drivers/clk/berlin/berlin2-div.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2014 Marvell Technology Group Ltd.
   4  *
   5  * Alexandre Belloni <alexandre.belloni@free-electrons.com>
   6  * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
   7  */
   8 #include <linux/bitops.h>
   9 #include <linux/clk-provider.h>
  10 #include <linux/io.h>
  11 #include <linux/of.h>
  12 #include <linux/of_address.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15
  16 #include "berlin2-div.h"
  17
  18 /*
  19  * Clock dividers in Berlin2 SoCs comprise a complex cell to select
  20  * input pll and divider. The virtual structure as it is used in Marvell
  21  * BSP code can be seen as:
  22  *
  23  *                      +---+
  24  * pll0 --------------->| 0 |                   +---+
  25  *           +---+      |(B)|--+--------------->| 0 |      +---+
  26  * pll1.0 -->| 0 |  +-->| 1 |  |   +--------+   |(E)|----->| 0 |   +---+
  27  * pll1.1 -->| 1 |  |   +---+  +-->|(C) 1:M |-->| 1 |      |(F)|-->|(G)|->
  28  * ...    -->|(A)|--+          |   +--------+   +---+  +-->| 1 |   +---+
  29  * ...    -->|   |             +-->|(D) 1:3 |----------+   +---+
  30  * pll1.N -->| N |                 +---------
  31  *           +---+
  32  *
  33  * (A) input pll clock mux controlled by               <PllSelect[1:n]>
  34  * (B) input pll bypass mux controlled by              <PllSwitch>
  35  * (C) programmable clock divider controlled by        <Select[1:n]>
  36  * (D) constant div-by-3 clock divider
  37  * (E) programmable clock divider bypass controlled by <Switch>
  38  * (F) constant div-by-3 clock mux controlled by       <D3Switch>
  39  * (G) clock gate controlled by                        <Enable>
  40  *
  41  * For whatever reason, above control signals come in two flavors:
  42  * - single register dividers with all bits in one register
  43  * - shared register dividers with bits spread over multiple registers
  44  *   (including signals for the same cell spread over consecutive registers)
  45  *
  46  * Also, clock gate and pll mux is not available on every div cell, so
  47  * we have to deal with those, too. We reuse common clock composite driver
  48  * for it.
  49  */
  50
  51 #define PLL_SELECT_MASK 0x7
  52 #define DIV_SELECT_MASK 0x7
  53
  54 struct berlin2_div {
  55         struct clk_hw hw;
  56         void __iomem *base;
  57         struct berlin2_div_map map;
  58         spinlock_t *lock;
  59 };
  60
  61 #define to_berlin2_div(hw) container_of(hw, struct berlin2_div, hw)
  62
  63 static u8 clk_div[] = { 1, 2, 4, 6, 8, 12, 1, 1 };
  64
  65 static int berlin2_div_is_enabled(struct clk_hw *hw)
  66 {
  67         struct berlin2_div *div = to_berlin2_div(hw);
  68         struct berlin2_div_map *map = &div->map;
  69         u32 reg;
  70
  71         if (div->lock)
  72                 spin_lock(div->lock);
  73
  74         reg = readl_relaxed(div->base + map->gate_offs);
  75         reg >>= map->gate_shift;
  76
  77         if (div->lock)
  78                 spin_unlock(div->lock);
  79
  80         return (reg & 0x1);
  81 }
  82
  83 static int berlin2_div_enable(struct clk_hw *hw)
  84 {
  85         struct berlin2_div *div = to_berlin2_div(hw);
  86         struct berlin2_div_map *map = &div->map;
  87         u32 reg;
  88
  89         if (div->lock)
  90                 spin_lock(div->lock);
  91
  92         reg = readl_relaxed(div->base + map->gate_offs);
  93         reg |= BIT(map->gate_shift);
  94         writel_relaxed(reg, div->base + map->gate_offs);
  95
  96         if (div->lock)
  97                 spin_unlock(div->lock);
  98
  99         return 0;
 100 }
 101
 102 static void berlin2_div_disable(struct clk_hw *hw)
 103 {
 104         struct berlin2_div *div = to_berlin2_div(hw);
 105         struct berlin2_div_map *map = &div->map;
 106         u32 reg;
 107
 108         if (div->lock)
 109                 spin_lock(div->lock);
 110
 111         reg = readl_relaxed(div->base + map->gate_offs);
 112         reg &= ~BIT(map->gate_shift);
 113         writel_relaxed(reg, div->base + map->gate_offs);
 114
 115         if (div->lock)
 116                 spin_unlock(div->lock);
 117 }
 118
 119 static int berlin2_div_set_parent(struct clk_hw *hw, u8 index)
 120 {
 121         struct berlin2_div *div = to_berlin2_div(hw);
 122         struct berlin2_div_map *map = &div->map;
 123         u32 reg;
 124
 125         if (div->lock)
 126                 spin_lock(div->lock);
 127
 128         /* index == 0 is PLL_SWITCH */
 129         reg = readl_relaxed(div->base + map->pll_switch_offs);
 130         if (index == 0)
 131                 reg &= ~BIT(map->pll_switch_shift);
