[PATCHv10 07/41] CLK: ti: add support for ti divider-clock
Tero Kristo
t-kristo at ti.com
Tue Nov 26 03:05:48 EST 2013
This patch adds support for TI divider clock binding, which simply uses
the basic clock divider to provide the features needed.
Signed-off-by: Tero Kristo <t-kristo at ti.com>
---
.../devicetree/bindings/clock/ti/divider.txt | 114 ++++++++++
drivers/clk/ti/Makefile | 3 +-
drivers/clk/ti/divider.c | 228 ++++++++++++++++++++
3 files changed, 344 insertions(+), 1 deletion(-)
create mode 100644 Documentation/devicetree/bindings/clock/ti/divider.txt
create mode 100644 drivers/clk/ti/divider.c
diff --git a/Documentation/devicetree/bindings/clock/ti/divider.txt b/Documentation/devicetree/bindings/clock/ti/divider.txt
new file mode 100644
index 0000000..35a6f5c
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/ti/divider.txt
@@ -0,0 +1,114 @@
+Binding for TI divider clock
+
+Binding status: Unstable - ABI compatibility may be broken in the future
+
+This binding uses the common clock binding[1]. It assumes a
+register-mapped adjustable clock rate divider that does not gate and has
+only one input clock or parent. By default the value programmed into
+the register is one less than the actual divisor value. E.g:
+
+register value actual divisor value
+0 1
+1 2
+2 3
+
+This assumption may be modified by the following optional properties:
+
+ti,index-starts-at-one - valid divisor values start at 1, not the default
+of 0. E.g:
+register value actual divisor value
+1 1
+2 2
+3 3
+
+ti,index-power-of-two - valid divisor values are powers of two. E.g:
+register value actual divisor value
+0 1
+1 2
+2 4
+
+Additionally an array of valid dividers may be supplied like so:
+
+ ti,dividers = <4>, <8>, <0>, <16>;
+
+Which will map the resulting values to a divisor table by their index:
+register value actual divisor value
+0 4
+1 8
+2 <invalid divisor, skipped>
+3 16
+
+Any zero value in this array means the corresponding bit-value is invalid
+and must not be used.
+
+The binding must also provide the register to control the divider and
+unless the divider array is provided, min and max dividers. Optionally
+the number of bits to shift that mask, if necessary. If the shift value
+is missing it is the same as supplying a zero shift.
+
+This binding can also optionally provide support to the hardware autoidle
+feature, see [2].
+
+[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
+[2] Documentation/devicetree/bindings/clock/ti/autoidle.txt
+
+Required properties:
+- compatible : shall be "ti,divider-clock" or "ti,composite-divider-clock".
+- #clock-cells : from common clock binding; shall be set to 0.
+- clocks : link to phandle of parent clock
+- reg : offset for register controlling adjustable divider
+
+Optional properties:
+- clock-output-names : from common clock binding.
+- ti,dividers : array of integers defining divisors
+- ti,bit-shift : number of bits to shift the divider value, defaults to 0
+- ti,min-div : min divisor for dividing the input clock rate, only
+ needed if the first divisor is offset from the default value (1)
+- ti,max-div : max divisor for dividing the input clock rate, only needed
+ if ti,dividers is not defined.
+- ti,index-starts-at-one : valid divisor programming starts at 1, not zero,
+ only valid if ti,dividers is not defined.
+- ti,index-power-of-two : valid divisor programming must be a power of two,
+ only valid if ti,dividers is not defined.
