diff options
Diffstat (limited to 'drivers/spi/spi-imx.c')
| -rw-r--r-- | drivers/spi/spi-imx.c | 39 |
1 files changed, 29 insertions, 10 deletions
diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 4aee3db6d6df..8d8df51c5466 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -505,7 +505,9 @@ static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx, struct spi_message *msg) { struct spi_device *spi = msg->spi; + struct spi_transfer *xfer; u32 ctrl = MX51_ECSPI_CTRL_ENABLE; + u32 min_speed_hz = ~0U; u32 testreg, delay; u32 cfg = readl(spi_imx->base + MX51_ECSPI_CONFIG); @@ -577,9 +579,21 @@ static int mx51_ecspi_prepare_message(struct spi_imx_data *spi_imx, * be asserted before the SCLK polarity changes, which would disrupt * the SPI communication as the device on the other end would consider * the change of SCLK polarity as a clock tick already. + * + * Because spi_imx->spi_bus_clk is only set in bitbang prepare_message + * callback, iterate over all the transfers in spi_message, find the + * one with lowest bus frequency, and use that bus frequency for the + * delay calculation. In case all transfers have speed_hz == 0, then + * min_speed_hz is ~0 and the resulting delay is zero. */ - delay = (2 * 1000000) / spi_imx->spi_bus_clk; - if (likely(delay < 10)) /* SCLK is faster than 100 kHz */ + list_for_each_entry(xfer, &msg->transfers, transfer_list) { + if (!xfer->speed_hz) + continue; + min_speed_hz = min(xfer->speed_hz, min_speed_hz); + } + + delay = (2 * 1000000) / min_speed_hz; + if (likely(delay < 10)) /* SCLK is faster than 200 kHz */ udelay(delay); else /* SCLK is _very_ slow */ usleep_range(delay, delay + 10); @@ -1038,12 +1052,8 @@ static void spi_imx_set_burst_len(struct spi_imx_data *spi_imx, int n_bits) static void spi_imx_push(struct spi_imx_data *spi_imx) { - unsigned int burst_len, fifo_words; + unsigned int burst_len; - if (spi_imx->dynamic_burst) - fifo_words = 4; - else - fifo_words = spi_imx_bytes_per_word(spi_imx->bits_per_word); /* * Reload the FIFO when the remaining bytes to be transferred in the * current burst is 0. This only applies when bits_per_word is a @@ -1062,7 +1072,7 @@ static void spi_imx_push(struct spi_imx_data *spi_imx) spi_imx->remainder = burst_len; } else { - spi_imx->remainder = fifo_words; + spi_imx->remainder = spi_imx_bytes_per_word(spi_imx->bits_per_word); } } @@ -1070,8 +1080,7 @@ static void spi_imx_push(struct spi_imx_data *spi_imx) if (!spi_imx->count) break; if (spi_imx->dynamic_burst && - spi_imx->txfifo >= DIV_ROUND_UP(spi_imx->remainder, - fifo_words)) + spi_imx->txfifo >= DIV_ROUND_UP(spi_imx->remainder, 4)) break; spi_imx->tx(spi_imx); spi_imx->txfifo++; @@ -1181,6 +1190,7 @@ static int spi_imx_setupxfer(struct spi_device *spi, * dynamic_burst in that case. */ if (spi_imx->devtype_data->dynamic_burst && !spi_imx->slave_mode && + !(spi->mode & SPI_CS_WORD) && (spi_imx->bits_per_word == 8 || spi_imx->bits_per_word == 16 || spi_imx->bits_per_word == 32)) { @@ -1616,6 +1626,15 @@ static int spi_imx_probe(struct platform_device *pdev) is_imx53_ecspi(spi_imx)) spi_imx->bitbang.master->mode_bits |= SPI_LOOP | SPI_READY; + if (is_imx51_ecspi(spi_imx) && + device_property_read_u32(&pdev->dev, "cs-gpios", NULL)) + /* + * When using HW-CS implementing SPI_CS_WORD can be done by just + * setting the burst length to the word size. This is + * considerably faster than manually controlling the CS. + */ + spi_imx->bitbang.master->mode_bits |= SPI_CS_WORD; + spi_imx->spi_drctl = spi_drctl; init_completion(&spi_imx->xfer_done); |