diff options
| -rw-r--r-- | Documentation/devicetree/bindings/clock/ti/divider.txt | 114 | ||||
| -rw-r--r-- | drivers/clk/ti/Makefile | 2 | ||||
| -rw-r--r-- | drivers/clk/ti/composite.c | 2 | ||||
| -rw-r--r-- | drivers/clk/ti/divider.c | 487 | ||||
| -rw-r--r-- | include/linux/clk/ti.h | 2 |
5 files changed, 605 insertions, 2 deletions
diff --git a/Documentation/devicetree/bindings/clock/ti/divider.txt b/Documentation/devicetree/bindings/clock/ti/divider.txt new file mode 100644 index 000000000000..35a6f5c7e5c2 --- /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@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@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 ac4ea50672ed..8690b0b442c0 100644 --- a/drivers/clk/ti/Makefile +++ b/drivers/clk/ti/Makefile @@ -1,4 +1,4 @@ ifneq ($(CONFIG_OF),) obj-y += clk.o autoidle.o -clk-common = dpll.o composite.o +clk-common = dpll.o composite.o divider.o endif diff --git a/drivers/clk/ti/composite.c b/drivers/clk/ti/composite.c index 6539b650cae0..ffb8db4829bf 100644 --- a/drivers/clk/ti/composite.c +++ b/drivers/clk/ti/composite.c @@ -31,7 +31,7 @@ static unsigned long ti_composite_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) { - return clk_divider_ops.recalc_rate(hw, parent_rate); + return ti_clk_divider_ops.recalc_rate(hw, parent_rate); } static long ti_composite_round_rate(struct clk_hw *hw, unsigned long rate, diff --git a/drivers/clk/ti/divider.c b/drivers/clk/ti/divider.c new file mode 100644 index 000000000000..a15e445570b2 --- /dev/null +++ b/drivers/clk/ti/divider.c @@ -0,0 +1,487 @@ +/* + * TI Divider Clock + * + * Copyright (C) 2013 Texas Instruments, Inc. + * + * Tero Kristo <t-kristo@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__ + +#define to_clk_divider(_hw) container_of(_hw, struct clk_divider, hw) + +#define div_mask(d) ((1 << ((d)->width)) - 1) + +static unsigned int _get_table_maxdiv(const struct clk_div_table *table) +{ + unsigned int maxdiv = 0; + const struct clk_div_table *clkt; + + for (clkt = table; clkt->div; clkt++) + if (clkt->div > maxdiv) + maxdiv = clkt->div; + return maxdiv; +} + +static unsigned int _get_maxdiv(struct clk_divider *divider) +{ + if (divider->flags & CLK_DIVIDER_ONE_BASED) + return div_mask(divider); + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + return 1 << div_mask(divider); + if (divider->table) + return _get_table_maxdiv(divider->table); + return div_mask(divider) + 1; +} + +static unsigned int _get_table_div(const struct clk_div_table *table, + unsigned int val) +{ + const struct clk_div_table *clkt; + + for (clkt = table; clkt->div; clkt++) + if (clkt->val == val) + return clkt->div; + return 0; +} + +static unsigned int _get_div(struct clk_divider *divider, unsigned int val) +{ + if (divider->flags & CLK_DIVIDER_ONE_BASED) + return val; + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + return 1 << val; + if (divider->table) + return _get_table_div(divider->table, val); + return val + 1; +} + +static unsigned int _get_table_val(const struct clk_div_table *table, + unsigned int div) +{ + const struct clk_div_table *clkt; + + for (clkt = table; clkt->div; clkt++) + if (clkt->div == div) + return clkt->val; + return 0; +} + +static unsigned int _get_val(struct clk_divider *divider, u8 div) +{ + if (divider->flags & CLK_DIVIDER_ONE_BASED) + return div; + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + return __ffs(div); + if (divider->table) + return _get_table_val(divider->table, div); + return div - 1; +} + +static unsigned long ti_clk_divider_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_divider *divider = to_clk_divider(hw); + unsigned int div, val; + + val = ti_clk_ll_ops->clk_readl(divider->reg) >> divider->shift; + val &= div_mask(divider); + + div = _get_div(divider, val); + if (!div) { + WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO), + "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n", + __clk_get_name(hw->clk)); + return parent_rate; + } + + return parent_rate / div; +} + +/* + * The reverse of DIV_ROUND_UP: The maximum number which + * divided by m is r + */ +#define MULT_ROUND_UP(r, m) ((r) * (m) + (m) - 1) + +static bool _is_valid_table_div(const struct clk_div_table *table, + unsigned int div) +{ + const struct clk_div_table *clkt; + + for (clkt = table; clkt->div; clkt++) + if (clkt->div == div) + return true; + return false; +} + +static bool _is_valid_div(struct clk_divider *divider, unsigned int div) +{ + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + return is_power_of_2(div); + if (divider->table) + return _is_valid_table_div(divider->table, div); + return true; +} + +static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate) +{ + struct clk_divider *divider = to_clk_divider(hw); + int i, bestdiv = 0; + unsigned long parent_rate, best = 0, now, maxdiv; + unsigned long parent_rate_saved = *best_parent_rate; + + if (!rate) + rate = 1; + + maxdiv = _get_maxdiv(divider); + + if (!(__clk_get_flags(hw->clk) & CLK_SET_RATE_PARENT)) { + parent_rate = *best_parent_rate; + bestdiv = DIV_ROUND_UP(parent_rate, rate); + bestdiv = bestdiv == 0 ? 