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/of_irq.h>
  17 #include <linux/io.h>
  18 #include <linux/wait.h>
  19 #include <linux/sched.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/irq.h>
  22
  23 #include "pmc.h"
  24
  25 #define PROG_SOURCE_MAX         5
  26 #define PROG_ID_MAX             7
  27
  28 #define PROG_STATUS_MASK(id)    (1 << ((id) + 8))
  29 #define PROG_PRES_MASK          0x7
  30 #define PROG_MAX_RM9200_CSS     3
  31
  32 struct clk_programmable_layout {
  33         u8 pres_shift;
  34         u8 css_mask;
  35         u8 have_slck_mck;
  36 };
  37
  38 struct clk_programmable {
  39         struct clk_hw hw;
  40         struct at91_pmc *pmc;
  41         unsigned int irq;
  42         wait_queue_head_t wait;
  43         u8 id;
  44         u8 css;
  45         u8 pres;
  46         u8 slckmck;
  47         const struct clk_programmable_layout *layout;
  48 };
  49
  50 #define to_clk_programmable(hw) container_of(hw, struct clk_programmable, hw)
  51
  52
  53 static irqreturn_t clk_programmable_irq_handler(int irq, void *dev_id)
  54 {
  55         struct clk_programmable *prog = (struct clk_programmable *)dev_id;
  56
  57         wake_up(&prog->wait);
  58
  59         return IRQ_HANDLED;
  60 }
  61
  62 static int clk_programmable_prepare(struct clk_hw *hw)
  63 {
  64         u32 tmp;
  65         struct clk_programmable *prog = to_clk_programmable(hw);
  66         struct at91_pmc *pmc = prog->pmc;
  67         const struct clk_programmable_layout *layout = prog->layout;
  68         u8 id = prog->id;
  69         u32 mask = PROG_STATUS_MASK(id);
  70
  71         tmp = prog->css | (prog->pres << layout->pres_shift);
  72         if (layout->have_slck_mck && prog->slckmck)
  73                 tmp |= AT91_PMC_CSSMCK_MCK;
  74
  75         pmc_write(pmc, AT91_PMC_PCKR(id), tmp);
  76
  77         while (!(pmc_read(pmc, AT91_PMC_SR) & mask))
  78                 wait_event(prog->wait, pmc_read(pmc, AT91_PMC_SR) & mask);
  79
  80         return 0;
  81 }
  82
  83 static int clk_programmable_is_ready(struct clk_hw *hw)
  84 {
  85         struct clk_programmable *prog = to_clk_programmable(hw);
  86         struct at91_pmc *pmc = prog->pmc;
  87
  88         return !!(pmc_read(pmc, AT91_PMC_SR) & AT91_PMC_PCKR(prog->id));
  89 }
  90
  91 static unsigned long clk_programmable_recalc_rate(struct clk_hw *hw,
  92                                                   unsigned long parent_rate)
  93 {
  94         u32 tmp;
  95         struct clk_programmable *prog = to_clk_programmable(hw);
  96         struct at91_pmc *pmc = prog->pmc;
  97         const struct clk_programmable_layout *layout = prog->layout;
  98
  99         tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
 100         prog->pres = (tmp >> layout->pres_shift) & PROG_PRES_MASK;
 101
 102         return parent_rate >> prog->pres;
 103 }
 104
 105 static long clk_programmable_round_rate(struct clk_hw *hw, unsigned long rate,
 106                                         unsigned long *parent_rate)
 107 {
 108         unsigned long best_rate = *parent_rate;
 109         unsigned long best_diff;
 110         unsigned long new_diff;
 111         unsigned long cur_rate;
 112         int shift = shift;
 113
 114         if (rate > *parent_rate)
 115                 return *parent_rate;
 116         else
 117                 best_diff = *parent_rate - rate;
 118
 119         if (!best_diff)
 120                 return best_rate;
 121
 122         for (shift = 1; shift < PROG_PRES_MASK; shift++) {
 123                 cur_rate = *parent_rate >> shift;
 124
 125                 if (cur_rate > rate)
 126                         new_diff = cur_rate - rate;
 127                 else
 128                         new_diff = rate - cur_rate;
 129
 130                 if (!new_diff)
 131                         return cur_rate;
 132
 133                 if (new_diff < best_diff) {
 134                         best_diff = new_diff;
 135                         best_rate = cur_rate;
 136                 }
 137
