drivers/clk/mvebu/dove-divider.c

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