drivers/clk/sunxi/clk-factors.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2013 Emilio López <emilio@elopez.com.ar>
   4  *
   5  * Adjustable factor-based clock implementation
   6  */
   7
   8 #include <linux/clk-provider.h>
   9 #include <linux/delay.h>
  10 #include <linux/err.h>
  11 #include <linux/io.h>
  12 #include <linux/of_address.h>
  13 #include <linux/slab.h>
  14 #include <linux/string.h>
  15
  16 #include "clk-factors.h"
  17
  18 /*
  19  * DOC: basic adjustable factor-based clock
  20  *
  21  * Traits of this clock:
  22  * prepare - clk_prepare only ensures that parents are prepared
  23  * enable - clk_enable only ensures that parents are enabled
  24  * rate - rate is adjustable.
  25  *        clk->rate = (parent->rate * N * (K + 1) >> P) / (M + 1)
  26  * parent - fixed parent.  No clk_set_parent support
  27  */
  28
  29 #define to_clk_factors(_hw) container_of(_hw, struct clk_factors, hw)
  30
  31 #define FACTORS_MAX_PARENTS             5
  32
  33 #define SETMASK(len, pos)               (((1U << (len)) - 1) << (pos))
  34 #define CLRMASK(len, pos)               (~(SETMASK(len, pos)))
  35 #define FACTOR_GET(bit, len, reg)       (((reg) & SETMASK(len, bit)) >> (bit))
  36
  37 #define FACTOR_SET(bit, len, reg, val) \
  38         (((reg) & CLRMASK(len, bit)) | (val << (bit)))
  39
  40 static unsigned long clk_factors_recalc_rate(struct clk_hw *hw,
  41                                              unsigned long parent_rate)
  42 {
  43         u8 n = 1, k = 0, p = 0, m = 0;
  44         u32 reg;
  45         unsigned long rate;
  46         struct clk_factors *factors = to_clk_factors(hw);
  47         const struct clk_factors_config *config = factors->config;
  48
  49         /* Fetch the register value */
  50         reg = readl(factors->reg);
  51
  52         /* Get each individual factor if applicable */
  53         if (config->nwidth != SUNXI_FACTORS_NOT_APPLICABLE)
  54                 n = FACTOR_GET(config->nshift, config->nwidth, reg);
  55         if (config->kwidth != SUNXI_FACTORS_NOT_APPLICABLE)
  56                 k = FACTOR_GET(config->kshift, config->kwidth, reg);
  57         if (config->mwidth != SUNXI_FACTORS_NOT_APPLICABLE)
  58                 m = FACTOR_GET(config->mshift, config->mwidth, reg);
  59         if (config->pwidth != SUNXI_FACTORS_NOT_APPLICABLE)
  60                 p = FACTOR_GET(config->pshift, config->pwidth, reg);
  61
  62         if (factors->recalc) {
  63                 struct factors_request factors_req = {
  64                         .parent_rate = parent_rate,
  65                         .n = n,
  66                         .k = k,
  67                         .m = m,
  68                         .p = p,
  69                 };
  70
  71                 /* get mux details from mux clk structure */
  72                 if (factors->mux)
  73                         factors_req.parent_index =
  74                                 (reg >> factors->mux->shift) &
  75                                 factors->mux->mask;
  76
  77                 factors->recalc(&factors_req);
  78
  79                 return factors_req.rate;
  80         }
  81
  82         /* Calculate the rate */
  83         rate = (parent_rate * (n + config->n_start) * (k + 1) >> p) / (m + 1);
  84
  85         return rate;
  86 }
  87
  88 static int clk_factors_determine_rate(struct clk_hw *hw,
  89                                       struct clk_rate_request *req)
  90 {
  91         struct clk_factors *factors = to_clk_factors(hw);
  92         struct clk_hw *parent, *best_parent = NULL;
  93         int i, num_parents;
  94         unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0;
  95
  96         /* find the parent that can help provide the fastest rate <= rate */
  97         num_parents = clk_hw_get_num_parents(hw);
  98         for (i = 0; i < num_parents; i++) {
  99                 struct factors_request factors_req = {
 100                         .rate = req->rate,
 101                         .parent_index = i,
 102                 };
 103                 parent = clk_hw_get_parent_by_index(hw, i);
 104                 if (!parent)
 105                         continue;
 106                 if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)
 107                         parent_rate = clk_hw_round_rate(parent, req->rate);
 108                 else
 109                         parent_rate = clk_hw_get_rate(parent);
 110
 111                 factors_req.parent_rate = parent_rate;
 112                 factors->get_factors(&factors_req);
 113                 child_rate = factors_req.rate;
 114
 115                 if (child_rate <= req->rate && child_rate > best_child_rate) {
 116                         best_parent = parent;
 117                         best = parent_rate;
 118                         best_child_rate = child_rate;
 119                 }
 120         }
 121
 122         if (!best_parent)
 123                 return -EINVAL;
 124
 125         req->best_parent_hw = best_parent;
 126         req->best_parent_rate = best;
 127         req->rate = best_child_rate;
 128
 129         return 0;
 130 }
 131
 132 static int clk_factors_set_rate(struct clk_hw *hw, unsigned long rate,
 133                                 unsigned long parent_rate)
 134 {
 135         struct factors_request req = {
 136                 .rate = rate,
 137                 .parent_rate = parent_rate,
 138         };
 139         u32 reg;
 140         struct clk_factors *factors = to_clk_factors(hw);
 141         const struct clk_factors_config *config = factors->config;
 142         unsigned long flags = 0;
 143
 144         factors->get_factors(&req);
 145
 146         if (factors->lock)
 147                 spin_lock_irqsave(factors->lock, flags);
 148
 149         /* Fetch the register value */
