drivers/clk/ti/mux.c

   1 /*
   2  * TI Multiplexer Clock
   3  *
   4  * Copyright (C) 2013 Texas Instruments, Inc.
   5  *
   6  * Tero Kristo <t-kristo@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  13  * kind, whether express or implied; without even the implied warranty
  14  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/clk-provider.h>
  19 #include <linux/slab.h>
  20 #include <linux/err.h>
  21 #include <linux/of.h>
  22 #include <linux/of_address.h>
  23 #include <linux/clk/ti.h>
  24 #include "clock.h"
  25
  26 #undef pr_fmt
  27 #define pr_fmt(fmt) "%s: " fmt, __func__
  28
  29 static u8 ti_clk_mux_get_parent(struct clk_hw *hw)
  30 {
  31         struct clk_omap_mux *mux = to_clk_omap_mux(hw);
  32         int num_parents = clk_hw_get_num_parents(hw);
  33         u32 val;
  34
  35         /*
  36          * FIXME need a mux-specific flag to determine if val is bitwise or
  37          * numeric. e.g. sys_clkin_ck's clksel field is 3 bits wide, but ranges
  38          * from 0x1 to 0x7 (index starts at one)
  39          * OTOH, pmd_trace_clk_mux_ck uses a separate bit for each clock, so
  40          * val = 0x4 really means "bit 2, index starts at bit 0"
  41          */
  42         val = ti_clk_ll_ops->clk_readl(&mux->reg) >> mux->shift;
  43         val &= mux->mask;
  44
  45         if (mux->table) {
  46                 int i;
  47
  48                 for (i = 0; i < num_parents; i++)
  49                         if (mux->table[i] == val)
  50                                 return i;
  51                 return -EINVAL;
  52         }
  53
  54         if (val && (mux->flags & CLK_MUX_INDEX_BIT))
  55                 val = ffs(val) - 1;
  56
  57         if (val && (mux->flags & CLK_MUX_INDEX_ONE))
  58                 val--;
  59
  60         if (val >= num_parents)
  61                 return -EINVAL;
  62
  63         return val;
  64 }
  65
  66 static int ti_clk_mux_set_parent(struct clk_hw *hw, u8 index)
  67 {
  68         struct clk_omap_mux *mux = to_clk_omap_mux(hw);
  69         u32 val;
  70
  71         if (mux->table) {
  72                 index = mux->table[index];
  73         } else {
  74                 if (mux->flags & CLK_MUX_INDEX_BIT)
  75                         index = (1 << ffs(index));
  76
  77                 if (mux->flags & CLK_MUX_INDEX_ONE)
  78                         index++;
  79         }
  80
  81         if (mux->flags & CLK_MUX_HIWORD_MASK) {
  82                 val = mux->mask << (mux->shift + 16);
  83         } else {
  84                 val = ti_clk_ll_ops->clk_readl(&mux->reg);
  85                 val &= ~(mux->mask << mux->shift);
  86         }
  87         val |= index << mux->shift;
  88         ti_clk_ll_ops->clk_writel(val, &mux->reg);
  89         ti_clk_latch(&mux->reg, mux->latch);
  90
  91         return 0;
  92 }
  93
  94 /**
  95  * clk_mux_save_context - Save the parent selcted in the mux
  96  * @hw: pointer  struct clk_hw
  97  *
  98  * Save the parent mux value.
  99  */
 100 static int clk_mux_save_context(struct clk_hw *hw)
 101 {
 102         struct clk_omap_mux *mux = to_clk_omap_mux(hw);
 103
 104         mux->saved_parent = ti_clk_mux_get_parent(hw);
 105         return 0;
 106 }
 107
 108 /**
 109  * clk_mux_restore_context - Restore the parent in the mux
 110  * @hw: pointer  struct clk_hw
 111  *
 112  * Restore the saved parent mux value.
 113  */
 114 static void clk_mux_restore_context(struct clk_hw *hw)
 115 {
 116         struct clk_omap_mux *mux = to_clk_omap_mux(hw);
 117
 118         ti_clk_mux_set_parent(hw, mux->saved_parent);
 119 }
 120
 121 const struct clk_ops ti_clk_mux_ops = {
 122         .get_parent = ti_clk_mux_get_parent,
 123         .set_parent = ti_clk_mux_set_parent,
 124         .determine_rate = __clk_mux_determine_rate,
 125         .save_context = clk_mux_save_context,
 126         .restore_context = clk_mux_restore_context,
 127 };
 128
 129 static struct clk *_register_mux(struct device *dev, const char *name,
 130                                  const char * const *parent_names,
 131                                  u8 num_parents, unsigned long flags,
 132                                  struct clk_omap_reg *reg, u8 shift, u32 mask,
 133                                  s8 latch, u8 clk_mux_flags, u32 *table)
 134 {
 135         struct clk_omap_mux *mux;
 136         struct clk *clk;
 137         struct clk_init_data init;
 138
 139         /* allocate the mux */
 140         mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 141         if (!mux)
 142                 return ERR_PTR(-ENOMEM);
 143
 144         init.name = name;
 145         init.ops = &ti_clk_mux_ops;
 146         init.flags = flags;
 147         init.parent_names = parent_names;
 148         init.num_parents = num_parents;
 149
 150         /* struct clk_mux assignments */
 151         memcpy(&mux->reg, reg, sizeof(*reg));
 152         mux->shift = shift;
 153         mux->mask = mask;
 154         mux->latch = latch;
 155         mux->flags = clk_mux_flags;
 156         mux->table = table;
 157         mux->hw.init = &init;
 158
 159         clk = ti_clk_register(dev, &mux->hw, name);
 160
 161         if (IS_ERR(clk))
 162                 kfree(mux);
 163
 164         return clk;
 165 }
 166
 167 /**
 168  * of_mux_clk_setup - Setup function for simple mux rate clock
 169  * @node: DT node for the clock
 170  *
 171  * Sets up a basic clock multiplexer.