1 : bestdiv; + bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv; + return bestdiv; + } + + /* + * The maximum divider we can use without overflowing + * unsigned long in rate * i below + */ + maxdiv = min(ULONG_MAX / rate, maxdiv); + + for (i = 1; i <= maxdiv; i++) { + if (!_is_valid_div(divider, i)) + continue; + if (rate * i == parent_rate_saved) { + /* + * It's the most ideal case if the requested rate can be + * divided from parent clock without needing to change + * parent rate, so return the divider immediately. + */ + *best_parent_rate = parent_rate_saved; + return i; + } + parent_rate = __clk_round_rate(__clk_get_parent(hw->clk), + MULT_ROUND_UP(rate, i)); + now = parent_rate / i; + if (now <= rate && now > best) { + bestdiv = i; + best = now; + *best_parent_rate = parent_rate; + } + } + + if (!bestdiv) { + bestdiv = _get_maxdiv(divider); + *best_parent_rate = + __clk_round_rate(__clk_get_parent(hw->clk), 1); + } + + return bestdiv; +} + +static long ti_clk_divider_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + int div; + div = ti_clk_divider_bestdiv(hw, rate, prate); + + return *prate / div; +} + +static int ti_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_divider *divider = to_clk_divider(hw); + unsigned int div, value; + unsigned long flags = 0; + u32 val; + + div = parent_rate / rate; + value = _get_val(divider, div); + + if (value > div_mask(divider)) + value = div_mask(divider); + + if (divider->lock) + spin_lock_irqsave(divider->lock, flags); + + if (divider->flags & CLK_DIVIDER_HIWORD_MASK) { + val = div_mask(divider) << (divider->shift + 16); + } else { + val = ti_clk_ll_ops->clk_readl(divider->reg); + val &= ~(div_mask(divider) << divider->shift); + } + val |= value << divider->shift; + ti_clk_ll_ops->clk_writel(val, divider->reg); + + if (divider->lock) + spin_unlock_irqrestore(divider->lock, flags); + + return 0; +} + +const struct clk_ops ti_clk_divider_ops = { + .recalc_rate = ti_clk_divider_recalc_rate, + .round_rate = ti_clk_divider_round_rate, + .set_rate = ti_clk_divider_set_rate, +}; + +static struct clk *_register_divider(struct device *dev, const char *name, + const char *parent_name, + unsigned long flags, void __iomem *reg, + u8 shift, u8 width, u8 clk_divider_flags, + const struct clk_div_table *table, + spinlock_t *lock) +{ + struct clk_divider *div; + struct clk *clk; + struct clk_init_data init; + + if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) { + if (width + shift > 16) { + pr_warn("divider value exceeds LOWORD field\n"); + return ERR_PTR(-EINVAL); + } + } + + /* allocate the divider */ + div = kzalloc(sizeof(*div), GFP_KERNEL); + if (!div) { + pr_err("%s: could not allocate divider clk\n", __func__); + return ERR_PTR(-ENOMEM); + } + + init.name = name; + init.ops = &ti_clk_divider_ops; + init.flags = flags | CLK_IS_BASIC; + init.parent_names = (parent_name ? &parent_name : NULL); + init.num_parents = (parent_name ? 1 : 0); + + /* struct clk_divider assignments */ + div->reg = reg; + div->shift = shift; + div->width = width; + div->flags = clk_divider_flags; + div->lock = lock; + div->hw.init = &init; + div->table = table; + + /* register the clock */ + clk = clk_register(dev, &div->hw); + + if (IS_ERR(clk)) + kfree(div); + + return clk; +} + +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); + + 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 void __init of_ti_divider_clk_setup(struct device_node *node) +{ + struct clk *clk; + const char *parent_name; + void __iomem *reg; + u8 clk_divider_flags = 0; + u8 width = 0; + u8 shift = 0; + const struct clk_div_table *table = NULL; + u32 flags = 0; + + parent_name = of_clk_get_parent_name(node, 0); + + if (ti_clk_divider_populate(node, ®, &table, &flags, + &clk_divider_flags, &width, &shift)) + goto cleanup; + + clk = _register_divider(NULL, node->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; + } + +cleanup: + kfree(table); +} +CLK_OF_DECLARE(divider_clk, "ti,divider-clock", of_ti_divider_clk_setup); + +static void __init of_ti_composite_divider_clk_setup(struct device_node *node) +{ + struct clk_divider *div; + u32 val; + + div = kzalloc(sizeof(*div), GFP_KERNEL); + if (!div) + return; + + if (ti_clk_divider_populate(node, &div->reg, &div->table, &val, + &div->flags, &div->width, &div->shift) < 0) + goto cleanup; + + if (!ti_clk_add_component(node, &div->hw, CLK_COMPONENT_TYPE_DIVIDER)) + return; + +cleanup: + kfree(div->table); + kfree(div); +} +CLK_OF_DECLARE(ti_composite_divider_clk, "ti,composite-divider-clock", + of_ti_composite_divider_clk_setup); diff --git a/include/linux/clk/ti.h b/include/linux/clk/ti.h index c8c591dd3261..17fb49e4ff5e 100644 --- a/include/linux/clk/ti.h +++ b/include/linux/clk/ti.h @@ -223,6 +223,8 @@ struct ti_clk_ll_ops { extern struct ti_clk_ll_ops *ti_clk_ll_ops; +extern const struct clk_ops ti_clk_divider_ops; + #define to_clk_hw_omap(_hw) container_of(_hw, struct clk_hw_omap, hw) void omap2_init_clk_hw_omap_clocks(struct clk *clk); |