i.MX8M mini: CCM_CLK02

[saidjazouly]

Hello NXP,

We have designed a board based on the i.MX8M mini reference design.

Our customer would like to output a clock of 24MHz on CCM_CLK02 pad AB9 of the chip

1. What is the configuration needed to be done in the dts or any other relevant code to output the 24MHz?
2. Is it possible to output this clock @24MHz in Linux only or in both u-boot and Linux?

Best regards!

[weidong_sun · Accepted solution]

No matter which version of bsp, you can modify the clock driver manually. However, do not copy these codes directly. Because each version will be different.

[weidong_sun]

Hi,

  Try below, please!

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

diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c
index 5709bfce578c..2ef53f153728 100644
--- a/drivers/clk/imx/clk-imx8mm.c
+++ b/drivers/clk/imx/clk-imx8mm.c
@@ -404,6 +404,9 @@ static struct clk ** const uart_clks[] __initconst = {
static const char *imx8mm_clko1_sels[] = {"osc_24m", "sys_pll1_800m", "osc_27m", "sys_pll1_200m", "audio_pll2_clk",
"vpu_pll", "sys_pll1_80m", };

+static const char *imx8mm_clko2_sels[] = {"osc_24m", "sys_pll2_200m", "sys_pll1_400m", "sys_pll2_166m", "sys_pll3_out",
+ "audio_pll1_clk", "vpu_pll_out", "osc_32k", };
+
static int __init imx_clk_init_on(struct device_node *np,
struct clk * const clks[])
{
@@ -665,6 +668,7 @@ static void __init imx8mm_clocks_init(struct device_node *ccm_node)
clks[IMX8MM_CLK_WDOG_SRC] = imx_clk_mux2("wdog_src", base + 0xb900, 24, 3, imx8mm_wdog_sels, ARRAY_SIZE(imx8mm_wdog_sels));
clks[IMX8MM_CLK_WRCLK_SRC] = imx_clk_mux2("wrclk_src", base + 0xb980, 24, 3, imx8mm_wrclk_sels, ARRAY_SIZE(imx8mm_wrclk_sels));
clks[IMX8MM_CLK_CLKO1_SRC] = imx_clk_mux2("clko1_src", base + 0xba00, 24, 3, imx8mm_clko1_sels, ARRAY_SIZE(imx8mm_clko1_sels));
+ clks[IMX8MM_CLK_CLKO2_SRC] = imx_clk_mux2("clko2_src", base + 0xba80, 24, 3, imx8mm_clko2_sels, ARRAY_SIZE(imx8mm_clko2_sels));
clks[IMX8MM_CLK_DSI_CORE_SRC] = imx_clk_mux2("dsi_core_src", base + 0xbb00, 24, 3, imx8mm_dsi_core_sels, ARRAY_SIZE(imx8mm_dsi_core_sels));
clks[IMX8MM_CLK_DSI_PHY_REF_SRC] = imx_clk_mux2("dsi_phy_ref_src", base + 0xbb80, 24, 3, imx8mm_dsi_phy_sels, ARRAY_SIZE(imx8mm_dsi_phy_sels));
clks[IMX8MM_CLK_DSI_DBI_SRC] = imx_clk_mux2("dsi_dbi_src", base + 0xbc00, 24, 3, imx8mm_dsi_dbi_sels, ARRAY_SIZE(imx8mm_dsi_dbi_sels));
diff --git a/include/dt-bindings/clock/imx8mm-clock.h b/include/dt-bindings/clock/imx8mm-clock.h
index 083dd6d0116d..0745122611ca 100644
--- a/include/dt-bindings/clock/imx8mm-clock.h
+++ b/include/dt-bindings/clock/imx8mm-clock.h
@@ -469,5 +469,7 @@
#define IMX8MM_CLK_NAND_USDHC_BUS_RAWNAND_CLK 455
#define IMX8MM_CLK_SIM_HSIO 456

-#define IMX8MM_CLK_END 457
+#define IMX8MM_CLK_CLKO2_SRC 457
+
+#define IMX8MM_CLK_END 458
#endif
--

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

Hope it is helpful to you.

Have a nice day!

B.R,

Weidong

[saidjazouly]

Thank you Sun for your reply!

1. Can you please tell me what kernel version is the diff generated from?
2. Do you have a more recent patch based on kernel 5.4.24?

Best regards.