clk: at91: sama7g5: do not allow cpu pll to go higher than 1GHz

Since CPU PLL feeds both CPU clock and MCK0, MCK0 cannot go higher
than 200MHz and MCK0 maximum prescaller is 5 limit the CPU PLL at
1GHz to avoid MCK0 overclocking while CPU PLL is changed by DVFS.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1605800597-16720-10-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

diff --git a/drivers/clk/at91/sama7g5.c b/drivers/clk/at91/sama7g5.c
index 29d9781e67122ae44b3b16c0a9d6611abbbb9710..e0c4d2eb9f597faa3d0488da2a2b6d5ecbb5af61 100644 (file)
--- a/drivers/clk/at91/sama7g5.c
+++ b/drivers/clk/at91/sama7g5.c
@@ -89,11 +89,40 @@ static const struct clk_pll_layout pll_layout_divio = {
        .endiv_shift    = 30,
 };
 
+/*
+ * CPU PLL output range.
+ * Notice: The upper limit has been setup to 1000000002 due to hardware
+ * block which cannot output exactly 1GHz.
+ */
+static const struct clk_range cpu_pll_outputs[] = {
+       { .min = 2343750, .max = 1000000002 },
+};
+
+/* PLL output range. */
+static const struct clk_range pll_outputs[] = {
+       { .min = 2343750, .max = 1200000000 },
+};
+
+/* CPU PLL characteristics. */
+static const struct clk_pll_characteristics cpu_pll_characteristics = {
+       .input = { .min = 12000000, .max = 50000000 },
+       .num_output = ARRAY_SIZE(cpu_pll_outputs),
+       .output = cpu_pll_outputs,
+};
+
+/* PLL characteristics. */
+static const struct clk_pll_characteristics pll_characteristics = {
+       .input = { .min = 12000000, .max = 50000000 },
+       .num_output = ARRAY_SIZE(pll_outputs),
+       .output = pll_outputs,
+};
+
 /**
  * PLL clocks description
  * @n:         clock name
  * @p:         clock parent
  * @l:         clock layout
+ * @c:         clock characteristics
  * @t:         clock type
  * @f:         clock flags
  * @eid:       export index in sama7g5->chws[] array
@@ -102,6 +131,7 @@ static const struct {
        const char *n;
        const char *p;
        const struct clk_pll_layout *l;
+       const struct clk_pll_characteristics *c;
        unsigned long f;
        u8 t;
        u8 eid;
@@ -110,6 +140,7 @@ static const struct {
                { .n = "cpupll_fracck",
                  .p = "mainck",
                  .l = &pll_layout_frac,
+                 .c = &cpu_pll_characteristics,
                  .t = PLL_TYPE_FRAC,
                   /*
                    * This feeds cpupll_divpmcck which feeds CPU. It should
@@ -120,6 +151,7 @@ static const struct {
                { .n = "cpupll_divpmcck",
                  .p = "cpupll_fracck",
                  .l = &pll_layout_divpmc,
+                 .c = &cpu_pll_characteristics,
                  .t = PLL_TYPE_DIV,
                   /* This feeds CPU. It should not be disabled. */
                  .f = CLK_IS_CRITICAL | CLK_SET_RATE_PARENT,
@@ -130,6 +162,7 @@ static const struct {
                { .n = "syspll_fracck",
                  .p = "mainck",
                  .l = &pll_layout_frac,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_FRAC,
                   /*
                    * This feeds syspll_divpmcck which may feed critial parts
@@ -141,6 +174,7 @@ static const struct {
                { .n = "syspll_divpmcck",
                  .p = "syspll_fracck",
                  .l = &pll_layout_divpmc,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_DIV,
                   /*
                    * This may feed critial parts of the systems like timers.
@@ -154,6 +188,7 @@ static const struct {
                { .n = "ddrpll_fracck",
                  .p = "mainck",
                  .l = &pll_layout_frac,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_FRAC,
                   /*
                    * This feeds ddrpll_divpmcck which feeds DDR. It should not
@@ -164,6 +199,7 @@ static const struct {
                { .n = "ddrpll_divpmcck",
                  .p = "ddrpll_fracck",
                  .l = &pll_layout_divpmc,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_DIV,
                   /* This feeds DDR. It should not be disabled. */
                  .f = CLK_IS_CRITICAL | CLK_SET_RATE_GATE, },
@@ -173,12 +209,14 @@ static const struct {
                { .n = "imgpll_fracck",
                  .p = "mainck",
                  .l = &pll_layout_frac,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_FRAC,
                  .f = CLK_SET_RATE_GATE, },
 
