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         void __iomem            *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 static LIST_HEAD(clk_hw_omap_clocks);
  39
  40 /**
  41  * omap2_clk_deny_idle - disable autoidle on an OMAP clock
  42  * @clk: struct clk * to disable autoidle for
  43  *
  44  * Disable autoidle on an OMAP clock.
  45  */
  46 int omap2_clk_deny_idle(struct clk *clk)
  47 {
  48         struct clk_hw_omap *c;
  49
  50         c = to_clk_hw_omap(__clk_get_hw(clk));
  51         if (c->ops && c->ops->deny_idle)
  52                 c->ops->deny_idle(c);
  53         return 0;
  54 }
  55
  56 /**
  57  * omap2_clk_allow_idle - enable autoidle on an OMAP clock
  58  * @clk: struct clk * to enable autoidle for
  59  *
  60  * Enable autoidle on an OMAP clock.
  61  */
  62 int omap2_clk_allow_idle(struct clk *clk)
  63 {
  64         struct clk_hw_omap *c;
  65
  66         c = to_clk_hw_omap(__clk_get_hw(clk));
  67         if (c->ops && c->ops->allow_idle)
  68                 c->ops->allow_idle(c);
  69         return 0;
  70 }
  71
  72 static void _allow_autoidle(struct clk_ti_autoidle *clk)
  73 {
  74         u32 val;
  75
  76         val = ti_clk_ll_ops->clk_readl(clk->reg);
  77
  78         if (clk->flags & AUTOIDLE_LOW)
  79                 val &= ~(1 << clk->shift);
  80         else
  81                 val |= (1 << clk->shift);
  82
  83         ti_clk_ll_ops->clk_writel(val, clk->reg);
  84 }
  85
  86 static void _deny_autoidle(struct clk_ti_autoidle *clk)
  87 {
  88         u32 val;
  89
  90         val = ti_clk_ll_ops->clk_readl(clk->reg);
  91
  92         if (clk->flags & AUTOIDLE_LOW)
  93                 val |= (1 << clk->shift);
  94         else
  95                 val &= ~(1 << clk->shift);
  96
  97         ti_clk_ll_ops->clk_writel(val, clk->reg);
  98 }
  99
 100 /**
 101  * _clk_generic_allow_autoidle_all - enable autoidle for all clocks
 102  *
 103  * Enables hardware autoidle for all registered DT clocks, which have
 104  * the feature.
 105  */
 106 static void _clk_generic_allow_autoidle_all(void)
 107 {
 108         struct clk_ti_autoidle *c;
 109
 110         list_for_each_entry(c, &autoidle_clks, node)
 111                 _allow_autoidle(c);
 112 }
 113
 114 /**
 115  * _clk_generic_deny_autoidle_all - disable autoidle for all clocks
 116  *
 117  * Disables hardware autoidle for all registered DT clocks, which have
 118  * the feature.
 119  */
 120 static void _clk_generic_deny_autoidle_all(void)
 121 {
 122         struct clk_ti_autoidle *c;
 123
 124         list_for_each_entry(c, &autoidle_clks, node)
 125                 _deny_autoidle(c);
 126 }
 127
 128 /**
 129  * of_ti_clk_autoidle_setup - sets up hardware autoidle for a clock
 130  * @node: pointer to the clock device node
 131  *
 132  * Checks if a clock has hardware autoidle support or not (check
 133  * for presence of 'ti,autoidle-shift' property in the device tree
 134  * node) and sets up the hardware autoidle feature for the clock
 135  * if available. If autoidle is available, the clock is also added
 136  * to the autoidle list for later processing. Returns 0 on success,
 137  * negative error value on failure.
 138  */
 139 int __init of_ti_clk_autoidle_setup(struct device_node *node)
 140 {
 141         u32 shift;
 142         struct clk_ti_autoidle *clk;
 143
 144         /* Check if this clock has autoidle support or not */
 145         if (of_property_read_u32(node, "ti,autoidle-shift", &shift))
 146                 return 0;
 147
 148         clk = kzalloc(sizeof(*clk), GFP_KERNEL);
 149
 150         if (!clk)
 151                 return -ENOMEM;
 152
 153         clk->shift = shift;
 154         clk->name = node->name;
 155         clk->reg = ti_clk_get_reg_addr(node, 0);
 156
 157         if (IS_ERR(clk->reg)) {
 158                 kfree(clk);
 159                 return -EINVAL;
 160         }
 161
 162         if (of_property_read_bool(node, "ti,invert-autoidle-bit"))
 163                 clk->flags |= AUTOIDLE_LOW;
 164
 165         list_add(&clk->node, &autoidle_clks);
 166
 167         return 0;
 168 }
 169
 170 /**
 171  * omap2_init_clk_hw_omap_clocks - initialize an OMAP clock
 172  * @hw: struct clk_hw * to initialize
 173  *
 174  * Add an OMAP clock @clk to the internal list of OMAP clocks.  Used
 175  * temporarily for autoidle handling, until this support can be
 176  * integrated into the common clock framework code in some way.  No
 177  * return value.
 178  */
 179 void omap2_init_clk_hw_omap_clocks(struct clk_hw *hw)
 180 {
 181         struct clk_hw_omap *c;
 182
 183         if (clk_hw_get_flags(hw) & CLK_IS_BASIC)
 184                 return;
 185
 186         c = to_clk_hw_omap(hw);
 187         list_add(&c->node, &clk_hw_omap_clocks);
 188 }
 189
 190 /**
 191  * omap2_clk_enable_autoidle_all - enable autoidle on all OMAP clocks that
 192  * support it
 193  *
 194  * Enable clock autoidle on all OMAP clocks that have allow_idle
 195  * function pointers associated with them.  This function is intended
 196  * to be temporary until support for this is added to the common clock
 197  * code.  Returns 0.
 198  */
 199 int omap2_clk_enable_autoidle_all(void)
 200 {
 201         struct clk_hw_omap *c;
 202
 203         list_for_each_entry(c, &clk_hw_omap_clocks, node)
 204                 if (c->ops && c->ops->allow_idle)
 205                         c->ops->allow_idle(c);
 206
 207         _clk_generic_allow_autoidle_all();
 208
 209         return 0;
 210 }
 211
 212 /**
 213  * omap2_clk_disable_autoidle_all - disable autoidle on all OMAP clocks that
 214  * support it
 215  *
 216  * Disable clock autoidle on all OMAP clocks that have allow_idle
 217  * function pointers associated with them.  This function is intended
 218  * to be temporary until support for this is added to the common clock
 219  * code.  Returns 0.
 220  */
 221 int omap2_clk_disable_autoidle_all(void)
 222 {
 223         struct clk_hw_omap *c;
 224
 225         list_for_each_entry(c, &clk_hw_omap_clocks, node)
 226                 if (c->ops && c->ops->deny_idle)
 227                         c->ops->deny_idle(c);
 228
 229         _clk_generic_deny_autoidle_all();
 230
 231         return 0;
 232 }