drivers/clk/at91/clk-generated.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2015 Atmel Corporation,
   4  *                     Nicolas Ferre <nicolas.ferre@atmel.com>
   5  *
   6  * Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON.
   7  */
   8
   9 #include <linux/bitfield.h>
  10 #include <linux/clk-provider.h>
  11 #include <linux/clkdev.h>
  12 #include <linux/clk/at91_pmc.h>
  13 #include <linux/of.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/regmap.h>
  16
  17 #include "pmc.h"
  18
  19 #define GENERATED_MAX_DIV       255
  20
  21 struct clk_generated {
  22         struct clk_hw hw;
  23         struct regmap *regmap;
  24         struct clk_range range;
  25         spinlock_t *lock;
  26         u32 *mux_table;
  27         u32 id;
  28         u32 gckdiv;
  29         const struct clk_pcr_layout *layout;
  30         u8 parent_id;
  31         int chg_pid;
  32 };
  33
  34 #define to_clk_generated(hw) \
  35         container_of(hw, struct clk_generated, hw)
  36
  37 static int clk_generated_enable(struct clk_hw *hw)
  38 {
  39         struct clk_generated *gck = to_clk_generated(hw);
  40         unsigned long flags;
  41
  42         pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
  43                  __func__, gck->gckdiv, gck->parent_id);
  44
  45         spin_lock_irqsave(gck->lock, flags);
  46         regmap_write(gck->regmap, gck->layout->offset,
  47                      (gck->id & gck->layout->pid_mask));
  48         regmap_update_bits(gck->regmap, gck->layout->offset,
  49                            AT91_PMC_PCR_GCKDIV_MASK | gck->layout->gckcss_mask |
  50                            gck->layout->cmd | AT91_PMC_PCR_GCKEN,
  51                            field_prep(gck->layout->gckcss_mask, gck->parent_id) |
  52                            gck->layout->cmd |
  53                            FIELD_PREP(AT91_PMC_PCR_GCKDIV_MASK, gck->gckdiv) |
  54                            AT91_PMC_PCR_GCKEN);
  55         spin_unlock_irqrestore(gck->lock, flags);
  56         return 0;
  57 }
  58
  59 static void clk_generated_disable(struct clk_hw *hw)
  60 {
  61         struct clk_generated *gck = to_clk_generated(hw);
  62         unsigned long flags;
  63
  64         spin_lock_irqsave(gck->lock, flags);
  65         regmap_write(gck->regmap, gck->layout->offset,
  66                      (gck->id & gck->layout->pid_mask));
  67         regmap_update_bits(gck->regmap, gck->layout->offset,
  68                            gck->layout->cmd | AT91_PMC_PCR_GCKEN,
  69                            gck->layout->cmd);
  70         spin_unlock_irqrestore(gck->lock, flags);
  71 }
  72
  73 static int clk_generated_is_enabled(struct clk_hw *hw)
  74 {
  75         struct clk_generated *gck = to_clk_generated(hw);
  76         unsigned long flags;
  77         unsigned int status;
  78
  79         spin_lock_irqsave(gck->lock, flags);
  80         regmap_write(gck->regmap, gck->layout->offset,
  81                      (gck->id & gck->layout->pid_mask));
  82         regmap_read(gck->regmap, gck->layout->offset, &status);
  83         spin_unlock_irqrestore(gck->lock, flags);
  84
  85         return !!(status & AT91_PMC_PCR_GCKEN);
  86 }
  87
  88 static unsigned long
  89 clk_generated_recalc_rate(struct clk_hw *hw,
  90                           unsigned long parent_rate)
  91 {
  92         struct clk_generated *gck = to_clk_generated(hw);
  93
  94         return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
  95 }
  96
  97 static void clk_generated_best_diff(struct clk_rate_request *req,
  98                                     struct clk_hw *parent,
  99                                     unsigned long parent_rate, u32 div,
 100                                     int *best_diff, long *best_rate)
 101 {
 102         unsigned long tmp_rate;
 103         int tmp_diff;
 104
 105         if (!div)
 106                 tmp_rate = parent_rate;
 107         else
 108                 tmp_rate = parent_rate / div;
 109
 110         if (tmp_rate < req->min_rate || tmp_rate > req->max_rate)
 111                 return;
