[PATCH 4.5 058/101] spi: spi-ti-qspi: Fix FLEN and WLEN settings if bits_per_word is overridden

Greg Kroah-Hartman
2016-05-17T01:27:04Z

From: Ben Hutchings <ben.hutchings@codethink.co.uk>

commit ea1b60fb085839a9544cb3a0069992991beabb7f upstream.

Each transfer can specify 8, 16 or 32 bits per word independently of
the default for the device being addressed. However, currently we
calculate the number of words in the frame assuming that the word size
is the device default.

If multiple transfers in the same message have differing
bits_per_word, we bitwise-or the different values in the WLEN register
field.

Fix both of these. Also rename 'frame_length' to 'frame_len_words' to
make clear that it's not a byte count like spi_message::frame_length.

Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/spi/spi-ti-qspi.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

--- a/drivers/spi/spi-ti-qspi.c
+++ b/drivers/spi/spi-ti-qspi.c
@@ -94,6 +94,7 @@ struct ti_qspi {
#define QSPI_FLEN(n) ((n - 1) << 0)
#define QSPI_WLEN_MAX_BITS 128
#define QSPI_WLEN_MAX_BYTES 16
+#define QSPI_WLEN_MASK QSPI_WLEN(QSPI_WLEN_MAX_BITS)

/* STATUS REGISTER */
#define BUSY 0x01
@@ -373,7 +374,7 @@ static int ti_qspi_start_transfer_one(st
struct spi_device *spi = m->spi;
struct spi_transfer *t;
int status = 0, ret;
- int frame_length;
+ unsigned int frame_len_words;

/* setup device control reg */
qspi->dc = 0;
@@ -385,21 +386,23 @@ static int ti_qspi_start_transfer_one(st
if (spi->mode & SPI_CS_HIGH)
qspi->dc |= QSPI_CSPOL(spi->chip_select);

- frame_length = (m->frame_length << 3) / spi->bits_per_word;
-
- frame_length = clamp(frame_length, 0, QSPI_FRAME);
+ frame_len_words = 0;
+ list_for_each_entry(t, &m->transfers, transfer_list)
+ frame_len_words += t->len / (t->bits_per_word >> 3);
+ frame_len_words = min_t(unsigned int, frame_len_words, QSPI_FRAME);

/* setup command reg */
qspi->cmd = 0;
qspi->cmd |= QSPI_EN_CS(spi->chip_select);
- qspi->cmd |= QSPI_FLEN(frame_length);
+ qspi->cmd |= QSPI_FLEN(frame_len_words);

ti_qspi_write(qspi, qspi->dc, QSPI_SPI_DC_REG);

mutex_lock(&qspi->list_lock);

list_for_each_entry(t, &m->transfers, transfer_list) {
- qspi->cmd |= QSPI_WLEN(t->bits_per_word);
+ qspi->cmd = ((qspi->cmd & ~QSPI_WLEN_MASK) |
+ QSPI_WLEN(t->bits_per_word));

ret = qspi_transfer_msg(qspi, t);
if (ret) {