 138                 if (rate > cur_rate)
 139                         break;
 140         }
 141
 142         return best_rate;
 143 }
 144
 145 static int clk_programmable_set_parent(struct clk_hw *hw, u8 index)
 146 {
 147         struct clk_programmable *prog = to_clk_programmable(hw);
 148         const struct clk_programmable_layout *layout = prog->layout;
 149         if (index > layout->css_mask) {
 150                 if (index > PROG_MAX_RM9200_CSS && layout->have_slck_mck) {
 151                         prog->css = 0;
 152                         prog->slckmck = 1;
 153                         return 0;
 154                 } else {
 155                         return -EINVAL;
 156                 }
 157         }
 158
 159         prog->css = index;
 160         return 0;
 161 }
 162
 163 static u8 clk_programmable_get_parent(struct clk_hw *hw)
 164 {
 165         u32 tmp;
 166         u8 ret;
 167         struct clk_programmable *prog = to_clk_programmable(hw);
 168         struct at91_pmc *pmc = prog->pmc;
 169         const struct clk_programmable_layout *layout = prog->layout;
 170
 171         tmp = pmc_read(pmc, AT91_PMC_PCKR(prog->id));
 172         prog->css = tmp & layout->css_mask;
 173         ret = prog->css;
 174         if (layout->have_slck_mck) {
 175                 prog->slckmck = !!(tmp & AT91_PMC_CSSMCK_MCK);
 176                 if (prog->slckmck && !ret)
 177                         ret = PROG_MAX_RM9200_CSS + 1;
 178         }
 179
 180         return ret;
 181 }
 182
 183 static int clk_programmable_set_rate(struct clk_hw *hw, unsigned long rate,
 184                                      unsigned long parent_rate)
 185 {
 186         struct clk_programmable *prog = to_clk_programmable(hw);
 187         unsigned long best_rate = parent_rate;
 188         unsigned long best_diff;
 189         unsigned long new_diff;
 190         unsigned long cur_rate;
 191         int shift = 0;
 192
 193         if (rate > parent_rate)
 194                 return parent_rate;
 195         else
 196                 best_diff = parent_rate - rate;
 197
 198         if (!best_diff) {
 199                 prog->pres = shift;
 200                 return 0;
 201         }
 202
 203         for (shift = 1; shift < PROG_PRES_MASK; shift++) {
 204                 cur_rate = parent_rate >> shift;
 205
 206                 if (cur_rate > rate)
 207                         new_diff = cur_rate - rate;
 208                 else
 209                         new_diff = rate - cur_rate;
 210
 211                 if (!new_diff)
 212                         break;
 213
 214                 if (new_diff < best_diff) {
 215                         best_diff = new_diff;
 216                         best_rate = cur_rate;
 217                 }
 218
 219                 if (rate > cur_rate)
 220                         break;
 221         }
 222
 223         prog->pres = shift;
 224         return 0;
 225 }
 226
 227 static const struct clk_ops programmable_ops = {
 228         .prepare = clk_programmable_prepare,
 229         .is_prepared = clk_programmable_is_ready,
 230         .recalc_rate = clk_programmable_recalc_rate,
 231         .round_rate = clk_programmable_round_rate,
 232         .get_parent = clk_programmable_get_parent,
 233         .set_parent = clk_programmable_set_parent,
 234         .set_rate = clk_programmable_set_rate,
 235 };
 236
 237 static struct clk * __init
 238 at91_clk_register_programmable(struct at91_pmc *pmc, unsigned int irq,
 239                                const char *name, const char **parent_names,
 240                                u8 num_parents, u8 id,
 241                                const struct clk_programmable_layout *layout)
 242 {
 243         int ret;
 244         struct clk_programmable *prog;
 245         struct clk *clk = NULL;
 246         struct clk_init_data init;
 247         char irq_name[11];
 248
 249         if (id > PROG_ID_MAX)
 250                 return ERR_PTR(-EINVAL);
 251
 252         prog = kzalloc(sizeof(*prog), GFP_KERNEL);
 253         if (!prog)
 254                 return ERR_PTR(-ENOMEM);
