kernel/drivers/clk/at91/clk-generated.c

   1 /*
   2  *  Copyright (C) 2015 Atmel Corporation,
   3  *                     Nicolas Ferre <nicolas.ferre@atmel.com>
   4  *
   5  * Based on clk-programmable & clk-peripheral drivers by Boris BREZILLON.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  */
  13
  14 #include <linux/clk-provider.h>
  15 #include <linux/clkdev.h>
  16 #include <linux/clk/at91_pmc.h>
  17 #include <linux/of.h>
  18 #include <linux/mfd/syscon.h>
  19 #include <linux/regmap.h>
  20
  21 #include "pmc.h"
  22
  23 #define PERIPHERAL_MAX          64
  24 #define PERIPHERAL_ID_MIN       2
  25
  26 #define GENERATED_SOURCE_MAX    6
  27 #define GENERATED_MAX_DIV       255
  28
  29 struct clk_generated {
  30         struct clk_hw hw;
  31         struct regmap *regmap;
  32         struct clk_range range;
  33         spinlock_t *lock;
  34         u32 id;
  35         u32 gckdiv;
  36         u8 parent_id;
  37 };
  38
  39 #define to_clk_generated(hw) \
  40         container_of(hw, struct clk_generated, hw)
  41
  42 static int clk_generated_enable(struct clk_hw *hw)
  43 {
  44         struct clk_generated *gck = to_clk_generated(hw);
  45         unsigned long flags;
  46
  47         pr_debug("GCLK: %s, gckdiv = %d, parent id = %d\n",
  48                  __func__, gck->gckdiv, gck->parent_id);
  49
  50         spin_lock_irqsave(gck->lock, flags);
  51         regmap_write(gck->regmap, AT91_PMC_PCR,
  52                      (gck->id & AT91_PMC_PCR_PID_MASK));
  53         regmap_update_bits(gck->regmap, AT91_PMC_PCR,
  54                            AT91_PMC_PCR_GCKDIV_MASK | AT91_PMC_PCR_GCKCSS_MASK |
  55                            AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN,
  56                            AT91_PMC_PCR_GCKCSS(gck->parent_id) |
  57                            AT91_PMC_PCR_CMD |
  58                            AT91_PMC_PCR_GCKDIV(gck->gckdiv) |
  59                            AT91_PMC_PCR_GCKEN);
  60         spin_unlock_irqrestore(gck->lock, flags);
  61         return 0;
  62 }
  63
  64 static void clk_generated_disable(struct clk_hw *hw)
  65 {
  66         struct clk_generated *gck = to_clk_generated(hw);
  67         unsigned long flags;
  68
  69         spin_lock_irqsave(gck->lock, flags);
  70         regmap_write(gck->regmap, AT91_PMC_PCR,
  71                      (gck->id & AT91_PMC_PCR_PID_MASK));
  72         regmap_update_bits(gck->regmap, AT91_PMC_PCR,
  73                            AT91_PMC_PCR_CMD | AT91_PMC_PCR_GCKEN,
  74                            AT91_PMC_PCR_CMD);
  75         spin_unlock_irqrestore(gck->lock, flags);
  76 }
  77
  78 static int clk_generated_is_enabled(struct clk_hw *hw)
  79 {
  80         struct clk_generated *gck = to_clk_generated(hw);
  81         unsigned long flags;
  82         unsigned int status;
  83
  84         spin_lock_irqsave(gck->lock, flags);
  85         regmap_write(gck->regmap, AT91_PMC_PCR,
  86                      (gck->id & AT91_PMC_PCR_PID_MASK));
  87         regmap_read(gck->regmap, AT91_PMC_PCR, &status);
  88         spin_unlock_irqrestore(gck->lock, flags);
  89
  90         return status & AT91_PMC_PCR_GCKEN ? 1 : 0;
  91 }
  92
  93 static unsigned long
  94 clk_generated_recalc_rate(struct clk_hw *hw,
  95                           unsigned long parent_rate)
  96 {
  97         struct clk_generated *gck = to_clk_generated(hw);
  98
  99         return DIV_ROUND_CLOSEST(parent_rate, gck->gckdiv + 1);
 100 }
 101
 102 static int clk_generated_determine_rate(struct clk_hw *hw,
 103                                         struct clk_rate_request *req)
 104 {
 105         struct clk_generated *gck = to_clk_generated(hw);
 106         struct clk_hw *parent = NULL;
 107         long best_rate = -EINVAL;
 108         unsigned long tmp_rate, min_rate;
