clk: actions: Add Actions Semi Owl SoCs Reset Management Unit support

Add Reset Management Unit (RMU) support for Actions Semi Owl SoCs.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

5 files changed, 101 insertions, 0 deletions

diff --git a/drivers/clk/actions/Kconfig b/drivers/clk/actions/Kconfig
index dc38c85a4833..04f0a6355726 100644
--- a/drivers/clk/actions/Kconfig
+++ b/drivers/clk/actions/Kconfig
@@ -2,6 +2,7 @@ config CLK_ACTIONS
         bool "Clock driver for Actions Semi SoCs"
         depends on ARCH_ACTIONS || COMPILE_TEST
         select REGMAP_MMIO
+        select RESET_CONTROLLER
         default ARCH_ACTIONS
 
 if CLK_ACTIONS
diff --git a/drivers/clk/actions/Makefile b/drivers/clk/actions/Makefile
index 78c17d56f991..ccfdf9781cef 100644
--- a/drivers/clk/actions/Makefile
+++ b/drivers/clk/actions/Makefile
@@ -7,6 +7,7 @@ clk-owl-y			+= owl-divider.o
 clk-owl-y                       += owl-factor.o
 clk-owl-y                       += owl-composite.o
 clk-owl-y                       += owl-pll.o
+clk-owl-y                       += owl-reset.o
 
 # SoC support
 obj-$(CONFIG_CLK_OWL_S700)      += owl-s700.o
diff --git a/drivers/clk/actions/owl-common.h b/drivers/clk/actions/owl-common.h
index 56f01f7774aa..5a866a8b913d 100644
--- a/drivers/clk/actions/owl-common.h
+++ b/drivers/clk/actions/owl-common.h
@@ -26,6 +26,8 @@ struct owl_clk_desc {
         struct owl_clk_common           **clks;
         unsigned long                   num_clks;
         struct clk_hw_onecell_data      *hw_clks;
+        const struct owl_reset_map      *resets;
+        unsigned long                   num_resets;
         struct regmap                   *regmap;
 };
 
diff --git a/drivers/clk/actions/owl-reset.c b/drivers/clk/actions/owl-reset.c
new file mode 100644
index 000000000000..203f8f34a8d4
--- /dev/null
+++ b/drivers/clk/actions/owl-reset.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// Actions Semi Owl SoCs Reset Management Unit driver
+//
+// Copyright (c) 2018 Linaro Ltd.
+// Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+
+#include <linux/delay.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+
+#include "owl-reset.h"
+
+static int owl_reset_assert(struct reset_controller_dev *rcdev,
+                            unsigned long id)
+{
+        struct owl_reset *reset = to_owl_reset(rcdev);
+        const struct owl_reset_map *map = &reset->reset_map[id];
+
+        return regmap_update_bits(reset->regmap, map->reg, map->bit, 0);
+}
+
+static int owl_reset_deassert(struct reset_controller_dev *rcdev,
+                              unsigned long id)
+{
+        struct owl_reset *reset = to_owl_reset(rcdev);
+        const struct owl_reset_map *map = &reset->reset_map[id];
+
+        return regmap_update_bits(reset->regmap, map->reg, map->bit, map->bit);
+}
+
+static int owl_reset_reset(struct reset_controller_dev *rcdev,
+                           unsigned long id)
+{
+        owl_reset_assert(rcdev, id);
+        udelay(1);
+        owl_reset_deassert(rcdev, id);
+
+        return 0;
+}
+
+static int owl_reset_status(struct reset_controller_dev *rcdev,
+                            unsigned long id)
+{
+        struct owl_reset *reset = to_owl_reset(rcdev);
+        const struct owl_reset_map *map = &reset->reset_map[id];
+        u32 reg;
+        int ret;
+
+        ret = regmap_read(reset->regmap, map->reg, &reg);
+        if (ret)
+                return ret;
+
+        /*
+         * The reset control API expects 0 if reset is not asserted,
+         * which is the opposite of what our hardware uses.
+         */
+        return !(map->bit & reg);
+}
+
+const struct reset_control_ops owl_reset_ops = {
+        .assert         = owl_reset_assert,
+        .deassert       = owl_reset_deassert,
+        .reset          = owl_reset_reset,
+        .status         = owl_reset_status,
+};
diff --git a/drivers/clk/actions/owl-reset.h b/drivers/clk/actions/owl-reset.h
new file mode 100644
index 000000000000..10f5774979a6
--- /dev/null
+++ b/drivers/clk/actions/owl-reset.h
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+//
+// Actions Semi Owl SoCs Reset Management Unit driver
+//
+// Copyright (c) 2018 Linaro Ltd.
+// Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
+
+#ifndef _OWL_RESET_H_
+#define _OWL_RESET_H_
+
+#include <linux/reset-controller.h>
+
+struct owl_reset_map {
+        u32     reg;
+        u32     bit;
+};
+
+struct owl_reset {
+        struct reset_controller_dev     rcdev;
+        const struct owl_reset_map      *reset_map;
+        struct regmap                   *regmap;
+};
+
+static inline struct owl_reset *to_owl_reset(struct reset_controller_dev *rcdev)
+{
+        return container_of(rcdev, struct owl_reset, rcdev);
+}
+
+extern const struct reset_control_ops owl_reset_ops;
+
+#endif /* _OWL_RESET_H_ */