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 *best_parent_rate,
  60                                             struct clk **best_parent_clk)
  61 {
  62         struct clk *parent = NULL;
  63         long best_rate = -EINVAL;
  64         unsigned long parent_rate;
  65         unsigned long tmp_rate;
  66         int shift;
  67         int i;
  68
  69         for (i = 0; i < __clk_get_num_parents(hw->clk); i++) {
  70                 parent = clk_get_parent_by_index(hw->clk, i);
  71                 if (!parent)
  72                         continue;
  73
  74                 parent_rate = __clk_get_rate(parent);
  75                 for (shift = 0; shift < PROG_PRES_MASK; shift++) {
  76                         tmp_rate = parent_rate >> shift;
  77                         if (tmp_rate <= rate)
  78                                 break;
  79                 }
  80
  81                 if (tmp_rate > rate)
  82                         continue;
  83
  84                 if (best_rate < 0 || (rate - tmp_rate) < (rate - best_rate)) {
  85                         best_rate = tmp_rate;
  86                         *best_parent_rate = parent_rate;
  87                         *best_parent_clk = parent;
  88                 }
  89
  90                 if (!best_rate)
  91                         break;
  92         }
  93
  94         return best_rate;
  95 }
  96
  97 static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
  98 {
  99         struct clk_programmable *prog = to_clk_programmable(hw);
 100         const struct clk_programmable_layout *layout = prog->layout;
 101         struct at91_pmc *pmc = prog->pmc;
 102         u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & ~layout->css_mask;
 103
 104         if (layout->have_slck_mck)
 105                 tmp &= AT91_PMC_CSSMCK_MCK;
 106
 107         if (index > layout->css_mask) {
 108                 if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
 109                         tmp |= AT91_PMC_CSSMCK_MCK;
 110                         return 0;
 111                 } else {
 112                         return -EINVAL;
 113                 }
 114         }
 115
 116         pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | index);
 117         return 0;
 118 }
 119
 120 static u8 clk_programmable_get_parent(struct clk_hw *hw)
 121 {
 122         u32 tmp;
 123         u8 ret;
 124         struct clk_programmable *prog = to_clk_programmable(hw);
 125         struct at91_pmc *pmc = prog->pmc;
 126         const struct clk_programmable_layout *layout = prog->layout;
 127
 128         tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
 129         ret = tmp & layout->css_mask;
 130         if (layout->have_slck_mck && (tmp & AT91_PMC_CSSMCK_MCK) && !ret)
 131                 ret = PROG_MAX_RM9200_CSS + 1;
 132
 133         return ret;
 134 }
 135
 136 static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 137                                      unsigned long parent_rate)
 138 {
 139         struct clk_programmable *prog = to_clk_programmable(hw);
 140         struct at91_pmc *pmc = prog->pmc;
 141         const struct clk_programmable_layout *layout = prog->layout;
 142         unsigned long div = parent_rate / rate;
 143         int shift = 0;
 144         u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
 145                   ~(PROG_PRES_MASK << layout->pres_shift);
 146
 147         if (!div)
 148                 return -EINVAL;
 149
 150         shift = fls(div) - 1;
 151
 152         if (div != (1<<shift))
 153                 return -EINVAL;
 154
 155         if (shift >= PROG_PRES_MASK)
 156                 return -EINVAL;
 157
 158         pmc_write(pmc, AT91_PMC_PCKR(prog->id),
 159                   tmp | (shift << layout->pres_shift));
 160
 161         return 0;
 162 }
 163
 164 static const struct clk_ops programmable_ops = {
 165         .recalc_rate = clk_programmable_recalc_rate,
 166         .determine_rate = clk_programmable_determine_rate,
 167         .get_parent = clk_programmable_get_parent,
 168         .set_parent = clk_programmable_set_parent,
 169         .set_rate = clk_programmable_set_rate,
 170 };
 171
 172 static struct clk * __init
 173 at91_clk_register_programmable(struct at91_pmc *pmc,
 174                                const char *name, const char **parent_names,
 175                                u8 num_parents, u8 id,
 176                                const struct clk_programmable_layout *layout)
 177 {
 178         struct clk_programmable *prog;
 179         struct clk *clk = NULL;
 180         struct clk_init_data init;
 181
 182         if (id > PROG_ID_MAX)
 183                 return ERR_PTR(-EINVAL);
 184
 185         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 186         if (!prog)
 187                 return ERR_PTR(-ENOMEM);
 188
 189         init.name = name;
 190         init.ops = &programmable_ops;
 191         init.parent_names = parent_names;
 192         init.num_parents = num_parents;
 193         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 194
 195         prog->id = id;
 196         prog->layout = layout;
 197         prog->hw.init = &init;
 198         prog->pmc = pmc;
 199
 200         clk = clk_register(NULL, &prog->hw);
 201         if (IS_ERR(clk))
 202                 kfree(prog);
 203
 204         return clk;
 205 }
 206
 207 static const struct clk_programmable_layout at91rm9200_programmable_layout = {
 208         .pres_shift = 2,
 209         .css_mask = 0x3,
 210         .have_slck_mck = 0,
 211 };
 212
 213 static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
 214         .pres_shift = 2,
 215         .css_mask = 0x3,
 216         .have_slck_mck = 1,
 217 };
 218
 219 static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
 220         .pres_shift = 4,
 221         .css_mask = 0x7,
 222         .have_slck_mck = 0,
 223 };
 224
 225 static void __init
 226 of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
 227                        const struct clk_programmable_layout *layout)
 228 {
 229         int num;
 230         u32 id;
 231         int i;
 232         struct clk *clk;
 233         int num_parents;
 234         const char *parent_names[PROG_SOURCE_MAX];
 235         const char *name;
 236         struct device_node *progclknp;
 237
 238         num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
 239         if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)
 240                 return;
 241
 242         for (i = 0; i < num_parents; ++i) {
 243                 parent_names[i] = of_clk_get_parent_name(np, i);
 244                 if (!parent_names[i])
 245                         return;
 246         }
 247
 248         num = of_get_child_count(np);
 249         if (!num || num > (PROG_ID_MAX + 1))
 250                 return;
 251
 252         for_each_child_of_node(np, progclknp) {
 253                 if (of_property_read_u32(progclknp, "reg", &id))
 254                         continue;
 255
 256                 if (of_property_read_string(np, "clock-output-names", &name))
 257                         name = progclknp->name;
 258
 259                 clk = at91_clk_register_programmable(pmc, name,
 260                                                      parent_names, num_parents,
 261                                                      id, layout);
 262                 if (IS_ERR(clk))
 263                         continue;
 264
 265                 of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);
 266         }
 267 }
 268
 269
 270 void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
 271                                          struct at91_pmc *pmc)
 272 {
 273         of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
 274 }
 275
 276 void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
 277                                           struct at91_pmc *pmc)
 278 {
 279         of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
 280 }
 281
 282 void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
 283                                          struct at91_pmc *pmc)
 284 {
 285         of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
 286 }