From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- drivers/clk/sunxi/clk-factors.c | 244 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 244 insertions(+) create mode 100644 drivers/clk/sunxi/clk-factors.c (limited to 'drivers/clk/sunxi/clk-factors.c') diff --git a/drivers/clk/sunxi/clk-factors.c b/drivers/clk/sunxi/clk-factors.c new file mode 100644 index 000000000..8c20190a3 --- /dev/null +++ b/drivers/clk/sunxi/clk-factors.c @@ -0,0 +1,244 @@ +/* + * Copyright (C) 2013 Emilio López + * + * 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. + * + * Adjustable factor-based clock implementation + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "clk-factors.h" + +/* + * DOC: basic adjustable factor-based clock + * + * Traits of this clock: + * prepare - clk_prepare only ensures that parents are prepared + * enable - clk_enable only ensures that parents are enabled + * rate - rate is adjustable. + * clk->rate = (parent->rate * N * (K + 1) >> P) / (M + 1) + * parent - fixed parent. No clk_set_parent support + */ + +#define to_clk_factors(_hw) container_of(_hw, struct clk_factors, hw) + +#define FACTORS_MAX_PARENTS 5 + +#define SETMASK(len, pos) (((1U << (len)) - 1) << (pos)) +#define CLRMASK(len, pos) (~(SETMASK(len, pos))) +#define FACTOR_GET(bit, len, reg) (((reg) & SETMASK(len, bit)) >> (bit)) + +#define FACTOR_SET(bit, len, reg, val) \ + (((reg) & CLRMASK(len, bit)) | (val << (bit))) + +static unsigned long clk_factors_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + u8 n = 1, k = 0, p = 0, m = 0; + u32 reg; + unsigned long rate; + struct clk_factors *factors = to_clk_factors(hw); + struct clk_factors_config *config = factors->config; + + /* Fetch the register value */ + reg = readl(factors->reg); + + /* Get each individual factor if applicable */ + if (config->nwidth != SUNXI_FACTORS_NOT_APPLICABLE) + n = FACTOR_GET(config->nshift, config->nwidth, reg); + if (config->kwidth != SUNXI_FACTORS_NOT_APPLICABLE) + k = FACTOR_GET(config->kshift, config->kwidth, reg); + if (config->mwidth != SUNXI_FACTORS_NOT_APPLICABLE) + m = FACTOR_GET(config->mshift, config->mwidth, reg); + if (config->pwidth != SUNXI_FACTORS_NOT_APPLICABLE) + p = FACTOR_GET(config->pshift, config->pwidth, reg); + + /* Calculate the rate */ + rate = (parent_rate * (n + config->n_start) * (k + 1) >> p) / (m + 1); + + return rate; +} + +static long clk_factors_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + struct clk_factors *factors = to_clk_factors(hw); + factors->get_factors((u32 *)&rate, (u32)*parent_rate, + NULL, NULL, NULL, NULL); + + return rate; +} + +static long clk_factors_determine_rate(struct clk_hw *hw, unsigned long rate, + unsigned long min_rate, + unsigned long max_rate, + unsigned long *best_parent_rate, + struct clk_hw **best_parent_p) +{ + struct clk *clk = hw->clk, *parent, *best_parent = NULL; + int i, num_parents; + unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0; + + /* find the parent that can help provide the fastest rate <= rate */ + num_parents = __clk_get_num_parents(clk); + for (i = 0; i < num_parents; i++) { + parent = clk_get_parent_by_index(clk, i); + if (!parent) + continue; + if (__clk_get_flags(clk) & CLK_SET_RATE_PARENT) + parent_rate = __clk_round_rate(parent, rate); + else + parent_rate = __clk_get_rate(parent); + + child_rate = clk_factors_round_rate(hw, rate, &parent_rate); + + if (child_rate <= rate && child_rate > best_child_rate) { + best_parent = parent; + best = parent_rate; + best_child_rate = child_rate; + } + } + + if (best_parent) + *best_parent_p = __clk_get_hw(best_parent); + *best_parent_rate = best; + + return best_child_rate; +} + +static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + u8 n = 0, k = 0, m = 0, p = 0; + u32 reg; + struct clk_factors *factors = to_clk_factors(hw); + struct clk_factors_config *config = factors->config; + unsigned long flags = 0; + + factors->get_factors((u32 *)&rate, (u32)parent_rate, &n, &k, &m, &p); + + if (factors->lock) + spin_lock_irqsave(factors->lock, flags); + + /* Fetch the register value */ + reg = readl(factors->reg); + + /* Set up the new factors - macros do not do anything if width is 0 */ + reg = FACTOR_SET(config->nshift, config->nwidth, reg, n); + reg = FACTOR_SET(config->kshift, config->kwidth, reg, k); + reg = FACTOR_SET(config->mshift, config->mwidth, reg, m); + reg = FACTOR_SET(config->pshift, config->pwidth, reg, p); + + /* Apply them now */ + writel(reg, factors->reg); + + /* delay 500us so pll stabilizes */ + __delay((rate >> 20) * 500 / 2); + + if (factors->lock) + spin_unlock_irqrestore(factors->lock, flags); + + return 0; +} + +static const struct clk_ops clk_factors_ops = { + .determine_rate = clk_factors_determine_rate, + .recalc_rate = clk_factors_recalc_rate, + .round_rate = clk_factors_round_rate, + .set_rate = clk_factors_set_rate, +}; + +struct clk *sunxi_factors_register(struct device_node *node, + const struct factors_data *data, + spinlock_t *lock, + void __iomem *reg) +{ + struct clk *clk; + struct clk_factors *factors; + struct clk_gate *gate = NULL; + struct clk_mux *mux = NULL; + struct clk_hw *gate_hw = NULL; + struct clk_hw *mux_hw = NULL; + const char *clk_name = node->name; + const char *parents[FACTORS_MAX_PARENTS]; + int i = 0; + + /* if we have a mux, we will have >1 parents */ + while (i < FACTORS_MAX_PARENTS && + (parents[i] = of_clk_get_parent_name(node, i)) != NULL) + i++; + + /* + * some factor clocks, such as pll5 and pll6, may have multiple + * outputs, and have their name designated in factors_data + */ + if (data->name) + clk_name = data->name; + else + of_property_read_string(node, "clock-output-names", &clk_name); + + factors = kzalloc(sizeof(struct clk_factors), GFP_KERNEL); + if (!factors) + return NULL; + + /* set up factors properties */ + factors->reg = reg; + factors->config = data->table; + factors->get_factors = data->getter; + factors->lock = lock; + + /* Add a gate if this factor clock can be gated */ + if (data->enable) { + gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL); + if (!gate) { + kfree(factors); + return NULL; + } + + /* set up gate properties */ + gate->reg = reg; + gate->bit_idx = data->enable; + gate->lock = factors->lock; + gate_hw = &gate->hw; + } + + /* Add a mux if this factor clock can be muxed */ + if (data->mux) { + mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL); + if (!mux) { + kfree(factors); + kfree(gate); + return NULL; + } + + /* set up gate properties */ + mux->reg = reg; + mux->shift = data->mux; + mux->mask = data->muxmask; + mux->lock = factors->lock; + mux_hw = &mux->hw; + } + + clk = clk_register_composite(NULL, clk_name, + parents, i, + mux_hw, &clk_mux_ops, + &factors->hw, &clk_factors_ops, + gate_hw, &clk_gate_ops, 0); + + if (!IS_ERR(clk)) { + of_clk_add_provider(node, of_clk_src_simple_get, clk); + clk_register_clkdev(clk, clk_name, NULL); + } + + return clk; +} -- cgit v1.2.3-54-g00ecf