From: Clark Wang <xiaoning.wang@nxp.com>
To: "broonie@kernel.org" <broonie@kernel.org>
Cc: "linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Clark Wang <xiaoning.wang@nxp.com>
Subject: [PATCH 6/8] spi: lpspi: add the error info of transfer speed setting
Date: Mon, 7 Jan 2019 07:47:45 +0000 [thread overview]
Message-ID: <20190107074639.6336-7-xiaoning.wang@nxp.com> (raw)
In-Reply-To: <20190107074639.6336-1-xiaoning.wang@nxp.com>
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>
---
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;
--
2.17.1
next prev parent reply other threads:[~2019-01-07 7:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-07 7:47 [PATCH 0/8] spi: lpspi: Fix bugs and Add some functions support Clark Wang
2019-01-07 7:47 ` [PATCH 1/8] spi: lpspi: Add i.MX8 boards support for lpspi Clark Wang
2019-01-07 15:15 ` Mark Brown
2019-01-07 7:47 ` [PATCH 2/8] spi: lpspi: enable runtime pm " Clark Wang
2019-01-07 15:16 ` Mark Brown
2019-01-07 7:47 ` [PATCH 3/8] spi: lpspi: Improve the stability of lpspi data transmission Clark Wang
2019-01-07 7:47 ` [PATCH 4/8] spi: lpspi: Fix wrong transmission when don't use CONT Clark Wang
2019-01-07 18:59 ` Applied "spi: lpspi: Fix wrong transmission when don't use CONT" to the spi tree Mark Brown
2019-01-07 7:47 ` [PATCH 5/8] spi: lpspi: Fix CLK pin becomes low before one transfer Clark Wang
2019-01-07 7:47 ` Clark Wang [this message]
2019-01-09 12:43 ` [PATCH 6/8] spi: lpspi: add the error info of transfer speed setting Mark Brown
2019-01-07 7:47 ` [PATCH 7/8] spi: lpspi: Add cs-gpio support Clark Wang
2019-01-09 12:33 ` Mark Brown
2019-01-07 7:47 ` [PATCH 8/8] spi: lpspi: add dma mode support Clark Wang
2019-01-07 15:22 ` Mark Brown
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