 112
 113         tmp_diff = abs(req->rate - tmp_rate);
 114
 115         if (*best_diff < 0 || *best_diff >= tmp_diff) {
 116                 *best_rate = tmp_rate;
 117                 *best_diff = tmp_diff;
 118                 req->best_parent_rate = parent_rate;
 119                 req->best_parent_hw = parent;
 120         }
 121 }
 122
 123 static int clk_generated_determine_rate(struct clk_hw *hw,
 124                                         struct clk_rate_request *req)
 125 {
 126         struct clk_generated *gck = to_clk_generated(hw);
 127         struct clk_hw *parent = NULL;
 128         struct clk_rate_request req_parent = *req;
 129         long best_rate = -EINVAL;
 130         unsigned long min_rate, parent_rate;
 131         int best_diff = -1;
 132         int i;
 133         u32 div;
 134
 135         /* do not look for a rate that is outside of our range */
 136         if (gck->range.max && req->rate > gck->range.max)
 137                 req->rate = gck->range.max;
 138         if (gck->range.min && req->rate < gck->range.min)
 139                 req->rate = gck->range.min;
 140
 141         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 142                 if (gck->chg_pid == i)
 143                         continue;
 144
 145                 parent = clk_hw_get_parent_by_index(hw, i);
 146                 if (!parent)
 147                         continue;
 148
 149                 parent_rate = clk_hw_get_rate(parent);
 150                 min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
 151                 if (!parent_rate ||
 152                     (gck->range.max && min_rate > gck->range.max))
 153                         continue;
 154
 155                 div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
 156                 if (div > GENERATED_MAX_DIV + 1)
 157                         div = GENERATED_MAX_DIV + 1;
 158
 159                 clk_generated_best_diff(req, parent, parent_rate, div,
 160                                         &best_diff, &best_rate);
 161
 162                 if (!best_diff)
 163                         break;
 164         }
 165
 166         /*
 167          * The audio_pll rate can be modified, unlike the five others clocks
 168          * that should never be altered.
 169          * The audio_pll can technically be used by multiple consumers. However,
 170          * with the rate locking, the first consumer to enable to clock will be
 171          * the one definitely setting the rate of the clock.
 172          * Since audio IPs are most likely to request the same rate, we enforce
 173          * that the only clks able to modify gck rate are those of audio IPs.
 174          */
 175
 176         if (gck->chg_pid < 0)
 177                 goto end;
 178
 179         parent = clk_hw_get_parent_by_index(hw, gck->chg_pid);
 180         if (!parent)
 181                 goto end;
 182
 183         for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
 184                 req_parent.rate = req->rate * div;
 185                 if (__clk_determine_rate(parent, &req_parent))
 186                         continue;
 187                 clk_generated_best_diff(req, parent, req_parent.rate, div,
 188                                         &best_diff, &best_rate);
 189
 190                 if (!best_diff)
 191                         break;
 192         }
 193
 194 end:
 195         pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
 196                  __func__, best_rate,
 197                  __clk_get_name((req->best_parent_hw)->clk),
 198                  req->best_parent_rate);
 199
 200         if (best_rate < 0 || (gck->range.max && best_rate > gck->range.max))
 201                 return -EINVAL;
 202
 203         req->rate = best_rate;
 204         return 0;
 205 }
 206
 207 /* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
 208 static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
 209 {
 210         struct clk_generated *gck = to_clk_generated(hw);
 211
 212         if (index >= clk_hw_get_num_parents(hw))
 213                 return -EINVAL;
 214
