Thread (12 messages) 12 messages, 3 authors, 2022-11-21

Re: [PATCH 1/5] clk: imx8mn: rename vpu_pll to m7_alt_pll

From: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Date: 2022-11-14 17:20:54
Also in: linux-clk, linux-devicetree, lkml

Hi Marco,

On Mon, Nov 14, 2022 at 9:34 AM Marco Felsch [off-list ref] wrote:
Hi Dario,

On 22-11-13, Dario Binacchi wrote:
quoted
There is no occurrence of vpu pll in the reference manual (document
IMX8MNRM Rev 2, 07/2022). From an analysis of the code and the RM
itself, I think vpu pll is used instead of m7 alternate pll, probably
for copy and paste of code taken from modules of similar architectures.

As an example for all, if we consider the second row of the "Clock Root"
table of chapter 5 (Clocks and Power Management) of the RM:

     Clock Root     offset     Source Select (CCM_TARGET_ROOTn[MUX])
        ...          ...                    ...
  ARM_M7_CLK_ROOT   0x8080            000 - 24M_REF_CLK
                                      001 - SYSTEM_PLL2_DIV5
                                    010 - SYSTEM_PLL2_DIV4
                                    011 - M7_ALT_PLL_CLK
                                    100 - SYSTEM_PLL1_CLK
                                    101 - AUDIO_PLL1_CLK
                                    110 - VIDEO_PLL_CLK
                                    111 - SYSTEM_PLL3_CLK
        ...          ...                    ...

but in the source code, the imx8mn_m7_sels clocks list contains vpu_pll
for the source select bits 011b.
Thanks for the real detailed description. Maybe we should mention, that
the 8MN has no VPU complex at all.
quoted
So, let's rename "vpu_pll" to "m7_alt_pll" to be consistent with the RM.

No functional changes intended.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

 drivers/clk/imx/clk-imx8mn.c             | 16 ++++++++--------
 include/dt-bindings/clock/imx8mn-clock.h |  8 ++++----
 2 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/clk/imx/clk-imx8mn.c b/drivers/clk/imx/clk-imx8mn.c
index d37c45b676ab..72f9563a0ff6 100644
--- a/drivers/clk/imx/clk-imx8mn.c
+++ b/drivers/clk/imx/clk-imx8mn.c
@@ -30,7 +30,7 @@ static const char * const audio_pll2_bypass_sels[] = {"audio_pll2", "audio_pll2_
 static const char * const video_pll1_bypass_sels[] = {"video_pll1", "video_pll1_ref_sel", };
 static const char * const dram_pll_bypass_sels[] = {"dram_pll", "dram_pll_ref_sel", };
 static const char * const gpu_pll_bypass_sels[] = {"gpu_pll", "gpu_pll_ref_sel", };
-static const char * const vpu_pll_bypass_sels[] = {"vpu_pll", "vpu_pll_ref_sel", };
+static const char * const m7_alt_pll_bypass_sels[] = {"m7_alt_pll", "m7_alt_pll_ref_sel", };
 static const char * const arm_pll_bypass_sels[] = {"arm_pll", "arm_pll_ref_sel", };
 static const char * const sys_pll3_bypass_sels[] = {"sys_pll3", "sys_pll3_ref_sel", };
@@ -40,7 +40,7 @@ static const char * const imx8mn_a53_sels[] = {"osc_24m", "arm_pll_out", "sys_pl

 static const char * const imx8mn_a53_core_sels[] = {"arm_a53_div", "arm_pll_out", };

-static const char * const imx8mn_m7_sels[] = {"osc_24m", "sys_pll2_200m", "sys_pll2_250m", "vpu_pll_out",
+static const char * const imx8mn_m7_sels[] = {"osc_24m", "sys_pll2_200m", "sys_pll2_250m", "m7_alt_pll_out",
                                     "sys_pll1_800m", "audio_pll1_out", "video_pll1_out", "sys_pll3_out", };

 static const char * const imx8mn_gpu_core_sels[] = {"osc_24m", "gpu_pll_out", "sys_pll1_800m",
@@ -252,10 +252,10 @@ static const char * const imx8mn_gpt6_sels[] = {"osc_24m", "sys_pll2_100m", "sys
                                              "audio_pll1_out", "clk_ext1", };

 static const char * const imx8mn_wdog_sels[] = {"osc_24m", "sys_pll1_133m", "sys_pll1_160m",
-                                             "vpu_pll_out", "sys_pll2_125m", "sys_pll3_out",
+                                             "m7_alt_pll_out", "sys_pll2_125m", "sys_pll3_out",
                                              "sys_pll1_80m", "sys_pll2_166m", };