 109         int best_diff = -1;
 110         int tmp_diff;
 111         int i;
 112
 113         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 114                 u32 div;
 115                 unsigned long parent_rate;
 116
 117                 parent = clk_hw_get_parent_by_index(hw, i);
 118                 if (!parent)
 119                         continue;
 120
 121                 parent_rate = clk_hw_get_rate(parent);
 122                 min_rate = DIV_ROUND_CLOSEST(parent_rate, GENERATED_MAX_DIV + 1);
 123                 if (!parent_rate ||
 124                     (gck->range.max && min_rate > gck->range.max))
 125                         continue;
 126
 127                 for (div = 1; div < GENERATED_MAX_DIV + 2; div++) {
 128                         tmp_rate = DIV_ROUND_CLOSEST(parent_rate, div);
 129                         tmp_diff = abs(req->rate - tmp_rate);
 130
 131                         if (best_diff < 0 || best_diff > tmp_diff) {
 132                                 best_rate = tmp_rate;
 133                                 best_diff = tmp_diff;
 134                                 req->best_parent_rate = parent_rate;
 135                                 req->best_parent_hw = parent;
 136                         }
 137
 138                         if (!best_diff || tmp_rate < req->rate)
 139                                 break;
 140                 }
 141
 142                 if (!best_diff)
 143                         break;
 144         }
 145
 146         pr_debug("GCLK: %s, best_rate = %ld, parent clk: %s @ %ld\n",
 147                  __func__, best_rate,
 148                  __clk_get_name((req->best_parent_hw)->clk),
 149                  req->best_parent_rate);
 150
 151         if (best_rate < 0)
 152                 return best_rate;
 153
 154         req->rate = best_rate;
 155         return 0;
 156 }
 157
 158 /* No modification of hardware as we have the flag CLK_SET_PARENT_GATE set */
 159 static int clk_generated_set_parent(struct clk_hw *hw, u8 index)
 160 {
 161         struct clk_generated *gck = to_clk_generated(hw);
 162
 163         if (index >= clk_hw_get_num_parents(hw))
 164                 return -EINVAL;
 165
 166         gck->parent_id = index;
 167         return 0;
 168 }
 169
 170 static u8 clk_generated_get_parent(struct clk_hw *hw)
 171 {
 172         struct clk_generated *gck = to_clk_generated(hw);
 173
 174         return gck->parent_id;
 175 }
 176
 177 /* No modification of hardware as we have the flag CLK_SET_RATE_GATE set */
 178 static int clk_generated_set_rate(struct clk_hw *hw,
 179                                   unsigned long rate,
 180                                   unsigned long parent_rate)
 181 {
 182         struct clk_generated *gck = to_clk_generated(hw);
 183         u32 div;
 184
 185         if (!rate)
 186                 return -EINVAL;
 187
 188         if (gck->range.max && rate > gck->range.max)
 189                 return -EINVAL;
 190
 191         div = DIV_ROUND_CLOSEST(parent_rate, rate);
 192         if (div > GENERATED_MAX_DIV + 1 || !div)
 193                 return -EINVAL;
 194
 195         gck->gckdiv = div - 1;
 196         return 0;
 197 }
 198
 199 static const struct clk_ops generated_ops = {
 200         .enable = clk_generated_enable,
 201         .disable = clk_generated_disable,
 202         .is_enabled = clk_generated_is_enabled,
 203         .recalc_rate = clk_generated_recalc_rate,
 204         .determine_rate = clk_generated_determine_rate,
 205         .get_parent = clk_generated_get_parent,
 206         .set_parent = clk_generated_set_parent,
 207         .set_rate = clk_generated_set_rate,
 208 };
 209
 210 /**
 211  * clk_generated_startup - Initialize a given clock to its default parent and
 212  * divisor parameter.
