drivers/clk/qcom/clk-pll.c

   1 /*
   2  * Copyright (c) 2013, The Linux Foundation. All rights reserved.
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/bitops.h>
  16 #include <linux/err.h>
  17 #include <linux/bug.h>
  18 #include <linux/delay.h>
  19 #include <linux/export.h>
  20 #include <linux/clk-provider.h>
  21 #include <linux/regmap.h>
  22
  23 #include <asm/div64.h>
  24
  25 #include "clk-pll.h"
  26
  27 #define PLL_OUTCTRL             BIT(0)
  28 #define PLL_BYPASSNL            BIT(1)
  29 #define PLL_RESET_N             BIT(2)
  30 #define PLL_LOCK_COUNT_SHIFT    8
  31 #define PLL_LOCK_COUNT_MASK     0x3f
  32 #define PLL_BIAS_COUNT_SHIFT    14
  33 #define PLL_BIAS_COUNT_MASK     0x3f
  34 #define PLL_VOTE_FSM_ENA        BIT(20)
  35 #define PLL_VOTE_FSM_RESET      BIT(21)
  36
  37 static int clk_pll_enable(struct clk_hw *hw)
  38 {
  39         struct clk_pll *pll = to_clk_pll(hw);
  40         int ret;
  41         u32 mask, val;
  42
  43         mask = PLL_OUTCTRL | PLL_RESET_N | PLL_BYPASSNL;
  44         ret = regmap_read(pll->clkr.regmap, pll->mode_reg, &val);
  45         if (ret)
  46                 return ret;
  47
  48         /* Skip if already enabled or in FSM mode */
  49         if ((val & mask) == mask || val & PLL_VOTE_FSM_ENA)
  50                 return 0;
  51
  52         /* Disable PLL bypass mode. */
  53         ret = regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_BYPASSNL,
  54                                  PLL_BYPASSNL);
  55         if (ret)
  56                 return ret;
  57
  58         /*
  59          * H/W requires a 5us delay between disabling the bypass and
  60          * de-asserting the reset. Delay 10us just to be safe.
  61          */
  62         udelay(10);
  63
  64         /* De-assert active-low PLL reset. */
  65         ret = regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_RESET_N,
  66                                  PLL_RESET_N);
  67         if (ret)
  68                 return ret;
  69
  70         /* Wait until PLL is locked. */
  71         udelay(50);
  72
  73         /* Enable PLL output. */
  74         return regmap_update_bits(pll->clkr.regmap, pll->mode_reg, PLL_OUTCTRL,
  75                                  PLL_OUTCTRL);
  76 }
  77
  78 static void clk_pll_disable(struct clk_hw *hw)
  79 {
  80         struct clk_pll *pll = to_clk_pll(hw);
  81         u32 mask;
  82         u32 val;
  83
  84         regmap_read(pll->clkr.regmap, pll->mode_reg, &val);
  85         /* Skip if in FSM mode */
  86         if (val & PLL_VOTE_FSM_ENA)
  87                 return;
  88         mask = PLL_OUTCTRL | PLL_RESET_N | PLL_BYPASSNL;
  89         regmap_update_bits(pll->clkr.regmap, pll->mode_reg, mask, 0);
  90 }
  91
  92 static unsigned long
  93 clk_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
  94 {
  95         struct clk_pll *pll = to_clk_pll(hw);
  96         u32 l, m, n, config;
  97         unsigned long rate;
  98         u64 tmp;
  99
 100         regmap_read(pll->clkr.regmap, pll->l_reg, &l);
 101         regmap_read(pll->clkr.regmap, pll->m_reg, &m);
 102         regmap_read(pll->clkr.regmap, pll->n_reg, &n);
 103
 104         l &= 0x3ff;
 105         m &= 0x7ffff;
 106         n &= 0x7ffff;
 107
 108         rate = parent_rate * l;
 109         if (n) {
 110                 tmp = parent_rate;
 111                 tmp *= m;
 112                 do_div(tmp, n);
 113                 rate += tmp;
 114         }
 115         if (pll->post_div_width) {
 116                 regmap_read(pll->clkr.regmap, pll->config_reg, &config);
 117                 config >>= pll->post_div_shift;
 118                 config &= BIT(pll->post_div_width) - 1;
 119                 rate /= config + 1;
 120         }
 121
 122         return rate;
 123 }
 124
 125 static const
 126 struct pll_freq_tbl *find_freq(const struct pll_freq_tbl *f, unsigned long rate)
 127 {
 128         if (!f)
 129                 return NULL;
 130
 131         for (; f->freq; f++)
 132                 if (rate <= f->freq)
 133                         return f;
 134
 135         return NULL;
 136 }
 137
 138 static long
 139 clk_pll_determine_rate(struct clk_hw *hw, unsigned long rate,
 140                        unsigned long min_rate, unsigned long max_rate,
 141                        unsigned long *p_rate, struct clk_hw **p)
 142 {
 143         struct clk_pll *pll = to_clk_pll(hw);
 144         const struct pll_freq_tbl *f;
 145
 146         f = find_freq(pll->freq_tbl, rate);
 147         if (!f)
 148                 return clk_pll_recalc_rate(hw, *p_rate);
 149
 150         return f->freq;
 151 }
 152
 153 static int
 154 clk_pll_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long p_rate)
 155 {
 156         struct clk_pll *pll = to_clk_pll(hw);
 157         const struct pll_freq_tbl *f;