-static const char * const imx8mn_wrclk_sels[] = {"osc_24m", "sys_pll1_40m", "vpu_pll_out",
+static const char * const imx8mn_wrclk_sels[] = {"osc_24m", "sys_pll1_40m", "m7_alt_pll_out",
                                               "sys_pll3_out", "sys_pll2_200m", "sys_pll1_266m",
                                               "sys_pll2_500m", "sys_pll1_100m", };
@@ -352,7 +352,7 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
      hws[IMX8MN_VIDEO_PLL1_REF_SEL] = imx_clk_hw_mux("video_pll1_ref_sel", base + 0x28, 0, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
      hws[IMX8MN_DRAM_PLL_REF_SEL] = imx_clk_hw_mux("dram_pll_ref_sel", base + 0x50, 0, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
      hws[IMX8MN_GPU_PLL_REF_SEL] = imx_clk_hw_mux("gpu_pll_ref_sel", base + 0x64, 0, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
-     hws[IMX8MN_VPU_PLL_REF_SEL] = imx_clk_hw_mux("vpu_pll_ref_sel", base + 0x74, 0, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
+     hws[IMX8MN_M7_ALT_PLL_REF_SEL] = imx_clk_hw_mux("m7_alt_pll_ref_sel", base + 0x74, 0, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
      hws[IMX8MN_ARM_PLL_REF_SEL] = imx_clk_hw_mux("arm_pll_ref_sel", base + 0x84, 0, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
      hws[IMX8MN_SYS_PLL3_REF_SEL] = imx_clk_hw_mux("sys_pll3_ref_sel", base + 0x114, 0, 2, pll_ref_sels, ARRAY_SIZE(pll_ref_sels));
@@ -361,7 +361,7 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
      hws[IMX8MN_VIDEO_PLL1] = imx_clk_hw_pll14xx("video_pll1", "video_pll1_ref_sel", base + 0x28, &imx_1443x_pll);
      hws[IMX8MN_DRAM_PLL] = imx_clk_hw_pll14xx("dram_pll", "dram_pll_ref_sel", base + 0x50, &imx_1443x_dram_pll);
      hws[IMX8MN_GPU_PLL] = imx_clk_hw_pll14xx("gpu_pll", "gpu_pll_ref_sel", base + 0x64, &imx_1416x_pll);
-     hws[IMX8MN_VPU_PLL] = imx_clk_hw_pll14xx("vpu_pll", "vpu_pll_ref_sel", base + 0x74, &imx_1416x_pll);
+     hws[IMX8MN_M7_ALT_PLL] = imx_clk_hw_pll14xx("m7_alt_pll", "m7_alt_pll_ref_sel", base + 0x74, &imx_1416x_pll);
      hws[IMX8MN_ARM_PLL] = imx_clk_hw_pll14xx("arm_pll", "arm_pll_ref_sel", base + 0x84, &imx_1416x_pll);
      hws[IMX8MN_SYS_PLL1] = imx_clk_hw_fixed("sys_pll1", 800000000);
      hws[IMX8MN_SYS_PLL2] = imx_clk_hw_fixed("sys_pll2", 1000000000);
@@ -373,7 +373,7 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
      hws[IMX8MN_VIDEO_PLL1_BYPASS] = imx_clk_hw_mux_flags("video_pll1_bypass", base + 0x28, 16, 1, video_pll1_bypass_sels, ARRAY_SIZE(video_pll1_bypass_sels), CLK_SET_RATE_PARENT);
