drivers/clk/sunxi/clk-sun4i-tcon-ch1.c

   1 /*
   2  * Copyright 2015 Maxime Ripard
   3  *
   4  * Maxime Ripard <maxime.ripard@free-electrons.com>
   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; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/clk-provider.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22
  23 #define TCON_CH1_SCLK2_PARENTS          4
  24
  25 #define TCON_CH1_SCLK2_GATE_BIT         BIT(31)
  26 #define TCON_CH1_SCLK2_MUX_MASK         3
  27 #define TCON_CH1_SCLK2_MUX_SHIFT        24
  28 #define TCON_CH1_SCLK2_DIV_MASK         0xf
  29 #define TCON_CH1_SCLK2_DIV_SHIFT        0
  30
  31 #define TCON_CH1_SCLK1_GATE_BIT         BIT(15)
  32 #define TCON_CH1_SCLK1_HALF_BIT         BIT(11)
  33
  34 struct tcon_ch1_clk {
  35         struct clk_hw   hw;
  36         spinlock_t      lock;
  37         void __iomem    *reg;
  38 };
  39
  40 #define hw_to_tclk(hw)  container_of(hw, struct tcon_ch1_clk, hw)
  41
  42 static void tcon_ch1_disable(struct clk_hw *hw)
  43 {
  44         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  45         unsigned long flags;
  46         u32 reg;
  47
  48         spin_lock_irqsave(&tclk->lock, flags);
  49         reg = readl(tclk->reg);
  50         reg &= ~(TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT);
  51         writel(reg, tclk->reg);
  52         spin_unlock_irqrestore(&tclk->lock, flags);
  53 }
  54
  55 static int tcon_ch1_enable(struct clk_hw *hw)
  56 {
  57         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  58         unsigned long flags;
  59         u32 reg;
  60
  61         spin_lock_irqsave(&tclk->lock, flags);
  62         reg = readl(tclk->reg);
  63         reg |= TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT;
  64         writel(reg, tclk->reg);
  65         spin_unlock_irqrestore(&tclk->lock, flags);
  66
  67         return 0;
  68 }
  69
  70 static int tcon_ch1_is_enabled(struct clk_hw *hw)
  71 {
  72         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  73         u32 reg;
  74
  75         reg = readl(tclk->reg);
  76         return reg & (TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT);
  77 }
  78
  79 static u8 tcon_ch1_get_parent(struct clk_hw *hw)
  80 {
  81         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  82         u32 reg;
  83
  84         reg = readl(tclk->reg) >> TCON_CH1_SCLK2_MUX_SHIFT;
  85         reg &= reg >> TCON_CH1_SCLK2_MUX_MASK;
  86
  87         return reg;
  88 }
  89
  90 static int tcon_ch1_set_parent(struct clk_hw *hw, u8 index)
  91 {
  92         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  93         unsigned long flags;
  94         u32 reg;
  95
  96         spin_lock_irqsave(&tclk->lock, flags);
  97         reg = readl(tclk->reg);
  98         reg &= ~(TCON_CH1_SCLK2_MUX_MASK << TCON_CH1_SCLK2_MUX_SHIFT);
  99         reg |= index << TCON_CH1_SCLK2_MUX_SHIFT;
 100         writel(reg, tclk->reg);
 101         spin_unlock_irqrestore(&tclk->lock, flags);
 102
 103         return 0;
 104 };
 105
 106 static unsigned long tcon_ch1_calc_divider(unsigned long rate,
 107                                            unsigned long parent_rate,
 108                                            u8 *div,
 109                                            bool *half)
 110 {
 111         unsigned long best_rate = 0;
 112         u8 best_m = 0, m;
 113         bool is_double;
 114
 115         for (m = 1; m < 16; m++) {
 116                 u8 d;
 117
 118                 for (d = 1; d < 3; d++) {
 119                         unsigned long tmp_rate;
 120
 121                         tmp_rate = parent_rate / m / d;
 122
 123                         if (tmp_rate > rate)
 124                                 continue;
 125
 126                         if (!best_rate ||
 127                             (rate - tmp_rate) < (rate - best_rate)) {
 128                                 best_rate = tmp_rate;
 129                                 best_m = m;
 130                                 is_double = d;
 131                         }
 132                 }
 133         }
 134
 135         if (div && half) {
 136                 *div = best_m;
 137                 *half = is_double;
 138         }
 139
 140         return best_rate;
 141 }
 142
 143 static int tcon_ch1_determine_rate(struct clk_hw *hw,
 144                                    struct clk_rate_request *req)
 145 {
 146         long best_rate = -EINVAL;
 147         int i;
 148
 149         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 150                 unsigned long parent_rate;
 151                 unsigned long tmp_rate;
 152                 struct clk_hw *parent;
 153
 154                 parent = clk_hw_get_parent_by_index(hw, i);
 155                 if (!parent)