+- ti,autoidle-shift : bit shift of the autoidle enable bit for the clock,
+ see [2]
+- ti,invert-autoidle-bit : autoidle is enabled by setting the bit to 0,
+ see [2]
+- ti,set-rate-parent : clk_set_rate is propagated to parent
+
+Examples:
+dpll_usb_m2_ck: dpll_usb_m2_ck at 4a008190 {
+ #clock-cells = <0>;
+ compatible = "ti,divider-clock";
+ clocks = <&dpll_usb_ck>;
+ ti,max-div = <127>;
+ reg = <0x190>;
+ ti,index-starts-at-one;
+};
+
+aess_fclk: aess_fclk at 4a004528 {
+ #clock-cells = <0>;
+ compatible = "ti,divider-clock";
+ clocks = <&abe_clk>;
+ ti,bit-shift = <24>;
+ reg = <0x528>;
+ ti,max-div = <2>;
+};
+
+dpll_core_m3x2_div_ck: dpll_core_m3x2_div_ck {
+ #clock-cells = <0>;
+ compatible = "ti,composite-divider-clock";
+ clocks = <&dpll_core_x2_ck>;
+ ti,max-div = <31>;
+ reg = <0x0134>;
+ ti,index-starts-at-one;
+};
+
+ssi_ssr_div_fck_3430es2: ssi_ssr_div_fck_3430es2 {
+ #clock-cells = <0>;
+ compatible = "ti,composite-divider-clock";
+ clocks = <&corex2_fck>;
+ ti,bit-shift = <8>;
+ reg = <0x0a40>;
+ ti,dividers = <0>, <1>, <2>, <3>, <4>, <0>, <6>, <0>, <8>;
+};
diff --git a/drivers/clk/ti/Makefile b/drivers/clk/ti/Makefile
index a4a7595..640ebf9 100644
--- a/drivers/clk/ti/Makefile
+++ b/drivers/clk/ti/Makefile
@@ -1,3 +1,4 @@
ifneq ($(CONFIG_OF),)
-obj-y += clk.o dpll.o autoidle.o composite.o
+obj-y += clk.o dpll.o autoidle.o divider.o \
+ composite.o
endif
diff --git a/drivers/clk/ti/divider.c b/drivers/clk/ti/divider.c
new file mode 100644
index 0000000..818549f
--- /dev/null
+++ b/drivers/clk/ti/divider.c
@@ -0,0 +1,228 @@
+/*
+ * TI Divider Clock
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ *
+ * Tero Kristo <t-kristo at ti.com>
+ *
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/clk/ti.h>
+
+#undef pr_fmt
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+static struct clk_div_table
+__init *ti_clk_get_div_table(struct device_node *node)
+{
+ struct clk_div_table *table;
+ const __be32 *divspec;
+ u32 val;
+ u32 num_div;
+ u32 valid_div;
+ int i;
+
+ divspec = of_get_property(node, "ti,dividers", &num_div);
+
+ if (!divspec)
+ return NULL;
+
+ num_div /= 4;
+
+ valid_div = 0;
+
+ /* Determine required size for divider table */
+ for (i = 0; i < num_div; i++) {
+ of_property_read_u32_index(node, "ti,dividers", i, &val);
+ if (val)
+ valid_div++;
+ }
+
+ if (!valid_div) {
+ pr_err("no valid dividers for %s table\n", node->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ table = kzalloc(sizeof(*table) * (valid_div + 1), GFP_KERNEL);
+
+ if (!table)
+ return ERR_PTR(-ENOMEM);
+
+ valid_div = 0;
+
+ for (i = 0; i < num_div; i++) {
+ of_property_read_u32_index(node, "ti,dividers", i, &val);
+ if (val) {
+ table[valid_div].div = val;
+ table[valid_div].val = i;
+ valid_div++;
+ }
+ }
+
+ return table;
+}
+
+static int _get_divider_width(struct device_node *node,
+ const struct clk_div_table *table,
+ u8 flags)
+{
+ u32 min_div;
+ u32 max_div;
+ u32 val = 0;
+ u32 div;
+
+ if (!table) {
+ /* Clk divider table not provided, determine min/max divs */
+ if (of_property_read_u32(node, "ti,min-div", &min_div))
