diff options
| author | Maxime Chevallier <maxime.chevallier@bootlin.com> | 2018-07-17 16:31:51 +0200 |
|---|---|---|
| committer | Oleksandr Suvorov <oleksandr.suvorov@toradex.com> | 2020-02-11 11:20:48 +0200 |
| commit | a48f249cf4ff45198bbb08394bbdf7e280568f76 (patch) | |
| tree | b14fa410fed72b76742c7e955511faf317265f8d | |
| parent | de7675d607f587513eeff9f2e993bed607543577 (diff) | |
spi: imx: Use dynamic bursts only when bits_per_word is 8, 16 or 32
commit 2801b2f5fad3d1e9ea0ac8484584051071065645 upstream
The dynamic bursts mode allows to group together multiple words into a
single burst. To do so, it's necessary that words can be packed into the
32-bits FIFO entries, so we can't allow using this mode with bit_per_words
different to 8, 16 or 32.
This prevents shitfing out extra clock ticks for transfers with
bit_per_word values not aligned on 8 bits.
With that , we are sure that only the correct number of bits is
shifted out at each transfer, so we don't need to mask out the remaining
parts of the words.
Related-to: ELB-1418
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
| -rw-r--r-- | drivers/spi/spi-imx.c | 23 |
1 files changed, 9 insertions, 14 deletions
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 9c3902555730..84e2041d0a31 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -113,7 +113,6 @@ struct spi_imx_data { const void *tx_buf; unsigned int txfifo; /* number of words pushed in tx FIFO */ unsigned int dynamic_burst, read_u32; - unsigned int word_mask; /* Slave mode */ bool slave_mode; @@ -304,7 +303,6 @@ static void spi_imx_buf_rx_swap_u32(struct spi_imx_data *spi_imx) else if (bytes_per_word == 2) val = (val << 16) | (val >> 16); #endif - val &= spi_imx->word_mask; *(u32 *)spi_imx->rx_buf = val; spi_imx->rx_buf += sizeof(u32); } @@ -335,7 +333,6 @@ static void spi_imx_buf_tx_swap_u32(struct spi_imx_data *spi_imx) if (spi_imx->tx_buf) { val = *(u32 *)spi_imx->tx_buf; - val &= spi_imx->word_mask; spi_imx->tx_buf += sizeof(u32); } @@ -1149,27 +1146,25 @@ static int spi_imx_setupxfer(struct spi_device *spi, spi_imx->bits_per_word = t->bits_per_word; spi_imx->speed_hz = t->speed_hz; - /* Initialize the functions for transfer */ - if (spi_imx->devtype_data->dynamic_burst && !spi_imx->slave_mode) { - u32 mask; + /* + * Initialize the functions for transfer. To transfer non byte-aligned + * words, we have to use multiple word-size bursts, we can't use + * dynamic_burst in that case. + */ + if (spi_imx->devtype_data->dynamic_burst && !spi_imx->slave_mode && + (spi_imx->bits_per_word == 8 || + spi_imx->bits_per_word == 16 || + spi_imx->bits_per_word == 32)) { spi_imx->dynamic_burst = 0; spi_imx->remainder = 0; spi_imx->read_u32 = 1; - mask = (1 << spi_imx->bits_per_word) - 1; spi_imx->rx = spi_imx_buf_rx_swap; spi_imx->tx = spi_imx_buf_tx_swap; spi_imx->dynamic_burst = 1; spi_imx->remainder = t->len; - if (spi_imx->bits_per_word <= 8) - spi_imx->word_mask = mask << 24 | mask << 16 - | mask << 8 | mask; - else if (spi_imx->bits_per_word <= 16) - spi_imx->word_mask = mask << 16 | mask; - else - spi_imx->word_mask = mask; } else { if (spi_imx->bits_per_word <= 8) { spi_imx->rx = spi_imx_buf_rx_u8; |