 150         reg = readl(factors->reg);
 151
 152         /* Set up the new factors - macros do not do anything if width is 0 */
 153         reg = FACTOR_SET(config->nshift, config->nwidth, reg, req.n);
 154         reg = FACTOR_SET(config->kshift, config->kwidth, reg, req.k);
 155         reg = FACTOR_SET(config->mshift, config->mwidth, reg, req.m);
 156         reg = FACTOR_SET(config->pshift, config->pwidth, reg, req.p);
 157
 158         /* Apply them now */
 159         writel(reg, factors->reg);
 160
 161         /* delay 500us so pll stabilizes */
 162         __delay((rate >> 20) * 500 / 2);
 163
 164         if (factors->lock)
 165                 spin_unlock_irqrestore(factors->lock, flags);
 166
 167         return 0;
 168 }
 169
 170 static const struct clk_ops clk_factors_ops = {
 171         .determine_rate = clk_factors_determine_rate,
 172         .recalc_rate = clk_factors_recalc_rate,
 173         .set_rate = clk_factors_set_rate,
 174 };
 175
 176 static struct clk *__sunxi_factors_register(struct device_node *node,
 177                                             const struct factors_data *data,
 178                                             spinlock_t *lock, void __iomem *reg,
 179                                             unsigned long flags)
 180 {
 181         struct clk *clk;
 182         struct clk_factors *factors;
 183         struct clk_gate *gate = NULL;
 184         struct clk_mux *mux = NULL;
 185         struct clk_hw *gate_hw = NULL;
 186         struct clk_hw *mux_hw = NULL;
 187         const char *clk_name = node->name;
 188         const char *parents[FACTORS_MAX_PARENTS];
 189         int ret, i = 0;
 190
 191         /* if we have a mux, we will have >1 parents */
 192         i = of_clk_parent_fill(node, parents, FACTORS_MAX_PARENTS);
 193
 194         /*
 195          * some factor clocks, such as pll5 and pll6, may have multiple
 196          * outputs, and have their name designated in factors_data
 197          */
 198         if (data->name)
 199                 clk_name = data->name;
 200         else
 201                 of_property_read_string(node, "clock-output-names", &clk_name);
 202
 203         factors = kzalloc(sizeof(struct clk_factors), GFP_KERNEL);
 204         if (!factors)
 205                 goto err_factors;
 206
 207         /* set up factors properties */
 208         factors->reg = reg;
 209         factors->config = data->table;
 210         factors->get_factors = data->getter;
 211         factors->recalc = data->recalc;
 212         factors->lock = lock;
 213
 214         /* Add a gate if this factor clock can be gated */
 215         if (data->enable) {
 216                 gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
 217                 if (!gate)
 218                         goto err_gate;
 219
 220                 factors->gate = gate;
 221
 222                 /* set up gate properties */
 223                 gate->reg = reg;
 224                 gate->bit_idx = data->enable;
 225                 gate->lock = factors->lock;
 226                 gate_hw = &gate->hw;
 227         }
 228
 229         /* Add a mux if this factor clock can be muxed */
 230         if (data->mux) {
 231                 mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);
 232                 if (!mux)
 233                         goto err_mux;
 234
 235                 factors->mux = mux;
 236
 237                 /* set up gate properties */
 238                 mux->reg = reg;
 239                 mux->shift = data->mux;
 240                 mux->mask = data->muxmask;
 241                 mux->lock = factors->lock;
 242                 mux_hw = &mux->hw;
 243         }
 244
 245         clk = clk_register_composite(NULL, clk_name,
 246                         parents, i,
 247                         mux_hw, &clk_mux_ops,
 248                         &factors->hw, &clk_factors_ops,
 249                         gate_hw, &clk_gate_ops, CLK_IS_CRITICAL);
 250         if (IS_ERR(clk))
 251                 goto err_register;
 252
 253         ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
 254         if (ret)
 255                 goto err_provider;
 256
 257         return clk;
 258
 259 err_provider:
 260         /* TODO: The composite clock stuff will leak a bit here. */
 261         clk_unregister(clk);
 262 err_register:
 263         kfree(mux);
 264 err_mux:
 265         kfree(gate);
 266 err_gate:
 267         kfree(factors);
 268 err_factors:
 269         return NULL;
 270 }
 271
 272 struct clk *sunxi_factors_register(struct device_node *node,
 273                                    const struct factors_data *data,
 274                                    spinlock_t *lock,
 275                                    void __iomem *reg)
 276 {
 277         return __sunxi_factors_register(node, data, lock, reg, 0);
 278 }
 279
 280 struct clk *sunxi_factors_register_critical(struct device_node *node,
 281                                             const struct factors_data *data,
 282                                             spinlock_t *lock,
 283                                             void __iomem *reg)
 284 {
 285         return __sunxi_factors_register(node, data, lock, reg, CLK_IS_CRITICAL);
 286 }
 287
 288 void sunxi_factors_unregister(struct device_node *node, struct clk *clk)
 289 {
 290         struct clk_hw *hw = __clk_get_hw(clk);
 291         struct clk_factors *factors;
 292
 293         if (!hw)
 294                 return;
 295
 296         factors = to_clk_factors(hw);
 297
 298         of_clk_del_provider(node);
 299         /* TODO: The composite clock stuff will leak a bit here. */
 300         clk_unregister(clk);
 301         kfree(factors->mux);
 302         kfree(factors->gate);
 303         kfree(factors);
 304 }