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 int clk_programmable_determine_rate(struct clk_hw *hw,
  58                                            struct clk_rate_request *req)
  59 {
  60         struct clk_hw *parent;
  61         long best_rate = -EINVAL;
  62         unsigned long parent_rate;
  63         unsigned long tmp_rate;
  64         int shift;
  65         int i;
  66
  67         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
  68                 parent = clk_hw_get_parent_by_index(hw, i);
  69                 if (!parent)
  70                         continue;
  71
  72                 parent_rate = clk_hw_get_rate(parent);
  73                 for (shift = 0; shift < PROG_PRES_MASK; shift++) {
  74                         tmp_rate = parent_rate >> shift;
  75                         if (tmp_rate <= req->rate)
  76                                 break;
  77                 }
  78
  79                 if (tmp_rate > req->rate)
  80                         continue;
  81
  82                 if (best_rate < 0 ||
  83                     (req->rate - tmp_rate) < (req->rate - best_rate)) {
  84                         best_rate = tmp_rate;
  85                         req->best_parent_rate = parent_rate;
  86                         req->best_parent_hw = parent;
  87                 }
  88
  89                 if (!best_rate)
  90                         break;
  91         }
  92
  93         if (best_rate < 0)
  94                 return best_rate;
  95
  96         req->rate = best_rate;
  97         return 0;
  98 }
  99
 100 static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
 101 {
 102         struct clk_programmable *prog = to_clk_programmable(hw);
 103         const struct clk_programmable_layout *layout = prog->layout;
 104         struct at91_pmc *pmc = prog->pmc;
 105         u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) & ~layout->css_mask;
 106
 107         if (layout->have_slck_mck)
 108                 tmp &= AT91_PMC_CSSMCK_MCK;
 109
 110         if (index > layout->css_mask) {
 111                 if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
 112                         tmp |= AT91_PMC_CSSMCK_MCK;
 113                         return 0;
 114                 } else {
 115                         return -EINVAL;
 116                 }
 117         }
 118
 119         pmc_write(pmc, AT91_PMC_PCKR(prog->id), tmp | index);
 120         return 0;
 121 }
 122
 123 static u8 clk_programmable_get_parent(struct clk_hw *hw)
 124 {
 125         u32 tmp;
 126         u8 ret;
 127         struct clk_programmable *prog = to_clk_programmable(hw);
 128         struct at91_pmc *pmc = prog->pmc;
 129         const struct clk_programmable_layout *layout = prog->layout;
 130
 131         tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
 132         ret = tmp & layout->css_mask;
 133         if (layout->have_slck_mck && (tmp & AT91_PMC_CSSMCK_MCK) && !ret)
 134                 ret = PROG_MAX_RM9200_CSS + 1;
 135
 136         return ret;
 137 }
 138
 139 static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 140                                      unsigned long parent_rate)
 141 {
 142         struct clk_programmable *prog = to_clk_programmable(hw);
 143         struct at91_pmc *pmc = prog->pmc;
 144         const struct clk_programmable_layout *layout = prog->layout;
 145         unsigned long div = parent_rate / rate;
 146         int shift = 0;
 147         u32 tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id)) &
 148                   ~(PROG_PRES_MASK << layout->pres_shift);
 149
 150         if (!div)
 151                 return -EINVAL;
 152
 153         shift = fls(div) - 1;
 154
 155         if (div != (1<<shift))
 156                 return -EINVAL;
 157
 158         if (shift >= PROG_PRES_MASK)
 159                 return -EINVAL;
 160
 161         pmc_write(pmc, AT91_PMC_PCKR(prog->id),
 162                   tmp | (shift << layout->pres_shift));
 163
 164         return 0;
 165 }
 166
 167 static const struct clk_ops programmable_ops = {
 168         .recalc_rate = clk_programmable_recalc_rate,
 169         .determine_rate = clk_programmable_determine_rate,
 170         .get_parent = clk_programmable_get_parent,
 171         .set_parent = clk_programmable_set_parent,
 172         .set_rate = clk_programmable_set_rate,
 173 };
 174
 175 static struct clk * __init
 176 at91_clk_register_programmable(struct at91_pmc *pmc,
 177                                const char *name, const char **parent_names,
 178                                u8 num_parents, u8 id,
 179                                const struct clk_programmable_layout *layout)
 180 {
 181         struct clk_programmable *prog;
 182         struct clk *clk = NULL;
 183         struct clk_init_data init;
 184
 185         if (id > PROG_ID_MAX)
 186                 return ERR_PTR(-EINVAL);
 187
 188         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 189         if (!prog)
 190                 return ERR_PTR(-ENOMEM);
 191
 192         init.name = name;
 193         init.ops = &programmable_ops;
 194         init.parent_names = parent_names;
 195         init.num_parents = num_parents;
 196         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 197
 198         prog->id = id;
 199         prog->layout = layout;
 200         prog->hw.init = &init;
 201         prog->pmc = pmc;
 202
 203         clk = clk_register(NULL, &prog->hw);
 204         if (IS_ERR(clk))
 205                 kfree(prog);
 206
 207         return clk;
 208 }
 209
 210 static const struct clk_programmable_layout at91rm9200_programmable_layout = {
 211         .pres_shift = 2,
 212         .css_mask = 0x3,
 213         .have_slck_mck = 0,
 214 };
 215
 216 static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
 217         .pres_shift = 2,
 218         .css_mask = 0x3,
 219         .have_slck_mck = 1,
 220 };
 221
 222 static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
 223         .pres_shift = 4,
 224         .css_mask = 0x7,
 225         .have_slck_mck = 0,
 226 };
 227
 228 static void __init
 229 of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
 230                        const struct clk_programmable_layout *layout)
 231 {
 232         int num;
 233         u32 id;
 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_clk_get_parent_count(np);
 241         if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)
 242                 return;
 243
 244         of_clk_parent_fill(np, parent_names, num_parents);
 245
 246         num = of_get_child_count(np);
 247         if (!num || num > (PROG_ID_MAX + 1))
 248                 return;
 249
 250         for_each_child_of_node(np, progclknp) {
 251                 if (of_property_read_u32(progclknp, "reg", &id))
 252                         continue;
 253
 254                 if (of_property_read_string(np, "clock-output-names", &name))
 255                         name = progclknp->name;
 256
 257                 clk = at91_clk_register_programmable(pmc, name,
 258                                                      parent_names, num_parents,
 259                                                      id, layout);
 260                 if (IS_ERR(clk))
 261                         continue;
 262
 263                 of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);
 264         }
 265 }
 266
 267
 268 void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
 269                                          struct at91_pmc *pmc)
 270 {
 271         of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
 272 }
 273
 274 void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
 275                                           struct at91_pmc *pmc)
 276 {
 277         of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
 278 }
 279
 280 void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
 281                                          struct at91_pmc *pmc)
 282 {
 283         of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
 284 }