drivers/clk/mvebu/dove-divider.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Marvell Dove PMU Core PLL divider driver
   4  *
   5  * Cleaned up by substantially rewriting, and converted to DT by
   6  * Russell King.  Origin is not known.
   7  */
   8 #include <linux/clk-provider.h>
   9 #include <linux/delay.h>
  10 #include <linux/io.h>
  11 #include <linux/kernel.h>
  12 #include <linux/of.h>
  13 #include <linux/of_address.h>
  14
  15 #include "dove-divider.h"
  16
  17 struct dove_clk {
  18         const char *name;
  19         struct clk_hw hw;
  20         void __iomem *base;
  21         spinlock_t *lock;
  22         u8 div_bit_start;
  23         u8 div_bit_end;
  24         u8 div_bit_load;
  25         u8 div_bit_size;
  26         u32 *divider_table;
  27 };
  28
  29 enum {
  30         DIV_CTRL0 = 0,
  31         DIV_CTRL1 = 4,
  32         DIV_CTRL1_N_RESET_MASK = BIT(10),
  33 };
  34
  35 #define to_dove_clk(hw) container_of(hw, struct dove_clk, hw)
  36
  37 static void dove_load_divider(void __iomem *base, u32 val, u32 mask, u32 load)
  38 {
  39         u32 v;
  40
  41         v = readl_relaxed(base + DIV_CTRL1) | DIV_CTRL1_N_RESET_MASK;
  42         writel_relaxed(v, base + DIV_CTRL1);
  43
  44         v = (readl_relaxed(base + DIV_CTRL0) & ~(mask | load)) | val;
  45         writel_relaxed(v, base + DIV_CTRL0);
  46         writel_relaxed(v | load, base + DIV_CTRL0);
  47         ndelay(250);
  48         writel_relaxed(v, base + DIV_CTRL0);
  49 }
  50
  51 static unsigned int dove_get_divider(struct dove_clk *dc)
  52 {
  53         unsigned int divider;
  54         u32 val;
  55
  56         val = readl_relaxed(dc->base + DIV_CTRL0);
  57         val >>= dc->div_bit_start;
  58
  59         divider = val & ~(~0 << dc->div_bit_size);
  60
  61         if (dc->divider_table)
  62                 divider = dc->divider_table[divider];
  63
  64         return divider;
  65 }
  66
  67 static int dove_calc_divider(const struct dove_clk *dc, unsigned long rate,
  68                              unsigned long parent_rate, bool set)
  69 {
  70         unsigned int divider, max;
  71
  72         divider = DIV_ROUND_CLOSEST(parent_rate, rate);
  73
  74         if (dc->divider_table) {
  75                 unsigned int i;
  76
  77                 for (i = 0; dc->divider_table[i]; i++)
  78                         if (divider == dc->divider_table[i]) {
  79                                 divider = i;
  80                                 break;
  81                         }
  82
  83                 if (!dc->divider_table[i])
  84                         return -EINVAL;
  85         } else {
  86                 max = 1 << dc->div_bit_size;
  87
  88                 if (set && (divider == 0 || divider >= max))
  89                         return -EINVAL;
  90                 if (divider >= max)
  91                         divider = max - 1;
  92                 else if (divider == 0)
  93                         divider = 1;
  94         }
  95
  96         return divider;
  97 }
  98
  99 static unsigned long dove_recalc_rate(struct clk_hw *hw, unsigned long parent)
 100 {
 101         struct dove_clk *dc = to_dove_clk(hw);
 102         unsigned int divider = dove_get_divider(dc);
 103         unsigned long rate = DIV_ROUND_CLOSEST(parent, divider);
 104
 105         pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
 106                  __func__, dc->name, divider, parent, rate);
 107
 108         return rate;
 109 }
 110
 111 static long dove_round_rate(struct clk_hw *hw, unsigned long rate,
 112                             unsigned long *parent)
 113 {
 114         struct dove_clk *dc = to_dove_clk(hw);
 115         unsigned long parent_rate = *parent;
 116         int divider;
 117
 118         divider = dove_calc_divider(dc, rate, parent_rate, false);
 119         if (divider < 0)
 120                 return divider;
 121
 122         rate = DIV_ROUND_CLOSEST(parent_rate, divider);
 123
 124         pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
 125                  __func__, dc->name, divider, parent_rate, rate);
 126
 127         return rate;
 128 }
 129
 130 static int dove_set_clock(struct clk_hw *hw, unsigned long rate,
 131                           unsigned long parent_rate)
 132 {
 133         struct dove_clk *dc = to_dove_clk(hw);
