clk: stm32mp1: correctly handle Clock Spreading Generator
To activate the CSG option, the driver needs to set the bit2
of PLLNCR register = SSCG_CTRL: Spread Spectrum Clock Generator.
This bit should not be cleared when starting the PLL.
Change-Id: Ie5c720ff03655f27a7e7e9e7ccf8295dd046112f
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/drivers/st/clk/stm32mp1_clk.c b/drivers/st/clk/stm32mp1_clk.c
index 855e98b..cea1c46 100644
--- a/drivers/st/clk/stm32mp1_clk.c
+++ b/drivers/st/clk/stm32mp1_clk.c
@@ -1313,7 +1313,11 @@
const struct stm32mp1_clk_pll *pll = pll_ref(pll_id);
uintptr_t pllxcr = stm32mp_rcc_base() + pll->pllxcr;
- mmio_write_32(pllxcr, RCC_PLLNCR_PLLON);
+ /* Preserve RCC_PLLNCR_SSCG_CTRL value */
+ mmio_clrsetbits_32(pllxcr,
+ RCC_PLLNCR_DIVPEN | RCC_PLLNCR_DIVQEN |
+ RCC_PLLNCR_DIVREN,
+ RCC_PLLNCR_PLLON);
}
static int stm32mp1_pll_output(enum stm32mp1_pll_id pll_id, uint32_t output)
@@ -1442,6 +1446,9 @@
RCC_PLLNCSGR_SSCG_MODE_MASK;
mmio_write_32(stm32mp_rcc_base() + pll->pllxcsgr, pllxcsg);
+
+ mmio_setbits_32(stm32mp_rcc_base() + pll->pllxcr,
+ RCC_PLLNCR_SSCG_CTRL);
}
static int stm32mp1_set_clksrc(unsigned int clksrc)