+ min_div = 1;
+
+ if (of_property_read_u32(node, "ti,max-div", &max_div)) {
+ pr_err("no max-div for %s!\n", node->name);
+ return -EINVAL;
+ }
+
+ /* Determine bit width for the field */
+ if (flags & CLK_DIVIDER_ONE_BASED)
+ val = 1;
+
+ div = min_div;
+
+ while (div < max_div) {
+ if (flags & CLK_DIVIDER_POWER_OF_TWO)
+ div <<= 1;
+ else
+ div++;
+ val++;
+ }
+ } else {
+ div = 0;
+
+ while (table[div].div) {
+ val = table[div].val;
+ div++;
+ }
+ }
+
+ return fls(val);
+}
+
+static int __init ti_clk_divider_populate(struct device_node *node,
+ void __iomem **reg, const struct clk_div_table **table, u32 *flags,
+ u8 *div_flags, u8 *width, u8 *shift)
+{
+ u32 val;
+
+ *reg = ti_clk_get_reg_addr(node, 0);
+ if (!*reg)
+ return -EINVAL;
+
+ if (!of_property_read_u32(node, "ti,bit-shift", &val))
+ *shift = val;
+ else
+ *shift = 0;
+
+ *flags = 0;
+ *div_flags = 0;
+
+ if (of_property_read_bool(node, "ti,index-starts-at-one"))
+ *div_flags |= CLK_DIVIDER_ONE_BASED;
+
+ if (of_property_read_bool(node, "ti,index-power-of-two"))
+ *div_flags |= CLK_DIVIDER_POWER_OF_TWO;
+
+ if (of_property_read_bool(node, "ti,set-rate-parent"))
+ *flags |= CLK_SET_RATE_PARENT;
+
+ *table = ti_clk_get_div_table(node);
+
+ if (IS_ERR(*table))
+ return PTR_ERR(*table);
+
+ *width = _get_divider_width(node, *table, *div_flags);
+
+ kfree(*table);
+ *table = NULL;
+
+ return 0;
+}
+
+/**
+ * of_ti_divider_clk_setup - Setup function for simple div rate clock
+ * @node: device node for this clock
+ *
+ * Sets up a basic divider clock.
+ */
+static int __init of_ti_divider_clk_setup(struct device_node *node)
+{
+ struct clk *clk;
+ const char *clk_name = node->name;
+ void __iomem *reg;
+ const char *parent_name;
+ u8 clk_divider_flags = 0;
+ u8 width = 0;
+ u8 shift = 0;
+ const struct clk_div_table *table = NULL;
+ u32 flags = 0;
+ int ret = 0;
+
+ parent_name = of_clk_get_parent_name(node, 0);
+
+ ret = ti_clk_divider_populate(node, ®, &table, &flags,
+ &clk_divider_flags, &width, &shift);
+ if (ret < 0)
+ return ret;
+
+ clk = clk_register_divider_table(NULL, clk_name, parent_name,
+ flags, reg, shift, width,
+ clk_divider_flags, table, NULL);
+
+ if (!IS_ERR(clk)) {
+ of_clk_add_provider(node, of_clk_src_simple_get, clk);
+ of_ti_clk_autoidle_setup(node);
+ return 0;
+ }
+
+ kfree(table);
+ return PTR_ERR(clk);
+}
+CLK_OF_DECLARE(divider_clk, "ti,divider-clock", of_ti_divider_clk_setup);
+
+static int __init of_ti_composite_divider_clk_setup(struct device_node *node)
+{
+ struct clk_divider *div;
+ u32 val;
+ int ret;
+
+ div = kzalloc(sizeof(*div), GFP_KERNEL);
+ if (!div)
+ return -ENOMEM;
+
+ ret = ti_clk_divider_populate(node, &div->reg, &div->table, &val,
+ &div->flags, &div->width, &div->shift);
+ if (ret < 0)
+ goto cleanup;
+
+ ret = ti_clk_add_component(node, &div->hw, CLK_COMPONENT_TYPE_DIVIDER);
+ if (!ret)
+ return 0;
+
+cleanup:
+ kfree(div->table);
+ kfree(div);
+ return ret;
+}
+CLK_OF_DECLARE(ti_composite_divider_clk, "ti,composite-divider-clock",
+ of_ti_composite_divider_clk_setup);
--
1.7.9.5
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