kernel/drivers/clk/shmobile/clk-r8a73a4.c

   1 /*
   2  * r8a73a4 Core CPG Clocks
   3  *
   4  * Copyright (C) 2014  Ulrich Hecht
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; version 2 of the License.
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/clk/shmobile.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/of.h>
  17 #include <linux/of_address.h>
  18 #include <linux/spinlock.h>
  19
  20 struct r8a73a4_cpg {
  21         struct clk_onecell_data data;
  22         spinlock_t lock;
  23         void __iomem *reg;
  24 };
  25
  26 #define CPG_CKSCR       0xc0
  27 #define CPG_FRQCRA      0x00
  28 #define CPG_FRQCRB      0x04
  29 #define CPG_FRQCRC      0xe0
  30 #define CPG_PLL0CR      0xd8
  31 #define CPG_PLL1CR      0x28
  32 #define CPG_PLL2CR      0x2c
  33 #define CPG_PLL2HCR     0xe4
  34 #define CPG_PLL2SCR     0xf4
  35
  36 #define CLK_ENABLE_ON_INIT BIT(0)
  37
  38 struct div4_clk {
  39         const char *name;
  40         unsigned int reg;
  41         unsigned int shift;
  42 };
  43
  44 static struct div4_clk div4_clks[] = {
  45         { "i",  CPG_FRQCRA, 20 },
  46         { "m3", CPG_FRQCRA, 12 },
  47         { "b",  CPG_FRQCRA,  8 },
  48         { "m1", CPG_FRQCRA,  4 },
  49         { "m2", CPG_FRQCRA,  0 },
  50         { "zx", CPG_FRQCRB, 12 },
  51         { "zs", CPG_FRQCRB,  8 },
  52         { "hp", CPG_FRQCRB,  4 },
  53         { NULL, 0, 0 },
  54 };
  55
  56 static const struct clk_div_table div4_div_table[] = {
  57         { 0, 2 }, { 1, 3 }, { 2, 4 }, { 3, 6 }, { 4, 8 }, { 5, 12 },
  58         { 6, 16 }, { 7, 18 }, { 8, 24 }, { 10, 36 }, { 11, 48 },
  59         { 12, 10 }, { 0, 0 }
  60 };
  61
  62 static struct clk * __init
  63 r8a73a4_cpg_register_clock(struct device_node *np, struct r8a73a4_cpg *cpg,
  64                              const char *name)
  65 {
  66         const struct clk_div_table *table = NULL;
  67         const char *parent_name;
  68         unsigned int shift, reg;
  69         unsigned int mult = 1;
  70         unsigned int div = 1;
  71
  72
  73         if (!strcmp(name, "main")) {
  74                 u32 ckscr = clk_readl(cpg->reg + CPG_CKSCR);
  75
  76                 switch ((ckscr >> 28) & 3) {
  77                 case 0: /* extal1 */
  78                         parent_name = of_clk_get_parent_name(np, 0);
  79                         break;
  80                 case 1: /* extal1 / 2 */
  81                         parent_name = of_clk_get_parent_name(np, 0);
  82                         div = 2;
  83                         break;
  84                 case 2: /* extal2 */
  85                         parent_name = of_clk_get_parent_name(np, 1);
  86                         break;
  87                 case 3: /* extal2 / 2 */
  88                         parent_name = of_clk_get_parent_name(np, 1);
  89                         div = 2;
  90                         break;
  91                 }
  92         } else if (!strcmp(name, "pll0")) {
  93                 /* PLL0/1 are configurable multiplier clocks. Register them as
  94                  * fixed factor clocks for now as there's no generic multiplier
  95                  * clock implementation and we currently have no need to change
  96                  * the multiplier value.