 158         bool enabled;
 159         u32 mode;
 160         u32 enable_mask = PLL_OUTCTRL | PLL_BYPASSNL | PLL_RESET_N;
 161
 162         f = find_freq(pll->freq_tbl, rate);
 163         if (!f)
 164                 return -EINVAL;
 165
 166         regmap_read(pll->clkr.regmap, pll->mode_reg, &mode);
 167         enabled = (mode & enable_mask) == enable_mask;
 168
 169         if (enabled)
 170                 clk_pll_disable(hw);
 171
 172         regmap_update_bits(pll->clkr.regmap, pll->l_reg, 0x3ff, f->l);
 173         regmap_update_bits(pll->clkr.regmap, pll->m_reg, 0x7ffff, f->m);
 174         regmap_update_bits(pll->clkr.regmap, pll->n_reg, 0x7ffff, f->n);
 175         regmap_write(pll->clkr.regmap, pll->config_reg, f->ibits);
 176
 177         if (enabled)
 178                 clk_pll_enable(hw);
 179
 180         return 0;
 181 }
 182
 183 const struct clk_ops clk_pll_ops = {
 184         .enable = clk_pll_enable,
 185         .disable = clk_pll_disable,
 186         .recalc_rate = clk_pll_recalc_rate,
 187         .determine_rate = clk_pll_determine_rate,
 188         .set_rate = clk_pll_set_rate,
 189 };
 190 EXPORT_SYMBOL_GPL(clk_pll_ops);
 191
 192 static int wait_for_pll(struct clk_pll *pll)
 193 {
 194         u32 val;
 195         int count;
 196         int ret;
 197         const char *name = __clk_get_name(pll->clkr.hw.clk);
 198
 199         /* Wait for pll to enable. */
 200         for (count = 200; count > 0; count--) {
 201                 ret = regmap_read(pll->clkr.regmap, pll->status_reg, &val);
 202                 if (ret)
 203                         return ret;
 204                 if (val & BIT(pll->status_bit))
 205                         return 0;
 206                 udelay(1);
 207         }
 208
 209         WARN(1, "%s didn't enable after voting for it!\n", name);
 210         return -ETIMEDOUT;
 211 }
 212
 213 static int clk_pll_vote_enable(struct clk_hw *hw)
 214 {
 215         int ret;
 216         struct clk_pll *p = to_clk_pll(__clk_get_hw(__clk_get_parent(hw->clk)));
 217
 218         ret = clk_enable_regmap(hw);
 219         if (ret)
 220                 return ret;
 221
 222         return wait_for_pll(p);
 223 }
 224
 225 const struct clk_ops clk_pll_vote_ops = {
 226         .enable = clk_pll_vote_enable,
 227         .disable = clk_disable_regmap,
 228 };
 229 EXPORT_SYMBOL_GPL(clk_pll_vote_ops);
 230
 231 static void
 232 clk_pll_set_fsm_mode(struct clk_pll *pll, struct regmap *regmap, u8 lock_count)
 233 {
 234         u32 val;
 235         u32 mask;
 236
 237         /* De-assert reset to FSM */
 238         regmap_update_bits(regmap, pll->mode_reg, PLL_VOTE_FSM_RESET, 0);
 239
 240         /* Program bias count and lock count */
 241         val = 1 << PLL_BIAS_COUNT_SHIFT | lock_count << PLL_LOCK_COUNT_SHIFT;
 242         mask = PLL_BIAS_COUNT_MASK << PLL_BIAS_COUNT_SHIFT;
 243         mask |= PLL_LOCK_COUNT_MASK << PLL_LOCK_COUNT_SHIFT;
 244         regmap_update_bits(regmap, pll->mode_reg, mask, val);
 245
 246         /* Enable PLL FSM voting */
 247         regmap_update_bits(regmap, pll->mode_reg, PLL_VOTE_FSM_ENA,
 248                 PLL_VOTE_FSM_ENA);
 249 }
 250
 251 static void clk_pll_configure(struct clk_pll *pll, struct regmap *regmap,
 252         const struct pll_config *config)
 253 {
 254         u32 val;
 255         u32 mask;
 256
 257         regmap_write(regmap, pll->l_reg, config->l);
 258         regmap_write(regmap, pll->m_reg, config->m);
 259         regmap_write(regmap, pll->n_reg, config->n);
 260
 261         val = config->vco_val;
 262         val |= config->pre_div_val;
 263         val |= config->post_div_val;
 264         val |= config->mn_ena_mask;
 265         val |= config->main_output_mask;
 266         val |= config->aux_output_mask;
 267
 268         mask = config->vco_mask;
 269         mask |= config->pre_div_mask;
 270         mask |= config->post_div_mask;
 271         mask |= config->mn_ena_mask;
 272         mask |= config->main_output_mask;
 273         mask |= config->aux_output_mask;
 274
 275         regmap_update_bits(regmap, pll->config_reg, mask, val);
 276 }
 277
 278 void clk_pll_configure_sr(struct clk_pll *pll, struct regmap *regmap,
 279                 const struct pll_config *config, bool fsm_mode)
 280 {
 281         clk_pll_configure(pll, regmap, config);
 282         if (fsm_mode)
 283                 clk_pll_set_fsm_mode(pll, regmap, 8);
 284 }
 285 EXPORT_SYMBOL_GPL(clk_pll_configure_sr);
 286
 287 void clk_pll_configure_sr_hpm_lp(struct clk_pll *pll, struct regmap *regmap,
 288                 const struct pll_config *config, bool fsm_mode)
 289 {
 290         clk_pll_configure(pll, regmap, config);
 291         if (fsm_mode)
 292                 clk_pll_set_fsm_mode(pll, regmap, 0);
 293 }
 294 EXPORT_SYMBOL_GPL(clk_pll_configure_sr_hpm_lp);