 213  *
 214  * @gck:        Generated clock to set the startup parameters for.
 215  *
 216  * Take parameters from the hardware and update local clock configuration
 217  * accordingly.
 218  */
 219 static void clk_generated_startup(struct clk_generated *gck)
 220 {
 221         u32 tmp;
 222         unsigned long flags;
 223
 224         spin_lock_irqsave(gck->lock, flags);
 225         regmap_write(gck->regmap, AT91_PMC_PCR,
 226                      (gck->id & AT91_PMC_PCR_PID_MASK));
 227         regmap_read(gck->regmap, AT91_PMC_PCR, &tmp);
 228         spin_unlock_irqrestore(gck->lock, flags);
 229
 230         gck->parent_id = (tmp & AT91_PMC_PCR_GCKCSS_MASK)
 231                                         >> AT91_PMC_PCR_GCKCSS_OFFSET;
 232         gck->gckdiv = (tmp & AT91_PMC_PCR_GCKDIV_MASK)
 233                                         >> AT91_PMC_PCR_GCKDIV_OFFSET;
 234 }
 235
 236 static struct clk * __init
 237 at91_clk_register_generated(struct regmap *regmap,  spinlock_t *lock, const char
 238                             *name, const char **parent_names, u8 num_parents,
 239                             u8 id, const struct clk_range *range)
 240 {
 241         struct clk_generated *gck;
 242         struct clk *clk = NULL;
 243         struct clk_init_data init;
 244
 245         gck = kzalloc(sizeof(*gck), GFP_KERNEL);
 246         if (!gck)
 247                 return ERR_PTR(-ENOMEM);
 248
 249         init.name = name;
 250         init.ops = &generated_ops;
 251         init.parent_names = parent_names;
 252         init.num_parents = num_parents;
 253         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 254
 255         gck->id = id;
 256         gck->hw.init = &init;
 257         gck->regmap = regmap;
 258         gck->lock = lock;
 259         gck->range = *range;
 260
 261         clk = clk_register(NULL, &gck->hw);
 262         if (IS_ERR(clk))
 263                 kfree(gck);
 264         else
 265                 clk_generated_startup(gck);
 266
 267         return clk;
 268 }
 269
 270 void __init of_sama5d2_clk_generated_setup(struct device_node *np)
 271 {
 272         int num;
 273         u32 id;
 274         const char *name;
 275         struct clk *clk;
 276         int num_parents;
 277         const char *parent_names[GENERATED_SOURCE_MAX];
 278         struct device_node *gcknp;
 279         struct clk_range range = CLK_RANGE(0, 0);
 280         struct regmap *regmap;
 281
 282         num_parents = of_clk_get_parent_count(np);
 283         if (num_parents <= 0 || num_parents > GENERATED_SOURCE_MAX)
 284                 return;
 285
 286         of_clk_parent_fill(np, parent_names, num_parents);
 287
 288         num = of_get_child_count(np);
 289         if (!num || num > PERIPHERAL_MAX)
 290                 return;
 291
 292         regmap = syscon_node_to_regmap(of_get_parent(np));
 293         if (IS_ERR(regmap))
 294                 return;
 295
 296         for_each_child_of_node(np, gcknp) {
 297                 if (of_property_read_u32(gcknp, "reg", &id))
 298                         continue;
 299
 300                 if (id < PERIPHERAL_ID_MIN || id >= PERIPHERAL_MAX)
 301                         continue;
 302
 303                 if (of_property_read_string(np, "clock-output-names", &name))
 304                         name = gcknp->name;
 305
 306                 of_at91_get_clk_range(gcknp, "atmel,clk-output-range",
 307                                       &range);
 308
 309                 clk = at91_clk_register_generated(regmap, &pmc_pcr_lock, name,
 310                                                   parent_names, num_parents,
 311                                                   id, &range);
 312                 if (IS_ERR(clk))
 313                         continue;
 314
 315                 of_clk_add_provider(gcknp, of_clk_src_simple_get, clk);
 316         }
 317 }
 318 CLK_OF_DECLARE(of_sama5d2_clk_generated_setup, "atmel,sama5d2-clk-generated",
 319                of_sama5d2_clk_generated_setup);