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authorJoakim Tjernlund <Joakim.Tjernlund@transmode.se>2010-05-14 09:14:26 +0000
committerGrant Likely <grant.likely@secretlab.ca>2010-05-25 00:17:51 -0600
commit0398fb70940e1f10939d6126eafb760bd48d1566 (patch)
treefabaaf8936b0e68ec058192cc155640672919694 /drivers/spi
parentf9218c2a60facc6ff9a793a9d9ab956194d70012 (diff)
spi/spi_mpc8xxx: Fix QE mode Litte Endian
QE mode uses Little Endian so words > 8 bits are byte swapped. Workaround this by always enforcing wordsize 8 for words > 8 bits. Unfortunately this will not work for LSB transfers where wordsize is > 8 bits so disable these for now. Also move the different quirks into its own function to keep mpc8xxx_spi_setup_transfer() sane. Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> Acked-by: Anton Vorontsov <cbouatmailru@gmail.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi_mpc8xxx.c101
1 files changed, 70 insertions, 31 deletions
diff --git a/drivers/spi/spi_mpc8xxx.c b/drivers/spi/spi_mpc8xxx.c
index 0dfc482bbff5..66517ce750f3 100644
--- a/drivers/spi/spi_mpc8xxx.c
+++ b/drivers/spi/spi_mpc8xxx.c
@@ -286,36 +286,12 @@ static void mpc8xxx_spi_chipselect(struct spi_device *spi, int value)
}
}
-static
-int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
+static int
+mspi_apply_cpu_mode_quirks(struct spi_mpc8xxx_cs *cs,
+ struct spi_device *spi,
+ struct mpc8xxx_spi *mpc8xxx_spi,
+ int bits_per_word)
{
- struct mpc8xxx_spi *mpc8xxx_spi;
- u8 bits_per_word, pm;
- u32 hz;
- struct spi_mpc8xxx_cs *cs = spi->controller_state;
-
- mpc8xxx_spi = spi_master_get_devdata(spi->master);
-
- if (t) {
- bits_per_word = t->bits_per_word;
- hz = t->speed_hz;
- } else {
- bits_per_word = 0;
- hz = 0;
- }
-
- /* spi_transfer level calls that work per-word */
- if (!bits_per_word)
- bits_per_word = spi->bits_per_word;
-
- /* Make sure its a bit width we support [4..16, 32] */
- if ((bits_per_word < 4)
- || ((bits_per_word > 16) && (bits_per_word != 32)))
- return -EINVAL;
-
- if (!hz)
- hz = spi->max_speed_hz;
-
cs->rx_shift = 0;
cs->tx_shift = 0;
if (bits_per_word <= 8) {
@@ -339,19 +315,82 @@ int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
return -EINVAL;
if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE &&
- spi->mode & SPI_LSB_FIRST) {
+ spi->mode & SPI_LSB_FIRST) {
cs->tx_shift = 0;
if (bits_per_word <= 8)
cs->rx_shift = 8;
else
cs->rx_shift = 0;
}
-
mpc8xxx_spi->rx_shift = cs->rx_shift;
mpc8xxx_spi->tx_shift = cs->tx_shift;
mpc8xxx_spi->get_rx = cs->get_rx;
mpc8xxx_spi->get_tx = cs->get_tx;
+ return bits_per_word;
+}
+
+static int
+mspi_apply_qe_mode_quirks(struct spi_mpc8xxx_cs *cs,
+ struct spi_device *spi,
+ int bits_per_word)
+{
+ /* QE uses Little Endian for words > 8
+ * so transform all words > 8 into 8 bits
+ * Unfortnatly that doesn't work for LSB so
+ * reject these for now */
+ /* Note: 32 bits word, LSB works iff
+ * tfcr/rfcr is set to CPMFCR_GBL */
+ if (spi->mode & SPI_LSB_FIRST &&
+ bits_per_word > 8)
+ return -EINVAL;
+ if (bits_per_word > 8)
+ return 8; /* pretend its 8 bits */
+ return bits_per_word;
+}
+
+static
+int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
+{
+ struct mpc8xxx_spi *mpc8xxx_spi;
+ int bits_per_word;
+ u8 pm;
+ u32 hz;
+ struct spi_mpc8xxx_cs *cs = spi->controller_state;
+
+ mpc8xxx_spi = spi_master_get_devdata(spi->master);
+
+ if (t) {
+ bits_per_word = t->bits_per_word;
+ hz = t->speed_hz;
+ } else {
+ bits_per_word = 0;
+ hz = 0;
+ }
+
+ /* spi_transfer level calls that work per-word */
+ if (!bits_per_word)
+ bits_per_word = spi->bits_per_word;
+
+ /* Make sure its a bit width we support [4..16, 32] */
+ if ((bits_per_word < 4)
+ || ((bits_per_word > 16) && (bits_per_word != 32)))
+ return -EINVAL;
+
+ if (!hz)
+ hz = spi->max_speed_hz;
+
+ if (!(mpc8xxx_spi->flags & SPI_CPM_MODE))
+ bits_per_word = mspi_apply_cpu_mode_quirks(cs, spi,
+ mpc8xxx_spi,
+ bits_per_word);
+ else if (mpc8xxx_spi->flags & SPI_QE)
+ bits_per_word = mspi_apply_qe_mode_quirks(cs, spi,
+ bits_per_word);
+
+ if (bits_per_word < 0)
+ return bits_per_word;
+
if (bits_per_word == 32)
bits_per_word = 0;
else