diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/clk/ti/divider.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/drivers/clk/ti/divider.c b/drivers/clk/ti/divider.c new file mode 100644 index 000000000..4cc0aaa6c --- /dev/null +++ b/drivers/clk/ti/divider.c @@ -0,0 +1,569 @@ +/* + * 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> +#include "clock.h" + +#undef pr_fmt +#define pr_fmt(fmt) "%s: " fmt, __func__ + +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 void _setup_mask(struct clk_omap_divider *divider) +{ + u16 mask; + u32 max_val; + const struct clk_div_table *clkt; + + if (divider->table) { + max_val = 0; + + for (clkt = divider->table; clkt->div; clkt++) + if (clkt->val > max_val) + max_val = clkt->val; + } else { + max_val = divider->max; + + if (!(divider->flags & CLK_DIVIDER_ONE_BASED) && + !(divider->flags & CLK_DIVIDER_POWER_OF_TWO)) + max_val--; + } + + if (divider->flags & CLK_DIVIDER_POWER_OF_TWO) + mask = fls(max_val) - 1; + else + mask = max_val; + + divider->mask = (1 << fls(mask)) - 1; +} + +static unsigned int _get_div(struct clk_omap_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_omap_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_omap_divider *divider = to_clk_omap_divider(hw); + unsigned int div, val; + + val = ti_clk_ll_ops->clk_readl(÷r->reg) >> divider->shift; + val &= divider->mask; + + 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_hw_get_name(hw)); + return parent_rate; + } + + return DIV_ROUND_UP(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_omap_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 _div_round_up(const struct clk_div_table *table, + unsigned long parent_rate, unsigned long rate) +{ + const struct clk_div_table *clkt; + int up = INT_MAX; + int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate); + + for (clkt = table; clkt->div; clkt++) { + if (clkt->div == div) + return clkt->div; + else if (clkt->div < div) + continue; + + if ((clkt->div - div) < (up - div)) + up = clkt->div; + } + + return up; +} + +static int _div_round(const struct clk_div_table *table, + unsigned long parent_rate, unsigned long rate) +{ + if (!table) + return DIV_ROUND_UP(parent_rate, rate); + + return _div_round_up(table, parent_rate, rate); +} + +static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate, + unsigned long *best_parent_rate) +{ + struct clk_omap_divider *divider = to_clk_omap_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 = divider->max; + + if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) { + parent_rate = *best_parent_rate; + bestdiv = _div_round(divider->table, 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_hw_round_rate(clk_hw_get_parent(hw), + MULT_ROUND_UP(rate, i)); + now = DIV_ROUND_UP(parent_rate, i); + if (now <= rate && now > best) { + bestdiv = i; + best = now; + *best_parent_rate = parent_rate; + } + } + + if (!bestdiv) { + bestdiv = divider->max; + *best_parent_rate = + clk_hw_round_rate(clk_hw_get_parent(hw), 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 DIV_ROUND_UP(*prate, div); +} + +static int ti_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_omap_divider *divider; + unsigned int div, value; + u32 val; + + if (!hw || !rate) + return -EINVAL; + + divider = to_clk_omap_divider(hw); + + div = DIV_ROUND_UP(parent_rate, rate); + + if (div > divider->max) + div = divider->max; + if (div < divider->min) + div = divider->min; + + value = _get_val(divider, div); + + val = ti_clk_ll_ops->clk_readl(÷r->reg); + val &= ~(divider->mask << divider->shift); + val |= value << divider->shift; + ti_clk_ll_ops->clk_writel(val, ÷r->reg); + + ti_clk_latch(÷r->reg, divider->latch); + + return 0; +} + +/** + * clk_divider_save_context - Save the divider value + * @hw: pointer struct clk_hw + * + * Save the divider value + */ +static int clk_divider_save_context(struct clk_hw *hw) +{ + struct clk_omap_divider *divider = to_clk_omap_divider(hw); + u32 val; + + val = ti_clk_ll_ops->clk_readl(÷r->reg) >> divider->shift; + divider->context = val & divider->mask; + + return 0; +} + +/** + * clk_divider_restore_context - restore the saved the divider value + * @hw: pointer struct clk_hw + * + * Restore the saved the divider value + */ +static void clk_divider_restore_context(struct clk_hw *hw) +{ + struct