Re: Applied "spi: imx: dynamic burst length adjust for PIO mode" to the spi tree

From: Jiada Wang
Date: Fri Jun 30 2017 - 10:56:12 EST


Hello Sascha

On 06/30/2017 05:14 AM, Sascha Hauer wrote:
Hi Mark,

On Fri, Jun 30, 2017 at 01:00:22PM +0100, Mark Brown wrote:
The patch

spi: imx: dynamic burst length adjust for PIO mode

has been applied to the spi tree at

git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git
Argh, I wasn't fast enough. I just ran spi-loopback-test.ko with this
patch and it doesn't work properly.

+ if (spi_imx->count == spi_imx->remainder) {
+ ctrl = readl(spi_imx->base + MX51_ECSPI_CTRL);
+ ctrl&= ~MX51_ECSPI_CTRL_BL_MASK;
+ if (spi_imx->count> MX51_ECSPI_CTRL_MAX_BURST) {
+ spi_imx->remainder = spi_imx->count %
+ MX51_ECSPI_CTRL_MAX_BURST;
+ val = MX51_ECSPI_CTRL_MAX_BURST;
This is wrong. MX51_ECSPI_CTRL_MAX_BURST contains the burst length in
bytes, but the register 'val' is written to takes the burst length in
bits - 1, so this should be:

val = MX51_ECSPI_CTRL_MAX_BURST * 8 - 1;

instead.
Thanks for pointing this out,
I will submit a fix patch.


Thanks,
Jiada
Sascha