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spi: spi-fsl-lpspi: Adjust type of scldiv

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The target value of scldiv is just a byte, but its calculation in
fsl_lpspi_set_bitrate could be negative. So use an adequate type to store
the result and avoid overflows. After that this needs range check
adjustments, but this should make the code less opaque.

Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20240930093056.93418-2-wahrenst@gmx.net
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Stefan Wahren 2024-09-30 11:30:54 +02:00 committed by Mark Brown
parent 9852d85ec9
commit fa8ecda987
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GPG Key ID: 24D68B725D5487D0
1 changed files with 4 additions and 3 deletions
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7
drivers/spi/spi-fsl-lpspi.c
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@ -315,9 +315,10 @@ static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi)
static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
{
struct lpspi_config config = fsl_lpspi->config;
unsigned int perclk_rate, scldiv, div;
unsigned int perclk_rate, div;
u8 prescale_max;
u8 prescale;
int scldiv;
perclk_rate = clk_get_rate(fsl_lpspi->clk_per);
prescale_max = fsl_lpspi->devtype_data->prescale_max;
@ -338,13 +339,13 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi)
for (prescale = 0; prescale <= prescale_max; prescale++) {
scldiv = div / (1 << prescale) - 2;
if (scldiv < 256) {
if (scldiv >= 0 && scldiv < 256) {
fsl_lpspi->config.prescale = prescale;
break;
}
}
if (scldiv >= 256)
if (scldiv < 0 || scldiv >= 256)
return -EINVAL;
writel(scldiv | (scldiv << 8) | ((scldiv >> 1) << 16),