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

   1 /*
   2  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/clk/at91_pmc.h>
  14 #include <linux/of.h>
  15 #include <linux/of_address.h>
  16 #include <linux/io.h>
  17 #include <linux/wait.h>
  18 #include <linux/sched.h>
  19
  20 #include "pmc.h"
  21
  22 #define PROG_SOURCE_MAX         5
  23 #define PROG_ID_MAX             7
  24
  25 #define PROG_STATUS_MASK(id)    (1 << ((id) + 8))
  26 #define PROG_PRES_MASK          0x7
  27 #define PROG_MAX_RM9200_CSS     3
  28
  29 struct clk_programmable_layout {
  30         u8 pres_shift;
  31         u8 css_mask;
  32         u8 have_slck_mck;
  33 };
  34
  35 struct clk_programmable {
  36         struct clk_hw hw;
  37         struct at91_pmc *pmc;
  38         u8 id;
  39         const struct clk_programmable_layout *layout;
  40 };
  41
  42 #define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)
  43
  44 static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
  45                                                   unsigned long parent_rate)
  46 {
  47         u32 pres;
  48         struct clk_programmable *prog = to_clk_programmable(hw);
  49         struct at91_pmc *pmc = prog->pmc;
  50         const struct clk_programmable_layout *layout = prog->layout;
  51
  52         pres = (pmc_read(pmc, AT91_PMC_PCKR(prog->id)) >> layout->pres_shift) &
  53                PROG_PRES_MASK;
  54         return parent_rate >> pres;
  55 }
  56
  57 static long clk_programmable_determine_rate(struct clk_hw *hw,
  58                                             unsigned long rate,
  59                                             unsigned long min_rate,
  60                                             unsigned long max_rate,
  61                                             unsigned long *best_parent_rate,
  62                                             struct clk_hw **best_parent_hw)
  63 {
  64         struct clk *parent = NULL;
  65         long best_rate = -EINVAL;
  66         unsigned long parent_rate;
  67         unsigned long tmp_rate;
  68         int shift;
  69         int i;
  70
  71         for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
  72                 parent = clk_get_parent_by_index(hw->clk, i);
  73                 if (!parent)
  74                         continue;
  75
  76                 parent_rate = __clk_get_rate(parent);
  77                 for (shift = 0; shift < PROG_PRES_MASK; shift++) {
  78                         tmp_rate = parent_rate >> shift;
  79                         if (tmp_rate <= rate)
  80                                 break;
  81                 }
  82
  83                 if (tmp_rate > rate)
  84                         continue;
  85
  86                 if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
  87                         best_rate = tmp_rate;
  88                         *best_parent_rate = parent_rate;
  89                         *best_parent_hw = __clk_get_hw(parent);
  90                 }
  91
  92                 if (!best_rate)
  93                         break;
  94         }
  95
  96         return best_rate;
  97 }
  98
  99 static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
 100 {
 101         struct clk_programmable *prog = to_clk_programmable(hw);
 102         const struct clk_programmable_layout *layout = prog->layout;
 103         struct at91_pmc *pmc = prog->pmc;
 104         u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & ~layout->css_mask;
 105
 106         if (layout->have_slck_mck)
 107                 tmp &= AT91_PMC_CSSMCK_MCK;
 108
 109         if (index > layout->css_mask) {
 110                 if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
 111                         tmp |= AT91_PMC_CSSMCK_MCK;
 112                         return 0;
 113                 } else {
 114                         return -EINVAL;
 115                 }
 116         }
 117
 118         pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | index);
 119         return 0;
 120 }
 121
 122 static u8 clk_programmable_get_parent(struct clk_hw *hw)
 123 {
 124         u32 tmp;
 125         u8 ret;
 126         struct clk_programmable *prog = to_clk_programmable(hw);
 127         struct at91_pmc *pmc = prog->pmc;
 128         const struct clk_programmable_layout *layout = prog->layout;
 129
 130         tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
 131         ret = tmp & layout->css_mask;
 132         if (layout->have_slck_mck && (tmp & AT91_PMC_CSSMCK_MCK) && !ret)
 133                 ret = PROG_MAX_RM9200_CSS + 1;
 134
 135         return ret;
 136 }
 137
 138 static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 139                                      unsigned long parent_rate)
 140 {
 141         struct clk_programmable *prog = to_clk_programmable(hw);
 142         struct at91_pmc *pmc = prog->pmc;
 143         const struct clk_programmable_layout *layout = prog->layout;
