memory: tegra124-emc: Make driver modular

Add modularization support to the Tegra124 EMC driver, which now can be
compiled as a loadable kernel module.

Note that EMC clock must be registered at clk-init time, otherwise PLLM
will be disabled as unused clock at boot time if EMC driver is compiled
as a module. Hence add a prepare/complete callbacks. similarly to what is
done for the Tegra20/30 EMC drivers.

Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Link: https://lore.kernel.org/r/20201228154920.18846-2-digetx@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

5 files changed, 75 insertions, 15 deletions

diff --git a/drivers/clk/tegra/Kconfig b/drivers/clk/tegra/Kconfig
index deaa4605824c..90df619dc087 100644
--- a/drivers/clk/tegra/Kconfig
+++ b/drivers/clk/tegra/Kconfig
@@ -7,3 +7,6 @@ config TEGRA_CLK_DFLL
 	depends on ARCH_TEGRA_124_SOC || ARCH_TEGRA_210_SOC
 	select PM_OPP
 	def_bool y
+
+config TEGRA124_CLK_EMC
+	bool
diff --git a/drivers/clk/tegra/Makefile b/drivers/clk/tegra/Makefile
index eec2313fd37e..7b1816856eb5 100644
--- a/drivers/clk/tegra/Makefile
+++ b/drivers/clk/tegra/Makefile
@@ -22,7 +22,7 @@ obj-$(CONFIG_ARCH_TEGRA_3x_SOC)		+= clk-tegra20-emc.o
 obj-$(CONFIG_ARCH_TEGRA_114_SOC)	+= clk-tegra114.o
 obj-$(CONFIG_ARCH_TEGRA_124_SOC)	+= clk-tegra124.o
 obj-$(CONFIG_TEGRA_CLK_DFLL)		+= clk-tegra124-dfll-fcpu.o
-obj-$(CONFIG_TEGRA124_EMC)		+= clk-tegra124-emc.o
+obj-$(CONFIG_TEGRA124_CLK_EMC)		+= clk-tegra124-emc.o
 obj-$(CONFIG_ARCH_TEGRA_132_SOC)	+= clk-tegra124.o
 obj-y					+= cvb.o
 obj-$(CONFIG_ARCH_TEGRA_210_SOC)	+= clk-tegra210.o
diff --git a/drivers/clk/tegra/clk-tegra124-emc.c b/drivers/clk/tegra/clk-tegra124-emc.c
index 745f9faa98d8..bdf6f4a51617 100644
--- a/drivers/clk/tegra/clk-tegra124-emc.c
+++ b/drivers/clk/tegra/clk-tegra124-emc.c
@@ -11,7 +11,9 @@
 #include <linux/clk-provider.h>
 #include <linux/clk.h>
 #include <linux/clkdev.h>
+#include <linux/clk/tegra.h>
 #include <linux/delay.h>
+#include <linux/export.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
@@ -21,7 +23,6 @@
 #include <linux/string.h>
 
 #include <soc/tegra/fuse.h>
-#include <soc/tegra/emc.h>
 
 #include "clk.h"
 
@@ -80,6 +81,9 @@ struct tegra_clk_emc {
 	int num_timings;
 	struct emc_timing *timings;
 	spinlock_t *lock;
+
+	tegra124_emc_prepare_timing_change_cb *prepare_timing_change;
+	tegra124_emc_complete_timing_change_cb *complete_timing_change;
 };
 
 /* Common clock framework callback implementations */
@@ -176,6 +180,9 @@ static struct tegra_emc *emc_ensure_emc_driver(struct tegra_clk_emc *tegra)
 	if (tegra->emc)
 		return tegra->emc;
 
+	if (!tegra->prepare_timing_change || !tegra->complete_timing_change)
+		return NULL;
+
 	if (!tegra->emc_node)
 		return NULL;
 
@@ -241,7 +248,7 @@ static int emc_set_timing(struct tegra_clk_emc *tegra,
 
 	div = timing->parent_rate / (timing->rate / 2) - 2;
 
-	err = tegra_emc_prepare_timing_change(emc, timing->rate);
+	err = tegra->prepare_timing_change(emc, timing->rate);
 	if (err)
 		return err;
 
@@ -259,7 +266,7 @@ static int emc_set_timing(struct tegra_clk_emc *tegra,
 
 	spin_unlock_irqrestore(tegra->lock, flags);
 
-	tegra_emc_complete_timing_change(emc, timing->rate);
+	tegra->complete_timing_change(emc, timing->rate);
 
 	clk_hw_reparent(&tegra->hw, __clk_get_hw(timing->parent));
 	clk_disable_unprepare(tegra->prev_parent);
@@ -473,8 +480,8 @@ static const struct clk_ops tegra_clk_emc_ops = {
 	.get_parent = emc_get_parent,
 };
 
