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>

1 files changed, 47 insertions, 14 deletions

diff --git a/drivers/clk/at91/sama7g5.c b/drivers/clk/at91/sama7g5.c
index 29d9781e6712..e0c4d2eb9f59 100644
--- 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;