 144         unsigned long div = parent_rate / rate;
 145         int shift = 0;
 146         u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
 147                   ~(PROG_PRES_MASK << layout->pres_shift);
 148
 149         if (!div)
 150                 return -EINVAL;
 151
 152         shift = fls(div) - 1;
 153
 154         if (div != (1<<shift))
 155                 return -EINVAL;
 156
 157         if (shift >= PROG_PRES_MASK)
 158                 return -EINVAL;
 159
 160         pmc_write(pmc, AT91_PMC_PCKR(prog->id),
 161                   tmp | (shift << layout->pres_shift));
 162
 163         return 0;
 164 }
 165
 166 static const struct clk_ops programmable_ops = {
 167         .recalc_rate = clk_programmable_recalc_rate,
 168         .determine_rate = clk_programmable_determine_rate,
 169         .get_parent = clk_programmable_get_parent,
 170         .set_parent = clk_programmable_set_parent,
 171         .set_rate = clk_programmable_set_rate,
 172 };
 173
 174 static struct clk * __init
 175 at91_clk_register_programmable(struct at91_pmc *pmc,
 176                                const char *name, const char **parent_names,
 177                                u8 num_parents, u8 id,
 178                                const struct clk_programmable_layout *layout)
 179 {
 180         struct clk_programmable *prog;
 181         struct clk *clk = NULL;
 182         struct clk_init_data init;
 183
 184         if (id > PROG_ID_MAX)
 185                 return ERR_PTR(-EINVAL);
 186
 187         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 188         if (!prog)
 189                 return ERR_PTR(-ENOMEM);
 190
 191         init.name = name;
 192         init.ops = &programmable_ops;
 193         init.parent_names = parent_names;
 194         init.num_parents = num_parents;
 195         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 196
 197         prog->id = id;
 198         prog->layout = layout;
 199         prog->hw.init = &init;
 200         prog->pmc = pmc;
 201
 202         clk = clk_register(NULL, &prog->hw);
 203         if (IS_ERR(clk))
 204                 kfree(prog);
 205
 206         return clk;
 207 }
 208
 209 static const struct clk_programmable_layout at91rm9200_programmable_layout = {
 210         .pres_shift = 2,
 211         .css_mask = 0x3,
 212         .have_slck_mck = 0,
 213 };
 214
 215 static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
 216         .pres_shift = 2,
 217         .css_mask = 0x3,
 218         .have_slck_mck = 1,
 219 };
 220
 221 static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
 222         .pres_shift = 4,
 223         .css_mask = 0x7,
 224         .have_slck_mck = 0,
 225 };
 226
 227 static void __init
 228 of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
 229                        const struct clk_programmable_layout *layout)
 230 {
 231         int num;
 232         u32 id;
 233         int i;
 234         struct clk *clk;
 235         int num_parents;
 236         const char *parent_names[PROG_SOURCE_MAX];
 237         const char *name;
 238         struct device_node *progclknp;
 239
 240         num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
 241         if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)
 242                 return;
 243
 244         for (i = 0; i < num_parents; ++i) {
 245                 parent_names[i] = of_clk_get_parent_name(np, i);
 246                 if (!parent_names[i])
 247                         return;
 248         }
 249
 250         num = of_get_child_count(np);
 251         if (!num || num > (PROG_ID_MAX + 1))
 252                 return;
 253
 254         for_each_child_of_node(np, progclknp) {
 255                 if (of_property_read_u32(progclknp, "reg", &id))
 256                         continue;
 257
 258                 if (of_property_read_string(np, "clock-output-names", &name))
 259                         name = progclknp->name;
 260
 261                 clk = at91_clk_register_programmable(pmc, name,
 262                                                      parent_names, num_parents,
 263                                                      id, layout);
 264                 if (IS_ERR(clk))
 265                         continue;
 266
 267                 of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);
 268         }
 269 }
 270
 271
 272 void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
 273                                          struct at91_pmc *pmc)
 274 {
 275         of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
 276 }
 277
 278 void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
 279                                           struct at91_pmc *pmc)
 280 {
 281         of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
 282 }
 283
 284 void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
 285                                          struct at91_pmc *pmc)
 286 {
 287         of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
 288 }