 132         else
 133                 reg |= BIT(map->pll_switch_shift);
 134         writel_relaxed(reg, div->base + map->pll_switch_offs);
 135
 136         /* index > 0 is PLL_SELECT */
 137         if (index > 0) {
 138                 reg = readl_relaxed(div->base + map->pll_select_offs);
 139                 reg &= ~(PLL_SELECT_MASK << map->pll_select_shift);
 140                 reg |= (index - 1) << map->pll_select_shift;
 141                 writel_relaxed(reg, div->base + map->pll_select_offs);
 142         }
 143
 144         if (div->lock)
 145                 spin_unlock(div->lock);
 146
 147         return 0;
 148 }
 149
 150 static u8 berlin2_div_get_parent(struct clk_hw *hw)
 151 {
 152         struct berlin2_div *div = to_berlin2_div(hw);
 153         struct berlin2_div_map *map = &div->map;
 154         u32 reg;
 155         u8 index = 0;
 156
 157         if (div->lock)
 158                 spin_lock(div->lock);
 159
 160         /* PLL_SWITCH == 0 is index 0 */
 161         reg = readl_relaxed(div->base + map->pll_switch_offs);
 162         reg &= BIT(map->pll_switch_shift);
 163         if (reg) {
 164                 reg = readl_relaxed(div->base + map->pll_select_offs);
 165                 reg >>= map->pll_select_shift;
 166                 reg &= PLL_SELECT_MASK;
 167                 index = 1 + reg;
 168         }
 169
 170         if (div->lock)
 171                 spin_unlock(div->lock);
 172
 173         return index;
 174 }
 175
 176 static unsigned long berlin2_div_recalc_rate(struct clk_hw *hw,
 177                                              unsigned long parent_rate)
 178 {
 179         struct berlin2_div *div = to_berlin2_div(hw);
 180         struct berlin2_div_map *map = &div->map;
 181         u32 divsw, div3sw, divider = 1;
 182
 183         if (div->lock)
 184                 spin_lock(div->lock);
 185
 186         divsw = readl_relaxed(div->base + map->div_switch_offs) &
 187                 (1 << map->div_switch_shift);
 188         div3sw = readl_relaxed(div->base + map->div3_switch_offs) &
 189                 (1 << map->div3_switch_shift);
 190
 191         /* constant divide-by-3 (dominant) */
 192         if (div3sw != 0) {
 193                 divider = 3;
 194         /* divider can be bypassed with DIV_SWITCH == 0 */
 195         } else if (divsw == 0) {
 196                 divider = 1;
 197         /* clock divider determined by DIV_SELECT */
 198         } else {
 199                 u32 reg;
 200                 reg = readl_relaxed(div->base + map->div_select_offs);
 201                 reg >>= map->div_select_shift;
 202                 reg &= DIV_SELECT_MASK;
 203                 divider = clk_div[reg];
 204         }
 205
 206         if (div->lock)
 207                 spin_unlock(div->lock);
 208
 209         return parent_rate / divider;
 210 }
 211
 212 static const struct clk_ops berlin2_div_rate_ops = {
 213         .recalc_rate    = berlin2_div_recalc_rate,
 214 };
 215
 216 static const struct clk_ops berlin2_div_gate_ops = {
 217         .is_enabled     = berlin2_div_is_enabled,
 218         .enable         = berlin2_div_enable,
 219         .disable        = berlin2_div_disable,
 220 };
 221
 222 static const struct clk_ops berlin2_div_mux_ops = {
 223         .set_parent     = berlin2_div_set_parent,
 224         .get_parent     = berlin2_div_get_parent,
 225 };
 226
 227 struct clk_hw * __init
 228 berlin2_div_register(const struct berlin2_div_map *map,
 229                      void __iomem *base, const char *name, u8 div_flags,
 230                      const char **parent_names, int num_parents,
 231                      unsigned long flags, spinlock_t *lock)
 232 {
 233         const struct clk_ops *mux_ops = &berlin2_div_mux_ops;
 234         const struct clk_ops *rate_ops = &berlin2_div_rate_ops;
 235         const struct clk_ops *gate_ops = &berlin2_div_gate_ops;
 236         struct berlin2_div *div;
 237
 238         div = kzalloc(sizeof(*div), GFP_KERNEL);
 239         if (!div)
 240                 return ERR_PTR(-ENOMEM);
 241
 242         /* copy div_map to allow __initconst */
 243         memcpy(&div->map, map, sizeof(*map));
 244         div->base = base;
 245         div->lock = lock;
 246
 247         if ((div_flags & BERLIN2_DIV_HAS_GATE) == 0)
 248                 gate_ops = NULL;
 249         if ((div_flags & BERLIN2_DIV_HAS_MUX) == 0)
 250                 mux_ops = NULL;
 251
 252         return clk_hw_register_composite(NULL, name, parent_names, num_parents,
 253                                       &div->hw, mux_ops, &div->hw, rate_ops,
 254                                       &div->hw, gate_ops, flags);
 255 }