clk_omap_divider *divider = to_clk_omap_divider(hw); + u32 val; + + val = ti_clk_ll_ops->clk_readl(÷r->reg); + val &= ~(divider->mask << divider->shift); + val |= divider->context << divider->shift; + ti_clk_ll_ops->clk_writel(val, ÷r->reg); +} + +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, + .save_context = clk_divider_save_context, + .restore_context = clk_divider_restore_context, +}; + +static struct clk *_register_divider(struct device_node *node, + u32 flags, + struct clk_omap_divider *div) +{ + struct clk_init_data init; + const char *parent_name; + const char *name; + + parent_name = of_clk_get_parent_name(node, 0); + + name = ti_dt_clk_name(node); + init.name = name; + init.ops = &ti_clk_divider_ops; + init.flags = flags; + init.parent_names = (parent_name ? &parent_name : NULL); + init.num_parents = (parent_name ? 1 : 0); + + div->hw.init = &init; + + /* register the clock */ + return of_ti_clk_register(node, &div->hw, name); +} + +int ti_clk_parse_divider_data(int *div_table, int num_dividers, int max_div, + u8 flags, struct clk_omap_divider *divider) +{ + int valid_div = 0; + int i; + struct clk_div_table *tmp; + u16 min_div = 0; + + if (!div_table) { + divider->min = 1; + divider->max = max_div; + _setup_mask(divider); + return 0; + } + + i = 0; + + while (!num_dividers || i < num_dividers) { + if (div_table[i] == -1) + break; + if (div_table[i]) + valid_div++; + i++; + } + + num_dividers = i; + + tmp = kcalloc(valid_div + 1, sizeof(*tmp), GFP_KERNEL); + if (!tmp) + return -ENOMEM; + + valid_div = 0; + + for (i = 0; i < num_dividers; i++) + if (div_table[i] > 0) { + tmp[valid_div].div = div_table[i]; + tmp[valid_div].val = i; + valid_div++; + if (div_table[i] > max_div) + max_div = div_table[i]; + if (!min_div || div_table[i] < min_div) + min_div = div_table[i]; + } + + divider->min = min_div; + divider->max = max_div; + divider->table = tmp; + _setup_mask(divider); + + return 0; +} + +static int __init ti_clk_get_div_table(struct device_node *node, + struct clk_omap_divider *div) +{ + 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 0; + + 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 %pOFn table\n", node); + return -EINVAL; + } + + table = kcalloc(valid_div + 1, sizeof(*table), GFP_KERNEL); + if (!table) + return -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++; + } + } + + div->table = table; + + return 0; +} + +static int _populate_divider_min_max(struct device_node *node, + struct clk_omap_divider *divider) +{ + u32 min_div = 0; + u32 max_div = 0; + u32 val; + const struct clk_div_table *clkt; + + if (!divider->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 %pOFn!\n", node); + return -EINVAL; + } + } else { + + for (clkt = divider->table; clkt->div; clkt++) { + val = clkt->div; + if (val > max_div) + max_div = val; + if (!min_div || val < min_div) + min_div = val; + } + } + + divider->min = min_div; + divider->max = max_div; + _setup_mask(divider); + + return 0; +} + +static int __init ti_clk_divider_populate(struct device_node *node, + struct clk_omap_divider *div, + u32 *flags) +{ + u32 val; + int ret; + + ret = ti_clk_get_reg_addr(node, 0, &div->reg); + if (ret) + return ret; + + if (!of_property_read_u32(node, "ti,bit-shift", &val)) + div->shift = val; + else + div->shift = 0; + + if (!of_property_read_u32(node, "ti,latch-bit", &val)) + div->latch = val; + else + div->latch = -EINVAL; + + *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; + + ret = ti_clk_get_div_table(node, div); + if (ret) + return ret; + + return _populate_divider_min_max(node, div); +} + +/** + * 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; + u32 flags = 0; + struct clk_omap_divider *div; + + div = kzalloc(sizeof(*div), GFP_KERNEL); + if (!div) + return; + + if (ti_clk_divider_populate(node, div, &flags)) + goto cleanup; + + clk = _register_divider(node, flags, div); + if (!IS_ERR(clk)) { + of_clk_add_provider(node, of_clk_src_simple_get, clk); + of_ti_clk_autoidle_setup(node); + return; + } + +cleanup: + kfree(div->table); + kfree(div); +} +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_omap_divider *div; + u32 tmp; + + div = kzalloc(sizeof(*div), GFP_KERNEL); + if (!div) + return; + + if (ti_clk_divider_populate(node, div, &tmp)) + 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); |