From 77736a98b859e2c64aebbd0f90b2ce4b17682396 Mon Sep 17 00:00:00 2001 From: Clark Wang Date: Wed, 6 Mar 2019 06:30:41 +0000 Subject: [PATCH] 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 Signed-off-by: Mark Brown --- drivers/spi/spi-fsl-lpspi.c | 16 +++++++++++++--- 1 file 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;