Commit a408d29d authored by Stefan Wahren's avatar Stefan Wahren Committed by Wen Zhiwei
Browse files

spi: spi-fsl-lpspi: Fix off-by-one in prescale max 

stable inclusion
from stable-v6.6.51
commit 50b6744c12fa49d7af51e37935c582efb41173f1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAYRVR

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=50b6744c12fa49d7af51e37935c582efb41173f1



--------------------------------

commit ff949d981c775332be94be70397ee1df20bc68e5 upstream.

The commit 783bf5d09f86 ("spi: spi-fsl-lpspi: limit PRESCALE bit in
TCR register") doesn't implement the prescaler maximum as intended.
The maximum allowed value for i.MX93 should be 1 and for i.MX7ULP
it should be 7. So this needs also a adjustment of the comparison
in the scldiv calculation.

Fixes: 783bf5d09f86 ("spi: spi-fsl-lpspi: limit PRESCALE bit in TCR register")
Signed-off-by: default avatarStefan Wahren <wahrenst@gmx.net>
Link: https://patch.msgid.link/20240905111537.90389-1-wahrenst@gmx.net


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent d3b187e6

drivers/spi/spi-fsl-lpspi.c

+2 −2
Original line number Diff line number Diff line
@@ -136,7 +136,7 @@ static struct fsl_lpspi_devtype_data imx93_lpspi_devtype_data = { 
};



static struct fsl_lpspi_devtype_data imx7ulp_lpspi_devtype_data = {

	.prescale_max = 8,

	.prescale_max = 7,

};



static const struct of_device_id fsl_lpspi_dt_ids[] = {
@@ -336,7 +336,7 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi) 


	div = DIV_ROUND_UP(perclk_rate, config.speed_hz);



	for (prescale = 0; prescale < prescale_max; prescale++) {

	for (prescale = 0; prescale <= prescale_max; prescale++) {

		scldiv = div / (1 << prescale) - 2;

		if (scldiv < 256) {

			fsl_lpspi->config.prescale = prescale;