ b/drivers/spi/atmel_spi.c
@@ -350,6 +350,7 @@ atmel_spi_interrupt(int irq, void *dev_id)
         return ret;
 }
 
+/* the spi->mode bits understood by this driver: */
 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 
 static int atmel_spi_setup(struct spi_device *spi)
diff --git a/drivers/spi/au1550_spi.c b/drivers/spi/au1550_spi.c
index ae2b1af0dba4..c47a650183a1 100644
--- a/drivers/spi/au1550_spi.c
+++ b/drivers/spi/au1550_spi.c
@@ -280,6 +280,9 @@ static int au1550_spi_setupxfer(struct spi_device *spi, struct spi_transfer *t)
         return 0;
 }
 
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST)
+
 static int au1550_spi_setup(struct spi_device *spi)
 {
         struct au1550_spi *hw = spi_master_get_devdata(spi->master);
@@ -292,6 +295,12 @@ static int au1550_spi_setup(struct spi_device *spi)
                 return -EINVAL;
         }
 
+        if (spi->mode & ~MODEBITS) {
+                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
+                return -EINVAL;
+        }
+
         if (spi->max_speed_hz == 0)
                 spi->max_speed_hz = hw->freq_max;
         if (spi->max_speed_hz > hw->freq_max
diff --git a/drivers/spi/mpc52xx_psc_spi.c b/drivers/spi/mpc52xx_psc_spi.c
index 11f36bef3057..d2a4b2bdb07b 100644
--- a/drivers/spi/mpc52xx_psc_spi.c
+++ b/drivers/spi/mpc52xx_psc_spi.c
@@ -270,6 +270,9 @@ static void mpc52xx_psc_spi_work(struct work_struct *work)
         spin_unlock_irq(&mps->lock);
 }
 
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST)
+
 static int mpc52xx_psc_spi_setup(struct spi_device *spi)
 {
         struct mpc52xx_psc_spi *mps = spi_master_get_devdata(spi->master);
@@ -279,6 +282,12 @@ static int mpc52xx_psc_spi_setup(struct spi_device *spi)
         if (spi->bits_per_word%8)
                 return -EINVAL;
 
+        if (spi->mode & ~MODEBITS) {
+                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
+                return -EINVAL;
+        }
+
         if (!cs) {
                 cs = kzalloc(sizeof *cs, GFP_KERNEL);
                 if (!cs)
diff --git a/drivers/spi/omap_uwire.c b/drivers/spi/omap_uwire.c
index 95183e1df525..d275c615a73e 100644
--- a/drivers/spi/omap_uwire.c
+++ b/drivers/spi/omap_uwire.c
@@ -445,10 +445,19 @@ done:
         return status;
 }
 
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
+
 static int uwire_setup(struct spi_device *spi)
 {
         struct uwire_state *ust = spi->controller_state;
 
+        if (spi->mode & ~MODEBITS) {
+                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
+                return -EINVAL;
+        }
+
         if (ust == NULL) {
                 ust = kzalloc(sizeof(*ust), GFP_KERNEL);
                 if (ust == NULL)
diff --git a/drivers/spi/pxa2xx_spi.c b/drivers/spi/pxa2xx_spi.c
index 9f2c887ffa04..e51311b2da0b 100644
--- a/drivers/spi/pxa2xx_spi.c
+++ b/drivers/spi/pxa2xx_spi.c
@@ -1067,6 +1067,9 @@ static int transfer(struct spi_device *spi, struct spi_message *msg)
         return 0;
 }
 
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA)
+
 static int setup(struct spi_device *spi)
 {
         struct pxa2xx_spi_chip *chip_info = NULL;
@@ -1093,6 +1096,12 @@ static int setup(struct spi_device *spi)
                 return -EINVAL;
         }
 
+        if (spi->mode & ~MODEBITS) {
+                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
+                return -EINVAL;
+        }
+
         /* Only alloc on first setup */
         chip = spi_get_ctldata(spi);
         if (!chip) {
diff --git a/drivers/spi/spi_bitbang.c b/drivers/spi/spi_bitbang.c
index 88425e1af4d3..0c85c984ccb4 100644
--- a/drivers/spi/spi_bitbang.c
+++ b/drivers/spi/spi_bitbang.c
@@ -187,12 +187,10 @@ int spi_bitbang_setup(struct spi_device *spi)
 
         bitbang = spi_master_get_devdata(spi->master);
 