 172  */
 173 static void of_mux_clk_setup(struct device_node *node)
 174 {
 175         struct clk *clk;
 176         struct clk_omap_reg reg;
 177         unsigned int num_parents;
 178         const char **parent_names;
 179         u8 clk_mux_flags = 0;
 180         u32 mask = 0;
 181         u32 shift = 0;
 182         s32 latch = -EINVAL;
 183         u32 flags = CLK_SET_RATE_NO_REPARENT;
 184
 185         num_parents = of_clk_get_parent_count(node);
 186         if (num_parents < 2) {
 187                 pr_err("mux-clock %pOFn must have parents\n", node);
 188                 return;
 189         }
 190         parent_names = kzalloc((sizeof(char *) * num_parents), GFP_KERNEL);
 191         if (!parent_names)
 192                 goto cleanup;
 193
 194         of_clk_parent_fill(node, parent_names, num_parents);
 195
 196         if (ti_clk_get_reg_addr(node, 0, &reg))
 197                 goto cleanup;
 198
 199         of_property_read_u32(node, "ti,bit-shift", &shift);
 200
 201         of_property_read_u32(node, "ti,latch-bit", &latch);
 202
 203         if (of_property_read_bool(node, "ti,index-starts-at-one"))
 204                 clk_mux_flags |= CLK_MUX_INDEX_ONE;
 205
 206         if (of_property_read_bool(node, "ti,set-rate-parent"))
 207                 flags |= CLK_SET_RATE_PARENT;
 208
 209         /* Generate bit-mask based on parent info */
 210         mask = num_parents;
 211         if (!(clk_mux_flags & CLK_MUX_INDEX_ONE))
 212                 mask--;
 213
 214         mask = (1 << fls(mask)) - 1;
 215
 216         clk = _register_mux(NULL, node->name, parent_names, num_parents,
 217                             flags, &reg, shift, mask, latch, clk_mux_flags,
 218                             NULL);
 219
 220         if (!IS_ERR(clk))
 221                 of_clk_add_provider(node, of_clk_src_simple_get, clk);
 222
 223 cleanup:
 224         kfree(parent_names);
 225 }
 226 CLK_OF_DECLARE(mux_clk, "ti,mux-clock", of_mux_clk_setup);
 227
 228 struct clk_hw *ti_clk_build_component_mux(struct ti_clk_mux *setup)
 229 {
 230         struct clk_omap_mux *mux;
 231         int num_parents;
 232
 233         if (!setup)
 234                 return NULL;
 235
 236         mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 237         if (!mux)
 238                 return ERR_PTR(-ENOMEM);
 239
 240         mux->shift = setup->bit_shift;
 241         mux->latch = -EINVAL;
 242
 243         mux->reg.index = setup->module;
 244         mux->reg.offset = setup->reg;
 245
 246         if (setup->flags & CLKF_INDEX_STARTS_AT_ONE)
 247                 mux->flags |= CLK_MUX_INDEX_ONE;
 248
 249         num_parents = setup->num_parents;
 250
 251         mux->mask = num_parents - 1;
 252         mux->mask = (1 << fls(mux->mask)) - 1;
 253
 254         return &mux->hw;
 255 }
 256
 257 static void __init of_ti_composite_mux_clk_setup(struct device_node *node)
 258 {
 259         struct clk_omap_mux *mux;
 260         unsigned int num_parents;
 261         u32 val;
 262
 263         mux = kzalloc(sizeof(*mux), GFP_KERNEL);
 264         if (!mux)
 265                 return;
 266
 267         if (ti_clk_get_reg_addr(node, 0, &mux->reg))
 268                 goto cleanup;
 269
 270         if (!of_property_read_u32(node, "ti,bit-shift", &val))
 271                 mux->shift = val;
 272
 273         if (of_property_read_bool(node, "ti,index-starts-at-one"))
 274                 mux->flags |= CLK_MUX_INDEX_ONE;
 275
 276         num_parents = of_clk_get_parent_count(node);
 277
 278         if (num_parents < 2) {
 279                 pr_err("%pOFn must have parents\n", node);
 280                 goto cleanup;
 281         }
 282
 283         mux->mask = num_parents - 1;
 284         mux->mask = (1 << fls(mux->mask)) - 1;
 285
 286         if (!ti_clk_add_component(node, &mux->hw, CLK_COMPONENT_TYPE_MUX))
 287                 return;
 288
 289 cleanup:
 290         kfree(mux);
 291 }
 292 CLK_OF_DECLARE(ti_composite_mux_clk_setup, "ti,composite-mux-clock",
 293                of_ti_composite_mux_clk_setup);