drivers/clk/ti/autoidle.c

   1 /*
   2  * TI clock autoidle support
   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/io.h>
  21 #include <linux/of.h>
  22 #include <linux/of_address.h>
  23 #include <linux/clk/ti.h>
  24
  25 #include "clock.h"
  26
  27 struct clk_ti_autoidle {
  28         struct clk_omap_reg     reg;
  29         u8                      shift;
  30         u8                      flags;
  31         const char              *name;
  32         struct list_head        node;
  33 };
  34
  35 #define AUTOIDLE_LOW            0x1
  36
  37 static LIST_HEAD(autoidle_clks);
  38
  39 /*
  40  * we have some non-atomic read/write
  41  * operations behind it, so lets
  42  * take one lock for handling autoidle
  43  * of all clocks
  44  */
  45 static DEFINE_SPINLOCK(autoidle_spinlock);
  46
  47 static int _omap2_clk_deny_idle(struct clk_hw_omap *clk)
  48 {
  49         if (clk->ops && clk->ops->deny_idle) {
  50                 unsigned long irqflags;
  51
  52                 spin_lock_irqsave(&autoidle_spinlock, irqflags);
  53                 clk->autoidle_count++;
  54                 if (clk->autoidle_count == 1)
  55                         clk->ops->deny_idle(clk);
  56
  57                 spin_unlock_irqrestore(&autoidle_spinlock, irqflags);
  58         }
  59         return 0;
  60 }
  61
  62 static int _omap2_clk_allow_idle(struct clk_hw_omap *clk)
  63 {
  64         if (clk->ops && clk->ops->allow_idle) {
  65                 unsigned long irqflags;
  66
  67                 spin_lock_irqsave(&autoidle_spinlock, irqflags);
  68                 clk->autoidle_count--;
  69                 if (clk->autoidle_count == 0)
  70                         clk->ops->allow_idle(clk);
  71
  72                 spin_unlock_irqrestore(&autoidle_spinlock, irqflags);
  73         }
  74         return 0;
  75 }
  76
  77 /**
  78  * omap2_clk_deny_idle - disable autoidle on an OMAP clock
  79  * @clk: struct clk * to disable autoidle for
  80  *
  81  * Disable autoidle on an OMAP clock.
  82  */
  83 int omap2_clk_deny_idle(struct clk *clk)
  84 {
  85         struct clk_hw *hw;
  86
  87         if (!clk)
  88                 return -EINVAL;
  89
  90         hw = __clk_get_hw(clk);
  91
  92         if (omap2_clk_is_hw_omap(hw)) {
  93                 struct clk_hw_omap *c = to_clk_hw_omap(hw);
  94
  95                 return _omap2_clk_deny_idle(c);
  96         }
  97
  98         return -EINVAL;
  99 }
 100
 101 /**
 102  * omap2_clk_allow_idle - enable autoidle on an OMAP clock
 103  * @clk: struct clk * to enable autoidle for
 104  *
 105  * Enable autoidle on an OMAP clock.
 106  */
 107 int omap2_clk_allow_idle(struct clk *clk)
 108 {
 109         struct clk_hw *hw;
 110
 111         if (!clk)
 112                 return -EINVAL;
 113
 114         hw = __clk_get_hw(clk);
 115
 116         if (omap2_clk_is_hw_omap(hw)) {
 117                 struct clk_hw_omap *c = to_clk_hw_omap(hw);
 118
 119                 return _omap2_clk_allow_idle(c);
 120         }
 121
 122         return -EINVAL;
 123 }
 124
 125 static void _allow_autoidle(struct clk_ti_autoidle *clk)
 126 {
 127         u32 val;
 128
 129         val = ti_clk_ll_ops->clk_readl(&clk->reg);
 130
 131         if (clk->flags & AUTOIDLE_LOW)
 132                 val &= ~(1 << clk->shift);
 133         else
 134                 val |= (1 << clk->shift);
 135
 136         ti_clk_ll_ops->clk_writel(val, &clk->reg);
 137 }
 138
 139 static void _deny_autoidle(struct clk_ti_autoidle *clk)
 140 {
 141         u32 val;
 142
 143         val = ti_clk_ll_ops->clk_readl(&clk->reg);
 144
 145         if (clk->flags & AUTOIDLE_LOW)
 146                 val |= (1 << clk->shift);
 147         else
 148                 val &= ~(1 << clk->shift);
 149
 150         ti_clk_ll_ops->clk_writel(val, &clk->reg);
 151 }
 152
 153 /**
 154  * _clk_generic_allow_autoidle_all - enable autoidle for all clocks
 155  *
 156  * Enables hardware autoidle for all registered DT clocks, which have
 157  * the feature.
