1 files changed, 24 insertions, 14 deletions

diff --git a/drivers/spi/omap2_mcspi.c b/drivers/spi/omap2_mcspi.c
index 36501adc125d..3a5ed06d3d2f 100644
--- a/drivers/spi/omap2_mcspi.c
+++ b/drivers/spi/omap2_mcspi.c
@@ -467,6 +467,9 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
         rx_reg          = base + OMAP2_MCSPI_RX0;
         chstat_reg      = base + OMAP2_MCSPI_CHSTAT0;
 
+        if (c < (word_len>>3))
+                return 0;
+
         if (word_len <= 8) {
                 u8              *rx;
                 const u8        *tx;
@@ -514,7 +517,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
                                 dev_vdbg(&spi->dev, "read-%d %02x\n",
                                                 word_len, *(rx - 1));
                         }
-                } while (c);
+                } while (c > (word_len>>3));
         } else if (word_len <= 16) {
                 u16             *rx;
                 const u16       *tx;
@@ -561,7 +564,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
                                 dev_vdbg(&spi->dev, "read-%d %04x\n",
                                                 word_len, *(rx - 1));
                         }
-                } while (c);
+                } while (c > (word_len>>3));
         } else if (word_len <= 32) {
                 u32             *rx;
                 const u32       *tx;
@@ -608,7 +611,7 @@ omap2_mcspi_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
                                 dev_vdbg(&spi->dev, "read-%d %08x\n",
                                                 word_len, *(rx - 1));
                         }
-                } while (c);
+                } while (c > (word_len>>3));
         }
 
         /* for TX_ONLY mode, be sure all words have shifted out */
@@ -631,6 +634,17 @@ out:
         return count - c;
 }
 
+static u32 omap2_mcspi_calc_divisor(u32 speed_hz)
+{
+        u32 div;
+
+        for (div = 0; div < 15; div++)
+                if (speed_hz >= (OMAP2_MCSPI_MAX_FREQ >> div))
+                        return div;
+
+        return 15;
+}
+
 /* called only when no transfer is active to this device */
 static int omap2_mcspi_setup_transfer(struct spi_device *spi,
                 struct spi_transfer *t)
@@ -653,12 +667,8 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
         if (t && t->speed_hz)
                 speed_hz = t->speed_hz;
 
-        if (speed_hz) {
-                while (div <= 15 && (OMAP2_MCSPI_MAX_FREQ / (1 << div))
-                                        > speed_hz)
-                        div++;
-        } else
-                div = 15;
+        speed_hz = min_t(u32, speed_hz, OMAP2_MCSPI_MAX_FREQ);
+        div = omap2_mcspi_calc_divisor(speed_hz);
 
         l = mcspi_cached_chconf0(spi);
 
@@ -695,7 +705,7 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
         mcspi_write_chconf0(spi, l);
 
         dev_dbg(&spi->dev, "setup: speed %d, sample %s edge, clk %s\n",
-                        OMAP2_MCSPI_MAX_FREQ / (1 << div),
+                        OMAP2_MCSPI_MAX_FREQ >> div,
                         (spi->mode & SPI_CPHA) ? "trailing" : "leading",
                         (spi->mode & SPI_CPOL) ? "inverted" : "normal");
 
@@ -996,10 +1006,10 @@ static int omap2_mcspi_transfer(struct spi_device *spi, struct spi_message *m)
                                         t->bits_per_word);
                         return -EINVAL;
                 }
-                if (t->speed_hz && t->speed_hz < OMAP2_MCSPI_MAX_FREQ/(1<<16)) {
-                        dev_dbg(&spi->dev, "%d Hz max exceeds %d\n",
-                                        t->speed_hz,
-                                        OMAP2_MCSPI_MAX_FREQ/(1<<16));
+                if (t->speed_hz && t->speed_hz < (OMAP2_MCSPI_MAX_FREQ >> 15)) {
+                        dev_dbg(&spi->dev, "speed_hz %d below minimum %d Hz\n",
+                                t->speed_hz,
+                                OMAP2_MCSPI_MAX_FREQ >> 15);
                         return -EINVAL;
                 }