 156                         continue;
 157
 158                 parent_rate = clk_hw_get_rate(parent);
 159
 160                 tmp_rate = tcon_ch1_calc_divider(req->rate, parent_rate,
 161                                                  NULL, NULL);
 162
 163                 if (best_rate < 0 ||
 164                     (req->rate - tmp_rate) < (req->rate - best_rate)) {
 165                         best_rate = tmp_rate;
 166                         req->best_parent_rate = parent_rate;
 167                         req->best_parent_hw = parent;
 168                 }
 169         }
 170
 171         if (best_rate < 0)
 172                 return best_rate;
 173
 174         req->rate = best_rate;
 175         return 0;
 176 }
 177
 178 static unsigned long tcon_ch1_recalc_rate(struct clk_hw *hw,
 179                                           unsigned long parent_rate)
 180 {
 181         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
 182         u32 reg;
 183
 184         reg = readl(tclk->reg);
 185
 186         parent_rate /= (reg & TCON_CH1_SCLK2_DIV_MASK) + 1;
 187
 188         if (reg & TCON_CH1_SCLK1_HALF_BIT)
 189                 parent_rate /= 2;
 190
 191         return parent_rate;
 192 }
 193
 194 static int tcon_ch1_set_rate(struct clk_hw *hw, unsigned long rate,
 195                              unsigned long parent_rate)
 196 {
 197         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
 198         unsigned long flags;
 199         bool half;
 200         u8 div_m;
 201         u32 reg;
 202
 203         tcon_ch1_calc_divider(rate, parent_rate, &div_m, &half);
 204
 205         spin_lock_irqsave(&tclk->lock, flags);
 206         reg = readl(tclk->reg);
 207         reg &= ~(TCON_CH1_SCLK2_DIV_MASK | TCON_CH1_SCLK1_HALF_BIT);
 208         reg |= (div_m - 1) & TCON_CH1_SCLK2_DIV_MASK;
 209
 210         if (half)
 211                 reg |= TCON_CH1_SCLK1_HALF_BIT;
 212
 213         writel(reg, tclk->reg);
 214         spin_unlock_irqrestore(&tclk->lock, flags);
 215
 216         return 0;
 217 }
 218
 219 static const struct clk_ops tcon_ch1_ops = {
 220         .disable        = tcon_ch1_disable,
 221         .enable         = tcon_ch1_enable,
 222         .is_enabled     = tcon_ch1_is_enabled,
 223
 224         .get_parent     = tcon_ch1_get_parent,
 225         .set_parent     = tcon_ch1_set_parent,
 226
 227         .determine_rate = tcon_ch1_determine_rate,
 228         .recalc_rate    = tcon_ch1_recalc_rate,
 229         .set_rate       = tcon_ch1_set_rate,
 230 };
 231
 232 static void __init tcon_ch1_setup(struct device_node *node)
 233 {
 234         const char *parents[TCON_CH1_SCLK2_PARENTS];
 235         const char *clk_name = node->name;
 236         struct clk_init_data init;
 237         struct tcon_ch1_clk *tclk;
 238         struct resource res;
 239         struct clk *clk;
 240         void __iomem *reg;
 241         int ret;
 242
 243         of_property_read_string(node, "clock-output-names", &clk_name);
 244
 245         reg = of_io_request_and_map(node, 0, of_node_full_name(node));
 246         if (IS_ERR(reg)) {
 247                 pr_err("%s: Could not map the clock registers\n", clk_name);
 248                 return;
 249         }
 250
 251         ret = of_clk_parent_fill(node, parents, TCON_CH1_SCLK2_PARENTS);
 252         if (ret != TCON_CH1_SCLK2_PARENTS) {
 253                 pr_err("%s Could not retrieve the parents\n", clk_name);
 254                 goto err_unmap;
 255         }
 256
 257         tclk = kzalloc(sizeof(*tclk), GFP_KERNEL);
 258         if (!tclk)
 259                 goto err_unmap;
 260
 261         init.name = clk_name;
 262         init.ops = &tcon_ch1_ops;
 263         init.parent_names = parents;
 264         init.num_parents = TCON_CH1_SCLK2_PARENTS;
 265         init.flags = CLK_SET_RATE_PARENT;
 266
 267         tclk->reg = reg;
 268         tclk->hw.init = &init;
 269         spin_lock_init(&tclk->lock);
 270
 271         clk = clk_register(NULL, &tclk->hw);
 272         if (IS_ERR(clk)) {
 273                 pr_err("%s: Couldn't register the clock\n", clk_name);
 274                 goto err_free_data;
 275         }
 276
 277         ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
 278         if (ret) {
 279                 pr_err("%s: Couldn't register our clock provider\n", clk_name);
 280                 goto err_unregister_clk;
 281         }
 282
 283         return;
 284
 285 err_unregister_clk:
 286         clk_unregister(clk);
 287 err_free_data:
 288         kfree(tclk);
 289 err_unmap:
 290         iounmap(reg);
 291         of_address_to_resource(node, 0, &res);
 292         release_mem_region(res.start, resource_size(&res));
 293 }
 294
 295 CLK_OF_DECLARE(tcon_ch1, "allwinner,sun4i-a10-tcon-ch1-clk",
 296                tcon_ch1_setup);