 158  */
 159 static void _clk_generic_allow_autoidle_all(void)
 160 {
 161         struct clk_ti_autoidle *c;
 162
 163         list_for_each_entry(c, &autoidle_clks, node)
 164                 _allow_autoidle(c);
 165 }
 166
 167 /**
 168  * _clk_generic_deny_autoidle_all - disable autoidle for all clocks
 169  *
 170  * Disables hardware autoidle for all registered DT clocks, which have
 171  * the feature.
 172  */
 173 static void _clk_generic_deny_autoidle_all(void)
 174 {
 175         struct clk_ti_autoidle *c;
 176
 177         list_for_each_entry(c, &autoidle_clks, node)
 178                 _deny_autoidle(c);
 179 }
 180
 181 /**
 182  * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock
 183  * @node: pointer to the clock device node
 184  *
 185  * Checks if a clock has hardware autoidle support or not (check
 186  * for presence of 'ti,autoidle-shift' property in the device tree
 187  * node) and sets up the hardware autoidle feature for the clock
 188  * if available. If autoidle is available, the clock is also added
 189  * to the autoidle list for later processing. Returns 0 on success,
 190  * negative error value on failure.
 191  */
 192 int __init of_ti_clk_autoidle_setup(struct device_node *node)
 193 {
 194         u32 shift;
 195         struct clk_ti_autoidle *clk;
 196         int ret;
 197
 198         /* Check if this clock has autoidle support or not */
 199         if (of_property_read_u32(node, "ti,autoidle-shift", &shift))
 200                 return 0;
 201
 202         clk = kzalloc(sizeof(*clk), GFP_KERNEL);
 203
 204         if (!clk)
 205                 return -ENOMEM;
 206
 207         clk->shift = shift;
 208         clk->name = node->name;
 209         ret = ti_clk_get_reg_addr(node, 0, &clk->reg);
 210         if (ret) {
 211                 kfree(clk);
 212                 return ret;
 213         }
 214
 215         if (of_property_read_bool(node, "ti,invert-autoidle-bit"))
 216                 clk->flags |= AUTOIDLE_LOW;
 217
 218         list_add(&clk->node, &autoidle_clks);
 219
 220         return 0;
 221 }
 222
 223 /**
 224  * omap2_clk_enable_autoidle_all - enable autoidle on all OMAP clocks that
 225  * support it
 226  *
 227  * Enable clock autoidle on all OMAP clocks that have allow_idle
 228  * function pointers associated with them.  This function is intended
 229  * to be temporary until support for this is added to the common clock
 230  * code.  Returns 0.
 231  */
 232 int omap2_clk_enable_autoidle_all(void)
 233 {
 234         int ret;
 235
 236         ret = omap2_clk_for_each(_omap2_clk_allow_idle);
 237         if (ret)
 238                 return ret;
 239
 240         _clk_generic_allow_autoidle_all();
 241
 242         return 0;
 243 }
 244
 245 /**
 246  * omap2_clk_disable_autoidle_all - disable autoidle on all OMAP clocks that
 247  * support it
 248  *
 249  * Disable clock autoidle on all OMAP clocks that have allow_idle
 250  * function pointers associated with them.  This function is intended
 251  * to be temporary until support for this is added to the common clock
 252  * code.  Returns 0.
 253  */
 254 int omap2_clk_disable_autoidle_all(void)
 255 {
 256         int ret;
 257
 258         ret = omap2_clk_for_each(_omap2_clk_deny_idle);
 259         if (ret)
 260                 return ret;
 261
 262         _clk_generic_deny_autoidle_all();
 263
 264         return 0;
 265 }