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