Add a clock driver for banks of clock muxes in the TZ1090 SoC. A single
32 bit register controls up to 32 separate clock muxes. The generic
clock mux clock operations are wrapped in order to acquire and release
the Meta global exclusive lock (__global_lock2) to ensure atomicity with
other non-Linux cores and threads which may need to control some of the
clocks.
The tz1090_clk_register_mux_bank() helper function can be used to
register a mux bank from static initialisation data. Macros are provided
in tz1090/clk.h to aid the creation of this data, for example:
MUX_BANK(tz1090_top_clkswitch, CLK_TOP_CLKSWITCH_BASE, TOP_CLKSWITCH,
/* bit in[0] in[1] out */
MUX( 0, "@xtal1" "@xtal2", "sys_sw")
MUX( 1, "@xtal1" "sys_div", "sys_x2_undeleted")
MUX( 2, "@xtal1" "@afe_progdiv1", "out0_sw0")
...
);
...
tz1090_clk_register_mux_bank(p, &tz1090_top_clkswitch);
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Mike Turquette <mturquette@xxxxxxxxxx>
Cc: linux-metag@xxxxxxxxxxxxxxx
---
Changes since v1 (patch 8):
- Renamed function prefixes from clk_tz1090_ to tz1090_clk_ for
consistency with the rest.
- Drop DT binding as it will be instantiated directly from a provider.
- Add tz1090_clk_register_mux_bank() to conveniently register a bank of
gates in a clock provider from static initilisation data.
- Extend tz1090/clk.h interface for easy static initialisation with
macros.
---
drivers/clk/tz1090/Makefile | 1 +
drivers/clk/tz1090/clk-tz1090-mux-bank.c | 139 +++++++++++++++++++++++++++++++
drivers/clk/tz1090/clk.h | 52 ++++++++++++
3 files changed, 192 insertions(+)
create mode 100644 drivers/clk/tz1090/clk-tz1090-mux-bank.c
diff --git a/drivers/clk/tz1090/Makefile b/drivers/clk/tz1090/Makefile
index ab88f53..d44acac 100644
--- a/drivers/clk/tz1090/Makefile
+++ b/drivers/clk/tz1090/Makefile
@@ -2,3 +2,4 @@
obj-y += clk.o
obj-y += clk-tz1090-gate-bank.o
+obj-y += clk-tz1090-mux-bank.o
diff --git a/drivers/clk/tz1090/clk-tz1090-mux-bank.c b/drivers/clk/tz1090/clk-tz1090-mux-bank.c
new file mode 100644
index 0000000..0c7732d
--- /dev/null
+++ b/drivers/clk/tz1090/clk-tz1090-mux-bank.c
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2013-2014 Imagination Technologies Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License version 2 as published by the
+ * Free Software Foundation.
+ *
+ * TZ1090 Clock mux bank
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <asm/global_lock.h>
+
+#include "clk.h"
+
+/**
+ * struct tz1090_clk_mux_priv - tz1090 multiplexer clock
+ *
+ * @mux: the parent class
+ * @ops: pointer to clk_ops of parent class
+ *
+ * Clock with multiple selectable parents. Extends basic mux by using a global
+ * exclusive lock when read-modify-writing the mux field so that multiple
+ * threads/cores can use different fields in the same register.
+ */
+struct tz1090_clk_mux_priv {
+ struct clk_mux mux;
+ const struct clk_ops *ops;
+};
+
+static inline struct tz1090_clk_mux_priv *to_tz1090_clk_mux(struct clk_hw *hw)
+{
+ struct clk_mux *mux = container_of(hw, struct clk_mux, hw);
+
+ return container_of(mux, struct tz1090_clk_mux_priv, mux);
+}
+
+static u8 tz1090_clk_mux_get_parent(struct clk_hw *hw)
+{
+ struct tz1090_clk_mux_priv *mux = to_tz1090_clk_mux(hw);
+
+ return mux->ops->get_parent(&mux->mux.hw);
+}
+
+/* Acquire exclusive lock since other cores may access the same register */
+static int tz1090_clk_mux_set_parent(struct clk_hw *hw, u8 index)
+{
+ struct tz1090_clk_mux_priv *mux = to_tz1090_clk_mux(hw);
+ int ret;
+ unsigned long flags;
+
+ __global_lock2(flags);
+ ret = mux->ops->set_parent(&mux->mux.hw, index);
+ __global_unlock2(flags);
+
+ return ret;
+}
+
+static long tz1090_clk_mux_determine_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate,