  97                  */
  98                 u32 value = clk_readl(cpg->reg + CPG_PLL0CR);
  99
 100                 parent_name = "main";
 101                 mult = ((value >> 24) & 0x7f) + 1;
 102                 if (value & BIT(20))
 103                         div = 2;
 104         } else if (!strcmp(name, "pll1")) {
 105                 u32 value = clk_readl(cpg->reg + CPG_PLL1CR);
 106
 107                 parent_name = "main";
 108                 /* XXX: enable bit? */
 109                 mult = ((value >> 24) & 0x7f) + 1;
 110                 if (value & BIT(7))
 111                         div = 2;
 112         } else if (!strncmp(name, "pll2", 4)) {
 113                 u32 value, cr;
 114
 115                 switch (name[4]) {
 116                 case 0:
 117                         cr = CPG_PLL2CR;
 118                         break;
 119                 case 's':
 120                         cr = CPG_PLL2SCR;
 121                         break;
 122                 case 'h':
 123                         cr = CPG_PLL2HCR;
 124                         break;
 125                 default:
 126                         return ERR_PTR(-EINVAL);
 127                 }
 128                 value = clk_readl(cpg->reg + cr);
 129                 switch ((value >> 5) & 7) {
 130                 case 0:
 131                         parent_name = "main";
 132                         div = 2;
 133                         break;
 134                 case 1:
 135                         parent_name = "extal2";
 136                         div = 2;
 137                         break;
 138                 case 3:
 139                         parent_name = "extal2";
 140                         div = 4;
 141                         break;
 142                 case 4:
 143                         parent_name = "main";
 144                         break;
 145                 case 5:
 146                         parent_name = "extal2";
 147                         break;
 148                 default:
 149                         pr_warn("%s: unexpected parent of %s\n", __func__,
 150                                 name);
 151                         return ERR_PTR(-EINVAL);
 152                 }
 153                 /* XXX: enable bit? */
 154                 mult = ((value >> 24) & 0x7f) + 1;
 155         } else if (!strcmp(name, "z") || !strcmp(name, "z2")) {
 156                 u32 shift = 8;
 157
 158                 parent_name = "pll0";
 159                 if (name[1] == '2') {
 160                         div = 2;
 161                         shift = 0;
 162                 }
 163                 div *= 32;
 164                 mult = 0x20 - ((clk_readl(cpg->reg + CPG_FRQCRC) >> shift)
 165                        & 0x1f);
 166         } else {
 167                 struct div4_clk *c;
 168
 169                 for (c = div4_clks; c->name; c++) {
 170                         if (!strcmp(name, c->name))
 171                                 break;
 172                 }
 173                 if (!c->name)
 174                         return ERR_PTR(-EINVAL);
 175
 176                 parent_name = "pll1";
 177                 table = div4_div_table;
 178                 reg = c->reg;
 179                 shift = c->shift;
 180         }
 181
 182         if (!table) {
 183                 return clk_register_fixed_factor(NULL, name, parent_name, 0,
 184                                                  mult, div);
 185         } else {
 186                 return clk_register_divider_table(NULL, name, parent_name, 0,
 187                                                   cpg->reg + reg, shift, 4, 0,
 188                                                   table, &cpg->lock);
 189         }
 190 }
 191
 192 static void __init r8a73a4_cpg_clocks_init(struct device_node *np)
 193 {
 194         struct r8a73a4_cpg *cpg;
 195         struct clk **clks;
 196         unsigned int i;
 197         int num_clks;
 198
 199         num_clks = of_property_count_strings(np, "clock-output-names");
 200         if (num_clks < 0) {
 201                 pr_err("%s: failed to count clocks\n", __func__);
 202                 return;
 203         }
 204
 205         cpg = kzalloc(sizeof(*cpg), GFP_KERNEL);
 206         clks = kcalloc(num_clks, sizeof(*clks), GFP_KERNEL);
 207         if (cpg == NULL || clks == NULL) {
 208                 /* We're leaking memory on purpose, there's no point in cleaning
 209                  * up as the system won't boot anyway.
 210                  */
 211                 return;
 212         }
 213
 214         spin_lock_init(&cpg->lock);
 215
 216         cpg->data.clks = clks;
 217         cpg->data.clk_num = num_clks;
 218
 219         cpg->reg = of_iomap(np, 0);
 220         if (WARN_ON(cpg->reg == NULL))
 221                 return;
 222
 223         for (i = 0; i < num_clks; ++i) {
 224                 const char *name;
 225                 struct clk *clk;
 226
 227                 of_property_read_string_index(np, "clock-output-names", i,
 228                                               &name);
 229
 230                 clk = r8a73a4_cpg_register_clock(np, cpg, name);
 231                 if (IS_ERR(clk))
 232                         pr_err("%s: failed to register %s %s clock (%ld)\n",
 233                                __func__, np->name, name, PTR_ERR(clk));
 234                 else
 235                         cpg->data.clks[i] = clk;
 236         }
 237
 238         of_clk_add_provider(np, of_clk_src_onecell_get, &cpg->data);
 239 }
 240 CLK_OF_DECLARE(r8a73a4_cpg_clks, "renesas,r8a73a4-cpg-clocks",
 241                r8a73a4_cpg_clocks_init);