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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2015 Maxime Ripard
   4  *
   5  * Maxime Ripard <maxime.ripard@free-electrons.com>
   6  */
   7
   8 #include <linux/clk-provider.h>
   9 #include <linux/io.h>
  10 #include <linux/of.h>
  11 #include <linux/of_address.h>
  12 #include <linux/slab.h>
  13 #include <linux/spinlock.h>
  14
  15 #define TCON_CH1_SCLK2_PARENTS          4
  16
  17 #define TCON_CH1_SCLK2_GATE_BIT         BIT(31)
  18 #define TCON_CH1_SCLK2_MUX_MASK         3
  19 #define TCON_CH1_SCLK2_MUX_SHIFT        24
  20 #define TCON_CH1_SCLK2_DIV_MASK         0xf
  21 #define TCON_CH1_SCLK2_DIV_SHIFT        0
  22
  23 #define TCON_CH1_SCLK1_GATE_BIT         BIT(15)
  24 #define TCON_CH1_SCLK1_HALF_BIT         BIT(11)
  25
  26 struct tcon_ch1_clk {
  27         struct clk_hw   hw;
  28         spinlock_t      lock;
  29         void __iomem    *reg;
  30 };
  31
  32 #define hw_to_tclk(hw)  container_of(hw, struct tcon_ch1_clk, hw)
  33
  34 static void tcon_ch1_disable(struct clk_hw *hw)
  35 {
  36         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  37         unsigned long flags;
  38         u32 reg;
  39
  40         spin_lock_irqsave(&tclk->lock, flags);
  41         reg = readl(tclk->reg);
  42         reg &= ~(TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT);
  43         writel(reg, tclk->reg);
  44         spin_unlock_irqrestore(&tclk->lock, flags);
  45 }
  46
  47 static int tcon_ch1_enable(struct clk_hw *hw)
  48 {
  49         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  50         unsigned long flags;
  51         u32 reg;
  52
  53         spin_lock_irqsave(&tclk->lock, flags);
  54         reg = readl(tclk->reg);
  55         reg |= TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT;
  56         writel(reg, tclk->reg);
  57         spin_unlock_irqrestore(&tclk->lock, flags);
  58
  59         return 0;
  60 }
  61
  62 static int tcon_ch1_is_enabled(struct clk_hw *hw)
  63 {
  64         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  65         u32 reg;
  66
  67         reg = readl(tclk->reg);
  68         return reg & (TCON_CH1_SCLK2_GATE_BIT | TCON_CH1_SCLK1_GATE_BIT);
  69 }
  70
  71 static u8 tcon_ch1_get_parent(struct clk_hw *hw)
  72 {
  73         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  74         u32 reg;
  75
  76         reg = readl(tclk->reg) >> TCON_CH1_SCLK2_MUX_SHIFT;
  77         reg &= reg >> TCON_CH1_SCLK2_MUX_MASK;
  78
  79         return reg;
  80 }
  81
  82 static int tcon_ch1_set_parent(struct clk_hw *hw, u8 index)
  83 {
  84         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
  85         unsigned long flags;
  86         u32 reg;
  87
  88         spin_lock_irqsave(&tclk->lock, flags);
  89         reg = readl(tclk->reg);
  90         reg &= ~(TCON_CH1_SCLK2_MUX_MASK << TCON_CH1_SCLK2_MUX_SHIFT);
  91         reg |= index << TCON_CH1_SCLK2_MUX_SHIFT;
  92         writel(reg, tclk->reg);
  93         spin_unlock_irqrestore(&tclk->lock, flags);
  94
  95         return 0;
  96 };
  97
  98 static unsigned long tcon_ch1_calc_divider(unsigned long rate,
  99                                            unsigned long parent_rate,
 100                                            u8 *div,
 101                                            bool *half)
 102 {
 103         unsigned long best_rate = 0;
 104         u8 best_m = 0, m;
 105         bool is_double;
 106
 107         for (m = 1; m < 16; m++) {
 108                 u8 d;
 109
 110                 for (d = 1; d < 3; d++) {
 111                         unsigned long tmp_rate;
 112
 113                         tmp_rate = parent_rate / m / d;
 114
 115                         if (tmp_rate > rate)
 116                                 continue;
 117
 118                         if (!best_rate ||
 119                             (rate - tmp_rate) < (rate - best_rate)) {
 120                                 best_rate = tmp_rate;
 121                                 best_m = m;
 122                                 is_double = d;
 123                         }
 124                 }
 125         }
 126
 127         if (div && half) {
 128                 *div = best_m;
 129                 *half = is_double;
 130         }
 131
 132         return best_rate;
 133 }
 134
 135 static int tcon_ch1_determine_rate(struct clk_hw *hw,
 136                                    struct clk_rate_request *req)
 137 {
 138         long best_rate = -EINVAL;
 139         int i;
 140
 141         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 142                 unsigned long parent_rate;
 143                 unsigned long tmp_rate;
 144                 struct clk_hw *parent;
 145
 146                 parent = clk_hw_get_parent_by_index(hw, i);
