[U-Boot] [PATCH v2 15/18] spi: mpc8xxx: Re-order transfer setup

Mario Six mario.six at gdsys.cc
Thu Apr 19 12:36:30 UTC 2018


Minize the time the adapter is disabled (via SPI_MODE_EN
clearing/setting) to just the character length setting, and only set up
the temporary data writing variable right before we need it, so there is
a more clear distinction between setting up the SPI adapter, and setting
up the data to be written.

Signed-off-by: Mario Six <mario.six at gdsys.cc>
---

Changes v1 -> v2:
None

---
 drivers/spi/mpc8xxx_spi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/mpc8xxx_spi.c b/drivers/spi/mpc8xxx_spi.c
index d22206f4b7..fe493f6d40 100644
--- a/drivers/spi/mpc8xxx_spi.c
+++ b/drivers/spi/mpc8xxx_spi.c
@@ -117,9 +117,6 @@ int spi_xfer(struct spi_slave *slave, uint bitlen, const void *dout, void *din,
 		u32 tmpdout = 0;
 		uchar xfer_bitlen = (bitlen >= 32 ? 32 : bitlen);

-		/* Shift data so it's msb-justified */
-		tmpdout = *(u32 *)dout >> (32 - xfer_bitlen);
-
 		clrbits_be32(&spi->mode, SPI_MODE_EN);

 		/* Set up length for this transfer */
@@ -131,14 +128,17 @@ int spi_xfer(struct spi_slave *slave, uint bitlen, const void *dout, void *din,
 		else /* more than 16 bits -> full 32 bit transfer */
 			set_char_len(spi, 0);

+		setbits_be32(&spi->mode, SPI_MODE_EN);
+
+		/* Shift data so it's msb-justified */
+		tmpdout = *(u32 *)dout >> (32 - xfer_bitlen);
+
 		if (bitlen > 16) {
 			/* Set up the next iteration if sending > 32 bits */
 			bitlen -= 32;
 			dout += 4;
 		}

-		setbits_be32(&spi->mode, SPI_MODE_EN);
-
 		/* Write the data out */
 		out_be32(&spi->tx, tmpdout);

--
2.16.1



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