clk: tegra: Add DFLL DVCO reset control for Tegra114

The DVCO present in the DFLL IP block has a separate reset line, exposed
via the CAR IP block.  This reset line is asserted upon SoC reset.
Unless something (such as the DFLL driver) deasserts this line, the DVCO
will not oscillate, although reads and writes to the DFLL IP block will
complete.

Based on a3c83ff ("clk: tegra: Add DFLL DVCO reset control for Tegra124")

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

Author: clamor-s

drivers/clk/tegra/clk-tegra114.c

@@ -11,6 +11,7 @@
 #include <linux/export.h>
 #include <linux/clk/tegra.h>
 #include <dt-bindings/clock/tegra114-car.h>
+#include <dt-bindings/reset/nvidia,tegra114-car.h>
 
 #include "clk.h"
 #include "clk-id.h"
@@ -1272,7 +1273,7 @@ EXPORT_SYMBOL(tegra114_clock_tune_cpu_trimmers_init);
  *
  * Assert the reset line of the DFLL's DVCO.  No return value.
  */
-void tegra114_clock_assert_dfll_dvco_reset(void)
+static void tegra114_clock_assert_dfll_dvco_reset(void)
 {
 	u32 v;
 
@@ -1281,15 +1282,14 @@ void tegra114_clock_assert_dfll_dvco_reset(void)
 	writel_relaxed(v, clk_base + RST_DFLL_DVCO);
 	tegra114_car_barrier();
 }
-EXPORT_SYMBOL(tegra114_clock_assert_dfll_dvco_reset);
 
 /**
  * tegra114_clock_deassert_dfll_dvco_reset - deassert the DFLL's DVCO reset
  *
  * Deassert the reset line of the DFLL's DVCO, allowing the DVCO to
  * operate.  No return value.
  */
-void tegra114_clock_deassert_dfll_dvco_reset(void)
+static void tegra114_clock_deassert_dfll_dvco_reset(void)
 {
 	u32 v;
 
@@ -1298,7 +1298,26 @@ void tegra114_clock_deassert_dfll_dvco_reset(void)
 	writel_relaxed(v, clk_base + RST_DFLL_DVCO);
 	tegra114_car_barrier();
 }
-EXPORT_SYMBOL(tegra114_clock_deassert_dfll_dvco_reset);
+
+static int tegra114_reset_assert(unsigned long id)
+{
+	if (id == TEGRA114_RST_DFLL_DVCO)
+		tegra114_clock_assert_dfll_dvco_reset();
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static int tegra114_reset_deassert(unsigned long id)
+{
+	if (id == TEGRA114_RST_DFLL_DVCO)
+		tegra114_clock_deassert_dfll_dvco_reset();
+	else
+		return -EINVAL;
+
+	return 0;
+}
 
 static void __init tegra114_clock_init(struct device_node *np)
 {
@@ -1344,6 +1363,9 @@ static void __init tegra114_clock_init(struct device_node *np)
 	tegra_super_clk_gen4_init(clk_base, pmc_base, tegra114_clks,
 					&pll_x_params);
 
+	tegra_init_special_resets(1, tegra114_reset_assert,
+				  tegra114_reset_deassert);
+
 	tegra_add_of_provider(np, of_clk_src_onecell_get);
 	tegra_register_devclks(devclks, ARRAY_SIZE(devclks));
 

drivers/clk/tegra/clk.h

@@ -897,8 +897,6 @@ static inline bool tegra124_clk_emc_driver_available(struct clk_hw *emc_hw)
 void tegra114_clock_tune_cpu_trimmers_high(void);
 void tegra114_clock_tune_cpu_trimmers_low(void);
 void tegra114_clock_tune_cpu_trimmers_init(void);
-void tegra114_clock_assert_dfll_dvco_reset(void);
-void tegra114_clock_deassert_dfll_dvco_reset(void);
 
 typedef void (*tegra_clk_apply_init_table_func)(void);
 extern tegra_clk_apply_init_table_func tegra_clk_apply_init_table;