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Unverified Commit 77736a98 authored by Clark Wang's avatar Clark Wang Committed by Mark Brown
Browse files

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: default avatarClark Wang <xiaoning.wang@nxp.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 944c01a8

drivers/spi/spi-fsl-lpspi.c

+13 −3
Original line number Diff line number Diff line
@@ -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;