Allow transfers to set the transmission speed, only fall back to board max_speed_hz if requested speed is not set or invalid.
Signed-off-by: Marcus Weseloh <[email protected]> --- drivers/spi/spi-sun4i.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c index fbb0a4d..0630691 100644 --- a/drivers/spi/spi-sun4i.c +++ b/drivers/spi/spi-sun4i.c @@ -173,6 +173,7 @@ static int sun4i_spi_transfer_one(struct spi_master *master, unsigned int tx_len = 0; int ret = 0; u32 reg; + u32 speed; /* We don't support transfer larger than the FIFO */ if (tfr->len > SUN4I_FIFO_DEPTH) @@ -227,10 +228,16 @@ static int sun4i_spi_transfer_one(struct spi_master *master, sun4i_spi_write(sspi, SUN4I_CTL_REG, reg); + /* Transfer speed setup with fallback to board max_speed_hz */ + if (tfr->speed_hz > 0 && tfr->speed_hz <= spi->max_speed_hz) + speed = tfr->speed_hz; + else + speed = spi->max_speed_hz; + /* Ensure that we have a parent clock fast enough */ mclk_rate = clk_get_rate(sspi->mclk); - if (mclk_rate < (2 * spi->max_speed_hz)) { - clk_set_rate(sspi->mclk, 2 * spi->max_speed_hz); + if (mclk_rate < (2 * speed)) { + clk_set_rate(sspi->mclk, 2 * speed); mclk_rate = clk_get_rate(sspi->mclk); } @@ -248,14 +255,14 @@ static int sun4i_spi_transfer_one(struct spi_master *master, * First try CDR2, and if we can't reach the expected * frequency, fall back to CDR1. */ - div = mclk_rate / (2 * spi->max_speed_hz); + div = mclk_rate / (2 * speed); if (div <= (SUN4I_CLK_CTL_CDR2_MASK + 1)) { if (div > 0) div--; reg = SUN4I_CLK_CTL_CDR2(div) | SUN4I_CLK_CTL_DRS; } else { - div = ilog2(mclk_rate) - ilog2(spi->max_speed_hz); + div = ilog2(mclk_rate) - ilog2(speed); reg = SUN4I_CLK_CTL_CDR1(div); } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