 147                 if (!parent)
 148                         continue;
 149
 150                 parent_rate = clk_hw_get_rate(parent);
 151
 152                 tmp_rate = tcon_ch1_calc_divider(req->rate, parent_rate,
 153                                                  NULL, NULL);
 154
 155                 if (best_rate < 0 ||
 156                     (req->rate - tmp_rate) < (req->rate - best_rate)) {
 157                         best_rate = tmp_rate;
 158                         req->best_parent_rate = parent_rate;
 159                         req->best_parent_hw = parent;
 160                 }
 161         }
 162
 163         if (best_rate < 0)
 164                 return best_rate;
 165
 166         req->rate = best_rate;
 167         return 0;
 168 }
 169
 170 static unsigned long tcon_ch1_recalc_rate(struct clk_hw *hw,
 171                                           unsigned long parent_rate)
 172 {
 173         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
 174         u32 reg;
 175
 176         reg = readl(tclk->reg);
 177
 178         parent_rate /= (reg & TCON_CH1_SCLK2_DIV_MASK) + 1;
 179
 180         if (reg & TCON_CH1_SCLK1_HALF_BIT)
 181                 parent_rate /= 2;
 182
 183         return parent_rate;
 184 }
 185
 186 static int tcon_ch1_set_rate(struct clk_hw *hw, unsigned long rate,
 187                              unsigned long parent_rate)
 188 {
 189         struct tcon_ch1_clk *tclk = hw_to_tclk(hw);
 190         unsigned long flags;
 191         bool half;
 192         u8 div_m;
 193         u32 reg;
 194
 195         tcon_ch1_calc_divider(rate, parent_rate, &div_m, &half);
 196
 197         spin_lock_irqsave(&tclk->lock, flags);
 198         reg = readl(tclk->reg);
 199         reg &= ~(TCON_CH1_SCLK2_DIV_MASK | TCON_CH1_SCLK1_HALF_BIT);
 200         reg |= (div_m - 1) & TCON_CH1_SCLK2_DIV_MASK;
 201
 202         if (half)
 203                 reg |= TCON_CH1_SCLK1_HALF_BIT;
 204
 205         writel(reg, tclk->reg);
 206         spin_unlock_irqrestore(&tclk->lock, flags);
 207
 208         return 0;
 209 }
 210
 211 static const struct clk_ops tcon_ch1_ops = {
 212         .disable        = tcon_ch1_disable,
 213         .enable         = tcon_ch1_enable,
 214         .is_enabled     = tcon_ch1_is_enabled,
 215
 216         .get_parent     = tcon_ch1_get_parent,
 217         .set_parent     = tcon_ch1_set_parent,
 218
 219         .determine_rate = tcon_ch1_determine_rate,
 220         .recalc_rate    = tcon_ch1_recalc_rate,
 221         .set_rate       = tcon_ch1_set_rate,
 222 };
 223
 224 static void __init tcon_ch1_setup(struct device_node *node)
 225 {
 226         const char *parents[TCON_CH1_SCLK2_PARENTS];
 227         const char *clk_name = node->name;
 228         struct clk_init_data init;
 229         struct tcon_ch1_clk *tclk;
 230         struct resource res;
 231         struct clk *clk;
 232         void __iomem *reg;
 233         int ret;
 234
 235         of_property_read_string(node, "clock-output-names", &clk_name);
 236
 237         reg = of_io_request_and_map(node, 0, of_node_full_name(node));
 238         if (IS_ERR(reg)) {
 239                 pr_err("%s: Could not map the clock registers\n", clk_name);
 240                 return;
 241         }
 242
 243         ret = of_clk_parent_fill(node, parents, TCON_CH1_SCLK2_PARENTS);
 244         if (ret != TCON_CH1_SCLK2_PARENTS) {
 245                 pr_err("%s Could not retrieve the parents\n", clk_name);
 246                 goto err_unmap;
 247         }
 248
 249         tclk = kzalloc(sizeof(*tclk), GFP_KERNEL);
 250         if (!tclk)
 251                 goto err_unmap;
 252
 253         init.name = clk_name;
 254         init.ops = &tcon_ch1_ops;
 255         init.parent_names = parents;
 256         init.num_parents = TCON_CH1_SCLK2_PARENTS;
 257         init.flags = CLK_SET_RATE_PARENT;
 258
 259         tclk->reg = reg;
 260         tclk->hw.init = &init;
 261         spin_lock_init(&tclk->lock);
 262
 263         clk = clk_register(NULL, &tclk->hw);
 264         if (IS_ERR(clk)) {
 265                 pr_err("%s: Couldn't register the clock\n", clk_name);
 266                 goto err_free_data;
 267         }
 268
 269         ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
 270         if (ret) {
 271                 pr_err("%s: Couldn't register our clock provider\n", clk_name);
 272                 goto err_unregister_clk;
 273         }
 274
 275         return;
 276
 277 err_unregister_clk:
 278         clk_unregister(clk);
 279 err_free_data:
 280         kfree(tclk);
 281 err_unmap:
 282         iounmap(reg);
 283         of_address_to_resource(node, 0, &res);
 284         release_mem_region(res.start, resource_size(&res));
 285 }
 286
 287 CLK_OF_DECLARE(tcon_ch1, "allwinner,sun4i-a10-tcon-ch1-clk",
 288                tcon_ch1_setup);