 255
 256         init.name = name;
 257         init.ops = &programmable_ops;
 258         init.parent_names = parent_names;
 259         init.num_parents = num_parents;
 260         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 261
 262         prog->id = id;
 263         prog->layout = layout;
 264         prog->hw.init = &init;
 265         prog->pmc = pmc;
 266         prog->irq = irq;
 267         init_waitqueue_head(&prog->wait);
 268         irq_set_status_flags(prog->irq, IRQ_NOAUTOEN);
 269         snprintf(irq_name, sizeof(irq_name), "clk-prog%d", id);
 270         ret = request_irq(prog->irq, clk_programmable_irq_handler,
 271                           IRQF_TRIGGER_HIGH, irq_name, prog);
 272         if (ret)
 273                 return ERR_PTR(ret);
 274
 275         clk = clk_register(NULL, &prog->hw);
 276         if (IS_ERR(clk))
 277                 kfree(prog);
 278
 279         return clk;
 280 }
 281
 282 static const struct clk_programmable_layout at91rm9200_programmable_layout = {
 283         .pres_shift = 2,
 284         .css_mask = 0x3,
 285         .have_slck_mck = 0,
 286 };
 287
 288 static const struct clk_programmable_layout at91sam9g45_programmable_layout = {
 289         .pres_shift = 2,
 290         .css_mask = 0x3,
 291         .have_slck_mck = 1,
 292 };
 293
 294 static const struct clk_programmable_layout at91sam9x5_programmable_layout = {
 295         .pres_shift = 4,
 296         .css_mask = 0x7,
 297         .have_slck_mck = 0,
 298 };
 299
 300 static void __init
 301 of_at91_clk_prog_setup(struct device_node *np, struct at91_pmc *pmc,
 302                        const struct clk_programmable_layout *layout)
 303 {
 304         int num;
 305         u32 id;
 306         int i;
 307         unsigned int irq;
 308         struct clk *clk;
 309         int num_parents;
 310         const char *parent_names[PROG_SOURCE_MAX];
 311         const char *name;
 312         struct device_node *progclknp;
 313
 314         num_parents = of_count_phandle_with_args(np, "clocks", "#clock-cells");
 315         if (num_parents <= 0 || num_parents > PROG_SOURCE_MAX)
 316                 return;
 317
 318         for (i = 0; i < num_parents; ++i) {
 319                 parent_names[i] = of_clk_get_parent_name(np, i);
 320                 if (!parent_names[i])
 321                         return;
 322         }
 323
 324         num = of_get_child_count(np);
 325         if (!num || num > (PROG_ID_MAX + 1))
 326                 return;
 327
 328         for_each_child_of_node(np, progclknp) {
 329                 if (of_property_read_u32(progclknp, "reg", &id))
 330                         continue;
 331
 332                 if (of_property_read_string(np, "clock-output-names", &name))
 333                         name = progclknp->name;
 334
 335                 irq = irq_of_parse_and_map(progclknp, 0);
 336                 if (!irq)
 337                         continue;
 338
 339                 clk = at91_clk_register_programmable(pmc, irq, name,
 340                                                      parent_names, num_parents,
 341                                                      id, layout);
 342                 if (IS_ERR(clk))
 343                         continue;
 344
 345                 of_clk_add_provider(progclknp, of_clk_src_simple_get, clk);
 346         }
 347 }
 348
 349
 350 void __init of_at91rm9200_clk_prog_setup(struct device_node *np,
 351                                          struct at91_pmc *pmc)
 352 {
 353         of_at91_clk_prog_setup(np, pmc, &at91rm9200_programmable_layout);
 354 }
 355
 356 void __init of_at91sam9g45_clk_prog_setup(struct device_node *np,
 357                                           struct at91_pmc *pmc)
 358 {
 359         of_at91_clk_prog_setup(np, pmc, &at91sam9g45_programmable_layout);
 360 }
 361
 362 void __init of_at91sam9x5_clk_prog_setup(struct device_node *np,
 363                                          struct at91_pmc *pmc)
 364 {
 365         of_at91_clk_prog_setup(np, pmc, &at91sam9x5_programmable_layout);
 366 }