From 4ffb61fc922c410212ef4f1c1be986057c99fc44 Mon Sep 17 00:00:00 2001
From: Clark Wang <xiaoning.wang@nxp.com>
Date: Thu, 3 Jan 2019 15:26:46 +0800
Subject: [PATCH] MLK-20060-2 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>
Acked-by: Fugang Duan <Fugang.duan@nxp.com>
(cherry picked from commit d13f9515c1378d778e82a72c24a99892389710c4)
---
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 2fdc6cf23b3324..02f6d86dbbdf09 100644
--- a/drivers/spi/spi-fsl-lpspi.c
+++ b/drivers/spi/spi-fsl-lpspi.c
@@ -307,6 +307,13 @@ 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;
@@ -357,7 +364,7 @@ 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 =
@@ -390,7 +397,7 @@ 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)
@@ -482,7 +489,10 @@ 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;
--
GitLab