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         tmp_diff = abs(req->rate - tmp_rate);
 110
 111         if (*best_diff < 0 || *best_diff >= tmp_diff) {
 112                 *best_rate = tmp_rate;
 113                 *best_diff = tmp_diff;
 114                 req->best_parent_rate = parent_rate;
 115                 req->best_parent_hw = parent;
 116         }
 117 }
 118
 119 static int clk_generated_determine_rate(struct clk_hw *hw,
 120                                         struct clk_rate_request *req)
 121 {
 122         struct clk_generated *gck = to_clk_generated(hw);
 123         struct clk_hw *parent = NULL;
 124         struct clk_rate_request req_parent = *req;
 125         long best_rate = -EINVAL;
 126         unsigned long min_rate, parent_rate;
 127         int best_diff = -1;
 128         int i;
 129         u32 div;
 130
 131         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 132                 if (gck->chg_pid == i)
 133                         continue;
 134
 135                 parent = clk_hw_get_parent_by_index(hw, i);
 136                 if (!parent)
 137                         continue;
 138
 139                 parent_rate = clk_hw_get_rate(parent);
 140                 min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
 141                 if (!parent_rate ||
 142                     (gck->range.max && min_rate > gck->range.max))
 143                         continue;
 144
 145                 div = DIV_ROUND_CLOSEST(parent_rate, req->rate);
 146                 if (div > GENERATED_MAX_DIV + 1)
 147                         div = GENERATED_MAX_DIV + 1;
 148
 149                 clk_generated_best_diff(req, parent, parent_rate, div,
 150                                         &best_diff, &best_rate);
 151
 152                 if (!best_diff)
 153                         break;
 154         }
 155
 156         /*
 157          * The audio_pll rate can be modified, unlike the five others clocks
 158          * that should never be altered.
 159          * The audio_pll can technically be used by multiple consumers. However,
 160          * with the rate locking, the first consumer to enable to clock will be
 161          * the one definitely setting the rate of the clock.
 162          * Since audio IPs are most likely to request the same rate, we enforce
 163          * that the only clks able to modify gck rate are those of audio IPs.
 164          */
 165
 166         if (gck->chg_pid < 0)
 167                 goto end;
 168
 169         parent = clk_hw_get_parent_by_index(hw, gck->chg_pid);
 170         if (!parent)
 171                 goto end;
 172
 173         for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
 174                 req_parent.rate = req->rate * div;
 175                 if (__clk_determine_rate(parent, &req_parent))
 176                         continue;
 177                 clk_generated_best_diff(req, parent, req_parent.rate, div,
 178                                         &best_diff, &best_rate);
 179
 180                 if (!best_diff)
 181                         break;
 182         }
 183
 184 end:
 185         pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
 186                  __func__, best_rate,
 187                  __clk_get_name((req->best_parent_hw)->clk),
 188                  req->best_parent_rate);
 189
 190         if (best_rate < 0 || (gck->range.max && best_rate > gck->range.max))
 191                 return -EINVAL;
 192
 193         req->rate = best_rate;
 194         return 0;
 195 }
 196
 197 /* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
 198 static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
 199 {
 200         struct clk_generated *gck = to_clk_generated(hw);
 201
 202         if (index >= clk_hw_get_num_parents(hw))
 203                 return -EINVAL;
 204
 205         if (gck->mux_table)
 206                 gck->parent_id = clk_mux_index_to_val(gck->mux_table, 0, index);
 207         else
 208                 gck->parent_id = index;
 209
 210         return 0;
 211 }
 212
 213 static u8 clk_generated_get_parent(struct clk_hw *hw)
 214 {
 215         struct clk_generated *gck = to_clk_generated(hw);
 216
 217         return gck->parent_id;
 218 }
 219
 220 /* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
 221 static int clk_generated_set_rate(struct clk_hw *hw,
 222                                   unsigned long rate,
 223                                   unsigned long parent_rate)
 224 {
 225         struct clk_generated *gck = to_clk_generated(hw);
 226         u32 div;
 227
 228         if (!rate)
 229                 return -EINVAL;
 230
 231         if (gck->range.max && rate > gck->range.max)
 232                 return -EINVAL;
 233
 234         div = DIV_ROUND_CLOSEST(parent_rate, rate);
 235         if (div > GENERATED_MAX_DIV + 1 || !div)
 236                 return -EINVAL;
 237
 238         gck->gckdiv = div - 1;
 239         return 0;
 240 }
 241
 242 static const struct clk_ops generated_ops = {
 243         .enable = clk_generated_enable,
 244         .disable = clk_generated_disable,
 245         .is_enabled = clk_generated_is_enabled,
 246         .recalc_rate = clk_generated_recalc_rate,
 247         .determine_rate = clk_generated_determine_rate,
 248         .get_parent = clk_generated_get_parent,
 249         .set_parent = clk_generated_set_parent,
 250         .set_rate = clk_generated_set_rate,
 251 };
 252
 253 /**
 254  * clk_generated_startup - Initialize a given clock to its default parent and
 255  * divisor parameter.
 256  *
 257  * @gck:        Generated clock to set the startup parameters for.
 258  *
 259  * Take parameters from the hardware and update local clock configuration
 260  * accordingly.
 261  */
 262 static void clk_generated_startup(struct clk_generated *gck)
 263 {
 264         u32 tmp;
 265         unsigned long flags;
 266
 267         spin_lock_irqsave(gck->lock, flags);
 268         regmap_write(gck->regmap, gck->layout->offset,
 269                      (gck->id & gck->layout->pid_mask));
 270         regmap_read(gck->regmap, gck->layout->offset, &tmp);
 271         spin_unlock_irqrestore(gck->lock, flags);
 272
 273         gck->parent_id = field_get(gck->layout->gckcss_mask, tmp);
 274         gck->gckdiv = FIELD_GET(AT91_PMC_PCR_GCKDIV_MASK, tmp);
 275 }
 276
 277 struct clk_hw * __init
 278 at91_clk_register_generated(struct regmap *regmap, spinlock_t *lock,
 279                             const struct clk_pcr_layout *layout,
 280                             const char *name, const char **parent_names,
 281                             u32 *mux_table, u8 num_parents, u8 id,
 282                             const struct clk_range *range,
 283                             int chg_pid)
 284 {
 285         struct clk_generated *gck;
 286         struct clk_init_data init;
 287         struct clk_hw *hw;
 288         int ret;
 289
 290         gck = kzalloc(sizeof(*gck), GFP_KERNEL);
 291         if (!gck)
 292                 return ERR_PTR(-ENOMEM);
 293
 294         init.name = name;
 295         init.ops = &generated_ops;
 296         init.parent_names = parent_names;
 297         init.num_parents = num_parents;
 298         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 299         if (chg_pid >= 0)
 300                 init.flags |= CLK_SET_RATE_PARENT;
 301
 302         gck->id = id;
 303         gck->hw.init = &init;
 304         gck->regmap = regmap;
 305         gck->lock = lock;
 306         gck->range = *range;
 307         gck->chg_pid = chg_pid;
 308         gck->layout = layout;
 309         gck->mux_table = mux_table;
 310
 311         clk_generated_startup(gck);
 312         hw = &gck->hw;
 313         ret = clk_hw_register(NULL, &gck->hw);
 314         if (ret) {
 315                 kfree(gck);
 316                 hw = ERR_PTR(ret);
 317         } else {
 318                 pmc_register_id(id);
 319         }
 320
 321         return hw;
 322 }