--- /dev/null
+/*
+ * Copyright (C) 2013 Emilio López <emilio@elopez.com.ar>
+ *
+ * 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 <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#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;
+}
Code Review / kvmfornfv.git / blobdiff