Most Rockchip socs have optional phase inverters connected to some
clocks that move the clock-phase by 180 degrees.
While not having any actual influence on the rate, the inverter
provides its own simple recalc_rate callback as relying on the
fallback in the framework is for "lazy developers" according
to the documentation in the code.
Signed-off-by: Heiko Stuebner <heiko at sntech.de>
---
drivers/clk/rockchip/Makefile | 1 +
drivers/clk/rockchip/clk-inverter.c | 126 ++++++++++++++++++++++++++++++++++++
drivers/clk/rockchip/clk.c | 7 ++
drivers/clk/rockchip/clk.h | 20 ++++++
4 files changed, 154 insertions(+)
create mode 100644 drivers/clk/rockchip/clk-inverter.c
diff --git a/drivers/clk/rockchip/Makefile b/drivers/clk/rockchip/Makefile
index 2714097..fd71c7d 100644
--- a/drivers/clk/rockchip/Makefile
+++ b/drivers/clk/rockchip/Makefile
@@ -6,6 +6,7 @@ obj-y += clk-rockchip.o
obj-y += clk.o
obj-y += clk-pll.o
obj-y += clk-cpu.o
+obj-y += clk-inverter.o
obj-y += clk-mmc-phase.o
obj-$(CONFIG_RESET_CONTROLLER) += softrst.o
diff --git a/drivers/clk/rockchip/clk-inverter.c b/drivers/clk/rockchip/clk-inverter.c
new file mode 100644
index 0000000..db852cd
--- /dev/null
+++ b/drivers/clk/rockchip/clk-inverter.c
@@ -0,0 +1,126 @@
+/*
+ * Copyright 2015 Heiko Stuebner <heiko at sntech.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/slab.h>
+#include <linux/clk-provider.h>
+#include "clk.h"
+
+struct rockchip_inv_clock {
+ struct clk_hw hw;
+ void __iomem *reg;
+ int shift;
+ int flags;
+ spinlock_t *lock;
+};
+
+#define to_inv_clock(_hw) container_of(_hw, struct rockchip_inv_clock, hw)
+
+#define INVERTER_MASK 0x1
+
+static unsigned long rockchip_inv_recalc(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ return parent_rate;
+}
+
+static int rockchip_inv_get_phase(struct clk_hw *hw)
+{
+ struct rockchip_inv_clock *inv_clock = to_inv_clock(hw);
+ u32 val;
+
+ val = readl(inv_clock->reg) >> (inv_clock->shift) & INVERTER_MASK;
+ return val ? 180 : 0;
+}
+
+static int rockchip_inv_set_phase(struct clk_hw *hw, int degrees)
+{
+ struct rockchip_inv_clock *inv_clock = to_inv_clock(hw);
+ u32 val;
+
+ switch (degrees) {
+ case 0:
+ val = 0;
+ break;
+ case 180:
+ val = 1;
+ break;
+ default:
+ pr_err("%s: unsupported phase %d for %s\n",
+ __func__, degrees, __clk_get_name(hw->clk));
+ return -EINVAL;
+ }
+
+ if (inv_clock->flags & ROCKCHIP_INVERTER_HIWORD_MASK) {
+ writel(HIWORD_UPDATE(val, INVERTER_MASK, inv_clock->shift),
+ inv_clock->reg);
+ } else {
+ unsigned long flags;
+ u32 reg;
+
+ spin_lock_irqsave(inv_clock->lock, flags);
+
+ reg = readl(inv_clock->reg);
+ reg &= ~BIT(inv_clock->shift);
+ reg |= val;
+ writel(reg, inv_clock->reg);
+
+ spin_unlock_irqrestore(inv_clock->lock, flags);
+ }
+
+ return 0;
+}
+
+static const struct clk_ops rockchip_inv_clk_ops = {
+ .recalc_rate = rockchip_inv_recalc,
+ .get_phase = rockchip_inv_get_phase,
+ .set_phase = rockchip_inv_set_phase,
+};
+
+struct clk *rockchip_clk_register_inverter(const char *name,
+ const char *const *parent_names, u8 num_parents,
+ void __iomem *reg, int shift, int flags,
+ spinlock_t *lock)
+{
+ struct clk_init_data init;
+ struct rockchip_inv_clock *inv_clock;
+ struct clk *clk;
+
+ inv_clock = kmalloc(sizeof(*inv_clock), GFP_KERNEL);
+ if (!inv_clock)
+ return NULL;
+
+ init.num_parents = num_parents;
+ init.flags = CLK_SET_RATE_PARENT;
+ init.parent_names = parent_names;
+ init.ops = &rockchip_inv_clk_ops;
+
+ inv_clock->hw.init = &init;
+ inv_clock->reg = reg;
+ inv_clock->shift = shift;
+ inv_clock->flags = flags;
+ inv_clock->lock = lock;
+
+ if (name)
+ init.name = name;
+
+ clk = clk_register(NULL, &inv_clock->hw);
+ if (IS_ERR(clk))
+ goto err_free;
+
+ return clk;
+
+err_free:
+ kfree(inv_clock);
+ return NULL;
+}
diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c
index 052b94d..2493881 100644
--- a/drivers/clk/rockchip/clk.c
+++ b/drivers/clk/rockchip/clk.c
@@ -277,6 +277,13 @@ void __init rockchip_clk_register_branches(
list->div_shift
);
break;
+ case branch_inverter:
+ clk = rockchip_clk_register_inverter(
+ list->name, list->parent_names,
+ list->num_parents,
+ reg_base + list->muxdiv_offset,
+ list->div_shift, list->div_flags, &clk_lock);
+ break;
}
/* none of the cases above matched */
diff --git a/drivers/clk/rockchip/clk.h b/drivers/clk/rockchip/clk.h
index 501f02e..b72dad0 100644
--- a/drivers/clk/rockchip/clk.h
+++ b/drivers/clk/rockchip/clk.h
@@ -182,6 +182,13 @@ struct clk *rockchip_clk_register_mmc(const char *name,
const char *const *parent_names, u8 num_parents,
void __iomem *reg, int shift);
+#define ROCKCHIP_INVERTER_HIWORD_MASK BIT(0)
+
+struct clk *rockchip_clk_register_inverter(const char *name,
+ const char *const *parent_names, u8 num_parents,
+ void __iomem *reg, int shift, int flags,
+ spinlock_t *lock);
+
#define PNAME(x) static const char *const x[] __initconst
enum rockchip_clk_branch_type {
@@ -191,6 +198,7 @@ enum rockchip_clk_branch_type {
branch_fraction_divider,
branch_gate,
branch_mmc,
+ branch_inverter,
};
struct rockchip_clk_branch {
@@ -414,6 +422,18 @@ struct rockchip_clk_branch {
.div_shift = shift, \
}
+#define INVERTER(_id, cname, pname, io, is, if) \
+ { \
+ .id = _id, \
+ .branch_type = branch_inverter, \
+ .name = cname, \
+ .parent_names = (const char *[]){ pname }, \
+ .num_parents = 1, \
+ .muxdiv_offset = io, \
+ .div_shift = is, \
+ .div_flags = if, \
+ }
+
void rockchip_clk_init(struct device_node *np, void __iomem *base,
unsigned long nr_clks);
struct regmap *rockchip_clk_get_grf(void);
--
2.1.4