-struct clk *tegra_clk_register_emc(void __iomem *base, struct device_node *np,
-				   spinlock_t *lock)
+struct clk *tegra124_clk_register_emc(void __iomem *base, struct device_node *np,
+				      spinlock_t *lock)
 {
 	struct tegra_clk_emc *tegra;
 	struct clk_init_data init;
@@ -538,3 +545,27 @@ struct clk *tegra_clk_register_emc(void __iomem *base, struct device_node *np,
 
 	return clk;
 };
+
+void tegra124_clk_set_emc_callbacks(tegra124_emc_prepare_timing_change_cb *prep_cb,
+				    tegra124_emc_complete_timing_change_cb *complete_cb)
+{
+	struct clk *clk = __clk_lookup("emc");
+	struct tegra_clk_emc *tegra;
+	struct clk_hw *hw;
+
+	if (clk) {
+		hw = __clk_get_hw(clk);
+		tegra = container_of(hw, struct tegra_clk_emc, hw);
+
+		tegra->prepare_timing_change = prep_cb;
+		tegra->complete_timing_change = complete_cb;
+	}
+}
+EXPORT_SYMBOL_GPL(tegra124_clk_set_emc_callbacks);
+
+bool tegra124_clk_emc_driver_available(struct clk_hw *hw)
+{
+	struct tegra_clk_emc *tegra = container_of(hw, struct tegra_clk_emc, hw);
+
+	return tegra->prepare_timing_change && tegra->complete_timing_change;
+}
diff --git a/drivers/clk/tegra/clk-tegra124.c b/drivers/clk/tegra/clk-tegra124.c
index e931319dcc9d..934520aab6e3 100644
--- a/drivers/clk/tegra/clk-tegra124.c
+++ b/drivers/clk/tegra/clk-tegra124.c
@@ -1500,6 +1500,26 @@ static void __init tegra124_132_clock_init_pre(struct device_node *np)
 	writel(plld_base, clk_base + PLLD_BASE);
 }
 
+static struct clk *tegra124_clk_src_onecell_get(struct of_phandle_args *clkspec,
+						void *data)
+{
+	struct clk_hw *hw;
+	struct clk *clk;
+
+	clk = of_clk_src_onecell_get(clkspec, data);
+	if (IS_ERR(clk))
+		return clk;
+
+	hw = __clk_get_hw(clk);
+
+	if (clkspec->args[0] == TEGRA124_CLK_EMC) {
+		if (!tegra124_clk_emc_driver_available(hw))
+			return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	return clk;
+}
+
 /**
  * tegra124_132_clock_init_post - clock initialization postamble for T124/T132
  * @np: struct device_node * of the DT node for the SoC CAR IP block
@@ -1516,10 +1536,10 @@ static void __init tegra124_132_clock_init_post(struct device_node *np)
 				  &pll_x_params);
 	tegra_init_special_resets(1, tegra124_reset_assert,
 				  tegra124_reset_deassert);
-	tegra_add_of_provider(np, of_clk_src_onecell_get);
+	tegra_add_of_provider(np, tegra124_clk_src_onecell_get);
 
-	clks[TEGRA124_CLK_EMC] = tegra_clk_register_emc(clk_base, np,
-							&emc_lock);
+	clks[TEGRA124_CLK_EMC] = tegra124_clk_register_emc(clk_base, np,
+							   &emc_lock);
 
 	tegra_register_devclks(devclks, ARRAY_SIZE(devclks));
 
diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
index 6b565f6b5f66..c3e36b5dcc75 100644
--- a/drivers/clk/tegra/clk.h
+++ b/drivers/clk/tegra/clk.h
@@ -881,16 +881,22 @@ void tegra_super_clk_gen5_init(void __iomem *clk_base,
 			void __iomem *pmc_base, struct tegra_clk *tegra_clks,
 			struct tegra_clk_pll_params *pll_params);
 
-#ifdef CONFIG_TEGRA124_EMC
-struct clk *tegra_clk_register_emc(void __iomem *base, struct device_node *np,
-				   spinlock_t *lock);
+#ifdef CONFIG_TEGRA124_CLK_EMC
+struct clk *tegra124_clk_register_emc(void __iomem *base, struct device_node *np,
+				      spinlock_t *lock);
+bool tegra124_clk_emc_driver_available(struct clk_hw *emc_hw);
 #else
-static inline struct clk *tegra_clk_register_emc(void __iomem *base,
-						 struct device_node *np,
-						 spinlock_t *lock)
+static inline struct clk *
+tegra124_clk_register_emc(void __iomem *base, struct device_node *np,
+			  spinlock_t *lock)
 {
 	return NULL;
 }
+
+static inline bool tegra124_clk_emc_driver_available(struct clk_hw *emc_hw)
+{
+	return false;
+}
 #endif
 
 void tegra114_clock_tune_cpu_trimmers_high(void);