                { .n = "imgpll_divpmcck",
                  .p = "imgpll_fracck",
                  .l = &pll_layout_divpmc,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_DIV,
                  .f = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
                       CLK_SET_RATE_PARENT, },
@@ -188,12 +226,14 @@ static const struct {
                { .n = "baudpll_fracck",
                  .p = "mainck",
                  .l = &pll_layout_frac,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_FRAC,
                  .f = CLK_SET_RATE_GATE, },
 
                { .n = "baudpll_divpmcck",
                  .p = "baudpll_fracck",
                  .l = &pll_layout_divpmc,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_DIV,
                  .f = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
                       CLK_SET_RATE_PARENT, },
@@ -203,12 +243,14 @@ static const struct {
                { .n = "audiopll_fracck",
                  .p = "main_xtal",
                  .l = &pll_layout_frac,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_FRAC,
                  .f = CLK_SET_RATE_GATE, },
 
                { .n = "audiopll_divpmcck",
                  .p = "audiopll_fracck",
                  .l = &pll_layout_divpmc,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_DIV,
                  .f = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
                       CLK_SET_RATE_PARENT,
@@ -217,6 +259,7 @@ static const struct {
                { .n = "audiopll_diviock",
                  .p = "audiopll_fracck",
                  .l = &pll_layout_divio,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_DIV,
                  .f = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
                       CLK_SET_RATE_PARENT,
@@ -227,12 +270,14 @@ static const struct {
                { .n = "ethpll_fracck",
                  .p = "main_xtal",
                  .l = &pll_layout_frac,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_FRAC,
                  .f = CLK_SET_RATE_GATE, },
 
                { .n = "ethpll_divpmcck",
                  .p = "ethpll_fracck",
                  .l = &pll_layout_divpmc,
+                 .c = &pll_characteristics,
                  .t = PLL_TYPE_DIV,
                  .f = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE |
                       CLK_SET_RATE_PARENT, },
@@ -793,18 +838,6 @@ static const struct {
          .pp_chg_id = INT_MIN, },
 };
 
-/* PLL output range. */
-static const struct clk_range pll_outputs[] = {
-       { .min = 2343750, .max = 1200000000 },
-};
-
-/* PLL characteristics. */
-static const struct clk_pll_characteristics pll_characteristics = {
-       .input = { .min = 12000000, .max = 50000000 },
-       .num_output = ARRAY_SIZE(pll_outputs),
-       .output = pll_outputs,
-};
-
 /* MCK0 characteristics. */
 static const struct clk_master_characteristics mck0_characteristics = {
        .output = { .min = 50000000, .max = 200000000 },
@@ -921,7 +954,7 @@ static void __init sama7g5_pmc_setup(struct device_node *np)
                                hw = sam9x60_clk_register_frac_pll(regmap,
                                        &pmc_pll_lock, sama7g5_plls[i][j].n,
                                        sama7g5_plls[i][j].p, parent_hw, i,
-                                       &pll_characteristics,
+                                       sama7g5_plls[i][j].c,
                                        sama7g5_plls[i][j].l,
                                        sama7g5_plls[i][j].f);
                                break;
@@ -930,7 +963,7 @@ static void __init sama7g5_pmc_setup(struct device_node *np)
                                hw = sam9x60_clk_register_div_pll(regmap,
                                        &pmc_pll_lock, sama7g5_plls[i][j].n,
                                        sama7g5_plls[i][j].p, i,
-                                       &pll_characteristics,
+                                       sama7g5_plls[i][j].c,
                                        sama7g5_plls[i][j].l,
                                        sama7g5_plls[i][j].f);
                                break;