-        /* REVISIT: some systems will want to support devices using lsb-first
-         * bit encodings on the wire.  In pure software that would be trivial,
-         * just bitbang_txrx_le_cphaX() routines shifting the other way, and
-         * some hardware controllers also have this support.
+        /* Bitbangers can support SPI_CS_HIGH, SPI_3WIRE, and so on;
+         * add those to master->flags, and provide the other support.
          */
-        if ((spi->mode & SPI_LSB_FIRST) != 0)
+        if ((spi->mode & ~(SPI_CPOL|SPI_CPHA|bitbang->flags)) != 0)
                 return -EINVAL;
 
         if (!cs) {
diff --git a/drivers/spi/spi_imx.c b/drivers/spi/spi_imx.c
index 656be4a5094a..aee9ad6f633c 100644
--- a/drivers/spi/spi_imx.c
+++ b/drivers/spi/spi_imx.c
@@ -1163,6 +1163,9 @@ msg_rejected:
         return -EINVAL;
 }
 
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
+
 /* On first setup bad values must free chip_data memory since will cause
    spi_new_device to fail. Bad value setup from protocol driver are simply not
    applied and notified to the calling driver. */
@@ -1174,6 +1177,12 @@ static int setup(struct spi_device *spi)
         u32 tmp;
         int status = 0;
 
+        if (spi->mode & ~MODEBITS) {
+                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
+                return -EINVAL;
+        }
+
         /* Get controller data */
         chip_info = spi->controller_data;
 
@@ -1245,21 +1254,6 @@ static int setup(struct spi_device *spi)
 
         /* SPI mode */
         tmp = spi->mode;
-        if (tmp & SPI_LSB_FIRST) {
-                status = -EINVAL;
-                if (first_setup) {
-                        dev_err(&spi->dev,
-                                "setup - "
-                                "HW doesn't support LSB first transfer\n");
-                        goto err_first_setup;
-                } else {
-                        dev_err(&spi->dev,
-                                "setup - "
-                                "HW doesn't support LSB first transfer, "
-                                "default to MSB first\n");
-                        spi->mode &= ~SPI_LSB_FIRST;
-                }
-        }
         if (tmp & SPI_CS_HIGH) {
                 u32_EDIT(chip->control,
                                 SPI_CONTROL_SSPOL, SPI_CONTROL_SSPOL_ACT_HIGH);
diff --git a/drivers/spi/spi_mpc83xx.c b/drivers/spi/spi_mpc83xx.c
index e9798bf7b8c6..9cdbc12278e5 100644
--- a/drivers/spi/spi_mpc83xx.c
+++ b/drivers/spi/spi_mpc83xx.c
@@ -232,12 +232,21 @@ int mpc83xx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
         return 0;
 }
 
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
+
 static int mpc83xx_spi_setup(struct spi_device *spi)
 {
         struct spi_bitbang *bitbang;
         struct mpc83xx_spi *mpc83xx_spi;
         int retval;
 
+        if (spi->mode & ~MODEBITS) {
+                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
+                return -EINVAL;
+        }
+
         if (!spi->max_speed_hz)
                 return -EINVAL;
 
diff --git a/drivers/spi/spi_s3c24xx.c b/drivers/spi/spi_s3c24xx.c
index d5a710f6e445..7071ff8da63e 100644
--- a/drivers/spi/spi_s3c24xx.c
+++ b/drivers/spi/spi_s3c24xx.c
@@ -146,6 +146,9 @@ static int s3c24xx_spi_setupxfer(struct spi_device *spi,
         return 0;
 }
 
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
+
 static int s3c24xx_spi_setup(struct spi_device *spi)
 {
         int ret;
@@ -153,8 +156,11 @@ static int s3c24xx_spi_setup(struct spi_device *spi)
         if (!spi->bits_per_word)
                 spi->bits_per_word = 8;
 
-        if ((spi->mode & SPI_LSB_FIRST) != 0)
+        if (spi->mode & ~MODEBITS) {
+                dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
+                        spi->mode & ~MODEBITS);
                 return -EINVAL;
+        }
 
         ret = s3c24xx_spi_setupxfer(spi, NULL);
         if (ret < 0) {
diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h
index 9dbca629dcfb..b8db32cea1de 100644
--- a/include/linux/spi/spi_bitbang.h
+++ b/include/linux/spi/spi_bitbang.h
@@ -26,6 +26,7 @@ struct spi_bitbang {
         struct list_head        queue;
         u8                      busy;
         u8                      use_dma;
+        u8                      flags;          /* extra spi->mode support */
 
         struct spi_master       *master;