 215         if (gck->mux_table)
 216                 gck->parent_id = clk_mux_index_to_val(gck->mux_table, 0, index);
 217         else
 218                 gck->parent_id = index;
 219
 220         return 0;
 221 }
 222
 223 static u8 clk_generated_get_parent(struct clk_hw *hw)
 224 {
 225         struct clk_generated *gck = to_clk_generated(hw);
 226
 227         return gck->parent_id;
 228 }
 229
 230 /* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
 231 static int clk_generated_set_rate(struct clk_hw *hw,
 232                                   unsigned long rate,
 233                                   unsigned long parent_rate)
 234 {
 235         struct clk_generated *gck = to_clk_generated(hw);
 236         u32 div;
 237
 238         if (!rate)
 239                 return -EINVAL;
 240
 241         if (gck->range.max && rate > gck->range.max)
 242                 return -EINVAL;
 243
 244         div = DIV_ROUND_CLOSEST(parent_rate, rate);
 245         if (div > GENERATED_MAX_DIV + 1 || !div)
 246                 return -EINVAL;
 247
 248         gck->gckdiv = div - 1;
 249         return 0;
 250 }
 251
 252 static const struct clk_ops generated_ops = {
 253         .enable = clk_generated_enable,
 254         .disable = clk_generated_disable,
 255         .is_enabled = clk_generated_is_enabled,
 256         .recalc_rate = clk_generated_recalc_rate,
 257         .determine_rate = clk_generated_determine_rate,
 258         .get_parent = clk_generated_get_parent,
 259         .set_parent = clk_generated_set_parent,
 260         .set_rate = clk_generated_set_rate,
 261 };
 262
 263 /**
 264  * clk_generated_startup - Initialize a given clock to its default parent and
 265  * divisor parameter.
 266  *
 267  * @gck:        Generated clock to set the startup parameters for.
 268  *
 269  * Take parameters from the hardware and update local clock configuration
 270  * accordingly.
 271  */
 272 static void clk_generated_startup(struct clk_generated *gck)
 273 {
 274         u32 tmp;
 275         unsigned long flags;
 276
 277         spin_lock_irqsave(gck->lock, flags);
 278         regmap_write(gck->regmap, gck->layout->offset,
 279                      (gck->id & gck->layout->pid_mask));
 280         regmap_read(gck->regmap, gck->layout->offset, &tmp);
 281         spin_unlock_irqrestore(gck->lock, flags);
 282
 283         gck->parent_id = field_get(gck->layout->gckcss_mask, tmp);
 284         gck->gckdiv = FIELD_GET(AT91_PMC_PCR_GCKDIV_MASK, tmp);
 285 }
 286
 287 struct clk_hw * __init
 288 at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
 289                             const struct clk_pcr_layout *layout,
 290                             const char *name, const char **parent_names,
 291                             u32 *mux_table, u8 num_parents, u8 id,
 292                             const struct clk_range *range,
 293                             int chg_pid)
 294 {
 295         struct clk_generated *gck;
 296         struct clk_init_data init;
 297         struct clk_hw *hw;
 298         int ret;
 299
 300         gck = kzalloc(sizeof(*gck), GFP_KERNEL);
 301         if (!gck)
 302                 return ERR_PTR(-ENOMEM);
 303
 304         init.name = name;
 305         init.ops = &generated_ops;
 306         init.parent_names = parent_names;
 307         init.num_parents = num_parents;
 308         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 309         if (chg_pid >= 0)
 310                 init.flags |= CLK_SET_RATE_PARENT;
 311
 312         gck->id = id;
 313         gck->hw.init = &init;
 314         gck->regmap = regmap;
 315         gck->lock = lock;
 316         gck->range = *range;
 317         gck->chg_pid = chg_pid;
 318         gck->layout = layout;
 319         gck->mux_table = mux_table;
 320
 321         clk_generated_startup(gck);
 322         hw = &gck->hw;
 323         ret = clk_hw_register(NULL, &gck->hw);
 324         if (ret) {
 325                 kfree(gck);
 326                 hw = ERR_PTR(ret);
 327         } else {
 328                 pmc_register_id(id);
 329         }
 330
 331         return hw;
 332 }