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spi/spi_mpc8xxx: Fix QE mode Litte Endian

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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>
This commit is contained in:
Joakim Tjernlund 2010-05-14 09:14:26 +00:00 committed by Grant Likely
parent f9218c2a60
commit 0398fb7094
1 changed files with 74 additions and 35 deletions
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109
drivers/spi/spi_mpc8xxx.c
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@ -286,11 +286,75 @@ static void mpc8xxx_spi_chipselect(struct spi_device *spi, int value)
} }
} }
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)
{
cs->rx_shift = 0;
cs->tx_shift = 0;
if (bits_per_word <= 8) {
cs->get_rx = mpc8xxx_spi_rx_buf_u8;
cs->get_tx = mpc8xxx_spi_tx_buf_u8;
if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
cs->rx_shift = 16;
cs->tx_shift = 24;
}
} else if (bits_per_word <= 16) {
cs->get_rx = mpc8xxx_spi_rx_buf_u16;
cs->get_tx = mpc8xxx_spi_tx_buf_u16;
if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
cs->rx_shift = 16;
cs->tx_shift = 16;
}
} else if (bits_per_word <= 32) {
cs->get_rx = mpc8xxx_spi_rx_buf_u32;
cs->get_tx = mpc8xxx_spi_tx_buf_u32;
} else
return -EINVAL;
if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE &&
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 static
int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{ {
struct mpc8xxx_spi *mpc8xxx_spi; struct mpc8xxx_spi *mpc8xxx_spi;
u8 bits_per_word, pm; int bits_per_word;
u8 pm;
u32 hz; u32 hz;
struct spi_mpc8xxx_cs *cs = spi->controller_state; struct spi_mpc8xxx_cs *cs = spi->controller_state;
@ -316,41 +380,16 @@ int mpc8xxx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
if (!hz) if (!hz)
hz = spi->max_speed_hz; hz = spi->max_speed_hz;
cs->rx_shift = 0; if (!(mpc8xxx_spi->flags & SPI_CPM_MODE))
cs->tx_shift = 0; bits_per_word = mspi_apply_cpu_mode_quirks(cs, spi,
if (bits_per_word <= 8) { mpc8xxx_spi,
cs->get_rx = mpc8xxx_spi_rx_buf_u8; bits_per_word);
cs->get_tx = mpc8xxx_spi_tx_buf_u8; else if (mpc8xxx_spi->flags & SPI_QE)
if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) { bits_per_word = mspi_apply_qe_mode_quirks(cs, spi,
cs->rx_shift = 16; bits_per_word);
cs->tx_shift = 24;
}
} else if (bits_per_word <= 16) {
cs->get_rx = mpc8xxx_spi_rx_buf_u16;
cs->get_tx = mpc8xxx_spi_tx_buf_u16;
if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE) {
cs->rx_shift = 16;
cs->tx_shift = 16;
}
} else if (bits_per_word <= 32) {
cs->get_rx = mpc8xxx_spi_rx_buf_u32;
cs->get_tx = mpc8xxx_spi_tx_buf_u32;
} else
return -EINVAL;
if (mpc8xxx_spi->flags & SPI_QE_CPU_MODE && if (bits_per_word < 0)
spi->mode & SPI_LSB_FIRST) { return bits_per_word;
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;
if (bits_per_word == 32) if (bits_per_word == 32)
bits_per_word = 0; bits_per_word = 0;