      hws[IMX8MN_DRAM_PLL_BYPASS] = imx_clk_hw_mux_flags("dram_pll_bypass", base + 0x50, 16, 1, dram_pll_bypass_sels, ARRAY_SIZE(dram_pll_bypass_sels), CLK_SET_RATE_PARENT);
      hws[IMX8MN_GPU_PLL_BYPASS] = imx_clk_hw_mux_flags("gpu_pll_bypass", base + 0x64, 28, 1, gpu_pll_bypass_sels, ARRAY_SIZE(gpu_pll_bypass_sels), CLK_SET_RATE_PARENT);
-     hws[IMX8MN_VPU_PLL_BYPASS] = imx_clk_hw_mux_flags("vpu_pll_bypass", base + 0x74, 28, 1, vpu_pll_bypass_sels, ARRAY_SIZE(vpu_pll_bypass_sels), CLK_SET_RATE_PARENT);
+     hws[IMX8MN_M7_ALT_PLL_BYPASS] = imx_clk_hw_mux_flags("m7_alt_pll_bypass", base + 0x74, 28, 1, m7_alt_pll_bypass_sels, ARRAY_SIZE(m7_alt_pll_bypass_sels), CLK_SET_RATE_PARENT);
      hws[IMX8MN_ARM_PLL_BYPASS] = imx_clk_hw_mux_flags("arm_pll_bypass", base + 0x84, 28, 1, arm_pll_bypass_sels, ARRAY_SIZE(arm_pll_bypass_sels), CLK_SET_RATE_PARENT);
      hws[IMX8MN_SYS_PLL3_BYPASS] = imx_clk_hw_mux_flags("sys_pll3_bypass", base + 0x114, 28, 1, sys_pll3_bypass_sels, ARRAY_SIZE(sys_pll3_bypass_sels), CLK_SET_RATE_PARENT);
@@ -383,7 +383,7 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
      hws[IMX8MN_VIDEO_PLL1_OUT] = imx_clk_hw_gate("video_pll1_out", "video_pll1_bypass", base + 0x28, 13);
      hws[IMX8MN_DRAM_PLL_OUT] = imx_clk_hw_gate("dram_pll_out", "dram_pll_bypass", base + 0x50, 13);
      hws[IMX8MN_GPU_PLL_OUT] = imx_clk_hw_gate("gpu_pll_out", "gpu_pll_bypass", base + 0x64, 11);
-     hws[IMX8MN_VPU_PLL_OUT] = imx_clk_hw_gate("vpu_pll_out", "vpu_pll_bypass", base + 0x74, 11);
+     hws[IMX8MN_M7_ALT_PLL_OUT] = imx_clk_hw_gate("m7_alt_pll_out", "m7_alt_pll_bypass", base + 0x74, 11);
      hws[IMX8MN_ARM_PLL_OUT] = imx_clk_hw_gate("arm_pll_out", "arm_pll_bypass", base + 0x84, 11);
      hws[IMX8MN_SYS_PLL3_OUT] = imx_clk_hw_gate("sys_pll3_out", "sys_pll3_bypass", base + 0x114, 11);
The driver changes looking good from my pov.
quoted
diff --git a/include/dt-bindings/clock/imx8mn-clock.h b/include/dt-bindings/clock/imx8mn-clock.h
index 07b8a282c268..f103b008a12a 100644
--- a/include/dt-bindings/clock/imx8mn-clock.h
+++ b/include/dt-bindings/clock/imx8mn-clock.h
@@ -19,7 +19,7 @@
 #define IMX8MN_VIDEO_PLL1_REF_SEL            10
 #define IMX8MN_DRAM_PLL_REF_SEL                      11
 #define IMX8MN_GPU_PLL_REF_SEL                       12
-#define IMX8MN_VPU_PLL_REF_SEL                       13
+#define IMX8MN_M7_ALT_PLL_REF_SEL            13
If we take backward compatibility serious we can't do that since this
may break existing device trees. What you can do is:

