diff options
| author | Clark Wang <xiaoning.wang@nxp.com> | 2019-03-06 06:30:41 +0000 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-03-18 12:17:15 +0000 |
| commit | 77736a98b859e2c64aebbd0f90b2ce4b17682396 (patch) | |
| tree | c92c1201be7e888563df6caec3921988974a52e0 /drivers/spi | |
| parent | 944c01a889d97dc08e1b71f4ed868f4023fd6034 (diff) | |
spi: lpspi: add the error info of transfer speed setting
Add a error info when set a speed which greater than half of per-clk of
spi module.
The minimum SCK period is 2 cycles(CCR[SCKDIV]). So the maximum transfer
speed is half of spi per-clk.
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/spi-fsl-lpspi.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c index 84dcb9e176b8..69635cde0e22 100644 --- a/drivers/spi/spi-fsl-lpspi.c +++ b/drivers/spi/spi-fsl-lpspi.c @@ -255,6 +255,13 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi) u8 prescale; perclk_rate = clk_get_rate(fsl_lpspi->clk_per); + + if (config.speed_hz > perclk_rate / 2) { + dev_err(fsl_lpspi->dev, + "per-clk should be at least two times of transfer speed"); + return -EINVAL; + } + for (prescale = 0; prescale < 8; prescale++) { scldiv = perclk_rate / (clkdivs[prescale] * config.speed_hz) - 2; @@ -304,7 +311,7 @@ static int fsl_lpspi_config(struct fsl_lpspi_data *fsl_lpspi) return 0; } -static void fsl_lpspi_setup_transfer(struct spi_device *spi, +static int fsl_lpspi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) { struct fsl_lpspi_data *fsl_lpspi = @@ -337,7 +344,7 @@ static void fsl_lpspi_setup_transfer(struct spi_device *spi, else fsl_lpspi->watermark = fsl_lpspi->txfifosize; - fsl_lpspi_config(fsl_lpspi); + return fsl_lpspi_config(fsl_lpspi); } static int fsl_lpspi_slave_abort(struct spi_controller *controller) @@ -429,7 +436,10 @@ static int fsl_lpspi_transfer_one_msg(struct spi_controller *controller, msg->actual_length = 0; list_for_each_entry(xfer, &msg->transfers, transfer_list) { - fsl_lpspi_setup_transfer(spi, xfer); + ret = fsl_lpspi_setup_transfer(spi, xfer); + if (ret < 0) + goto complete; + fsl_lpspi_set_cmd(fsl_lpspi, is_first_xfer); is_first_xfer = false; |