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>

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)

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

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)

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)

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) {

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) {

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);

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;
 

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) {

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;