#define IMX8MN_M7_ALT_PLL_REF_SEL               13
#define IMX8MN_VPU_PLL_REF_SEL                  IMX8MN_M7_ALT_PLL_REF_SEL

and add a comment that we need this for backward compatibility. Same
applies for the below defines.
If I run the command "git grep IMX8MN_VPU_PLL", this is the output:
drivers/clk/imx/clk-imx8mn.c:   hws[IMX8MN_VPU_PLL_REF_SEL] =
imx_clk_hw_mux("vpu_pll_ref_sel", base + 0x74, 0, 2, pll_ref_sels,
ARRAY_SIZE(pll_ref_sels));
drivers/clk/imx/clk-imx8mn.c:   hws[IMX8MN_VPU_PLL] =
imx_clk_hw_pll14xx("vpu_pll", "vpu_pll_ref_sel", base + 0x74,
&imx_1416x_pll);
drivers/clk/imx/clk-imx8mn.c:   hws[IMX8MN_VPU_PLL_BYPASS] =
imx_clk_hw_mux_flags("vpu_pll_bypass", base + 0x74, 28, 1,
vpu_pll_bypass_sels, ARRAY_SIZE(vpu_pll_bypass_sels),
CLK_SET_RATE_PARENT);
drivers/clk/imx/clk-imx8mn.c:   hws[IMX8MN_VPU_PLL_OUT] =
imx_clk_hw_gate("vpu_pll_out", "vpu_pll_bypass", base + 0x74, 11);
include/dt-bindings/clock/imx8mn-clock.h:#define
IMX8MN_VPU_PLL_REF_SEL                 13
include/dt-bindings/clock/imx8mn-clock.h:#define IMX8MN_VPU_PLL
                 23
include/dt-bindings/clock/imx8mn-clock.h:#define IMX8MN_VPU_PLL_BYPASS
                 33
include/dt-bindings/clock/imx8mn-clock.h:#define IMX8MN_VPU_PLL_OUT
                 43

No device tree comes out.
So can we say that backwards compatibility is guaranteed or am I
missing something ?

Thanks and regards,
Dario
Regards,
  Marco
quoted
 #define IMX8MN_ARM_PLL_REF_SEL                       14
 #define IMX8MN_SYS_PLL1_REF_SEL                      15
 #define IMX8MN_SYS_PLL2_REF_SEL                      16
@@ -29,7 +29,7 @@
 #define IMX8MN_VIDEO_PLL1                    20
 #define IMX8MN_DRAM_PLL                              21
 #define IMX8MN_GPU_PLL                               22
-#define IMX8MN_VPU_PLL                               23
+#define IMX8MN_M7_ALT_PLL                    23
 #define IMX8MN_ARM_PLL                               24
 #define IMX8MN_SYS_PLL1                              25
 #define IMX8MN_SYS_PLL2                              26
@@ -39,7 +39,7 @@
 #define IMX8MN_VIDEO_PLL1_BYPASS             30
 #define IMX8MN_DRAM_PLL_BYPASS                       31
 #define IMX8MN_GPU_PLL_BYPASS                        32
-#define IMX8MN_VPU_PLL_BYPASS                        33
+#define IMX8MN_M7_ALT_PLL_BYPASS             33
 #define IMX8MN_ARM_PLL_BYPASS                        34
 #define IMX8MN_SYS_PLL1_BYPASS                       35
 #define IMX8MN_SYS_PLL2_BYPASS                       36
@@ -49,7 +49,7 @@
 #define IMX8MN_VIDEO_PLL1_OUT                        40
 #define IMX8MN_DRAM_PLL_OUT                  41
 #define IMX8MN_GPU_PLL_OUT                   42
-#define IMX8MN_VPU_PLL_OUT                   43
+#define IMX8MN_M7_ALT_PLL_OUT                        43
 #define IMX8MN_ARM_PLL_OUT                   44
 #define IMX8MN_SYS_PLL1_OUT                  45
 #define IMX8MN_SYS_PLL2_OUT                  46
--
2.32.0



-- 

Dario Binacchi

Embedded Linux Developer

dario.binacchi@amarulasolutions.com

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Amarula Solutions SRL

Via Le Canevare 30, 31100 Treviso, Veneto, IT

T. +39 042 243 5310
info@amarulasolutions.com

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