+ struct clk **best_parent)
+{
+ struct tz1090_clk_mux_priv *mux = to_tz1090_clk_mux(hw);
+
+ return mux->ops->determine_rate(&mux->mux.hw, rate, prate, best_parent);
+}
+
+static const struct clk_ops tz1090_clk_mux_ops = {
+ .get_parent = tz1090_clk_mux_get_parent,
+ .set_parent = tz1090_clk_mux_set_parent,
+ .determine_rate = tz1090_clk_mux_determine_rate,
+};
+
+static struct clk *__init __register_mux(const char *name,
+ const char **parent_names,
+ unsigned long flags, void __iomem *reg,
+ u8 shift, u8 clk_mux_flags)
+{
+ struct tz1090_clk_mux_priv *mux;
+ struct clk *clk;
+ struct clk_init_data init;
+
+ /* allocate the mux */
+ mux = kzalloc(sizeof(struct tz1090_clk_mux_priv), GFP_KERNEL);
+ if (!mux)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &tz1090_clk_mux_ops;
+ init.flags = flags | CLK_IS_BASIC;
+ init.parent_names = parent_names;
+ init.num_parents = 2;
+
+ /* struct clk_mux assignments */
+ mux->mux.reg = reg;
+ mux->mux.shift = shift;
+ mux->mux.mask = 0x1;
+ mux->mux.flags = clk_mux_flags;
+ mux->mux.hw.init = &init;
+
+ /* struct tz1090_clk_mux_priv assignments */
+ mux->ops = &clk_mux_ops;
+
+ clk = clk_register(NULL, &mux->mux.hw);
+
+ if (IS_ERR(clk))
+ kfree(mux);
+
+ return clk;
+}
+
+/**
+ * tz1090_clk_register_mux_bank() - Register bank of muxes with a provider.
+ * @p: TZ1090 clock provider.
+ * @bank: Data describing mux bank.
+ */
+void __init tz1090_clk_register_mux_bank(struct tz1090_clk_provider *p,
+ const struct tz1090_clk_mux_bank *bank)
+{
+ const struct tz1090_clk_mux *mux;
+ struct clk *clk;
+ unsigned int id = bank->id_base;
+ const char *parents[2];
+
+ for (mux = bank->muxes; mux->name; ++mux, ++id) {
+ parents[0] = tz1090_clk_xlate(p, mux->parents[0]);
+ parents[1] = tz1090_clk_xlate(p, mux->parents[1]);
+ clk = __register_mux(tz1090_clk_xlate(p, mux->name), parents,
+ CLK_SET_RATE_PARENT,
+ p->base + bank->reg_base, mux->shift, 0);
+ p->clk_data.clks[id] = clk;
+ }
+}
diff --git a/drivers/clk/tz1090/clk.h b/drivers/clk/tz1090/clk.h
index 06274b7..c9fe6ca 100644
--- a/drivers/clk/tz1090/clk.h
+++ b/drivers/clk/tz1090/clk.h
@@ -83,4 +83,56 @@ struct tz1090_clk_gate_bank {
void tz1090_clk_register_gate_bank(struct tz1090_clk_provider *p,
const struct tz1090_clk_gate_bank *bank);
+
+/* Clock mux banks */
+
+/**
+ * struct tz1090_clk_mux - Describes an individual mux in a bank.
+ * @shift: Shift of bit controlling mux within the bank control register.
+ * @name: Name of muxed clock to provide.
+ * @parents: Name of two parent/source clocks for when the bit is 0 and 1.
+ */
+struct tz1090_clk_mux {
+ unsigned int shift;
+ const char *name;
+ const char *parents[2];
+};
+
+/**
+ * struct tz1090_clk_mux_bank - Describes a mux bank.
+ * @id_base: Base id of bank in provider.
+ * Individual muxes get the id id_base + index in muxes array.
+ * @reg_base: Offset of mux bank register in the MMIO region.
+ * @muxes: Pointer to array of muxes in the bank, terminated by one with a
+ * NULL name field.
+ */
+struct tz1090_clk_mux_bank {
+ unsigned int id_base;
+ unsigned long reg_base;
+ const struct tz1090_clk_mux *muxes;
+};
+
+#define MUX(_shift, _parent0, _parent1, _name) \
+ { \
+ .shift = (_shift), \
+ .name = (_name), \
+ .parents = { \
+ _parent0, \
+ _parent1 \
+ }, \
+ },
+
+#define MUX_BANK(_name, _id, _reg, _muxes) \
+ static const struct tz1090_clk_mux_bank _name __initconst = { \
+ .id_base = (_id), \
+ .reg_base = (_reg), \
+ .muxes = (const struct tz1090_clk_mux[]) { \
+ _muxes \
+ { .name = NULL } \
+ }, \
+ }
+
+void tz1090_clk_register_mux_bank(struct tz1090_clk_provider *p,
+ const struct tz1090_clk_mux_bank *bank);
+
#endif
--
2.0.4
--
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