 134         u32 mask, load, div;
 135         int divider;
 136
 137         divider = dove_calc_divider(dc, rate, parent_rate, true);
 138         if (divider < 0)
 139                 return divider;
 140
 141         pr_debug("%s(): %s divider=%u parent=%lu rate=%lu\n",
 142                  __func__, dc->name, divider, parent_rate, rate);
 143
 144         div = (u32)divider << dc->div_bit_start;
 145         mask = ~(~0 << dc->div_bit_size) << dc->div_bit_start;
 146         load = BIT(dc->div_bit_load);
 147
 148         spin_lock(dc->lock);
 149         dove_load_divider(dc->base, div, mask, load);
 150         spin_unlock(dc->lock);
 151
 152         return 0;
 153 }
 154
 155 static const struct clk_ops dove_divider_ops = {
 156         .set_rate       = dove_set_clock,
 157         .round_rate     = dove_round_rate,
 158         .recalc_rate    = dove_recalc_rate,
 159 };
 160
 161 static struct clk *clk_register_dove_divider(struct device *dev,
 162         struct dove_clk *dc, const char **parent_names, size_t num_parents,
 163         void __iomem *base)
 164 {
 165         char name[32];
 166         struct clk_init_data init = {
 167                 .name = name,
 168                 .ops = &dove_divider_ops,
 169                 .parent_names = parent_names,
 170                 .num_parents = num_parents,
 171         };
 172
 173         strlcpy(name, dc->name, sizeof(name));
 174
 175         dc->hw.init = &init;
 176         dc->base = base;
 177         dc->div_bit_size = dc->div_bit_end - dc->div_bit_start + 1;
 178
 179         return clk_register(dev, &dc->hw);
 180 }
 181
 182 static DEFINE_SPINLOCK(dove_divider_lock);
 183
 184 static u32 axi_divider[] = {-1, 2, 1, 3, 4, 6, 5, 7, 8, 10, 9, 0};
 185
 186 static struct dove_clk dove_hw_clocks[4] = {
 187         {
 188                 .name = "axi",
 189                 .lock = &dove_divider_lock,
 190                 .div_bit_start = 1,
 191                 .div_bit_end = 6,
 192                 .div_bit_load = 7,
 193                 .divider_table = axi_divider,
 194         }, {
 195                 .name = "gpu",
 196                 .lock = &dove_divider_lock,
 197                 .div_bit_start = 8,
 198                 .div_bit_end = 13,
 199                 .div_bit_load = 14,
 200         }, {
 201                 .name = "vmeta",
 202                 .lock = &dove_divider_lock,
 203                 .div_bit_start = 15,
 204                 .div_bit_end = 20,
 205                 .div_bit_load = 21,
 206         }, {
 207                 .name = "lcd",
 208                 .lock = &dove_divider_lock,
 209                 .div_bit_start = 22,
 210                 .div_bit_end = 27,
 211                 .div_bit_load = 28,
 212         },
 213 };
 214
 215 static const char *core_pll[] = {
 216         "core-pll",
 217 };
 218
 219 static int dove_divider_init(struct device *dev, void __iomem *base,
 220         struct clk **clks)
 221 {
 222         struct clk *clk;
 223         int i;
 224
 225         /*
 226          * Create the core PLL clock.  We treat this as a fixed rate
 227          * clock as we don't know any better, and documentation is sparse.
 228          */
 229         clk = clk_register_fixed_rate(dev, core_pll[0], NULL, 0, 2000000000UL);
 230         if (IS_ERR(clk))
 231                 return PTR_ERR(clk);
 232
 233         for (i = 0; i < ARRAY_SIZE(dove_hw_clocks); i++)
 234                 clks[i] = clk_register_dove_divider(dev, &dove_hw_clocks[i],
 235                                                     core_pll,
 236                                                     ARRAY_SIZE(core_pll), base);
 237
 238         return 0;
 239 }
 240
 241 static struct clk *dove_divider_clocks[4];
 242
 243 static struct clk_onecell_data dove_divider_data = {
 244         .clks = dove_divider_clocks,
 245         .clk_num = ARRAY_SIZE(dove_divider_clocks),
 246 };
 247
 248 void __init dove_divider_clk_init(struct device_node *np)
 249 {
 250         void __iomem *base;
 251
 252         base = of_iomap(np, 0);
 253         if (WARN_ON(!base))
 254                 return;
 255
 256         if (WARN_ON(dove_divider_init(NULL, base, dove_divider_clocks))) {
 257                 iounmap(base);
 258                 return;
 259         }
 260
 261         of_clk_add_provider(np, of_clk_src_onecell_get, &dove_divider_data);
 262 }