spi: stm32: fix stm32_spi_prepare_mbr in case of odd clk_rate

ADESTM · broonie · commit 9cc61973bf93 · 2020-08-10T19:46:43.000+01:00
Fix spi->clk_rate when it is odd to the nearest lowest even value because minimum SPI divider is 2. Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com> Signed-off-by: Alain Volmat <alain.volmat@st.com> Link: https://lore.kernel.org/r/1597043558-29668-4-git-send-email-alain.volmat@st.com Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
@@ -441,7 +441,8 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz,
 {
 	u32 div, mbrdiv;
 
-	div = DIV_ROUND_UP(spi->clk_rate, speed_hz);
+	/* Ensure spi->clk_rate is even */
+	div = DIV_ROUND_UP(spi->clk_rate & ~0x1, speed_hz);
 
 	/*
 	 * SPI framework set xfer->speed_hz to master->max_speed_hz if

Original file line number	Diff line number	Diff line change
`@@ -441,7 +441,8 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz,`
`441`	`441`	`{`
`442`	`442`	`u32 div, mbrdiv;`
`443`	`443`
`444`		`- div = DIV_ROUND_UP(spi->clk_rate, speed_hz);`
	`444`	`+ /* Ensure spi->clk_rate is even */`
	`445`	`+ div = DIV_ROUND_UP(spi->clk_rate & ~0x1, speed_hz);`
`445`	`446`
`446`	`447`	`/*`
`447`	`448`	`* SPI framework set xfer->speed_hz to master->max_speed_hz if`